from reportlab.lib.pagesizes import A4
from reportlab.lib import colors
from reportlab.lib.units import cm, mm
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_JUSTIFY
from reportlab.platypus import (
    SimpleDocTemplate, Paragraph, Spacer, Image, Table, TableStyle,
    PageBreak, HRFlowable, KeepTogether
)
from reportlab.platypus.flowables import Flowable
from reportlab.graphics.shapes import Drawing, Rect, String, Line, Polygon, Arrow
from reportlab.graphics import renderPDF
from reportlab.graphics.charts.barcharts import VerticalBarChart
import os

# ── Page setup ──────────────────────────────────────────────────────────────
doc = SimpleDocTemplate(
    "/tmp/workspace/sbt-pdf/Small_Bowel_Transplantation.pdf",
    pagesize=A4,
    leftMargin=2*cm, rightMargin=2*cm,
    topMargin=2.5*cm, bottomMargin=2.5*cm,
    title="Small Bowel Transplantation",
    author="Medical Library – Orris"
)

W, H = A4
CONTENT_W = W - 4*cm

# ── Colour palette ────────────────────────────────────────────────────────
DARK_BLUE   = colors.HexColor("#1A3A5C")
MID_BLUE    = colors.HexColor("#2E6DA4")
LIGHT_BLUE  = colors.HexColor("#D6E8F7")
ACCENT      = colors.HexColor("#E8523A")
GREEN       = colors.HexColor("#2E8B57")
LIGHT_GREEN = colors.HexColor("#D4EDDA")
ORANGE      = colors.HexColor("#E07B39")
LIGHT_ORANGE= colors.HexColor("#FFF3E0")
YELLOW_BG   = colors.HexColor("#FFFDE7")
GREY_BG     = colors.HexColor("#F5F5F5")
WHITE       = colors.white

# ── Styles ─────────────────────────────────────────────────────────────────
styles = getSampleStyleSheet()

title_style = ParagraphStyle("Title",
    fontName="Helvetica-Bold", fontSize=26, leading=32,
    textColor=WHITE, alignment=TA_CENTER, spaceAfter=4)

subtitle_style = ParagraphStyle("Subtitle",
    fontName="Helvetica", fontSize=13, leading=18,
    textColor=colors.HexColor("#B8D4F0"), alignment=TA_CENTER, spaceAfter=8)

h1 = ParagraphStyle("H1",
    fontName="Helvetica-Bold", fontSize=16, leading=20,
    textColor=WHITE, spaceBefore=14, spaceAfter=6,
    backColor=DARK_BLUE, leftIndent=-4, rightIndent=-4,
    borderPad=6)

h2 = ParagraphStyle("H2",
    fontName="Helvetica-Bold", fontSize=13, leading=17,
    textColor=MID_BLUE, spaceBefore=10, spaceAfter=4,
    borderPadding=(0,0,2,0))

h3 = ParagraphStyle("H3",
    fontName="Helvetica-Bold", fontSize=11, leading=14,
    textColor=DARK_BLUE, spaceBefore=6, spaceAfter=3)

body = ParagraphStyle("Body",
    fontName="Helvetica", fontSize=10, leading=14,
    textColor=colors.HexColor("#222222"), spaceAfter=5,
    alignment=TA_JUSTIFY)

bullet = ParagraphStyle("Bullet",
    fontName="Helvetica", fontSize=10, leading=13,
    textColor=colors.HexColor("#333333"),
    leftIndent=14, bulletIndent=4, spaceAfter=2)

caption = ParagraphStyle("Caption",
    fontName="Helvetica-Oblique", fontSize=8.5, leading=11,
    textColor=colors.HexColor("#555555"), alignment=TA_CENTER, spaceAfter=6)

box_title = ParagraphStyle("BoxTitle",
    fontName="Helvetica-Bold", fontSize=10, leading=13,
    textColor=DARK_BLUE)

box_body = ParagraphStyle("BoxBody",
    fontName="Helvetica", fontSize=9.5, leading=13,
    textColor=colors.HexColor("#333333"), leftIndent=8, spaceAfter=2)

# ── Helper: section header bar ─────────────────────────────────────────────
def section_header(text):
    tbl = Table([[Paragraph(text, h1)]], colWidths=[CONTENT_W])
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), DARK_BLUE),
        ("BOTTOMPADDING",(0,0),(-1,-1), 6),
        ("TOPPADDING",   (0,0),(-1,-1), 6),
        ("LEFTPADDING",  (0,0),(-1,-1), 10),
        ("RIGHTPADDING", (0,0),(-1,-1), 10),
        ("ROUNDEDCORNERS", [4]),
    ]))
    return tbl

def info_box(title, items, bg=LIGHT_BLUE, title_color=DARK_BLUE):
    content = [Paragraph(title, ParagraphStyle("BT", fontName="Helvetica-Bold",
                fontSize=10, textColor=title_color, spaceAfter=4))]
    for item in items:
        content.append(Paragraph(f"• {item}", box_body))
    tbl = Table([[content]], colWidths=[CONTENT_W])
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), bg),
        ("BOX", (0,0), (-1,-1), 1, title_color),
        ("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 tbl

# ── Flowchart helper ───────────────────────────────────────────────────────
class FlowchartBox(Flowable):
    """Draws a simple vertical flowchart with boxes and arrows."""
    def __init__(self, steps, width=None, step_height=28, gap=18, title=""):
        Flowable.__init__(self)
        self.steps = steps   # list of (text, bg_color, text_color)
        self.width = width or CONTENT_W
        self.step_height = step_height
        self.gap = gap
        self.title = title
        self.n = len(steps)
        self.height = self.n * step_height + (self.n-1)*gap + (30 if title else 0) + 10

    def draw(self):
        c = self.canv
        y = self.height - 5
        bw = self.width

        if self.title:
            c.setFont("Helvetica-Bold", 11)
            c.setFillColor(DARK_BLUE)
            c.drawCentredString(bw/2, y - 14, self.title)
            y -= 30

        for i, (text, bg, fg) in enumerate(self.steps):
            box_y = y - self.step_height
            # Drop shadow
            c.setFillColor(colors.HexColor("#CCCCCC"))
            c.roundRect(3, box_y - 3, bw - 6, self.step_height, 6, fill=1, stroke=0)
            # Box
            c.setFillColor(bg)
            c.setStrokeColor(DARK_BLUE)
            c.setLineWidth(0.8)
            c.roundRect(0, box_y, bw - 6, self.step_height, 6, fill=1, stroke=1)
            # Text
            c.setFillColor(fg)
            c.setFont("Helvetica-Bold" if i == 0 else "Helvetica", 9)
            # Wrap text manually
            words = text.split()
            lines, cur = [], []
            for w in words:
                test = " ".join(cur + [w])
                if c.stringWidth(test, "Helvetica", 9) < bw - 30:
                    cur.append(w)
                else:
                    lines.append(" ".join(cur))
                    cur = [w]
            if cur:
                lines.append(" ".join(cur))
            total_h = len(lines) * 11
            start_y = box_y + self.step_height/2 + total_h/2 - 3
            for li, line in enumerate(lines):
                c.drawCentredString((bw-6)/2, start_y - li*11, line)

