#!/usr/bin/env python3
"""
Chapter 3: Wound Healing and Tissue Repair
Comprehensive PDF Generator
"""

from reportlab.lib.pagesizes import A4
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.units import cm, mm
from reportlab.lib.colors import (HexColor, white, black, Color)
from reportlab.platypus import (SimpleDocTemplate, Paragraph, Spacer, Table,
                                 TableStyle, KeepTogether, HRFlowable,
                                 PageBreak, ListFlowable, ListItem)
from reportlab.lib.enums import TA_LEFT, TA_CENTER, TA_JUSTIFY
from reportlab.platypus.flowables import Flowable
from reportlab.graphics.shapes import Drawing, Rect, String, Line, Polygon, Arrow
from reportlab.graphics import renderPDF
from reportlab.pdfbase import pdfmetrics

# ─── Colour palette ───────────────────────────────────────────────────────────
C_ORANGE   = HexColor('#C0603A')   # chapter heading orange
C_SALMON   = HexColor('#E8927A')   # lighter accent
C_BANNER   = HexColor('#D4856A')   # section banners
C_BOX_BG   = HexColor('#FAF0EB')   # summary-box background
C_BOX_BDR  = HexColor('#C0603A')   # summary-box border
C_FLOW_BOX = HexColor('#C0603A')   # flowchart box fill
C_FLOW_TXT = white                  # flowchart text
C_FLOW_SEC = HexColor('#8B3A1F')   # flowchart secondary boxes
C_TABLE_H  = HexColor('#C0603A')   # table header
C_TABLE_R1 = HexColor('#FDF5F2')   # table row 1
C_TABLE_R2 = white                  # table row 2
C_LIGHT_H  = HexColor('#F5C9BB')   # light heading bar
C_DARK_TXT = HexColor('#1A1A1A')
C_MID_TXT  = HexColor('#3A3A3A')
C_TERM     = HexColor('#7B2D0E')   # term definition colour
C_GREEN_BOX= HexColor('#2E7D32')   # quick summary
C_GREEN_BG = HexColor('#E8F5E9')
C_BLUE_BOX = HexColor('#1565C0')
C_BLUE_BG  = HexColor('#E3F2FD')

# ─── Page setup ───────────────────────────────────────────────────────────────
PAGE_W, PAGE_H = A4
MARGIN = 1.8*cm
INNER_W = PAGE_W - 2*MARGIN

styles = getSampleStyleSheet()

def make_style(name, parent='Normal', **kwargs):
    return ParagraphStyle(name, parent=styles[parent], **kwargs)

# ─── Custom styles ────────────────────────────────────────────────────────────
s_title = make_style('ChTitle', fontSize=26, textColor=C_ORANGE,
                     fontName='Helvetica-Bold', spaceAfter=4,
                     alignment=TA_CENTER)
s_ch_num = make_style('ChNum', fontSize=48, textColor=C_SALMON,
                      fontName='Helvetica-Bold', alignment=TA_CENTER,
                      spaceAfter=2)
s_h1 = make_style('H1', fontSize=14, textColor=white,
                  fontName='Helvetica-Bold', spaceAfter=6, spaceBefore=14,
                  leftIndent=6, backColor=C_BANNER)
s_h2 = make_style('H2', fontSize=12, textColor=C_ORANGE,
                  fontName='Helvetica-Bold', spaceAfter=4, spaceBefore=10,
                  borderPad=3)
s_h3 = make_style('H3', fontSize=11, textColor=C_DARK_TXT,
                  fontName='Helvetica-BoldOblique', spaceAfter=3, spaceBefore=8)
s_body = make_style('Body', fontSize=9.5, textColor=C_DARK_TXT,
                    fontName='Helvetica', spaceAfter=5, leading=14,
                    alignment=TA_JUSTIFY)
s_term = make_style('Term', fontSize=9.5, textColor=C_TERM,
                    fontName='Helvetica-Bold', spaceAfter=2)
s_def  = make_style('Def', fontSize=9.5, textColor=C_MID_TXT,
                    fontName='Helvetica', spaceAfter=5, leftIndent=12,
                    leading=13)
s_bullet = make_style('Bullet', fontSize=9.5, textColor=C_DARK_TXT,
                      fontName='Helvetica', spaceAfter=3, leading=13,
                      leftIndent=14, bulletIndent=4)
s_sumbox_h = make_style('SumH', fontSize=10, textColor=C_ORANGE,
                        fontName='Helvetica-Bold', spaceAfter=3)
s_sumbox_b = make_style('SumB', fontSize=9, textColor=C_MID_TXT,
                        fontName='Helvetica', spaceAfter=2, leading=12,
                        leftIndent=8)
s_quick_h = make_style('QuickH', fontSize=10, textColor=C_GREEN_BOX,
                       fontName='Helvetica-Bold', spaceAfter=3)
s_quick_b = make_style('QuickB', fontSize=9.2, textColor=HexColor('#1B5E20'),
                       fontName='Helvetica', spaceAfter=3, leading=13,
                       leftIndent=8)
s_caption = make_style('Caption', fontSize=8, textColor=HexColor('#555555'),
                       fontName='Helvetica-Oblique', alignment=TA_CENTER,
                       spaceAfter=4)
s_tbl_h   = make_style('TblH', fontSize=9, textColor=white,
                        fontName='Helvetica-Bold', alignment=TA_CENTER)
s_tbl_c   = make_style('TblC', fontSize=8.5, textColor=C_DARK_TXT,
                        fontName='Helvetica', leading=12, alignment=TA_LEFT)
s_tbl_cC  = make_style('TblCC', fontSize=8.5, textColor=C_DARK_TXT,
                        fontName='Helvetica', leading=12, alignment=TA_CENTER)
s_note    = make_style('Note', fontSize=8, textColor=HexColor('#555555'),
                       fontName='Helvetica-Oblique', spaceAfter=4, leftIndent=8)

# ─── Helper: section banner ───────────────────────────────────────────────────
def section_banner(text):
    return [
        Spacer(1, 6),
        Table([[Paragraph(text.upper(), make_style('BanTxt', fontSize=13,
                textColor=white, fontName='Helvetica-Bold'))]],
              colWidths=[INNER_W],
              style=TableStyle([
                  ('BACKGROUND', (0,0), (-1,-1), C_BANNER),
                  ('TOPPADDING', (0,0), (-1,-1), 7),
                  ('BOTTOMPADDING', (0,0), (-1,-1), 7),
                  ('LEFTPADDING', (0,0), (-1,-1), 10),
              ])),
        Spacer(1, 6),
    ]

def sub_header(text):
    return [
        Spacer(1, 4),
        Table([[Paragraph(text, make_style('SubH', fontSize=11,
                textColor=C_ORANGE, fontName='Helvetica-Bold'))]],
              colWidths=[INNER_W],
              style=TableStyle([
                  ('BACKGROUND', (0,0), (-1,-1), C_BOX_BG),
                  ('TOPPADDING', (0,0), (-1,-1), 4),
                  ('BOTTOMPADDING', (0,0), (-1,-1), 4),
                  ('LEFTPADDING', (0,0), (-1,-1), 8),
                  ('LINEBELOW', (0,0), (-1,-1), 1, C_SALMON),
              ])),
        Spacer(1, 4),
    ]

def summary_box(title, items):
    """Bordered summary box with bullet list."""
    inner = [Paragraph(title, s_sumbox_h)]
    for item in items:
        if isinstance(item, str):
            inner.append(Paragraph(f"• {item}", s_sumbox_b))
        elif isinstance(item, tuple):  # (header, [subitems])
            inner.append(Paragraph(f"• <b>{item[0]}</b>", s_sumbox_b))
            for sub in item[1]:
                inner.append(Paragraph(f"   - {sub}", s_sumbox_b))
    t = Table([[inner]], colWidths=[INNER_W - 4])
    t.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (-1,-1), C_BOX_BG),
        ('BOX', (0,0), (-1,-1), 1.5, C_BOX_BDR),
        ('TOPPADDING', (0,0), (-1,-1), 8),
        ('BOTTOMPADDING', (0,0), (-1,-1), 8),
        ('LEFTPADDING', (0,0), (-1,-1), 10),
        ('RIGHTPADDING', (0,0), (-1,-1), 10),
    ]))
    return [Spacer(1,4), t, Spacer(1,6)]

