Spinothalamic Tract

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

OUTPUT = "/home/daytona/workspace/spinothalamic/Spinothalamic_Tract.pdf"
GUYTON_IMG = "/home/daytona/workspace/spinothalamic/guyton_diagram.png"

# ── Color palette ─────────────────────────────────────────────────────────────
C_NAVY    = colors.HexColor("#1a237e")
C_BLUE    = colors.HexColor("#1565c0")
C_LBLUE   = colors.HexColor("#e3f2fd")
C_TEAL    = colors.HexColor("#00838f")
C_LTEAL   = colors.HexColor("#e0f7fa")
C_RED     = colors.HexColor("#c62828")
C_LRED    = colors.HexColor("#ffebee")
C_ORANGE  = colors.HexColor("#e65100")
C_AMBER   = colors.HexColor("#fff8e1")
C_GREEN   = colors.HexColor("#2e7d32")
C_LGREEN  = colors.HexColor("#e8f5e9")
C_GRAY    = colors.HexColor("#455a64")
C_LGRAY   = colors.HexColor("#f5f5f5")
C_WHITE   = colors.white
C_PURPLE  = colors.HexColor("#6a1b9a")
C_LPURPLE = colors.HexColor("#f3e5f5")

W, H = A4  # 595 x 842 pt

# ── Page template with header/footer ──────────────────────────────────────────
def on_page(canv, doc):
    canv.saveState()
    # Top bar
    canv.setFillColor(C_NAVY)
    canv.rect(0, H - 28, W, 28, fill=1, stroke=0)
    canv.setFillColor(C_WHITE)
    canv.setFont("Helvetica-Bold", 9)
    canv.drawString(20, H - 18, "SPINOTHALAMIC TRACT")
    canv.setFont("Helvetica", 8)
    canv.drawRightString(W - 20, H - 18, "Ref: Guyton & Hall | Neuroanatomy through Clinical Cases 3e")
    # Bottom bar
    canv.setFillColor(C_NAVY)
    canv.rect(0, 0, W, 20, fill=1, stroke=0)
    canv.setFillColor(C_WHITE)
    canv.setFont("Helvetica", 7.5)
    canv.drawCentredString(W / 2, 7, f"Page {doc.page}")
    canv.restoreState()

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

def make_style(name, parent="Normal", **kw):
    s = ParagraphStyle(name, parent=styles[parent], **kw)
    return s

S_TITLE   = make_style("MyTitle",   fontSize=26, textColor=C_WHITE,
                        fontName="Helvetica-Bold", alignment=TA_CENTER, leading=32)
S_SUBTITLE= make_style("MySub",     fontSize=11, textColor=C_LBLUE,
                        fontName="Helvetica", alignment=TA_CENTER, leading=16)
S_H1      = make_style("MyH1",      fontSize=14, textColor=C_WHITE,
                        fontName="Helvetica-Bold", alignment=TA_LEFT, leading=18)
S_H2      = make_style("MyH2",      fontSize=11, textColor=C_NAVY,
                        fontName="Helvetica-Bold", alignment=TA_LEFT, leading=15,
                        spaceBefore=6, spaceAfter=3)
S_BODY    = make_style("MyBody",    fontSize=9.5, textColor=C_GRAY,
                        fontName="Helvetica", alignment=TA_JUSTIFY, leading=14,
                        spaceBefore=2, spaceAfter=2)
S_BULLET  = make_style("MyBullet",  fontSize=9.5, textColor=C_GRAY,
                        fontName="Helvetica", leftIndent=14, leading=14,
                        spaceBefore=1, spaceAfter=1)
S_CAPTION = make_style("MyCaption", fontSize=8, textColor=C_GRAY,
                        fontName="Helvetica-Oblique", alignment=TA_CENTER,
                        spaceBefore=3)
S_SMALL   = make_style("MySmall",   fontSize=8, textColor=C_GRAY,
                        fontName="Helvetica", leading=11)
S_BOX     = make_style("MyBox",     fontSize=9, textColor=C_NAVY,
                        fontName="Helvetica", leading=13, leftIndent=6, rightIndent=6)