            y = box_y - 2
            # Arrow to next
            if i < self.n - 1:
                c.setStrokeColor(MID_BLUE)
                c.setFillColor(MID_BLUE)
                c.setLineWidth(1.5)
                ax = (bw-6)/2
                ay_top = y
                ay_bot = y - self.gap + 6
                c.line(ax, ay_top, ax, ay_bot)
                # Arrowhead
                c.setFillColor(MID_BLUE)
                c.polygon([ax-5, ay_bot+7, ax+5, ay_bot+7, ax, ay_bot], fill=1, stroke=0)
                y -= self.gap

    def wrap(self, *args):
        return self.width, self.height


class DecisionFlowchart(Flowable):
    """Decision tree / branching flowchart."""
    def __init__(self, width=None):
        Flowable.__init__(self)
        self.width = width or CONTENT_W
        self.height = 310

    def draw(self):
        c = self.canv
        W = self.width
        cx = W / 2

        def box(x, y, w, h, text, bg, fg=WHITE, bold=True):
            c.setFillColor(colors.HexColor("#BBBBBB"))
            c.roundRect(x+2, y-2, w, h, 5, fill=1, stroke=0)
            c.setFillColor(bg)
            c.setStrokeColor(DARK_BLUE)
            c.setLineWidth(0.8)
            c.roundRect(x, y, w, h, 5, fill=1, stroke=1)
            c.setFillColor(fg)
            fn = "Helvetica-Bold" if bold else "Helvetica"
            c.setFont(fn, 8.5)
            words = text.split("\n")
            tot = len(words)*10
            sy = y + h/2 + tot/2 - 8
            for i, line in enumerate(words):
                c.drawCentredString(x + w/2, sy - i*10, line)

        def diamond(x, y, w, h, text, bg=ORANGE):
            pts = [x+w/2, y+h, x+w, y+h/2, x+w/2, y, x, y+h/2]
            c.setFillColor(bg)
            c.setStrokeColor(DARK_BLUE)
            c.setLineWidth(0.8)
            c.polygon(pts, fill=1, stroke=1)
            c.setFillColor(WHITE)
            c.setFont("Helvetica-Bold", 8)
            c.drawCentredString(x+w/2, y+h/2-4, text)

        def arrow(x1, y1, x2, y2, label=""):
            c.setStrokeColor(MID_BLUE)
            c.setLineWidth(1.2)
            c.line(x1, y1, x2, y2)
            dx, dy = x2-x1, y2-y1
            import math
            l = math.sqrt(dx*dx+dy*dy)
            if l > 0:
                ux, uy = dx/l, dy/l
                ax = x2 - 6*ux; ay = y2 - 6*uy
                c.setFillColor(MID_BLUE)
                perp_x, perp_y = -uy, ux
                c.polygon([x2, y2, ax+4*perp_x, ay+4*perp_y, ax-4*perp_x, ay-4*perp_y], fill=1, stroke=0)
            if label:
                mx, my = (x1+x2)/2, (y1+y2)/2
                c.setFillColor(colors.HexColor("#333333"))
                c.setFont("Helvetica", 7.5)
                c.drawCentredString(mx+8, my+3, label)

        BW = 140; BH = 28; DW = 110; DH = 36

        # START
        box(cx-70, 278, 140, 28, "Intestinal Failure", DARK_BLUE)
        arrow(cx, 278, cx, 258)

        # Diamond 1
        diamond(cx-DW/2, 222, DW, DH, "PN Dependent?", ORANGE)
        arrow(cx, 222, cx, 198)

        # Yes continue
        box(cx-70, 170, 140, 26, "Assess PN Complications", MID_BLUE)
        arrow(cx, 170, cx, 148)

        # Diamond 2
        diamond(cx-55, 108, 110, 38, "Life-threatening\nComplications?", colors.HexColor("#C0392B"))
        # No - right
        arrow(cx+55, 127, cx+110, 127, "No")
        box(cx+110, 113, 110, 28, "Continue PN\n+ Rehabilitation", GREEN, WHITE, False)

        # Yes - down
        arrow(cx, 108, cx, 86)

        box(cx-70, 60, 140, 26, "List for Transplant", DARK_BLUE)
        arrow(cx, 60, cx, 38)

        box(cx-70, 12, 140, 26, "Transplant Type Selection", MID_BLUE)

        # No from diamond 1 (right)
        arrow(cx+DW/2, 240, cx+140, 240, "No")
        box(cx+140, 226, 105, 28, "Medical\nManagement", GREEN, WHITE, False)

        # Title
        c.setFont("Helvetica-Bold", 10)
        c.setFillColor(DARK_BLUE)
        c.drawCentredString(W/2, self.height-12, "Decision Flowchart: Pathway to Small Bowel Transplantation")

    def wrap(self, *args):
        return self.width, self.height


# ── Cover page ─────────────────────────────────────────────────────────────
def cover_page(story):
    # Blue header block
    cover_tbl = Table(
        [[Paragraph("SMALL BOWEL\nTRANSPLANTATION", title_style)],
         [Paragraph("Comprehensive Clinical Reference with Illustrated Diagrams & Flowcharts", subtitle_style)],
         [Paragraph("Sources: Sabiston Textbook of Surgery (22e) · Bailey & Love's Surgery (28e)\n"
                    "Yamada's Gastroenterology (7e) · Fischer's Mastery of Surgery (8e)", subtitle_style)]],
        colWidths=[CONTENT_W]
    )
    cover_tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), DARK_BLUE),
        ("TOPPADDING", (0,0), (-1,-1), 24),
        ("BOTTOMPADDING", (0,-1), (-1,-1), 24),
        ("LEFTPADDING", (0,0), (-1,-1), 20),
        ("RIGHTPADDING", (0,0), (-1,-1), 20),
    ]))
    story.append(cover_tbl)
    story.append(Spacer(1, 0.5*cm))