def quick_summary(points):
    """Green quick-summary takeaway box."""
    inner = [Paragraph("Quick Summary / Takeaway", s_quick_h)]
    for p in points:
        inner.append(Paragraph(f"✓ {p}", s_quick_b))
    t = Table([[inner]], colWidths=[INNER_W - 4])
    t.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (-1,-1), C_GREEN_BG),
        ('BOX', (0,0), (-1,-1), 1.5, C_GREEN_BOX),
        ('TOPPADDING', (0,0), (-1,-1), 8),
        ('BOTTOMPADDING', (0,0), (-1,-1), 8),
        ('LEFTPADDING', (0,0), (-1,-1), 10),
        ('RIGHTPADDING', (0,0), (-1,-1), 10),
    ]))
    return [Spacer(1,4), t, Spacer(1,8)]

def term_entry(term, definition):
    return [
        Paragraph(term, s_term),
        Paragraph(definition, s_def),
    ]

def make_table(headers, rows, col_widths=None):
    """Generic styled table."""
    if col_widths is None:
        col_widths = [INNER_W / len(headers)] * len(headers)
    data = [[Paragraph(h, s_tbl_h) for h in headers]]
    for row in rows:
        data.append([Paragraph(str(c), s_tbl_c) for c in row])
    t = Table(data, colWidths=col_widths)
    ts = TableStyle([
        ('BACKGROUND', (0,0), (-1,0), C_TABLE_H),
        ('VALIGN', (0,0), (-1,-1), 'TOP'),
        ('GRID', (0,0), (-1,-1), 0.5, HexColor('#CCCCCC')),
        ('TOPPADDING', (0,0), (-1,-1), 5),
        ('BOTTOMPADDING', (0,0), (-1,-1), 5),
        ('LEFTPADDING', (0,0), (-1,-1), 6),
        ('RIGHTPADDING', (0,0), (-1,-1), 6),
    ])
    for i in range(1, len(data)):
        bg = C_TABLE_R1 if i % 2 == 1 else C_TABLE_R2
        ts.add('BACKGROUND', (0,i), (-1,i), bg)
    t.setStyle(ts)
    return [Spacer(1,4), t, Spacer(1,6)]

# ─── Flowchart helper ─────────────────────────────────────────────────────────
class FlowChart(Flowable):
    """
    Simple vertical flowchart drawn with ReportLab graphics.
    steps: list of (label_text, box_colour)  — use None colour for decision diamonds
    """
    def __init__(self, steps, width=None, box_h=30, gap=18, title=''):
        super().__init__()
        self.steps = steps
        self.chart_w = width or INNER_W - 20
        self.box_h   = box_h
        self.gap     = gap
        self.title   = title
        self.width   = self.chart_w + 20
        # total height
        self.height  = (len(steps) * (box_h + gap)) + (30 if title else 0) + 20

    def draw(self):
        c = self.canv
        x0 = 10
        y_top = self.height - 10
        bw = self.chart_w
        if self.title:
            c.setFont('Helvetica-Bold', 10)
            c.setFillColor(C_ORANGE)
            c.drawCentredString(x0 + bw/2, y_top - 12, self.title)
            y_top -= 28

        for i, (label, colour) in enumerate(self.steps):
            y = y_top - i*(self.box_h + self.gap)
            box_colour = colour or C_FLOW_BOX
            # Draw box
            c.setFillColor(box_colour)
            c.setStrokeColor(HexColor('#7B2D0E'))
            c.setLineWidth(0.8)
            c.roundRect(x0, y - self.box_h, bw, self.box_h, 5, fill=1, stroke=1)
            # Text
            c.setFillColor(white)
            c.setFont('Helvetica-Bold' if i == 0 else 'Helvetica', 8.5)
            # Wrap text
            words = label.split()
            lines = []
            line = ''
            for w in words:
                test = (line + ' ' + w).strip()
                if c.stringWidth(test, 'Helvetica', 8.5) < bw - 12:
                    line = test
                else:
                    if line:
                        lines.append(line)
                    line = w
            if line:
                lines.append(line)
            text_y = y - self.box_h/2 + (len(lines)-1)*5
            for li, ltext in enumerate(lines):
                c.drawCentredString(x0 + bw/2, text_y - li*11, ltext)
            # Arrow down (except last)
            if i < len(self.steps) - 1:
                ax = x0 + bw/2
                ay_start = y - self.box_h - 2
                ay_end   = y - self.box_h - self.gap + 6
                c.setStrokeColor(C_ORANGE)
                c.setFillColor(C_ORANGE)
                c.setLineWidth(1.5)
                c.line(ax, ay_start, ax, ay_end + 4)
                # arrowhead
                c.beginPath()
                c.moveTo(ax, ay_end)
                c.lineTo(ax - 5, ay_end + 8)
                c.lineTo(ax + 5, ay_end + 8)
                c.closePath()
                c.fill()

    def wrap(self, aW, aH):
        return self.width, self.height


class TwoColFlowChart(Flowable):
    """Two-column (branching) flowchart for scar management."""
    def __init__(self, left_steps, right_steps, common_steps,
                 left_title='', right_title='', width=None):
        super().__init__()
        self.left_steps   = left_steps
        self.right_steps  = right_steps
        self.common_steps = common_steps
        self.left_title   = left_title
        self.right_title  = right_title
        self.chart_w      = width or INNER_W - 10
        self.box_h        = 28
        self.gap          = 14
        col_steps = max(len(left_steps), len(right_steps))
        self.height = (col_steps * (self.box_h + self.gap)
                       + len(common_steps) * (self.box_h + self.gap)
                       + 60)
        self.width  = self.chart_w

    def draw(self):
        c    = self.canv
        bw   = (self.chart_w - 20) / 2   # box width per column
        gap  = self.gap
        bh   = self.box_h
        lx   = 5                          # left col x
        rx   = self.chart_w/2 + 5        # right col x
        y_top = self.height - 10

        def draw_box(x, y, label, colour, font_size=8):
            c.setFillColor(colour)
            c.setStrokeColor(HexColor('#7B2D0E'))
            c.setLineWidth(0.7)
            c.roundRect(x, y-bh, bw, bh, 4, fill=1, stroke=1)
            c.setFillColor(white)
            c.setFont('Helvetica', font_size)
            words = label.split()
            lines, line = [], ''
            for w in words:
                test = (line+' '+w).strip()
                if c.stringWidth(test, 'Helvetica', font_size) < bw-8:
                    line = test
                else:
                    if line: lines.append(line)
                    line = w
            if line: lines.append(line)
            ty = y - bh/2 + (len(lines)-1)*5
            for li, lt in enumerate(lines):
                c.drawCentredString(x+bw/2, ty-li*10, lt)

        def arrow_down(x, bw, y_start, y_end):
            ax = x+bw/2
            c.setStrokeColor(C_ORANGE)
            c.setFillColor(C_ORANGE)
            c.setLineWidth(1.2)
            c.line(ax, y_start, ax, y_end+4)
            c.beginPath()
            c.moveTo(ax, y_end)
            c.lineTo(ax-4, y_end+7)
            c.lineTo(ax+4, y_end+7)
            c.closePath()
            c.fill()

        # Column titles
        c.setFont('Helvetica-Bold', 9)
        c.setFillColor(C_ORANGE)
        c.drawCentredString(lx+bw/2, y_top-8, self.left_title)
        c.drawCentredString(rx+bw/2, y_top-8, self.right_title)
        y_top -= 20

        # Draw left column
        for i, (label, colour) in enumerate(self.left_steps):
            y = y_top - i*(bh+gap)
            draw_box(lx, y, label, colour or C_FLOW_BOX)
            if i < len(self.left_steps)-1:
                arrow_down(lx, bw, y-bh-2, y-bh-gap+6)

        # Draw right column
        for i, (label, colour) in enumerate(self.right_steps):
            y = y_top - i*(bh+gap)
            draw_box(rx, y, label, colour or C_FLOW_BOX)
            if i < len(self.right_steps)-1:
                arrow_down(rx, bw, y-bh-2, y-bh-gap+6)