# ── Helper flowables ───────────────────────────────────────────────────────────
class SectionHeader(Flowable):
    def __init__(self, text, color=C_NAVY, width=None):
        super().__init__()
        self.text = text
        self.color = color
        self._width = width or (W - 80)
        self.height = 26

    def draw(self):
        self.canv.setFillColor(self.color)
        self.canv.roundRect(0, 0, self._width, self.height, 4, fill=1, stroke=0)
        self.canv.setFillColor(C_WHITE)
        self.canv.setFont("Helvetica-Bold", 11)
        self.canv.drawString(10, 8, self.text)

    def wrap(self, aw, ah):
        return self._width, self.height

class ColorBox(Flowable):
    """Colored background box for highlighted content."""
    def __init__(self, content_lines, bg=C_LBLUE, border=C_BLUE, width=None):
        super().__init__()
        self.lines = content_lines
        self.bg = bg
        self.border = border
        self._w = width or (W - 80)
        self.height = 14 * len(content_lines) + 16

    def draw(self):
        c = self.canv
        c.setFillColor(self.bg)
        c.setStrokeColor(self.border)
        c.setLineWidth(0.8)
        c.roundRect(0, 0, self._w, self.height, 5, fill=1, stroke=1)
        c.setFillColor(C_GRAY)
        c.setFont("Helvetica", 9)
        y = self.height - 12
        for line in self.lines:
            c.drawString(10, y, line)
            y -= 14

    def wrap(self, aw, ah):
        return self._w, self.height

# ── Spine diagram (custom drawn) ───────────────────────────────────────────────
class SpinalCordDiagram(Flowable):
    """
    Simplified schematic cross-section + pathway diagram of spinothalamic tract.
    """
    W = 480
    H = 320

    def wrap(self, aw, ah):
        return self.W, self.H

    def draw(self):
        c = self.canv
        w, h = self.W, self.H

        # Background
        c.setFillColor(colors.HexColor("#fafafa"))
        c.setStrokeColor(colors.HexColor("#cccccc"))
        c.roundRect(0, 0, w, h, 6, fill=1, stroke=1)

        # Title
        c.setFillColor(C_NAVY)
        c.setFont("Helvetica-Bold", 10)
        c.drawCentredString(w/2, h - 16, "Spinothalamic Tract — Schematic Pathway")

        # ── Left side: spinal cord cross-section ──────────────────────
        cx, cy = 110, h/2 - 10  # center of cross-section
        r = 52  # outer radius

        # Outer oval
        c.setFillColor(colors.HexColor("#ffe0b2"))
        c.setStrokeColor(colors.HexColor("#bf360c"))
        c.setLineWidth(1.5)
        c.ellipse(cx-r, cy-r*0.85, cx+r, cy+r*0.85, fill=1, stroke=1)

        # Butterfly gray matter
        c.setFillColor(colors.HexColor("#ffccbc"))
        c.setStrokeColor(colors.HexColor("#bf360c"))
        c.setLineWidth(1)
        # Dorsal horns
        c.bezier(cx-8, cy+8, cx-25, cy+30, cx-35, cy+38, cx-22, cy+14)
        c.bezier(cx+8, cy+8, cx+25, cy+30, cx+35, cy+38, cx+22, cy+14)
        # Ventral horns
        c.bezier(cx-8, cy-8, cx-28, cy-26, cx-38, cy-34, cx-20, cy-12)
        c.bezier(cx+8, cy-8, cx+28, cy-26, cx+38, cy-34, cx+20, cy-12)

        # Gray matter ellipse (central)
        c.setFillColor(colors.HexColor("#ffccbc"))
        c.setStrokeColor(colors.HexColor("#bf360c"))
        c.ellipse(cx-22, cy-18, cx+22, cy+18, fill=1, stroke=1)

        # Anterior commissure label line
        c.setStrokeColor(C_RED)
        c.setLineWidth(1)
        c.line(cx-10, cy, cx+10, cy)
        c.setFillColor(C_RED)
        c.setFont("Helvetica", 6.5)
        c.drawCentredString(cx, cy - 8, "ant. commissure")

        # Dorsal column (blue, top)
        c.setFillColor(colors.HexColor("#bbdefb"))
        c.setStrokeColor(C_BLUE)
        c.setLineWidth(1)
        c.ellipse(cx-16, cy+26, cx+16, cy+44, fill=1, stroke=1)
        c.setFillColor(C_BLUE)
        c.setFont("Helvetica", 6)
        c.drawCentredString(cx, cy+37, "Dorsal col.")

        # Lat. spinothalamic (red dot, right side = already crossed)
        c.setFillColor(C_RED)
        c.circle(cx+36, cy+10, 8, fill=1, stroke=0)
        c.setFillColor(C_WHITE)
        c.setFont("Helvetica-Bold", 6)
        c.drawCentredString(cx+36, cy+8, "LST")

        # Ant. spinothalamic (orange dot, right)
        c.setFillColor(C_ORANGE)
        c.circle(cx+36, cy-12, 7, fill=1, stroke=0)
        c.setFillColor(C_WHITE)
        c.setFont("Helvetica-Bold", 6)
        c.drawCentredString(cx+36, cy-14, "AST")

        # Labels
        c.setFillColor(C_GRAY)
        c.setFont("Helvetica", 7)
        c.drawString(cx - r - 5, cy - r*0.85 - 12, "Spinal cord cross-section")