    # Quick facts boxes
    facts = [
        ("Least Common Solid Organ Transplant",
         "~82 performed in the USA in 2022 (UNOS). Peak ~200/year in 2007. "
         "Only ~3,400 total procedures since 1985."),
        ("1-Year Patient Survival",
         "~76% (ITR registry). Up from 25% in early 1990s cyclosporine era. "
         "Improved markedly after tacrolimus introduction (1994)."),
        ("Most Common Indication",
         "Short bowel syndrome (SBS) ~63–64% in both pediatric and adult recipients. "
         "Pediatric: gastroschisis, volvulus, NEC. Adults: ischaemia, Crohn disease."),
    ]
    cols = []
    for title, text in facts:
        cell = [
            Paragraph(title, ParagraphStyle("FT", fontName="Helvetica-Bold", fontSize=10,
                      textColor=DARK_BLUE, spaceAfter=4)),
            Paragraph(text, ParagraphStyle("FB", fontName="Helvetica", fontSize=9.5,
                      textColor=colors.HexColor("#333333")))
        ]
        cols.append(cell)
    ft = Table([cols], colWidths=[CONTENT_W/3 - 3]*3, rowHeights=None)
    ft.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (0,0), LIGHT_BLUE),
        ("BACKGROUND", (1,0), (1,0), LIGHT_GREEN),
        ("BACKGROUND", (2,0), (2,0), LIGHT_ORANGE),
        ("BOX", (0,0), (0,0), 1, MID_BLUE),
        ("BOX", (1,0), (1,0), 1, GREEN),
        ("BOX", (2,0), (2,0), 1, ORANGE),
        ("TOPPADDING", (0,0), (-1,-1), 8),
        ("BOTTOMPADDING", (0,0), (-1,-1), 8),
        ("LEFTPADDING", (0,0), (-1,-1), 8),
        ("RIGHTPADDING", (0,0), (-1,-1), 8),
        ("VALIGN", (0,0), (-1,-1), "TOP"),
        ("COLPADDING", (0,0), (-1,-1), 6),
    ]))
    story.append(ft)
    story.append(Spacer(1, 0.4*cm))

    # Trend image
    if os.path.exists("/tmp/workspace/sbt-pdf/trend.png"):
        img = Image("/tmp/workspace/sbt-pdf/trend.png", width=12*cm, height=4*cm)
        story.append(img)
        story.append(Paragraph(
            "Fig 1. Number of intestinal transplants performed annually in the United States, 1990–2023. "
            "(Source: UNOS OPTN Metrics / Sabiston Textbook of Surgery, 22e)",
            caption))

    story.append(PageBreak())


# ── Section 1: Background & History ───────────────────────────────────────
def section_history(story):
    story.append(section_header("1.  Background & Historical Overview"))
    story.append(Spacer(1, 0.2*cm))
    story.append(Paragraph(
        "The small bowel (intestine) is the most immunogenic solid organ due to its large lymphoid mass. "
        "This made early transplantation attempts uniformly fatal. The history of intestinal transplantation "
        "spans decades of incremental progress:", body))

    timeline = [
        ["1960s", "Starzl performs first experimental SBT in dogs; all died within 9 days. "
                  "Clinical attempts in humans fail — no patient achieves enteral autonomy."],
        ["Late 1960s", "PN introduced. Clinical SBT abandoned due to poor outcomes and the availability "
                       "of a safer alternative."],
        ["1983", "Cyclosporine enters clinical use. Renewed interest in SBT alongside growing awareness "
                 "of PN-related morbidity."],
        ["1988", "First successful SBT by Deltz (living donor) achieving enteral autonomy. "
                 "Same year: Grant et al. perform first cadaveric liver–intestine transplant with >1-year survival."],
        ["1990–94", "1-year survival ~25% with cyclosporine. Tacrolimus introduced (1994) — major "
                    "improvement in rejection control."],
        ["2007", "Peak activity: ~200 intestinal transplants/year in the USA."],
        ["2010s–present", "Volume stabilises at ~80–150/year. Improvement in pediatric intestinal "
                          "rehabilitation reduces need in children. Adults now dominate the waitlist."],
    ]
    tbl = Table(
        [[Paragraph(r[0], ParagraphStyle("Year", fontName="Helvetica-Bold", fontSize=9.5,
                    textColor=DARK_BLUE)),
          Paragraph(r[1], ParagraphStyle("Evt", fontName="Helvetica", fontSize=9.5, leading=13))]
         for r in timeline],
        colWidths=[2.8*cm, CONTENT_W - 2.8*cm]
    )
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (0,-1), LIGHT_BLUE),
        ("BACKGROUND", (1,0), (1,-1), GREY_BG),
        ("ROWBACKGROUNDS", (1,0), (1,-1), [WHITE, GREY_BG]),
        ("GRID", (0,0), (-1,-1), 0.4, colors.HexColor("#CCCCCC")),
        ("TOPPADDING", (0,0), (-1,-1), 5),
        ("BOTTOMPADDING", (0,0), (-1,-1), 5),
        ("LEFTPADDING", (0,0), (-1,-1), 8),
        ("VALIGN", (0,0), (-1,-1), "TOP"),
    ]))
    story.append(tbl)
    story.append(Spacer(1, 0.3*cm))


# ── Section 2: Indications ─────────────────────────────────────────────────
def section_indications(story):
    story.append(section_header("2.  Indications for Small Bowel Transplantation"))
    story.append(Spacer(1, 0.2*cm))
    story.append(Paragraph(
        "<b>PN dependence alone is NOT an indication.</b> Transplant is reserved for patients with "
        "irreversible intestinal failure AND at least one life-threatening PN complication "
        "(Sixth International SBT Symposium 2001; updated 2015 at XIV Symposium):", body))

    indications = [
        ("Advanced / Progressive IFALD",
         "Intestinal failure-associated liver disease progressing despite optimised management. "
         "Combined liver–intestine transplant is considered."),
        ("Loss of Central Venous Access",
         "Multiple central vein thromboses leaving <2 usable central venous sites."),
        ("Recurrent Life-Threatening Sepsis",
         "≥2 ICU admissions for catheter-related bloodstream infections."),
        ("Invasive Intraabdominal Desmoids",
         "Unresectable desmoid tumours rendering enteral feeding impossible."),
        ("Acute Diffuse Intestinal Infarction with Hepatic Failure",
         "Rare emergency indication — acute loss of entire gut with concomitant liver failure."),
        ("First Transplant Failure",
         "Retransplantation following graft loss."),
        ("High Morbidity / Poor QoL",
         "Frequent hospitalisation, severe electrolyte disturbances — not universally accepted."),
        ("Diffuse Portomesenteric Thrombosis (Yerdel grade 4)",
         "Multivisceral transplant replaces entire portal system; only definitive treatment."),
    ]

    rows = []
    for i, (ind, detail) in enumerate(indications):
        rows.append([
            Paragraph(f"{i+1}. {ind}", ParagraphStyle("IndT", fontName="Helvetica-Bold",
                      fontSize=9.5, textColor=DARK_BLUE)),
            Paragraph(detail, ParagraphStyle("IndD", fontName="Helvetica", fontSize=9.5, leading=13))
        ])
    tbl = Table(rows, colWidths=[5.2*cm, CONTENT_W-5.2*cm])
    tbl.setStyle(TableStyle([
        ("ROWBACKGROUNDS", (0,0), (-1,-1), [LIGHT_BLUE, WHITE]),
        ("GRID", (0,0), (-1,-1), 0.4, colors.HexColor("#BBBBBB")),
        ("TOPPADDING", (0,0), (-1,-1), 6),
        ("BOTTOMPADDING", (0,0), (-1,-1), 6),
        ("LEFTPADDING", (0,0), (-1,-1), 8),
        ("VALIGN", (0,0), (-1,-1), "TOP"),
        ("BOX", (0,0), (-1,-1), 1, MID_BLUE),
    ]))
    story.append(tbl)
    story.append(Spacer(1, 0.3*cm))