        # Common steps below columns
        col_h = max(len(self.left_steps), len(self.right_steps))
        y_common_start = y_top - col_h*(bh+gap) - 10
        # Draw merge lines
        lmid_x = lx + bw/2
        rmid_x = rx + bw/2
        cx_mid = self.chart_w/2
        c.setStrokeColor(C_ORANGE)
        c.setLineWidth(1.2)
        c.line(lmid_x, y_common_start+4, cx_mid, y_common_start-12)
        c.line(rmid_x, y_common_start+4, cx_mid, y_common_start-12)
        c.setFillColor(C_ORANGE)
        c.beginPath()
        c.moveTo(cx_mid, y_common_start-18)
        c.lineTo(cx_mid-4, y_common_start-10)
        c.lineTo(cx_mid+4, y_common_start-10)
        c.closePath()
        c.fill()

        full_bw = self.chart_w - 10
        y_c = y_common_start - 22
        for i, (label, colour) in enumerate(self.common_steps):
            y = y_c - i*(bh+gap)
            c.setFillColor(colour or C_FLOW_BOX)
            c.setStrokeColor(HexColor('#7B2D0E'))
            c.setLineWidth(0.7)
            c.roundRect(5, y-bh, full_bw, bh, 4, fill=1, stroke=1)
            c.setFillColor(white)
            c.setFont('Helvetica', 8)
            words = label.split()
            lines, line = [], ''
            for w in words:
                test = (line+' '+w).strip()
                if c.stringWidth(test, 'Helvetica', 8) < full_bw-12:
                    line = test
                else:
                    if line: lines.append(line)
                    line = w
            if line: lines.append(line)
            ty = y-bh/2+(len(lines)-1)*5
            for li, lt in enumerate(lines):
                c.drawCentredString(5+full_bw/2, ty-li*10, lt)
            if i < len(self.common_steps)-1:
                ax = 5+full_bw/2
                c.setStrokeColor(C_ORANGE)
                c.setFillColor(C_ORANGE)
                c.setLineWidth(1.2)
                ys = y-bh-2; ye = y-bh-gap+6
                c.line(ax, ys, ax, ye+4)
                c.beginPath()
                c.moveTo(ax, ye)
                c.lineTo(ax-4, ye+7)
                c.lineTo(ax+4, ye+7)
                c.closePath()
                c.fill()

    def wrap(self, aW, aH):
        return self.width, self.height

# ─── Page template ────────────────────────────────────────────────────────────
def on_page(canvas, doc):
    canvas.saveState()
    # Footer
    canvas.setFont('Helvetica', 8)
    canvas.setFillColor(HexColor('#888888'))
    canvas.drawString(MARGIN, 14*mm, 'Chapter 3 | Wound Healing and Tissue Repair')
    canvas.drawRightString(PAGE_W - MARGIN, 14*mm, f'Page {doc.page}')
    canvas.setStrokeColor(HexColor('#CCCCCC'))
    canvas.setLineWidth(0.5)
    canvas.line(MARGIN, 16*mm, PAGE_W - MARGIN, 16*mm)
    canvas.restoreState()

# ═══════════════════════════════════════════════════════════════════════════════
# BUILD CONTENT
# ═══════════════════════════════════════════════════════════════════════════════
def build_content():
    story = []

    # ──────────────────────────────────────────────────────────────────────────
    # TITLE PAGE
    # ──────────────────────────────────────────────────────────────────────────
    story.append(Spacer(1, 2*cm))
    story.append(Paragraph("CHAPTER", make_style('CLabel', fontSize=12,
                 textColor=C_SALMON, fontName='Helvetica', alignment=TA_CENTER)))
    story.append(Paragraph("3", s_ch_num))
    story.append(Paragraph("Wound Healing and Tissue Repair", s_title))
    story.append(Spacer(1, 0.4*cm))
    story.append(HRFlowable(width=INNER_W, color=C_SALMON, thickness=2))
    story.append(Spacer(1, 0.5*cm))

    story.append(Paragraph(
        "A beginner-friendly, illustrated study guide covering the entire chapter — "
        "from the biology of normal wound healing to clinical management of acute and "
        "chronic wounds, including scar treatment algorithms.",
        make_style('Intro', fontSize=10.5, textColor=C_MID_TXT,
                   fontName='Helvetica-Oblique', alignment=TA_CENTER, leading=16)
    ))
    story.append(Spacer(1, 0.6*cm))

    # Learning objectives box
    lo_data = [
        [Paragraph("Learning Objectives", make_style('LOH', fontSize=11,
                    textColor=white, fontName='Helvetica-Bold'))],
        [Paragraph(
            "After studying this chapter you will understand:<br/>"
            "• Normal wound healing and how it can be adversely affected<br/>"
            "• Types of healing (primary, secondary, tertiary) and how to classify wounds<br/>"
            "• The principles of wound management<br/>"
            "• The principles of scar management",
            make_style('LOB', fontSize=9.5, textColor=C_DARK_TXT,
                       fontName='Helvetica', leading=14)
        )]
    ]
    lo_tbl = Table(lo_data, colWidths=[INNER_W])
    lo_tbl.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (-1,0), C_BANNER),
        ('BACKGROUND', (0,1), (-1,1), C_BOX_BG),
        ('BOX', (0,0), (-1,-1), 1.5, C_BOX_BDR),
        ('TOPPADDING', (0,0), (-1,-1), 8),
        ('BOTTOMPADDING', (0,0), (-1,-1), 8),
        ('LEFTPADDING', (0,0), (-1,-1), 12),
    ]))
    story += [lo_tbl, Spacer(1, 0.5*cm)]
    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 1: NORMAL WOUND HEALING IN SKIN
    # ══════════════════════════════════════════════════════════════════════════
    story += section_banner("Section 1: Normal Wound Healing in Skin")

    story.append(Paragraph("Introduction", s_h2))
    story.append(Paragraph(
        "Wound healing is a <b>complex and dynamic biological process</b>. In adults, "
        "injury usually leads to <b>fibrosis</b> (scar tissue) rather than perfect "
        "regeneration. Interestingly, <b>fetal (unborn baby) tissue</b> can heal without "
        "scarring — which is why regenerative medicine is such an active research field.",
        s_body))

    # Key Terms
    story.append(Paragraph("Key Terms Defined", s_h2))
    story += term_entry("Fibrosis", "The formation of excess fibrous (scar) connective tissue during repair, which can impair normal organ function.")
    story += term_entry("Angiogenesis", "The growth of new blood vessels — essential for delivering oxygen and nutrients to healing tissue.")
    story += term_entry("Epithelialisation", "Re-growth of the outer skin layer (epithelium) over a wound surface.")
    story += term_entry("Chemotaxis", "The movement of cells towards a chemical signal — how immune cells are 'called' to the wound site.")
    story += term_entry("Extracellular Matrix (ECM)", "The scaffolding material that surrounds cells; made of collagen, proteoglycans, and other proteins.")
    story += term_entry("Granulation Tissue", "New, fragile connective tissue that grows to fill a wound — it has a pink, grainy appearance.")
    story += term_entry("Haemostasis", "Stopping the bleeding — the immediate first response to injury.")
    story += term_entry("Cytokines & Growth Factors", "Signalling proteins that tell cells what to do (multiply, migrate, die, etc.).")

    story.append(Spacer(1, 6))

    # ─── FLOWCHART 1: Phases of Wound Healing ─────────────────────────────────
    story.append(Paragraph("Process Flowchart: Phases of Normal Wound Healing", s_h2))
    story.append(Paragraph(
        "The four phases overlap and progress in sequence over days to years:",
        s_body))

    fc1_steps = [
        ("PHASE 1 — HAEMOSTASIS (Immediate: minutes)",         C_FLOW_BOX),
        ("Blood vessels constrict | Platelets adhere & form a plug | "
         "Coagulation cascade activates | Fibrin clot forms scaffold",  HexColor('#9E3318')),
        ("PHASE 2 — INFLAMMATION (Days 1–3)",                  C_FLOW_BOX),
        ("Neutrophils arrive (Days 1–2): kill bacteria, clean wound | "
         "Monocytes arrive → become Macrophages (Days 2–3): debride wound, "
         "release growth factors | Signs: Redness, Swelling, Heat, Pain",  HexColor('#9E3318')),
        ("PHASE 3 — PROLIFERATION (Days 3 to 2–4 weeks)",     C_FLOW_BOX),
        ("Fibroblasts produce collagen & ground substance | "
         "New blood vessels grow (angiogenesis) | "
         "Skin re-grows over wound (re-epithelialisation) | "
         "Myofibroblasts contract wound edges",               HexColor('#9E3318')),
        ("PHASE 4 — REMODELLING (Weeks 2–3 to 1+ year)",      C_FLOW_BOX),
        ("Type III collagen → replaced by stronger Type I collagen | "
         "Wound gains tensile strength (max at 12 weeks = ~80% of normal) | "
         "Scar matures, flattens, and fades",                 HexColor('#9E3318')),
    ]
    story.append(KeepTogether([FlowChart(fc1_steps, box_h=32, gap=10,
                                          title="Wound Healing — 4 Phases")]))
    story.append(Spacer(1, 8))