        # Dorsal horn label
        c.setFillColor(C_TEAL)
        c.setFont("Helvetica", 7)
        c.drawString(cx - r + 2, cy + 40, "Lamina I & V")
        c.drawString(cx - r + 2, cy + 30, "(2nd order neuron)")

        # ── Middle: crossing arrow ────────────────────────────────────
        mid_x = 210
        # Arrow showing crossing
        c.setStrokeColor(C_RED)
        c.setLineWidth(2)
        c.line(cx + r + 5, cy + 10, mid_x - 10, cy + 10)
        # Arrowhead
        c.setFillColor(C_RED)
        p = c.beginPath()
        p.moveTo(mid_x - 10, cy + 14)
        p.lineTo(mid_x, cy + 10)
        p.lineTo(mid_x - 10, cy + 6)
        p.close()
        c.drawPath(p, fill=1, stroke=0)

        c.setFillColor(C_RED)
        c.setFont("Helvetica-Bold", 7.5)
        c.drawString(cx + r + 6, cy + 14, "Crosses in ant. commissure")
        c.setFont("Helvetica", 7)
        c.drawString(cx + r + 6, cy + 5, "(2-3 segments)")

        # ── Right side: brainstem column ──────────────────────────────
        bx = 270  # x of brainstem column
        levels = [
            (h - 55,  "Cortex",         C_NAVY,   "(Postcentral gyrus)"),
            (h - 100, "Thalamus",        C_BLUE,   "VPL + Intralaminar nuclei"),
            (h - 148, "Midbrain",        C_TEAL,   "Lat. to med. lemniscus"),
            (h - 196, "Pons",            C_GREEN,  "Lat. to med. lemniscus"),
            (h - 244, "Medulla",         C_ORANGE, "Lat. groove (inf. olive)"),
            (h - 292, "Spinal cord",     C_RED,    "Anterolateral white col."),
        ]

        # Vertical tract line
        c.setStrokeColor(C_RED)
        c.setLineWidth(2.5)
        c.line(bx + 6, h - 295, bx + 6, h - 52)

        for (ly, lname, lcol, lsub) in levels:
            # Node circle
            c.setFillColor(lcol)
            c.setStrokeColor(C_WHITE)
            c.setLineWidth(1)
            c.circle(bx + 6, ly, 7, fill=1, stroke=1)

            # Label box
            c.setFillColor(lcol)
            c.setStrokeColor(lcol)
            box_x = bx + 18
            c.roundRect(box_x, ly - 8, 150, 18, 3, fill=1, stroke=0)
            c.setFillColor(C_WHITE)
            c.setFont("Helvetica-Bold", 8)
            c.drawString(box_x + 4, ly + 1, lname)

            c.setFillColor(colors.HexColor("#eeeeee"))
            c.roundRect(box_x, ly - 22, 150, 13, 2, fill=1, stroke=0)
            c.setFillColor(C_GRAY)
            c.setFont("Helvetica", 7)
            c.drawString(box_x + 4, ly - 18, lsub)

        # Arrow on tract line
        c.setFillColor(C_RED)
        p2 = c.beginPath()
        p2.moveTo(bx + 1, h - 60)
        p2.lineTo(bx + 6, h - 50)
        p2.lineTo(bx + 11, h - 60)
        p2.close()
        c.drawPath(p2, fill=1, stroke=0)

        # Legend
        legend_y = 15
        items = [
            (C_RED,    "Lateral Spinothalamic Tract (pain & temp)"),
            (C_ORANGE, "Anterior Spinothalamic Tract (crude touch)"),
        ]
        lx = 10
        for col, label in items:
            c.setFillColor(col)
            c.rect(lx, legend_y - 2, 12, 8, fill=1, stroke=0)
            c.setFillColor(C_GRAY)
            c.setFont("Helvetica", 7.5)
            c.drawString(lx + 16, legend_y, label)
            lx += 200


# ── Comparison diagram ─────────────────────────────────────────────────────────
class ComparisonDiagram(Flowable):
    W = 480
    H = 210

    def wrap(self, aw, ah):
        return self.W, self.H

    def draw(self):
        c = self.canv
        w, h = self.W, self.H

        # Background
        c.setFillColor(colors.HexColor("#fafafa"))
        c.setStrokeColor(colors.HexColor("#cccccc"))
        c.roundRect(0, 0, w, h, 6, fill=1, stroke=1)

        # Title
        c.setFillColor(C_NAVY)
        c.setFont("Helvetica-Bold", 10)
        c.drawCentredString(w/2, h - 14, "Comparison: Spinothalamic vs. Dorsal Column Pathways")