    # Underlying conditions table
    story.append(Paragraph("Underlying Conditions Necessitating Intestinal Transplantation (ITR Data):", h2))
    story.append(Spacer(1, 0.15*cm))
    cond_data = [
        [Paragraph("<b>Pediatric Condition</b>", box_title),
         Paragraph("<b>%</b>", box_title),
         Paragraph("<b>Adult Condition</b>", box_title),
         Paragraph("<b>%</b>", box_title)],
        ["Short bowel syndrome", "63%", "Short bowel syndrome", "64%"],
        ["Gastroschisis", "22%", "Ischaemia", "11%"],
        ["Volvulus", "16%", "Crohn disease", "10%"],
        ["Necrotising enterocolitis", "14%", "Volvulus", "7%"],
        ["Motility disorders", "18%", "Motility disorders", "11%"],
        ["Atresia", "4%", "Trauma", "7%"],
        ["Malabsorption syndromes", "8%", "Tumour", "13%"],
        ["Retransplantation", "8%", "Retransplantation", "7%"],
    ]
    cw = CONTENT_W / 4
    ctbl = Table(cond_data, colWidths=[cw*1.6, cw*0.4, cw*1.6, cw*0.4])
    ctbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,0), DARK_BLUE),
        ("TEXTCOLOR", (0,0), (-1,0), WHITE),
        ("FONTNAME", (0,0), (-1,0), "Helvetica-Bold"),
        ("FONTSIZE", (0,0), (-1,-1), 9),
        ("ROWBACKGROUNDS", (0,1), (-1,-1), [WHITE, LIGHT_BLUE]),
        ("GRID", (0,0), (-1,-1), 0.4, colors.HexColor("#CCCCCC")),
        ("TOPPADDING", (0,0), (-1,-1), 4),
        ("BOTTOMPADDING", (0,0), (-1,-1), 4),
        ("LEFTPADDING", (0,0), (-1,-1), 7),
        ("BOX", (0,0), (-1,-1), 1, MID_BLUE),
        ("ALIGN", (1,0), (1,-1), "CENTER"),
        ("ALIGN", (3,0), (3,-1), "CENTER"),
    ]))
    story.append(ctbl)
    story.append(Spacer(1, 0.3*cm))

    # Decision flowchart
    story.append(Paragraph("Decision Pathway – From Intestinal Failure to Transplant:", h2))
    story.append(Spacer(1, 0.2*cm))
    story.append(DecisionFlowchart(width=CONTENT_W))
    story.append(Spacer(1, 0.2*cm))


# ── Section 3: Types of Transplant ────────────────────────────────────────
def section_types(story):
    story.append(PageBreak())
    story.append(section_header("3.  Types of Intestinal / Multivisceral Transplant"))
    story.append(Spacer(1, 0.2*cm))
    story.append(Paragraph(
        "Intestinal transplantation encompasses several 'cluster' configurations depending on which "
        "organs are included. Selection depends on hepatic function, portal vein patency, "
        "intraabdominal anatomy, and intraoperative findings.", body))

    types_data = [
        [Paragraph("<b>Transplant Type</b>", box_title),
         Paragraph("<b>Organs Included</b>", box_title),
         Paragraph("<b>Extent of Resection</b>", box_title),
         Paragraph("<b>Proximal Anastomosis</b>", box_title)],
        ["Isolated Small Intestine (+/- colon)",
         "Small intestine ± colon ± pancreas",
         "Small intestine + part of colon",
         "Duodenum or proximal jejunum"],
        ["Liver + Small Bowel",
         "Liver, pancreas, small intestine, colon",
         "Liver, small intestine + part of colon",
         "Duodenum or proximal jejunum"],
        ["Modified Multivisceral",
         "Stomach, pancreas, small intestine, colon",
         "Stomach, pancreas, spleen, small intestine, colon",
         "Proximal stomach or oesophagus"],
        ["Full Multivisceral",
         "Liver, stomach, pancreas, small intestine, colon",
         "Liver, stomach, pancreas, spleen, small intestine, colon",
         "Proximal stomach or oesophagus"],
    ]
    cws = [3.5*cm, 4.2*cm, 4.5*cm, 3.8*cm]
    ttbl = Table(types_data, colWidths=cws)
    ttbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,0), DARK_BLUE),
        ("TEXTCOLOR", (0,0), (-1,0), WHITE),
        ("FONTNAME", (0,0), (-1,0), "Helvetica-Bold"),
        ("FONTSIZE", (0,0), (-1,-1), 9),
        ("ROWBACKGROUNDS", (0,1), (-1,-1), [WHITE, LIGHT_BLUE]),
        ("GRID", (0,0), (-1,-1), 0.4, colors.HexColor("#CCCCCC")),
        ("TOPPADDING", (0,0), (-1,-1), 5),
        ("BOTTOMPADDING", (0,0), (-1,-1), 5),
        ("LEFTPADDING", (0,0), (-1,-1), 6),
        ("BOX", (0,0), (-1,-1), 1, MID_BLUE),
        ("VALIGN", (0,0), (-1,-1), "TOP"),
    ]))
    story.append(ttbl)
    story.append(Spacer(1, 0.4*cm))