    # Haemostasis detail
    story += sub_header("Phase 1 — Haemostasis: What Actually Happens?")
    story.append(Paragraph(
        "When a blood vessel wall (vascular endothelium) is damaged, the body does the following:",
        s_body))
    hemo_steps = [
        ("Injury breaks blood vessel wall",                     HexColor('#8B3A1F')),
        ("Vasoconstriction: vessels narrow to reduce blood loss",C_FLOW_BOX),
        ("Platelets stick to exposed collagen (subendothelial ECM)", C_FLOW_BOX),
        ("Platelets activate & release Alpha granules (growth factors, cytokines)", C_FLOW_BOX),
        ("Platelet aggregation → forms a Platelet Plug",        C_FLOW_BOX),
        ("Coagulation cascade triggered by tissue factor → Thrombin formed", C_FLOW_BOX),
        ("Thrombin converts Fibrinogen → Fibrin mesh",          C_FLOW_BOX),
        ("Stable Fibrin Clot = scaffold for healing cells",     HexColor('#5A1A00')),
    ]
    story.append(KeepTogether([FlowChart(hemo_steps, box_h=26, gap=10)]))
    story.append(Spacer(1,6))

    # Coagulation cascade table
    story.append(Paragraph("The Coagulation Cascade — Simplified", s_h2))
    story.append(Paragraph(
        "Two pathways trigger blood clotting; both converge on a common final pathway:",
        s_body))
    coag_rows = [
        ("Intrinsic Pathway\n(Contact System)", "Triggered INSIDE the vessel by contact with damaged surface (Factor XII activation)", "Slower; amplifies the response"),
        ("Extrinsic Pathway", "Triggered OUTSIDE by Tissue Factor (TF) released from damaged tissue", "Faster; main initial trigger"),
        ("Common Pathway", "Both pathways activate Factor X → Prothrombin (FII) → Thrombin (FIIa) → Fibrin", "Final clot formation"),
        ("Fibrinolysis", "Plasminogen → Plasmin (activated by uPA/tPA) breaks down fibrin clot", "Controls clot size; prevents over-clotting"),
    ]
    story += make_table(
        ["Pathway", "Trigger / Mechanism", "Role"],
        coag_rows,
        col_widths=[4*cm, 8*cm, 4.5*cm]
    )

    # Inflammation detail
    story += sub_header("Phase 2 — Inflammation: Step-by-Step")
    inflam_steps = [
        ("Platelets & injured tissue release histamine & serotonin", HexColor('#8B3A1F')),
        ("Blood vessels dilate & become more permeable (leaky)", C_FLOW_BOX),
        ("DAY 1–2: Neutrophils flood in → destroy bacteria, remove debris", C_FLOW_BOX),
        ("DAY 2–3: Monocytes arrive from blood", C_FLOW_BOX),
        ("Monocytes differentiate (transform) into Macrophages", C_FLOW_BOX),
        ("Macrophages: phagocytose debris, release growth factors (PDGF, TGF-β, FGF, VEGF)", C_FLOW_BOX),
        ("Growth factors stimulate fibroblasts & new vessel growth → Enter Proliferation Phase", HexColor('#5A1A00')),
    ]
    story.append(KeepTogether([FlowChart(inflam_steps, box_h=26, gap=10)]))

    # Proliferation & Remodelling
    story += sub_header("Phase 3 — Proliferation")
    story.append(Paragraph(
        "Starting on Day 3 and lasting 2–4 weeks, this phase rebuilds the wound tissue. "
        "Key cells are <b>fibroblasts</b> — they produce collagen and the 'ground substance' "
        "that fills the wound. New blood vessels grow (angiogenesis), the skin grows back "
        "over the top (re-epithelialisation), and myofibroblasts pull wound edges together "
        "(contraction). Early wound tissue is called <b>granulation tissue</b>.",
        s_body))

    story += sub_header("Phase 4 — Remodelling")
    story.append(Paragraph(
        "Beginning 2–3 weeks after injury and lasting up to a year or more, this phase matures "
        "the repair. <b>Type III collagen</b> (weak, disordered) is replaced by stronger "
        "<b>Type I collagen</b> in an organised parallel arrangement. The scar gains tensile "
        "strength, reaching maximum (~80% of normal skin) at about 12 weeks. The 4:1 ratio "
        "of Type I to Type III collagen is re-established.",
        s_body))

    story += quick_summary([
        "Wound healing has 4 overlapping phases: Haemostasis → Inflammation → Proliferation → Remodelling.",
        "Platelets are the first responders; macrophages are the most important cells for directing the healing process.",
        "Full tensile strength (~80% of original) is only reached at ~12 weeks post-injury.",
    ])

    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 2: HEALING IN OTHER TISSUES
    # ══════════════════════════════════════════════════════════════════════════
    story += section_banner("Section 2: Normal Healing in Other Specific Tissues")

    # BONE
    story.append(Paragraph("2A — Bone Healing", s_h2))
    story += term_entry("Callus", "A mass of new bone tissue that bridges a fracture site before being remodelled into solid bone.")
    story += term_entry("Intramembranous ossification", "Direct conversion of soft tissue to bone, without cartilage as an intermediate — occurs at fracture ends.")
    story += term_entry("Endochondral ossification", "Bone formation via a cartilage (fibrocartilage) intermediate — the main route for fracture healing.")
    story += term_entry("Haematoma", "A collection of blood at the fracture site — the starting point for bone healing.")

    story.append(Paragraph("Bone Healing Flowchart (Indirect/Secondary Healing — most common)", s_h2))
    bone_steps = [
        ("FRACTURE occurs",                                      HexColor('#8B3A1F')),
        ("Haematoma forms at fracture site",                     C_FLOW_BOX),
        ("Inflammation: growth factors released",                C_FLOW_BOX),
        ("SOFT CALLUS forms (fibrocartilage replaces haematoma, new blood vessels grow)", C_FLOW_BOX),
        ("Endochondral ossification: fibrocartilage → HARD CALLUS (woven bone)", C_FLOW_BOX),
        ("REMODELLING: Osteoclasts remove woven bone, osteoblasts lay lamellar bone", C_FLOW_BOX),
        ("Normal bone anatomy restored",                         HexColor('#5A1A00')),
    ]
    story.append(KeepTogether([FlowChart(bone_steps, box_h=28, gap=12)]))
    story.append(Spacer(1,6))

    story.append(Paragraph(
        "<b>Primary bone healing</b> is direct union without callus — requires exact apposition "
        "(ends touching) and rigid fixation (e.g. surgical plates). It is less common. "
        "If a gap exists, secondary healing may cause delayed union, non-union, or malunion.",
        s_body))

    # NERVE
    story.append(Paragraph("2B — Peripheral Nerve Healing", s_h2))
    story += term_entry("Wallerian degeneration", "The breakdown and clearance of the nerve fibre and its myelin sheath below (distal to) the injury site.")
    story += term_entry("Neurotmesis", "Complete severing of a nerve (the most severe injury).")
    story += term_entry("Neurotropism", "The ability of regenerating nerve fibres to be guided back towards their target by chemical signals.")
    story += term_entry("Neuroma", "A painful lump caused by disorganised, failed nerve regeneration.")

    nerve_steps = [
        ("Nerve injury occurs",                                  HexColor('#8B3A1F')),
        ("Distal segment: Wallerian degeneration — myelin breaks down, debris cleared by macrophages & Schwann cells", C_FLOW_BOX),
        ("Proximal segment: degenerates back to nearest node of Ranvier", C_FLOW_BOX),
        ("Schwann cells proliferate → form Bands of Bungner (tubes guiding axon regrowth)", C_FLOW_BOX),
        ("Regenerating axon grows along tube, guided by growth factors & ECM proteins", C_FLOW_BOX),
        ("Axon reaches target → reinnervation and remyelination",HexColor('#5A1A00')),
        ("If guidance fails → Neuroma (disorganised, painful lump)", HexColor('#AA2222')),
    ]
    story.append(KeepTogether([FlowChart(nerve_steps, box_h=28, gap=10)]))
    story.append(Spacer(1,6))