        # Two columns
        col1_x, col2_x = 30, 270
        col_w = 220

        # Column headers
        for cx_, title_, color_ in [(col1_x, "Spinothalamic (Anterolateral)", C_RED),
                                     (col2_x, "Dorsal Column-Med. Lemniscal", C_BLUE)]:
            c.setFillColor(color_)
            c.roundRect(cx_, h - 42, col_w, 22, 4, fill=1, stroke=0)
            c.setFillColor(C_WHITE)
            c.setFont("Helvetica-Bold", 8.5)
            c.drawCentredString(cx_ + col_w/2, h - 34, title_)

        rows = [
            ("Sensations",    "Pain, Temp, Crude touch",     "Proprioception, Vibration,\nFine touch, 2-pt discrim."),
            ("Fiber type",    "Aδ, C (small, slow)",         "Aβ (large, fast myelinated)"),
            ("1st synapse",   "Dorsal horn (Lamina I, V)",   "Nucleus gracilis / cuneatus\n(medulla)"),
            ("Decussation",   "Spinal cord ant. commissure\n(2-3 segs below entry)",
                              "Medulla (sensory decussation)"),
            ("2nd neuron",    "→ VPL thalamus & intralaminar",  "→ VPL thalamus"),
            ("Speed",         "8-40 m/sec (slower)",         "30-110 m/sec (faster)"),
            ("Localization",  "Poor (crude)",                "Precise (discriminative)"),
        ]

        row_h = 22
        y = h - 50
        for i, (feat, left, right) in enumerate(rows):
            bg = colors.HexColor("#fff3e0") if i % 2 == 0 else C_WHITE
            c.setFillColor(bg)
            c.rect(col1_x - 5, y - row_h + 4, col_w * 2 + 20, row_h, fill=1, stroke=0)

            # Feature label
            c.setFillColor(C_NAVY)
            c.setFont("Helvetica-Bold", 7.5)
            c.drawString(col1_x - 4, y - 4, feat)

            # Left cell
            c.setFillColor(C_GRAY)
            c.setFont("Helvetica", 7.5)
            lines_l = left.split("\n")
            for li, line in enumerate(lines_l):
                c.drawString(col1_x + 70, y - 4 - li * 10, line)

            # Right cell
            lines_r = right.split("\n")
            for li, line in enumerate(lines_r):
                c.drawString(col2_x + 70, y - 4 - li * 10, line)

            # Divider
            c.setStrokeColor(colors.HexColor("#e0e0e0"))
            c.setLineWidth(0.4)
            c.line(col1_x - 5, y - row_h + 4, col1_x + col_w * 2 + 15, y - row_h + 4)

            y -= row_h


# ── Brown-Séquard diagram ──────────────────────────────────────────────────────
class BrownSequardDiagram(Flowable):
    W = 480
    H = 200

    def wrap(self, aw, ah):
        return self.W, self.H

    def draw(self):
        c = self.canv
        w, h = self.W, self.H

        c.setFillColor(colors.HexColor("#fafafa"))
        c.setStrokeColor(colors.HexColor("#cccccc"))
        c.roundRect(0, 0, w, h, 6, fill=1, stroke=1)

        c.setFillColor(C_NAVY)
        c.setFont("Helvetica-Bold", 10)
        c.drawCentredString(w/2, h - 15, "Brown-Séquard Syndrome (Right Hemisection)")

        # Spinal cord cross-section (right half lesion)
        cx, cy = 100, h/2 - 10
        r = 50

        # Full outline
        c.setFillColor(colors.HexColor("#fff9c4"))
        c.setStrokeColor(C_GRAY)
        c.setLineWidth(1.2)
        c.ellipse(cx-r, cy-r*0.85, cx+r, cy+r*0.85, fill=1, stroke=1)

        # Right half hatched (lesion)
        c.setFillColor(colors.HexColor("#ffcdd2"))
        c.setStrokeColor(C_RED)
        c.setLineWidth(1)
        # Simple right-half rectangle overlay
        c.rect(cx, cy - r*0.85, r, r*1.7, fill=1, stroke=0)
        c.setStrokeColor(C_RED)
        c.setLineWidth(0.5)
        for i in range(8):
            yy = cy - r*0.85 + i * (r*1.7/8)
            c.line(cx, yy, cx + r, yy + 10)

        # Midline
        c.setStrokeColor(C_RED)
        c.setLineWidth(1.5)
        c.setDash([4, 2])
        c.line(cx, cy - r*0.85, cx, cy + r*0.85)
        c.setDash([])

        # Label LESION
        c.setFillColor(C_RED)
        c.setFont("Helvetica-Bold", 8)
        c.drawCentredString(cx + r/2, cy + 4, "LESION")
        c.drawCentredString(cx + r/2, cy - 8, "(Right)")