    # Images in 2x2 grid
    img_data = []
    imgs_info = [
        ("full_multivisceral.png", "Full Multivisceral Transplant\n(Liver, stomach, pancreas, SB, colon)"),
        ("liver_small_bowel.png", "Liver + Small Bowel Transplant\n(Liver, pancreas, SB, colon)"),
        ("modified_multivisceral.png", "Modified Multivisceral Transplant\n(No liver: stomach, pancreas, SB, colon)"),
        ("sb_pancreas_colon.png", "Small Bowel, Pancreas & Colon Transplant\n(SMA, ileocolic, middle colic arteries shown)"),
    ]
    cell_w = CONTENT_W / 2 - 0.3*cm
    row1, row2 = [], []
    for i, (fname, cap) in enumerate(imgs_info):
        fp = f"/tmp/workspace/sbt-pdf/{fname}"
        if os.path.exists(fp):
            img = Image(fp, width=cell_w - 0.4*cm, height=7*cm, kind="proportional")
        else:
            img = Paragraph("[Image not found]", caption)
        cell = [img, Paragraph(cap, caption)]
        if i < 2:
            row1.append(cell)
        else:
            row2.append(cell)
    img_tbl = Table([row1, row2], colWidths=[cell_w, cell_w])
    img_tbl.setStyle(TableStyle([
        ("TOPPADDING", (0,0), (-1,-1), 4),
        ("BOTTOMPADDING", (0,0), (-1,-1), 4),
        ("LEFTPADDING", (0,0), (-1,-1), 4),
        ("RIGHTPADDING", (0,0), (-1,-1), 4),
        ("BOX", (0,0), (-1,-1), 0.5, colors.HexColor("#BBBBBB")),
        ("GRID", (0,0), (-1,-1), 0.5, colors.HexColor("#DDDDDD")),
        ("ALIGN", (0,0), (-1,-1), "CENTER"),
        ("VALIGN", (0,0), (-1,-1), "TOP"),
    ]))
    story.append(img_tbl)
    story.append(Paragraph(
        "Figure 2. Types of intestinal/multivisceral transplant — Bailey & Love's Short Practice of Surgery, 28th ed.", caption))
    story.append(Spacer(1, 0.3*cm))


# ── Section 4: Assessment ──────────────────────────────────────────────────
def section_assessment(story):
    story.append(PageBreak())
    story.append(section_header("4.  Pre-Transplant Assessment"))
    story.append(Spacer(1, 0.2*cm))
    story.append(Paragraph(
        "Assessment requires a dedicated multidisciplinary team (MDT). Key components include:", body))

    mdt = [
        ["Transplant Surgeons", "Transplant Anaesthetists", "Intestinal Failure Physicians"],
        ["Hepatologist", "Psychiatrist / Psychologist", "Radiologist"],
        ["Infectious Disease Physician", "Transplant Specialist Nurses", "Dietician"],
    ]
    mtbl = Table(mdt, colWidths=[CONTENT_W/3]*3)
    mtbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), LIGHT_BLUE),
        ("TEXTCOLOR", (0,0), (-1,-1), DARK_BLUE),
        ("FONTNAME", (0,0), (-1,-1), "Helvetica-Bold"),
        ("FONTSIZE", (0,0), (-1,-1), 9),
        ("ALIGN", (0,0), (-1,-1), "CENTER"),
        ("GRID", (0,0), (-1,-1), 0.5, colors.HexColor("#AAAAAA")),
        ("TOPPADDING", (0,0), (-1,-1), 6),
        ("BOTTOMPADDING", (0,0), (-1,-1), 6),
        ("BOX", (0,0), (-1,-1), 1, MID_BLUE),
    ]))
    story.append(mtbl)
    story.append(Spacer(1, 0.3*cm))

    assess_steps = [
        (DARK_BLUE, WHITE, "1. Venous Access Assessment", "Detailed venous mapping essential. "
         "Patients with prolonged PN or ultra-short gut at high risk for IFALD. "
         "Central venous patency determines feasibility."),
        (MID_BLUE, WHITE, "2. Liver Biopsy", "Patients at risk for IFALD require liver biopsy "
         "to stage fibrosis. Significant fibrosis may mandate combined liver–intestine transplant."),
        (GREEN, WHITE, "3. Cardiovascular & Respiratory Assessment",
         "Full cardiac workup (ECG, echo). Pulmonary function tests. "
         "Correct any reversible comorbidities."),
        (ORANGE, WHITE, "4. GI Endoscopy",
         "Upper and lower GI endoscopies may be required to assess residual gut anatomy."),
        (colors.HexColor("#7B2D8B"), WHITE, "5. Cross-Sectional Abdominal Imaging",
         "CT/MRI abdomen — essential for operative planning. "
         "Assess abdominal domain, vascular anatomy, and portal system."),
        (colors.HexColor("#C0392B"), WHITE, "6. Renal Assessment",
         "Significant renal impairment may necessitate inclusion of a kidney at transplant."),
        (DARK_BLUE, WHITE, "7. Anaesthetic & Psychiatric Assessment",
         "Anaesthetic risk stratification. Psychosocial evaluation mandatory. Dietetic review."),
    ]

    rows = []
    for bg, fg, title, detail in assess_steps:
        rows.append([
            Paragraph(title, ParagraphStyle("AT", fontName="Helvetica-Bold", fontSize=9.5,
                      textColor=fg, backColor=bg)),
            Paragraph(detail, ParagraphStyle("AD", fontName="Helvetica", fontSize=9.5, leading=13))
        ])
    atbl = Table(rows, colWidths=[5.5*cm, CONTENT_W - 5.5*cm])
    atbl.setStyle(TableStyle([
        ("ROWBACKGROUNDS", (1,0), (1,-1), [WHITE, GREY_BG]),
        ("GRID", (0,0), (-1,-1), 0.4, colors.HexColor("#CCCCCC")),
        ("TOPPADDING", (0,0), (-1,-1), 5),
        ("BOTTOMPADDING", (0,0), (-1,-1), 5),
        ("LEFTPADDING", (0,0), (-1,-1), 8),
        ("VALIGN", (0,0), (-1,-1), "TOP"),
        ("BOX", (0,0), (-1,-1), 1, MID_BLUE),
    ]))
    story.append(atbl)
    story.append(Spacer(1, 0.3*cm))


# ── Section 5: Surgical Technique ─────────────────────────────────────────
def section_surgery(story):
    story.append(section_header("5.  Surgical Technique"))
    story.append(Spacer(1, 0.2*cm))

    steps = [
        (DARK_BLUE, WHITE,  "Donor Procurement",
         "Modified abdominal perfusion technique. Rapid infusion of cold preservation solution "
         "(University of Wisconsin or HTK). En bloc procurement of relevant organs. "
         "SMA with Carrel patch preserved."),
        (MID_BLUE, WHITE,   "Back-Table Preparation",
         "Arterial reconstruction (if needed) using donor iliac vessels. "
         "Lymphatic channels oversewn to prevent chylous ascites. "
         "Length and viability assessed."),
        (colors.HexColor("#1A7A5C"), WHITE, "Recipient Preparation",
         "Extensive enterectomy. Careful identification and preservation of vascular structures. "
         "Assessment of abdominal domain — loss of domain may require staged closure."),
        (colors.HexColor("#A0522D"), WHITE, "Vascular Anastomoses",
         "Arterial: donor SMA to recipient aorta (infrarenal or supracoeliac). "
         "Venous: donor SMV/portal vein to recipient portal vein or IVC (systemic drainage). "
         "Portal drainage preferred (more physiological)."),
        (colors.HexColor("#7B2D8B"), WHITE, "Enteric Reconstruction",
         "Proximal anastomosis: jejunum to proximal recipient gut. "
         "Distal anastomosis: to native colon or ileostomy creation. "
         "Decompressing ileostomy (chimney stoma) created for endoscopic surveillance."),
        (colors.HexColor("#C0392B"), WHITE, "Abdominal Closure",
         "Temporary closure with mesh or VAC if domain loss. "
         "Feeding jejunostomy tube placed. Drain placement."),
    ]