    # TENDON
    story.append(Paragraph("2C — Tendon Healing", s_h2))
    story.append(Paragraph(
        "Tendons repair via two mechanisms: <b>intrinsic healing</b> (from the tendon's own "
        "cells, relying on blood flow and synovial fluid diffusion) and <b>extrinsic healing</b> "
        "(from surrounding tissue — forms adhesions that can restrict movement). Early "
        "mobilisation after tendon repair promotes the better intrinsic route and prevents "
        "stiffening. Splinting protects against rupture.",
        s_body))

    story += quick_summary([
        "Bone heals via a haematoma → soft callus → hard callus → remodelling sequence.",
        "Nerve regeneration depends on Schwann cells guiding axons back; failed guidance causes painful neuromas.",
        "Tendon healing favours early movement (promotes intrinsic, adhesion-free repair) with splinting for protection.",
    ])

    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 3: ABNORMAL WOUND HEALING
    # ══════════════════════════════════════════════════════════════════════════
    story += section_banner("Section 3: Abnormal Wound Healing")

    story.append(Paragraph("Introduction", s_h2))
    story.append(Paragraph(
        "Not all wounds heal normally. Some fail to progress through normal stages "
        "(becoming <b>chronic wounds</b>), while others overshoot and form excessive scar "
        "tissue (<b>hypertrophic scars</b> or <b>keloids</b>). Many local and systemic "
        "factors can interfere.",
        s_body))

    story.append(Paragraph("Key Terms Defined", s_h2))
    story += term_entry("Hypertrophic scar", "An overgrown scar that STAYS within the wound boundaries. Tends to regress over time. Red, raised, itchy.")
    story += term_entry("Keloid scar", "An overgrown scar that EXTENDS BEYOND the wound edges. Does NOT regress. More common in darker skin tones.")
    story += term_entry("Chronic wound", "A wound stuck in the inflammatory phase — fails to progress through normal healing stages.")
    story += term_entry("Debridement", "Removing dead/non-viable tissue from a wound to allow healing.")

    # Factors affecting healing
    story.append(Paragraph("Factors That Impair Wound Healing", s_h2))
    factor_rows = [
        ("Skin tension / traction", "Local", "Pulls wound edges apart"),
        ("Hypoxia & ischaemia", "Local", "Cells need oxygen to heal"),
        ("Vascular insufficiency", "Local", "Poor blood supply = poor delivery of nutrients"),
        ("Lymphoedema", "Local", "Fluid buildup prevents cell migration"),
        ("Contamination / Infection", "Local", "Bacteria consume resources, prolong inflammation"),
        ("Foreign bodies", "Local", "Prevent closure; trigger chronic inflammation"),
        ("Radiotherapy", "Local", "Damages blood vessels and fibroblasts"),
        ("Advancing age", "Systemic", "Slower cell turnover, poorer immune response"),
        ("Obesity", "Systemic", "Poor tissue perfusion, increased infection risk"),
        ("Malnutrition", "Systemic", "Lack of protein, vitamins (especially C) impairs collagen synthesis"),
        ("Smoking", "Systemic", "Vasoconstriction, reduced oxygen delivery"),
        ("Diabetes mellitus", "Systemic", "Neuropathy, vascular disease, immune impairment"),
        ("Immunocompromised (e.g. HIV/AIDS)", "Systemic", "Reduced ability to fight infection"),
        ("Steroids / Immunosuppressants", "Systemic", "Suppress inflammation needed for healing"),
        ("Chemotherapy", "Systemic", "Impairs cell division needed for repair"),
    ]
    story += make_table(
        ["Factor", "Type", "Why It Harms Healing"],
        factor_rows,
        col_widths=[5.5*cm, 2.5*cm, 8.5*cm]
    )

    # Scar types comparison
    story.append(Paragraph("Hypertrophic vs Keloid Scars — Comparison", s_h2))
    scar_rows = [
        ("Stays within wound boundaries", "Extends BEYOND wound edges"),
        ("Raised, red/pink, itchy", "Dark, raised, may be painful"),
        ("Usually regresses over time", "Does NOT spontaneously regress"),
        ("Common at high-tension areas (joints, burns)", "Common in darker skin; may arise from minor trauma"),
        ("Treatment: silicone gel, compression, steroids", "Difficult to treat; high recurrence after excision"),
    ]
    story += make_table(
        ["Hypertrophic Scar", "Keloid Scar"],
        scar_rows,
        col_widths=[8*cm, 8*cm]
    )

    story += quick_summary([
        "Both hypertrophic and keloid scars result from excess collagen — but keloids cross wound boundaries and never regress.",
        "Local factors (infection, tension, ischaemia) and systemic factors (diabetes, smoking, steroids) all delay healing.",
        "Prevention of poor healing is better than treatment — correct all modifiable factors early.",
    ])

    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 4: TYPES OF WOUND HEALING
    # ══════════════════════════════════════════════════════════════════════════
    story += section_banner("Section 4: Types of Wound Healing & Wound Classification")

    story.append(Paragraph("Types of Healing", s_h2))
    healing_rows = [
        ("Primary (1st intention)", "Wound edges are directly apposed (brought together) — e.g. a clean surgical incision closed with sutures.",
         "Fastest healing, minimal scar"),
        ("Delayed primary (3rd intention)", "Wound initially left open (e.g. contaminated wound); once clean, edges are then surgically closed.",
         "Used for dirty wounds; intermediate healing time"),
        ("Secondary (2nd intention)", "Wound left open to heal by granulation, contraction, and re-epithelialisation from the edges inward.",
         "Slower; more scarring; used when closure would trap infection"),
    ]
    story += make_table(
        ["Type", "What Happens", "Outcome"],
        healing_rows,
        col_widths=[4*cm, 8.5*cm, 4*cm]
    )

    story.append(Paragraph("Healing Types Flowchart", s_h2))
    healing_steps = [
        ("WOUND OCCURS",                                         HexColor('#8B3A1F')),
        ("Is the wound clean with close-able edges?",            HexColor('#5C7A2E')),
        ("YES → PRIMARY CLOSURE: suture, staple or glue edges together (1st intention) → Minimal scar", HexColor('#3A6020')),
        ("NO → Is wound contaminated / infected?",              HexColor('#5C7A2E')),
        ("YES → Leave wound OPEN; treat infection; debride",     C_FLOW_BOX),
        ("Once wound is clean → DELAYED PRIMARY CLOSURE (3rd intention)", C_FLOW_BOX),
        ("If closure still not appropriate → allow SECONDARY HEALING by granulation & contraction (2nd intention)", C_FLOW_SEC),
    ]
    story.append(KeepTogether([FlowChart(healing_steps, box_h=28, gap=10)]))
    story.append(Spacer(1, 6))

    # Wound Classification
    story.append(Paragraph("Wound Classification Systems", s_h2))
    story.append(Paragraph(
        "Wounds are classified along multiple dimensions. The main dimensions are shown below:",
        s_body))

    class_rows = [
        ("Aetiology (cause)", "Clean surgical / shearing / crush / blast / burn / bite / avulsion / pressure"),
        ("Depth", "Epidermal / Dermal (superficial or deep) / Full-thickness"),
        ("Contamination (CDC Class)", "Class I — Clean; Class II — Clean-contaminated; Class III — Contaminated; Class IV — Dirty"),
        ("Complexity", "Simple / Complex (significant soft tissue loss, open fracture, visceral involvement) / Complicated (infection, necrosis, haematoma, gas gangrene, compartment syndrome)"),
        ("Chronicity", "Acute / Chronic (vascular ulcers, pressure ulcers, diabetic ulcers)"),
    ]
    story += make_table(
        ["Classification Dimension", "Categories"],
        class_rows,
        col_widths=[5*cm, 11.5*cm]
    )

    # CDC Classification
    story.append(Paragraph("US CDC Surgical Wound Classification (Table 3.1)", s_h2))
    cdc_rows = [
        ("Class I — Clean", "Uninfected operative wound; no inflammation; respiratory/alimentary/genital tracts NOT entered; primarily closed; no break in technique"),
        ("Class II — Clean-contaminated", "Respiratory, alimentary, genital, or urinary tract entered under controlled conditions; no unusual contamination; no evidence of infection"),
        ("Class III — Contaminated", "Open, fresh, accidental wounds; or operations with major breaks in technique (e.g. open cardiac massage); gross spillage from GI tract; non-purulent inflammation"),
        ("Class IV — Dirty", "Old traumatic wounds with retained devitalised tissue; wounds with existing clinical infection or perforated viscera"),
    ]
    story += make_table(
        ["Class", "Definition"],
        cdc_rows,
        col_widths=[4.5*cm, 12*cm]
    )

    story += quick_summary([
        "Three main healing types: primary (best, fastest), secondary (open healing), and delayed primary (contaminated then closed).",
        "Wound classification uses multiple dimensions: cause, depth, contamination, complexity, and chronicity.",
        "The CDC Class IV 'Dirty' wound carries the highest infection risk.",
    ])