        # Results table
        tx = 185
        c.setFillColor(C_NAVY)
        c.setFont("Helvetica-Bold", 9)
        c.drawString(tx, h - 30, "Clinical Findings:")

        items = [
            ("IPSILATERAL (Right) — below lesion:",  C_BLUE,  True),
            ("  ✗  Loss of proprioception & vibration (dorsal column)",  C_BLUE,  False),
            ("  ✗  Loss of fine touch & 2-pt discrimination",           C_BLUE,  False),
            ("  ✗  UMN weakness / spasticity (corticospinal)",          C_BLUE,  False),
            ("CONTRALATERAL (Left) — below lesion:", C_RED,   True),
            ("  ✗  Loss of PAIN & TEMPERATURE (spinothalamic)", C_RED,   False),
            ("  ✓  Crude touch partially preserved",            C_GREEN, False),
        ]

        y = h - 48
        for text, col, bold in items:
            c.setFillColor(col)
            c.setFont("Helvetica-Bold" if bold else "Helvetica", 8)
            c.drawString(tx, y, text)
            y -= 13


# ── Build document ─────────────────────────────────────────────────────────────
def build():
    doc = SimpleDocTemplate(
        OUTPUT,
        pagesize=A4,
        leftMargin=2.2*cm, rightMargin=2.2*cm,
        topMargin=1.8*cm,  bottomMargin=1.5*cm,
        title="Spinothalamic Tract",
        author="Orris Medical Reference"
    )

    story = []
    pw = W - 4.4*cm  # printable width

    # ═══════════════════════════════════════════════════════
    # COVER BLOCK
    # ═══════════════════════════════════════════════════════
    class CoverBlock(Flowable):
        def wrap(self, aw, ah):
            return pw, 140
        def draw(self):
            c = self.canv
            c.setFillColor(C_NAVY)
            c.roundRect(0, 0, pw, 140, 8, fill=1, stroke=0)
            # accent strip
            c.setFillColor(C_TEAL)
            c.roundRect(0, 0, pw, 8, 4, fill=1, stroke=0)
            c.setFillColor(C_WHITE)
            c.setFont("Helvetica-Bold", 24)
            c.drawCentredString(pw/2, 100, "SPINOTHALAMIC TRACT")
            c.setFillColor(colors.HexColor("#90caf9"))
            c.setFont("Helvetica", 11)
            c.drawCentredString(pw/2, 78, "Anterolateral Pathway  |  Pain & Temperature")
            c.setFillColor(colors.HexColor("#80cbc4"))
            c.setFont("Helvetica", 9)
            c.drawCentredString(pw/2, 58, "Reference: Guyton & Hall Textbook of Medical Physiology  |  Neuroanatomy through Clinical Cases 3e")
            c.setFillColor(colors.HexColor("#b0bec5"))
            c.setFont("Helvetica", 8)
            c.drawCentredString(pw/2, 30, "Physiology  |  Neuroanatomy  |  Clinical Correlations")

    story.append(CoverBlock())
    story.append(Spacer(1, 14))

    # ═══════════════════════════════════════════════════════
    # SECTION 1 — Overview
    # ═══════════════════════════════════════════════════════
    story.append(SectionHeader("1.  OVERVIEW", C_NAVY, pw))
    story.append(Spacer(1, 6))

    story.append(Paragraph(
        "The <b>spinothalamic tract</b> is the primary ascending sensory pathway for <b>pain</b>, "
        "<b>temperature</b>, <b>crude touch</b>, tickle, itch, and sexual sensations. "
        "It forms part of the broader <i>anterolateral pathway</i> — so named because its fibers "
        "run in the anterolateral white matter of the spinal cord. It is the clinical counterpart "
        "to the dorsal column-medial lemniscal pathway, which handles discriminative touch and proprioception.",
        S_BODY))
    story.append(Spacer(1, 4))

    # Quick-reference colored box
    qr_data = [
        ["Modality", "Pain, Temperature, Crude touch, Tickle, Itch"],
        ["1st order neuron", "Peripheral sensory neuron (DRG) → dorsal horn"],
        ["2nd order neuron", "Dorsal horn (Lamina I, IV, V, VI) → crosses → VPL thalamus"],
        ["3rd order neuron", "Thalamus (VPL) → Postcentral gyrus (areas 3, 1, 2)"],
        ["Decussation", "Anterior commissure of spinal cord (2–3 segments)"],
        ["Somatotopy", "Sacral lateral → Cervical medial (legs outermost)"],
    ]
    tbl = Table(qr_data, colWidths=[pw*0.32, pw*0.68])
    tbl.setStyle(TableStyle([
        ("BACKGROUND",   (0,0), (0,-1), C_NAVY),
        ("TEXTCOLOR",    (0,0), (0,-1), C_WHITE),
        ("BACKGROUND",   (1,0), (1,-1), C_LBLUE),
        ("TEXTCOLOR",    (1,0), (1,-1), C_GRAY),
        ("FONTNAME",     (0,0), (0,-1), "Helvetica-Bold"),
        ("FONTNAME",     (1,0), (1,-1), "Helvetica"),
        ("FONTSIZE",     (0,0), (-1,-1), 9),
        ("ROWBACKGROUNDS", (0,0), (-1,-1), [C_LBLUE, C_WHITE]),
        ("BACKGROUND",   (0,0), (0,-1), C_NAVY),
        ("GRID",         (0,0), (-1,-1), 0.5, colors.HexColor("#b0bec5")),
        ("LEFTPADDING",  (0,0), (-1,-1), 8),
        ("TOPPADDING",   (0,0), (-1,-1), 5),
        ("BOTTOMPADDING",(0,0), (-1,-1), 5),
        ("ROWBACKGROUNDS", (1,0), (1,-1), [C_LBLUE, colors.HexColor("#f0f8ff")]),
    ]))
    story.append(tbl)
    story.append(Spacer(1, 10))