    for bg, fg, title, detail in steps:
        row = Table([[
            Paragraph(title, ParagraphStyle("ST", fontName="Helvetica-Bold", fontSize=10,
                      textColor=fg)),
            Paragraph(detail, ParagraphStyle("SD", fontName="Helvetica", fontSize=9.5,
                      leading=13, textColor=colors.HexColor("#222222")))
        ]], colWidths=[4.0*cm, CONTENT_W - 4.0*cm])
        row.setStyle(TableStyle([
            ("BACKGROUND", (0,0), (0,0), bg),
            ("BACKGROUND", (1,0), (1,0), GREY_BG),
            ("GRID", (0,0), (-1,-1), 0.4, colors.HexColor("#BBBBBB")),
            ("TOPPADDING", (0,0), (-1,-1), 6),
            ("BOTTOMPADDING", (0,0), (-1,-1), 6),
            ("LEFTPADDING", (0,0), (-1,-1), 8),
            ("VALIGN", (0,0), (-1,-1), "TOP"),
        ]))
        story.append(row)
    story.append(Spacer(1, 0.3*cm))

    # Surgical flowchart
    story.append(Paragraph("Operative Sequence – Flowchart:", h2))
    story.append(Spacer(1, 0.1*cm))
    op_steps = [
        ("DONOR PROCUREMENT\nSMA Carrel patch • Cold perfusion • En-bloc harvest",
         DARK_BLUE, WHITE),
        ("BACK-TABLE PREPARATION\nArterial reconstruction • Lymphatics oversewn",
         MID_BLUE, WHITE),
        ("RECIPIENT HEPATECTOMY / ENTERECTOMY\nAbdominal domain assessment",
         colors.HexColor("#1A7A5C"), WHITE),
        ("VASCULAR ANASTOMOSES\nArterial (aorta) • Venous (portal/IVC)",
         colors.HexColor("#A0522D"), WHITE),
        ("REPERFUSION & INSPECTION\nAssess perfusion, colour, peristalsis",
         colors.HexColor("#C0392B"), WHITE),
        ("ENTERIC ANASTOMOSES\nProximal & distal bowel continuity • Stoma creation",
         colors.HexColor("#7B2D8B"), WHITE),
        ("ABDOMINAL CLOSURE\nFeed tube • Drains • Temporary closure if needed",
         DARK_BLUE, WHITE),
    ]
    story.append(FlowchartBox(op_steps, width=CONTENT_W, step_height=32, gap=14))
    story.append(Spacer(1, 0.3*cm))


# ── Section 6: Immunosuppression ──────────────────────────────────────────
def section_immuno(story):
    story.append(PageBreak())
    story.append(section_header("6.  Immunosuppression"))
    story.append(Spacer(1, 0.2*cm))
    story.append(Paragraph(
        "The intestine is the most immunogenic solid organ transplant, requiring intensive "
        "immunosuppression. Tacrolimus-based triple therapy is the current standard.", body))

    immuno_data = [
        [Paragraph("<b>Agent</b>", box_title),
         Paragraph("<b>Role</b>", box_title),
         Paragraph("<b>Notes</b>", box_title)],
        ["Tacrolimus (FK506)",
         "Primary calcineurin inhibitor – backbone of all regimens",
         "Target trough 10–15 ng/mL early. Risk: nephrotoxicity, neurotoxicity, PTLD."],
        ["Corticosteroids",
         "Induction & maintenance",
         "High-dose perioperative. Wean to low dose or attempt withdrawal at 3–6 months."],
        ["Mycophenolate Mofetil",
         "Antiproliferative – often added as third agent",
         "Reduces tacrolimus requirement. GI side effects common."],
        ["Basiliximab / Daclizumab",
         "IL-2 receptor blockade – induction agent",
         "Used perioperatively to delay calcineurin initiation in renal impairment."],
        ["Anti-thymocyte Globulin (ATG)",
         "T-cell depletion – induction and rejection treatment",
         "Used perioperatively at many centres; also first-line for steroid-resistant rejection."],
        ["Sirolimus (mTOR inhibitor)",
         "Alternative / rescue immunosuppression",
         "Avoid early post-op due to wound healing impairment and thrombosis risk."],
        ["Rituximab (anti-CD20)",
         "Treatment of EBV-PTLD with B-cell proliferation",
         "Used when PTLD presents as B-cell tumour."],
    ]
    itbl = Table(immuno_data, colWidths=[3.8*cm, 4.8*cm, CONTENT_W - 8.6*cm])
    itbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,0), DARK_BLUE),
        ("TEXTCOLOR", (0,0), (-1,0), WHITE),
        ("FONTNAME", (0,0), (-1,0), "Helvetica-Bold"),
        ("FONTSIZE", (0,0), (-1,-1), 9),
        ("ROWBACKGROUNDS", (0,1), (-1,-1), [WHITE, LIGHT_BLUE]),
        ("GRID", (0,0), (-1,-1), 0.4, colors.HexColor("#CCCCCC")),
        ("TOPPADDING", (0,0), (-1,-1), 5),
        ("BOTTOMPADDING", (0,0), (-1,-1), 5),
        ("LEFTPADDING", (0,0), (-1,-1), 7),
        ("BOX", (0,0), (-1,-1), 1, MID_BLUE),
        ("VALIGN", (0,0), (-1,-1), "TOP"),
    ]))
    story.append(itbl)
    story.append(Spacer(1, 0.3*cm))

    # Immunosuppression flowchart
    story.append(Paragraph("Immunosuppression Protocol – Flowchart:", h2))
    story.append(Spacer(1, 0.1*cm))
    is_steps = [
        ("PRE-OPERATIVE INDUCTION\nATG or Basiliximab • High-dose methylprednisolone",
         DARK_BLUE, WHITE),
        ("EARLY POST-OP (0–3 months)\nTacrolimus (high trough) + Steroids + MMF\nCMV/PCP prophylaxis",
         MID_BLUE, WHITE),
        ("MAINTENANCE (3–12 months)\nTacrolimus (lower trough) + Taper steroids\nFrequent endoscopic surveillance",
         GREEN, WHITE),
        ("LONG-TERM (>12 months)\nMinimise steroids • Monitor for PTLD, CMV, rejection\nSirolimus switch if nephrotoxicity",
         colors.HexColor("#1A7A5C"), WHITE),
        ("REJECTION TREATMENT\nACR: pulse steroids + ATG\nChronic: optimise tacrolimus level",
         ACCENT, WHITE),
    ]
    story.append(FlowchartBox(is_steps, width=CONTENT_W, step_height=34, gap=14))
    story.append(Spacer(1, 0.3*cm))