    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 5: WOUND MANAGEMENT
    # ══════════════════════════════════════════════════════════════════════════
    story += section_banner("Section 5: Wound Management")

    story.append(Paragraph("Assessment", s_h2))
    story.append(Paragraph(
        "Clinical judgement governs wound management. Assessment follows <b>ATLS "
        "(Advanced Trauma Life Support)</b> principles — first treat life-threatening "
        "conditions, then address the wound. Assess: size, geometry, depth, nature of wound, "
        "signs of contamination/infection, swelling, bleeding, skin loss, degloving.",
        s_body))

    story.append(Paragraph("Principles of Wound Management (Table 3.2)", s_h2))
    mgmt_rows = [
        ("Preparation",  "• Antibiotic prophylaxis (if indicated)\n• Tetanus prophylaxis\n• Adequate analgesia/anaesthesia\n• Wound irrigation"),
        ("Wound",        "• Early debridement and irrigation\n• Exploration (to assess depth/damage)\n• Repair structures (nerves, tendons, vessels)\n• Haemostasis"),
        ("Closure",      "• Skin closure without tension\n• Consider reconstruction options (from reconstructive ladder/elevator)\n• Suture choice\n• Consider drains\n• Optimal dressings"),
        ("Follow-up",    "• Removal of sutures/splints\n• Physiotherapy\n• Wound monitoring for complications\n• Scar management"),
    ]
    story += make_table(
        ["Stage", "Key Actions"],
        mgmt_rows,
        col_widths=[3.5*cm, 13*cm]
    )

    # Management flowchart
    story.append(Paragraph("Wound Management Flowchart", s_h2))
    mgmt_steps = [
        ("PATIENT ARRIVES with wound",                          HexColor('#8B3A1F')),
        ("ATLS: treat life-threatening injuries first (ABC)",    C_FLOW_BOX),
        ("ASSESS wound: size, depth, contamination, mechanism", C_FLOW_BOX),
        ("PREPARE: analgesia, tetanus prophylaxis, antibiotics if needed, irrigate", C_FLOW_BOX),
        ("DEBRIDE: remove all non-viable tissue until bleeding",C_FLOW_BOX),
        ("EXPLORE: repair tendons, nerves, vessels as needed",   C_FLOW_BOX),
        ("CLOSE: use reconstructive ladder — simplest option that works safely", C_FLOW_BOX),
        ("DRESS: optimal wound dressing, drain if needed",       C_FLOW_BOX),
        ("FOLLOW-UP: monitor, physiotherapy, scar management",   HexColor('#5A1A00')),
    ]
    story.append(KeepTogether([FlowChart(mgmt_steps, box_h=26, gap=10)]))
    story.append(Spacer(1,6))

    # Debridement
    story.append(Paragraph("Types of Debridement (Table 3.4)", s_h2))
    debride_rows = [
        ("Surgical", "Cutting out non-viable tissue with scalpel, curette, scissors, or rongeur until healthy bleeding occurs at wound edges", "Fastest; most controllable"),
        ("Mechanical", "Non-selective — irrigation, wet-to-dry dressings, hydrotherapy. Removes both viable and non-viable tissue", "Simple; but non-selective"),
        ("Autolytic", "Hydrocolloids or transparent films keep wound moist; wound's own enzymes selectively digest dead tissue", "Selective; gentle; takes longer"),
        ("Enzymatic", "Topical collagenase or papain-urea chemically digests necrotic tissue", "Chemical breakdown"),
        ("Biological", "Medical-grade larvae (maggots) of Lucilia sericata release proteolytic and antimicrobial enzymes; also directly promote wound healing", "Highly selective; also antibacterial"),
    ]
    story += make_table(
        ["Method", "How It Works", "Key Feature"],
        debride_rows,
        col_widths=[3*cm, 9*cm, 4.5*cm]
    )

    # Tetanus
    story.append(Paragraph("Tetanus Prophylaxis", s_h2))
    story += term_entry("Tetanus-prone wound",
        "Deep puncture, bite, compound fracture, wound with foreign body, contaminated wound, or burn wound — especially with >6 hour delay to treatment.")
    story += term_entry("High-risk tetanus-prone wound",
        "Heavy contamination (soil/manure), requiring cleaning surgery with >6 hour delay, or with extensive devitalised tissue.")
    story.append(Paragraph(
        "<b>Key rule:</b> Whether a patient needs a tetanus vaccine booster AND/OR human tetanus "
        "immunoglobulin (HTI) depends on: (1) the type of wound, and (2) their vaccination status. "
        "Patients who never completed a primary vaccination course need both vaccine AND HTI for "
        "tetanus-prone wounds.",
        s_body))

    # Reconstruction options
    story.append(Paragraph("The Reconstructive Ladder", s_h2))
    story.append(Paragraph(
        "Wound closure uses the simplest option that safely achieves closure. The 'ladder' "
        "climbs from basic to complex techniques:",
        s_body))
    recon_steps = [
        ("1. Primary closure — direct suture of wound edges",    HexColor('#2E7D32')),
        ("2. Secondary closure — leave open to heal by granulation", HexColor('#388E3C')),
        ("3. Tertiary (delayed primary) closure",                 HexColor('#43A047')),
        ("4. NPWT — Negative Pressure Wound Therapy (vacuum dressing)", HexColor('#C0603A')),
        ("5. Split-thickness skin graft (STSG) — thin layer of skin harvested from donor site", C_FLOW_BOX),
        ("6. Full-thickness skin graft (FTSG) — full dermal thickness; better cosmesis", C_FLOW_BOX),
        ("7. Dermal matrices — artificial scaffolding",           C_FLOW_BOX),
        ("8. Local or regional flap — adjacent tissue with its blood supply", C_FLOW_SEC),
        ("9. Free flap — tissue transferred from a distant site with microsurgical vessel reconnection", HexColor('#8B3A1F')),
    ]
    story.append(KeepTogether([FlowChart(recon_steps, box_h=26, gap=8)]))
    story.append(Spacer(1,6))

    story += term_entry("NPWT (Negative Pressure Wound Therapy)",
        "A vacuum-sealed dressing that sucks fluid out of the wound, reduces swelling, draws "
        "edges together, and promotes granulation tissue growth. Not a replacement for "
        "definitive closure — an adjunct.")
    story += term_entry("Free flap",
        "Tissue (with its own blood vessels) taken from one part of the body and surgically "
        "reconnected to vessels at the recipient site using a microscope.")

    story += quick_summary([
        "Wound management follows a logical sequence: assess → prepare → debride → repair → close → dress → follow-up.",
        "Debridement (removal of dead tissue) is the single most important step; all non-viable tissue must be excised.",
        "Closure uses the simplest option from the reconstructive ladder that safely achieves the goal.",
    ])

    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 6: ACUTE WOUNDS (Bites, Degloving, Compartment Syndrome, NF)
    # ══════════════════════════════════════════════════════════════════════════
    story += section_banner("Section 6: Acute Wounds — Special Topics")

    # Bites
    story.append(Paragraph("Bites", s_h2))
    story.append(Paragraph(
        "Most bites are puncture wounds or avulsions. Wounds over the metacarpophalangeal "
        "joint (knuckle) should be treated as <b>human bites</b> until proven otherwise — "
        "even a punch to the mouth. High-pressure injection injuries (e.g. grease guns) to "
        "the hand look minor but can cause severe internal damage — urgent surgical exploration "
        "is mandatory.",
        s_body))

    # Degloving
    story.append(Paragraph("Degloving", s_h2))
    story += term_entry("Degloving",
        "The avulsion (peeling away) of skin and subcutaneous fat from the underlying fascia, "
        "muscle, or bone — like removing a glove.")
    story += term_entry("Morel-Lavallée lesion",
        "A closed degloving injury creating a haemolymphatic (blood + lymph) collection "
        "between the deep fascia and subcutaneous fat — caused by shearing forces.")