    # ═══════════════════════════════════════════════════════
    # SECTION 2 — Anatomy (3 neurons)
    # ═══════════════════════════════════════════════════════
    story.append(SectionHeader("2.  ANATOMY — THREE-NEURON ARC", C_TEAL, pw))
    story.append(Spacer(1, 6))

    story.append(Paragraph("<b>First-Order Neuron (Peripheral)</b>", S_H2))
    bullets_1 = [
        "Cell body in the <b>dorsal root ganglion (DRG)</b>",
        "Peripheral process: free nerve endings in skin/viscera → carries pain (Aδ, C fibers) and temperature",
        "Central process enters spinal cord via <b>dorsal root entry zone</b>",
        "Many collaterals ascend/descend 1–2 segments in <b>Lissauer's tract</b> (dorsolateral fasciculus) before synapsing",
    ]
    for b in bullets_1:
        story.append(Paragraph(f"• {b}", S_BULLET))

    story.append(Spacer(1, 4))
    story.append(Paragraph("<b>Second-Order Neuron (Spinal Cord → Thalamus)</b>", S_H2))
    bullets_2 = [
        "Cell body in dorsal horn: mainly <b>Lamina I</b> (marginal zone) and <b>Lamina V</b> (neck of dorsal horn); also laminae IV and VI",
        "Axon <b>immediately crosses</b> in the <b>anterior (ventral) commissure</b> to the opposite side",
        "<i>Note:</i> Crossing takes 2–3 segments → lateral cord lesion = contralateral sensory loss a few levels <b>below</b> the lesion",
        "Ascends in the <b>anterolateral white matter</b> as the spinothalamic tract",
        "<b>Lateral spinothalamic tract</b> (neospinothalamic) — pain and temperature (discriminative)",
        "<b>Anterior spinothalamic tract</b> — crude touch and pressure",
        "Terminates in <b>VPL nucleus</b> of thalamus (and intralaminar nuclei for pain)",
    ]
    for b in bullets_2:
        story.append(Paragraph(f"• {b}", S_BULLET))

    story.append(Spacer(1, 4))
    story.append(Paragraph("<b>Third-Order Neuron (Thalamus → Cortex)</b>", S_H2))
    bullets_3 = [
        "<b>VPL (ventroposterolateral)</b> nucleus of thalamus → somatosensory radiations → <b>postcentral gyrus</b> (areas 3, 1, 2) via internal capsule",
        "<b>Intralaminar nuclei</b> (centromedian) → diffuse cortical projections → arousal and affective pain",
        "Face is represented by the trigeminothalamic tract (analogous pathway)",
    ]
    for b in bullets_3:
        story.append(Paragraph(f"• {b}", S_BULLET))

    story.append(Spacer(1, 10))

    # ═══════════════════════════════════════════════════════
    # PATHWAY DIAGRAM
    # ═══════════════════════════════════════════════════════
    story.append(SectionHeader("3.  PATHWAY DIAGRAM", C_RED, pw))
    story.append(Spacer(1, 8))
    story.append(SpinalCordDiagram())
    story.append(Spacer(1, 4))
    story.append(Paragraph(
        "<i>Left: Spinal cord cross-section showing dorsal horn laminae (1st synapse) and lateral (LST) & anterior (AST) "
        "spinothalamic tracts in anterolateral white column.  Right: Ascending pathway from spinal cord through "
        "brainstem to thalamus and cortex. Fibers cross in the anterior commissure.</i>",
        S_CAPTION))
    story.append(Spacer(1, 10))