# ── Section 7: Complications ───────────────────────────────────────────────
def section_complications(story):
    story.append(section_header("7.  Complications"))
    story.append(Spacer(1, 0.2*cm))

    comps = [
        ("REJECTION", ACCENT, [
            "Acute Cellular Rejection (ACR): Most common. Villous blunting, crypt apoptosis on biopsy.",
            "Chronic Rejection: Foam cell arteriopathy; progressive graft dysfunction.",
            "Diagnosis: Protocol endoscopic biopsies via stoma (every 1–2 weeks initially).",
            "Grading: Indeterminate → Mild → Moderate → Severe (NEC-like).",
            "Treatment: Pulse methylprednisolone; ATG for steroid-resistant; retransplant for chronic.",
        ]),
        ("INFECTION", MID_BLUE, [
            "CMV Enteritis: Mimics rejection. Diagnose with biopsy (inclusion bodies) or PCR. "
            "Treat with IV ganciclovir ± CMV-IVIG.",
            "EBV / PTLD: Incidence 5–10% (much higher than other SOT). Risk with EBV-D+/R-. "
            "Reduce immunosuppression; rituximab; chemotherapy for Burkitt/T-cell lymphoma.",
            "Bacterial: High risk due to mucosal disruption. Gram-negatives & anaerobes. "
            "Selective gut decontamination used at some centres.",
            "Fungal: Candida, Aspergillus. Azole prophylaxis standard.",
        ]),
        ("GRAFT-VERSUS-HOST DISEASE (GVHD)", colors.HexColor("#7B2D8B"), [
            "Incidence ~10% — higher than other SOT due to massive intestinal lymphoid mass.",
            "Targets skin and epithelial cells. More common with large grafts (colon, liver inclusion).",
            "Treat with high-dose steroids, ATG. Survival <50% once established.",
            "Some centres use ATG donor pre-treatment to deplete graft lymphocytes.",
        ]),
        ("TECHNICAL COMPLICATIONS", GREEN, [
            "Vascular thrombosis (arterial or venous) → graft infarction, retransplantation urgently needed.",
            "Anastomotic leak → peritonitis, fistula.",
            "Abdominal domain loss → wound dehiscence, hernia.",
            "Chylous ascites → lymphatic disruption.",
        ]),
        ("POST-TRANSPLANT LYMPHOPROLIFERATIVE DISORDER (PTLD)", ORANGE, [
            "Incidence 5–10% after intestinal transplant (higher than any other SOT).",
            "Usually within 1st year. EBV-driven B-cell proliferation in most cases.",
            "Risk factors: EBV D+/R−, strong immunosuppression, history of rejection.",
            "Treatment: Reduce immunosuppression; rituximab; chemotherapy; surgical excision if localised.",
            "Mortality exceeds 25% despite treatment.",
        ]),
    ]

    for title, color, items in comps:
        content = [
            Paragraph(title, ParagraphStyle("CT", fontName="Helvetica-Bold", fontSize=10,
                      textColor=WHITE))
        ] + [Paragraph(f"• {item}", ParagraphStyle("CI", fontName="Helvetica", fontSize=9.5,
                       leading=13, textColor=colors.HexColor("#222222")))
             for item in items]
        header_cell = Table([[Paragraph(title, ParagraphStyle("CH",
            fontName="Helvetica-Bold", fontSize=10, textColor=WHITE))]],
            colWidths=[CONTENT_W])
        header_cell.setStyle(TableStyle([
            ("BACKGROUND", (0,0), (-1,-1), color),
            ("TOPPADDING", (0,0), (-1,-1), 5),
            ("BOTTOMPADDING", (0,0), (-1,-1), 5),
            ("LEFTPADDING", (0,0), (-1,-1), 10),
        ]))
        body_rows = [[Paragraph(f"• {item}", ParagraphStyle("CI", fontName="Helvetica",
                     fontSize=9.5, leading=13))] for item in items]
        body_tbl = Table(body_rows, colWidths=[CONTENT_W])
        body_tbl.setStyle(TableStyle([
            ("BACKGROUND", (0,0), (-1,-1), GREY_BG),
            ("TOPPADDING", (0,0), (-1,-1), 4),
            ("BOTTOMPADDING", (0,0), (-1,-1), 4),
            ("LEFTPADDING", (0,0), (-1,-1), 12),
            ("BOX", (0,0), (-1,-1), 1, color),
        ]))
        story.append(header_cell)
        story.append(body_tbl)
        story.append(Spacer(1, 0.15*cm))

    story.append(Spacer(1, 0.2*cm))

    # Complications flowchart
    story.append(Paragraph("Post-Transplant Monitoring & Complication Management:", h2))
    story.append(Spacer(1, 0.1*cm))
    mon_steps = [
        ("EARLY POST-OP MONITORING\nProtocol endoscopic biopsies via stoma • Tacrolimus levels\nCMV/EBV PCR weekly • Blood cultures if febrile",
         DARK_BLUE, WHITE),
        ("SIGNS OF DYSFUNCTION?\nIncreased stoma output • Abdominal pain • Fever\nRising creatinine • Abnormal LFTs",
         ORANGE, WHITE),
        ("ENDOSCOPIC BIOPSY\nVillous blunting → Rejection grading\nInclusion bodies / CMV IHC → CMV enteritis\nEBV ISH → PTLD",
         MID_BLUE, WHITE),
        ("TREAT ACCORDINGLY\nRejection: steroids/ATG | CMV: ganciclovir | PTLD: reduce IS + rituximab\nGVHD: steroids + ATG",
         ACCENT, WHITE),
        ("LONG-TERM FOLLOW-UP\nAnnual imaging • Nutritional status • QoL assessment\nMonitor for chronic rejection and malignancy",
         GREEN, WHITE),
    ]
    story.append(FlowchartBox(mon_steps, width=CONTENT_W, step_height=36, gap=14))
    story.append(Spacer(1, 0.3*cm))