    story.append(Paragraph("Degloving Classification (Summary box 3.5)", s_h3))
    deglov_rows = [
        ("1", "Limited degloving with abrasion or avulsion"),
        ("2", "Non-circumferential degloving"),
        ("3", "Circumferential single plane degloving"),
        ("4", "Circumferential multiplanar degloving (most severe)"),
    ]
    story += make_table(["Grade", "Description"], deglov_rows, col_widths=[2.5*cm, 14*cm])

    # Compartment Syndrome
    story.append(Paragraph("Acute Compartment Syndrome (ACS)", s_h2))
    story += term_entry("Compartment syndrome",
        "Dangerously raised pressure inside a closed muscle compartment — blood supply is cut "
        "off, muscles die. A surgical emergency.")
    story.append(Paragraph(
        "<b>Classic signs:</b> Pain out of proportion to injury; Pain on passive stretch of "
        "muscles; Paraesthesia (tingling/numbness); Pallor; Pulselessness (late sign).",
        s_body))
    story.append(Paragraph(
        "<b>Treatment: FASCIOTOMY</b> — surgical incision of the skin and deep fascia to "
        "release the pressure. Lower limb needs TWO incisions (medial and lateral). Delay "
        "leads to rhabdomyolysis, infection, amputation, and death.",
        s_body))

    acs_steps = [
        ("Injury / increasing compartment pressure detected",    HexColor('#8B3A1F')),
        ("Is diagnosis confirmed clinically? (ICP measurement if unconscious/uncertain)", HexColor('#5C7A2E')),
        ("Pressure ≥ 30 mmHg OR within 30 mmHg of diastolic BP → Emergency FASCIOTOMY", C_FLOW_BOX),
        ("Lower limb: medial incision (decompresses superficial + deep posterior) + lateral incision (peroneal + anterior compartments)", C_FLOW_BOX),
        ("If muscle bulges out → pressure adequately released",   C_FLOW_BOX),
        ("Leave wound open → delayed closure when swelling resolves", HexColor('#5A1A00')),
    ]
    story.append(KeepTogether([FlowChart(acs_steps, box_h=26, gap=10)]))
    story.append(Spacer(1,6))

    # Necrotising Fasciitis
    story.append(Paragraph("Necrotising Fasciitis (NF)", s_h2))
    story += term_entry("Necrotising fasciitis",
        "A rapidly progressing infection of the skin and fascia — called the 'flesh-eating "
        "infection'. High mortality: up to 26–40% even with treatment.")

    story.append(Paragraph("Signs and Symptoms (Summary box 3.6)", s_h3))
    nf_rows = [
        ("Unusual/severe pain", "Local"),
        ("Erythema, oedema, warmth", "Local"),
        ("Crepitus (crackling under skin = gas)", "Local — WARNING sign"),
        ("Blisters, bullae", "Local"),
        ("'Dishwater pus' / greyish drainage", "Local"),
        ("Fixed staining of skin", "Local"),
        ("Necrosis, gangrene", "Local — late"),
        ("Fever, tachycardia, tachypnoea", "Systemic"),
        ("Shock, coagulopathy, multiorgan failure", "Systemic — late"),
    ]
    story += make_table(["Sign/Symptom", "Category"], nf_rows, col_widths=[9*cm, 7.5*cm])

    story.append(Paragraph(
        "<b>Treatment:</b> Urgent IV antibiotics + radical surgical debridement. Second-look "
        "operations are often required. Common organisms: <i>Staphylococcus aureus, "
        "E. coli, Pseudomonas, Clostridium, Bacteroides</i>; Group A Streptococcus is frequent.",
        s_body))

    story += quick_summary([
        "Compartment syndrome and necrotising fasciitis are both surgical emergencies — delay causes permanent damage or death.",
        "Compartment syndrome: pain out of proportion + pain on passive stretch → emergency fasciotomy.",
        "Necrotising fasciitis: crepitus (gas under skin) + systemic sepsis + rapidly advancing infection → radical surgical debridement.",
    ])

    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 7: CHRONIC WOUNDS
    # ══════════════════════════════════════════════════════════════════════════
    story += section_banner("Section 7: Chronic Wounds")

    story.append(Paragraph("What Makes a Wound Chronic?", s_h2))
    story.append(Paragraph(
        "A chronic wound is one that <b>fails to progress through normal healing stages in a "
        "timely manner</b>. It is characterised by a prolonged inflammatory phase and persistent "
        "infection. Management involves debridement, infection control, and optimal dressings.",
        s_body))

    # Leg Ulcers
    story.append(Paragraph("Leg Ulcers", s_h2))
    story += term_entry("Leg ulcer", "A break in the skin below the knee that fails to heal — the most common chronic wound in developed countries.")
    story += term_entry("Marjolin's ulcer", "A squamous cell carcinoma (skin cancer) that develops in a chronic non-healing scar — must be biopsied if unresponsive to treatment.")

    story.append(Paragraph("Causes of Leg Ulcers (Summary box 3.7)", s_h3))
    ulcer_rows = [
        ("Vascular", "Venous (most common), arterial, or mixed"),
        ("Trauma", "Bites, self-inflicted, burns"),
        ("Infection", "Bacterial, fungal, mycobacterial, syphilis"),
        ("Metabolic", "Diabetes mellitus, gout, calciphylaxis"),
        ("Autoimmune", "Vasculitis, systemic sclerosis, rheumatoid arthritis"),
        ("Neoplastic", "Squamous cell carcinoma, basal cell carcinoma"),
    ]
    story += make_table(["Cause", "Examples"], ulcer_rows, col_widths=[4*cm, 12.5*cm])

    # Pressure ulcers
    story.append(Paragraph("Pressure Injuries (Pressure Ulcers)", s_h2))
    story += term_entry("Pressure injury",
        "Skin and tissue damage caused by sustained pressure over a bony prominence, or under "
        "a medical device. Largely preventable.")
    story.append(Paragraph(
        "<b>Common sites:</b> Ischium, sacrum, greater trochanter, heel, malleolus, occiput.",
        s_body))

    pressure_rows = [
        ("Stage 1", "Non-blanchable erythema (redness) of intact skin", "Skin intact"),
        ("Stage 2", "Partial-thickness skin loss with exposed dermis", "Open shallow wound"),
        ("Stage 3", "Full-thickness skin loss", "Deep wound, no bone/tendon visible"),
        ("Stage 4", "Full-thickness skin and tissue loss", "Bone/tendon/muscle exposed"),
        ("Unstageable", "Full-thickness loss covered by slough/eschar", "Depth unknown"),
        ("Deep Tissue", "Persistent non-blanchable, deep red/maroon/purple discolouration", "Often painful"),
    ]
    story += make_table(
        ["Stage", "Description", "Key Feature"],
        pressure_rows,
        col_widths=[3*cm, 8.5*cm, 5*cm]
    )

    story.append(Paragraph(
        "<b>Prevention</b> is paramount: use validated risk scores (Braden, Waterlow, Norton), "
        "reposition every 2–4 hours, use pressure-redistributing devices, optimise nutrition. "
        "Surgery is a last resort after all other measures have been tried.",
        s_body))

    story += quick_summary([
        "Chronic wounds are stuck in the inflammatory phase — treat the cause (infection, ischaemia, pressure) first.",
        "Venous disease is the most common cause of leg ulcers; always assess arterial circulation before applying compression.",
        "Pressure injuries are largely preventable with regular repositioning, skin assessment, and pressure-redistributing mattresses.",
    ])