    # ═══════════════════════════════════════════════════════
    # Guyton figure
    # ═══════════════════════════════════════════════════════
    story.append(SectionHeader("4.  GUYTON FIGURE — ANTEROLATERAL PATHWAY", C_BLUE, pw))
    story.append(Spacer(1, 6))
    if os.path.exists(GUYTON_IMG):
        img = Image(GUYTON_IMG, width=pw*0.42, height=pw*0.95)
        img.hAlign = "CENTER"
        story.append(img)
        story.append(Paragraph(
            "<i>Fig. 48.13 — Guyton & Hall Textbook of Medical Physiology. Anterior and lateral divisions "
            "of the anterolateral sensory pathway. Shows the crossing in the anterior commissure, ascent "
            "through the brainstem, and termination in the ventrobasal and intralaminar nuclei of the thalamus.</i>",
            S_CAPTION))
    story.append(Spacer(1, 10))

    # ═══════════════════════════════════════════════════════
    # SECTION 5 — Three tracts
    # ═══════════════════════════════════════════════════════
    story.append(SectionHeader("5.  THREE TRACTS OF THE ANTEROLATERAL SYSTEM", C_PURPLE, pw))
    story.append(Spacer(1, 6))

    tract_data = [
        ["Tract", "Termination", "Function", "Origin (laminae)"],
        ["Spinothalamic\n(neospinothalamic)", "VPL thalamus\n→ somatosensory cortex",
         "Discriminative pain & temp\n(location, intensity)", "I, V"],
        ["Spinoreticular\n(paleospinothalamic)", "Reticular formation\n→ intralaminar thalamus\n→ whole cortex",
         "Emotional / arousal aspects\nof pain ("ouch!")", "VI–VIII (diffuse)"],
        ["Spinomesencephalic", "Periaqueductal gray\n(PAG), sup. colliculus",
         "Central pain modulation\n("aah, relief")", "I, V"],
    ]
    tbl2 = Table(tract_data, colWidths=[pw*0.22, pw*0.28, pw*0.28, pw*0.22])
    tbl2.setStyle(TableStyle([
        ("BACKGROUND",    (0,0), (-1,0), C_PURPLE),
        ("TEXTCOLOR",     (0,0), (-1,0), C_WHITE),
        ("FONTNAME",      (0,0), (-1,0), "Helvetica-Bold"),
        ("FONTNAME",      (0,1), (-1,-1), "Helvetica"),
        ("FONTSIZE",      (0,0), (-1,-1), 8.5),
        ("ROWBACKGROUNDS",(0,1), (-1,-1), [C_LPURPLE, C_WHITE]),
        ("GRID",          (0,0), (-1,-1), 0.5, colors.HexColor("#ce93d8")),
        ("VALIGN",        (0,0), (-1,-1), "MIDDLE"),
        ("LEFTPADDING",   (0,0), (-1,-1), 6),
        ("TOPPADDING",    (0,0), (-1,-1), 5),
        ("BOTTOMPADDING", (0,0), (-1,-1), 5),
    ]))
    story.append(tbl2)
    story.append(Spacer(1, 10))

    # ═══════════════════════════════════════════════════════
    # SECTION 6 — Somatotopy
    # ═══════════════════════════════════════════════════════
    story.append(SectionHeader("6.  SOMATOTOPIC ORGANIZATION", C_GREEN, pw))
    story.append(Spacer(1, 6))

    story.append(Paragraph(
        "The anterolateral pathway has a <b>somatotopic arrangement</b> within the spinal cord — "
        "this is clinically important for interpreting lesion levels.",
        S_BODY))
    story.append(Spacer(1, 4))

    # Somatotopy visual
    class SomatotopyDiagram(Flowable):
        W = 460
        H = 90
        def wrap(self, aw, ah): return self.W, self.H
        def draw(self):
            c = self.canv
            c.setFillColor(colors.HexColor("#fafafa"))
            c.setStrokeColor(colors.HexColor("#cccccc"))
            c.roundRect(0, 0, self.W, self.H, 5, fill=1, stroke=1)

            c.setFillColor(C_NAVY)
            c.setFont("Helvetica-Bold", 8.5)
            c.drawString(10, self.H - 16, "Cross-section (right):")

            # Draw concentric half-circles representing layers
            cx, cy = 130, 25
            segs = [("S", C_RED, 40), ("L", C_ORANGE, 30), ("T", C_TEAL, 20), ("C", C_BLUE, 10)]
            for label, col, r in segs:
                c.setFillColor(col)
                c.setStrokeColor(C_WHITE)
                c.setLineWidth(0.5)
                c.circle(cx, cy, r, fill=1, stroke=1)