# ── Section 8: Outcomes ────────────────────────────────────────────────────
def section_outcomes(story):
    story.append(PageBreak())
    story.append(section_header("8.  Outcomes & Survival"))
    story.append(Spacer(1, 0.2*cm))

    out_data = [
        [Paragraph("<b>Era / Regimen</b>", box_title),
         Paragraph("<b>1-Year Patient Survival</b>", box_title),
         Paragraph("<b>Key Factor</b>", box_title)],
        ["1985–1992 (pre-tacrolimus)", "~25%", "Rejection poorly controlled with cyclosporine"],
        ["1992–2000 (tacrolimus era)", "~50–60%", "Tacrolimus introduced 1994 — major improvement"],
        ["2001–2010", "~70–76%", "ITR 76% 1-year survival (most recent registry report)"],
        ["2010–present (selected centres)", "60–90%", "Varies by centre volume and patient selection"],
        ["Paediatric cohort (2010–15)", "90% at 6 years", "Best outcomes: favourable anatomy + high-volume centre"],
    ]
    otbl = Table(out_data, colWidths=[5.5*cm, 4.5*cm, CONTENT_W - 10*cm])
    otbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,0), DARK_BLUE),
        ("TEXTCOLOR", (0,0), (-1,0), WHITE),
        ("FONTNAME", (0,0), (-1,0), "Helvetica-Bold"),
        ("FONTSIZE", (0,0), (-1,-1), 9),
        ("ROWBACKGROUNDS", (0,1), (-1,-1), [WHITE, LIGHT_BLUE]),
        ("GRID", (0,0), (-1,-1), 0.4, colors.HexColor("#CCCCCC")),
        ("TOPPADDING", (0,0), (-1,-1), 5),
        ("BOTTOMPADDING", (0,0), (-1,-1), 5),
        ("LEFTPADDING", (0,0), (-1,-1), 7),
        ("BOX", (0,0), (-1,-1), 1, MID_BLUE),
        ("VALIGN", (0,0), (-1,-1), "TOP"),
    ]))
    story.append(otbl)
    story.append(Spacer(1, 0.3*cm))

    story.append(info_box(
        "Favourable Prognostic Factors for Enteral Autonomy",
        [
            "≥50% small bowel length remaining",
            "Presence of ileocecal valve",
            "Short bowel syndrome as aetiology (vs. motility disorder)",
            "Absence of portal hypertension",
            "Treatment at high-volume transplantation centre",
            "Patient well enough to wait at home until transplant",
        ],
        bg=LIGHT_GREEN, title_color=GREEN
    ))
    story.append(Spacer(1, 0.3*cm))

    story.append(info_box(
        "Quality of Life After Transplant",
        [
            "SBT offers return to near-normal activities vs. lifelong PN dependency.",
            "Home PN: QoL affected by infusion time, catheter complications, social limitations.",
            "Post-transplant: freedom from PN, improved nutritional status, restored gut function.",
            "Key QoL determinants: self-esteem, family support, days of PN per week (pre-transplant).",
        ],
        bg=LIGHT_ORANGE, title_color=ORANGE
    ))
    story.append(Spacer(1, 0.3*cm))


# ── Section 9: Summary Flowchart ──────────────────────────────────────────
def section_summary(story):
    story.append(section_header("9.  Complete Management Summary Flowchart"))
    story.append(Spacer(1, 0.3*cm))
    summary_steps = [
        ("INTESTINAL FAILURE\nPN-dependent patient • Irreversible loss of gut function",
         DARK_BLUE, WHITE),
        ("INTESTINAL REHABILITATION\nGLP-2 analogues (teduglutide) • Surgical lengthening\nDietetic optimisation • Gut adaptation",
         MID_BLUE, WHITE),
        ("INDICATIONS MET?\nIFALD • Lost venous access • Recurrent sepsis\nDesmoids • Acute infarction • Retransplant",
         ORANGE, WHITE),
        ("MDT ASSESSMENT\nVenous mapping • Liver biopsy • CT abdomen • Echo\nPsychiatric + anaesthetic review",
         colors.HexColor("#1A7A5C"), WHITE),
        ("WAITLIST & ORGAN ALLOCATION\nUNOS / ETN registration • ABO matching • Size matching\nDonor CMV/EBV serostatus",
         colors.HexColor("#7B2D8B"), WHITE),
        ("TRANSPLANT OPERATION\nProcurement → Back-table → Recipient enterectomy\nVascular anastomoses → Enteric reconstruction",
         ACCENT, WHITE),
        ("EARLY POST-OP ICU CARE\nTacrolimus induction • Surveillance biopsies • Antimicrobials\nNutritional support (TPN transitioning to enteral)",
         DARK_BLUE, WHITE),
        ("DISCHARGE & LONG-TERM FOLLOW-UP\nEnteral autonomy goal • Monitor rejection/PTLD/CMV\nAnnual surveillance • QoL assessment",
         GREEN, WHITE),
    ]
    story.append(FlowchartBox(summary_steps, width=CONTENT_W, step_height=36, gap=14))
    story.append(Spacer(1, 0.5*cm))

    story.append(Paragraph(
        "Sources: Sabiston Textbook of Surgery 22e (Ch. 56) · Bailey & Love's Short Practice of Surgery 28e (Ch. 91) · "
        "Yamada's Textbook of Gastroenterology 7e (Ch. 59) · Fischer's Mastery of Surgery 8e",
        ParagraphStyle("Src", fontName="Helvetica-Oblique", fontSize=8, textColor=colors.grey,
                       alignment=TA_CENTER)))


# ── Page number footer ─────────────────────────────────────────────────────
def add_page_number(canvas, doc):
    canvas.saveState()
    canvas.setFont("Helvetica", 8)
    canvas.setFillColor(colors.HexColor("#777777"))
    canvas.drawRightString(W - 2*cm, 1.5*cm, f"Page {doc.page}")
    canvas.drawString(2*cm, 1.5*cm, "Small Bowel Transplantation | Orris Medical Library")
    canvas.setStrokeColor(colors.HexColor("#CCCCCC"))
    canvas.line(2*cm, 1.7*cm, W - 2*cm, 1.7*cm)
    canvas.restoreState()


# ── Build document ─────────────────────────────────────────────────────────
story = []
cover_page(story)
section_history(story)
section_indications(story)
section_types(story)
section_assessment(story)
section_surgery(story)
section_immuno(story)
section_complications(story)
section_outcomes(story)
section_summary(story)

doc.build(story, onFirstPage=add_page_number, onLaterPages=add_page_number)
print("PDF generated successfully!")

Successfully replaced 1 instance(s) of the string in '/tmp/workspace/sbt-pdf/generate_pdf.py'

Successfully replaced 1 instance(s) of the string in '/tmp/workspace/sbt-pdf/generate_pdf.py'

Successfully replaced 1 instance(s) of the string in '/tmp/workspace/sbt-pdf/generate_pdf.py'

Successfully replaced 1 instance(s) of the string in '/tmp/workspace/sbt-pdf/generate_pdf.py'