    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # SECTION 8: SCAR MANAGEMENT
    # ══════════════════════════════════════════════════════════════════════════
    story += section_banner("Section 8: Scar Management")

    story.append(Paragraph("Principles", s_h2))
    story.append(Paragraph(
        "Scars are the inevitable result of adult wound healing (except in early fetal life). "
        "The immature scar is pink, hard, raised, and itchy. Over 1–2 years (sometimes longer) "
        "it matures: paler, softer, flatter, and less itchy. Tensile strength reaches ~80% of "
        "normal. Good surgical technique (tension-free closure, along relaxed skin tension lines, "
        "early debridement) is the best scar prevention.",
        s_body))

    story.append(Paragraph("Scar Treatments", s_h2))
    scar_tx_rows = [
        ("Silicone gel / sheeting", "First-line for hypertrophic scars; applied for months; mechanism unclear but well-evidenced"),
        ("Pressure / compression therapy", "Continuous compression reduces blood flow to scar; flattens it"),
        ("Intralesional corticosteroid injection", "Triamcinolone; reduces collagen production; repeat monthly"),
        ("5-FU (5-fluorouracil)", "Chemotherapy agent injected into keloid; reduces fibroblast activity"),
        ("Laser therapy (PDL, fractional CO2)", "Pulsed-dye laser (PDL) for vascular scars; fractional laser for texture/thickness"),
        ("Surgical excision", "Used for severe or resistant scars; ALWAYS combined with adjuvant treatment (silicone, steroids, radiotherapy) to prevent recurrence"),
        ("Cryotherapy", "Freezing the scar; used especially with intralesional steroids"),
        ("Massage therapy", "Softens scar; improves mobility"),
        ("Radiotherapy", "For recurrent keloids after excision"),
        ("Bleomycin, mitomycin C, imiquimod", "Alternative injectable/topical agents for resistant keloids"),
    ]
    story += make_table(
        ["Treatment", "How It Works / Notes"],
        scar_tx_rows,
        col_widths=[5.5*cm, 11*cm]
    )

    # Hypertrophic scar algorithm
    story.append(Paragraph("Hypertrophic Scar Management Algorithm (Fig 3.17)", s_h2))
    story.append(Paragraph(
        "The management strategy depends on scar appearance:",
        s_body))

    hyp_steps = [
        ("IMMATURE HYPERTROPHIC SCAR (red, slightly raised): Apply prevention algorithm — silicone gel or sheeting, hypoallergenic paper tape, or onion extract cream", HexColor('#8B3A1F')),
        ("If persists > 1 month → treat as LINEAR HYPERTROPHIC SCAR", C_FLOW_BOX),
        ("LINEAR HYPERTROPHIC (red/raised, itchy): Intralesional corticosteroid injection — repeat monthly", C_FLOW_BOX),
        ("If inadequate response: PDL or fractional laser therapy", C_FLOW_BOX),
        ("Severe scar: Pressure therapy → PDL or fractional laser", C_FLOW_SEC),
        ("WIDESPREAD BURN HYPERTROPHIC: Admit to specialty burn unit; silicone gel + sheeting + pressure garments + onion extract cream", C_FLOW_SEC),
        ("REFRACTORY: Surgical excision + postoperative silicone gel or sheeting", HexColor('#5A1A00')),
    ]
    story.append(KeepTogether([FlowChart(hyp_steps, box_h=32, gap=10)]))
    story.append(Spacer(1,6))

    # Keloid algorithm
    story.append(Paragraph("Keloid Scar Management Algorithm (Fig 3.18)", s_h2))
    keloid_left = [
        ("MINOR KELOID (red/raised)", HexColor('#8B3A1F')),
        ("Silicone gel/sheeting + intralesional corticosteroids", C_FLOW_BOX),
    ]
    keloid_right = [
        ("MAJOR HIGH-RISK KELOID (dark/raised)", HexColor('#5A1A00')),
        ("Intralesional corticosteroids → 5-FU + intralesional corticosteroids", C_FLOW_SEC),
    ]
    keloid_common = [
        ("Fractional or pulsed-dye laser therapy",               C_FLOW_BOX),
        ("Patient counselling on recurrence rate and expectations",C_FLOW_BOX),
        ("Surgical excision + adjuvant: silicone gel/sheeting OR intralesional steroids OR radiotherapy OR alternative therapies (bleomycin, mitomycin C, imiquimod)", HexColor('#5A1A00')),
    ]
    story.append(KeepTogether([
        TwoColFlowChart(
            keloid_left, keloid_right, keloid_common,
            left_title="Minor Keloid", right_title="Major Keloid"
        )
    ]))
    story.append(Spacer(1,6))

    # Contractures
    story.append(Paragraph("Scar Contractures", s_h2))
    story += term_entry("Contracture",
        "A scar that tightens and shortens over time — can severely restrict joint movement, "
        "cause deformity, and impair function.")
    story += term_entry("Z-plasty",
        "A surgical technique that rearranges skin flaps in a Z-pattern to lengthen and "
        "reorient a scar — breaks up a straight contracture band.")
    story.append(Paragraph(
        "Contracture release involves replacing scar tissue with healthy pliable tissue. "
        "Flaps (local or free) are preferred over skin grafts because grafts can re-contract "
        "during healing. Full-thickness grafts are better than split-thickness grafts for "
        "contractures as they contract less.",
        s_body))

    story += quick_summary([
        "Scar maturation takes 1–2 years; early treatment with silicone and pressure gives the best results.",
        "Keloids require combined treatment (surgery + adjuvant therapy) to prevent recurrence — excision alone has very high recurrence rates.",
        "Scar contractures need flap coverage (not just grafts) to restore full movement.",
    ])

    story.append(PageBreak())

    # ══════════════════════════════════════════════════════════════════════════
    # FINAL SUMMARY PAGE
    # ══════════════════════════════════════════════════════════════════════════
    story += section_banner("Chapter 3 — Master Summary at a Glance")

    master_rows = [
        ("Normal wound healing", "4 phases: Haemostasis → Inflammation → Proliferation → Remodelling; overlapping; driven by platelets, neutrophils, macrophages, fibroblasts"),
        ("Haemostasis", "Platelet plug + fibrin clot; activated by tissue factor; coagulation cascade (intrinsic + extrinsic → common pathway → thrombin → fibrin)"),
        ("Inflammation (Days 1–3)", "Neutrophils (Days 1–2) → clean bacteria; Macrophages (Days 2–3) → debride + direct healing; Signs: rubor, tumor, calor, dolor"),
        ("Proliferation (Day 3 – Week 4)", "Fibroblasts produce collagen + ECM; angiogenesis; re-epithelialisation; granulation tissue; myofibroblast contraction"),
        ("Remodelling (Week 2 – Year+)", "Type III → Type I collagen; max tensile strength at 12 weeks = ~80% of normal"),
        ("Abnormal healing", "Hypertrophic (within wound, can regress) vs Keloid (beyond wound, never regresses); chronic wounds = stuck in inflammation"),
        ("Wound classification", "CDC Classes I–IV (clean to dirty); multiple dimensions: cause, depth, contamination, complexity, chronicity"),
        ("Management principles", "Assess → Prepare (antibiotics, tetanus, irrigation) → Debride → Repair → Close (reconstructive ladder) → Follow-up"),
        ("Debridement types", "Surgical / Mechanical / Autolytic / Enzymatic / Biological (maggots)"),
        ("Closure options", "Primary → Secondary → Delayed primary → NPWT → Skin graft (STSG/FTSG) → Dermal matrix → Local flap → Free flap"),
        ("Scar management", "Silicone first-line; pressure therapy; intralesional steroids; laser; surgery (always with adjuvant for keloids)"),
        ("Acute wound emergencies", "Compartment syndrome (fasciotomy) and Necrotising fasciitis (radical debridement) — both are surgical emergencies"),
        ("Chronic wounds", "Leg ulcers (venous most common); Pressure injuries (Stages 1–4 + unstageable + deep tissue); prevention > treatment"),
    ]
    story += make_table(
        ["Topic", "Key Points"],
        master_rows,
        col_widths=[5.5*cm, 11*cm]
    )

    story.append(Spacer(1, 1*cm))
    story.append(HRFlowable(width=INNER_W, color=C_SALMON, thickness=1.5))
    story.append(Spacer(1, 0.3*cm))
    story.append(Paragraph(
        "End of Chapter 3 Study Guide",
        make_style('End', fontSize=10, textColor=C_SALMON,
                   fontName='Helvetica-Oblique', alignment=TA_CENTER)
    ))

    return story

# ─── Build PDF ────────────────────────────────────────────────────────────────
OUTPUT = '/home/daytona/workspace/wound-healing/Wound_Healing_Chapter3.pdf'

doc = SimpleDocTemplate(
    OUTPUT,
    pagesize=A4,
    leftMargin=MARGIN, rightMargin=MARGIN,
    topMargin=2.2*cm, bottomMargin=2.2*cm,
    title='Chapter 3: Wound Healing and Tissue Repair',
    author='Study Guide'
)

story = build_content()
doc.build(story, onFirstPage=on_page, onLaterPages=on_page)
print(f"PDF created: {OUTPUT}")

Successfully replaced 1 instance(s) of the string in '/home/daytona/workspace/wound-healing/generate_pdf.py'