            # Labels
            c.setFillColor(C_WHITE)
            c.setFont("Helvetica-Bold", 7)
            c.drawCentredString(cx, 23, "C")
            c.setFillColor(C_NAVY)
            c.setFont("Helvetica", 7)

            offsets = [("S = Sacral (most lateral)", 50, 60), ("L = Lumbar", 50, 48),
                       ("T = Thoracic", 50, 36), ("C = Cervical (most medial)", 50, 24)]
            cols2 = [C_RED, C_ORANGE, C_TEAL, C_BLUE]
            for i, (lbl, lx, ly) in enumerate(offsets):
                c.setFillColor(cols2[i])
                c.rect(lx - 3, ly - 2, 10, 8, fill=1, stroke=0)
                c.setFillColor(C_GRAY)
                c.setFont("Helvetica", 8)
                c.drawString(lx + 12, ly, lbl)

            c.setFillColor(C_NAVY)
            c.setFont("Helvetica-Bold", 8)
            c.drawString(270, 65, "Rule to remember:")
            c.setFillColor(C_GRAY)
            c.setFont("Helvetica", 8)
            c.drawString(270, 52, "Fibers from LOWER segments (sacral)")
            c.drawString(270, 40, "are displaced LATERALLY as higher-")
            c.drawString(270, 28, "segment fibers add on MEDIALLY.")
            c.setFillColor(C_RED)
            c.setFont("Helvetica-Bold", 8)
            c.drawString(270, 14, "⟹  Lateral = sacral/lower limb")

    story.append(SomatotopyDiagram())
    story.append(Spacer(1, 4))
    story.append(Paragraph(
        "<i>Somatotopic layering of the spinothalamic tract in cross-section. "
        "Sacral (S) fibers are outermost (most lateral); cervical (C) fibers are innermost. "
        "This arrangement is preserved throughout the brainstem ascent.</i>",
        S_CAPTION))
    story.append(Spacer(1, 10))

    # PAGE BREAK before comparison
    story.append(PageBreak())

    # ═══════════════════════════════════════════════════════
    # SECTION 7 — Characteristics (Guyton)
    # ═══════════════════════════════════════════════════════
    story.append(SectionHeader("7.  CHARACTERISTICS OF TRANSMISSION (Guyton, Ch. 48)", C_ORANGE, pw))
    story.append(Spacer(1, 6))

    char_data = [
        ["Characteristic", "Spinothalamic / Anterolateral", "Dorsal Column-Med. Lemniscal"],
        ["Conduction velocity", "8–40 m/sec", "30–110 m/sec"],
        ["Spatial localization", "Poor", "Precise"],
        ["Intensity gradations", "~10–20 levels", "~100 levels"],
        ["Rapidly changing signals", "Poor", "Excellent"],
        ["System type", "Crude", "Discriminative"],
        ["Unique modalities", "Pain, Temp, Itch, Tickle, Sexual", "2-pt discrimination, Stereognosis"],
    ]
    tbl3 = Table(char_data, colWidths=[pw*0.30, pw*0.35, pw*0.35])
    tbl3.setStyle(TableStyle([
        ("BACKGROUND",    (0,0), (-1,0), C_ORANGE),
        ("TEXTCOLOR",     (0,0), (-1,0), C_WHITE),
        ("FONTNAME",      (0,0), (-1,0), "Helvetica-Bold"),
        ("FONTNAME",      (0,1), (-1,-1), "Helvetica"),
        ("FONTSIZE",      (0,0), (-1,-1), 8.5),
        ("ROWBACKGROUNDS",(0,1), (-1,-1), [C_AMBER, C_WHITE]),
        ("GRID",          (0,0), (-1,-1), 0.5, colors.HexColor("#ffcc80")),
        ("VALIGN",        (0,0), (-1,-1), "MIDDLE"),
        ("LEFTPADDING",   (0,0), (-1,-1), 7),
        ("TOPPADDING",    (0,0), (-1,-1), 5),
        ("BOTTOMPADDING", (0,0), (-1,-1), 5),
    ]))
    story.append(tbl3)
    story.append(Spacer(1, 10))

    # ═══════════════════════════════════════════════════════
    # SECTION 8 — Comparison diagram
    # ═══════════════════════════════════════════════════════
    story.append(SectionHeader("8.  PATHWAY COMPARISON DIAGRAM", C_TEAL, pw))
    story.append(Spacer(1, 6))
    story.append(ComparisonDiagram())
    story.append(Spacer(1, 10))

    # ═══════════════════════════════════════════════════════
    # SECTION 9 — Clinical correlations
    # ═══════════════════════════════════════════════════════
    story.append(SectionHeader("9.  CLINICAL CORRELATIONS", C_RED, pw))
    story.append(Spacer(1, 6))

    # Brown-Séquard
    story.append(Paragraph("<b>A. Brown-Séquard Syndrome (Cord Hemisection)</b>", S_H2))
    story.append(BrownSequardDiagram())
    story.append(Spacer(1, 6))

    # Syringomyelia
    story.append(Paragraph("<b>B. Syringomyelia</b>", S_H2))
    story.append(Paragraph(
        "Cavitation of the <b>central canal</b> preferentially damages the <b>anterior commissure</b> "
        "where spinothalamic fibers cross. This produces <b>bilateral loss of pain and temperature</b> "
        "at the level of the syrinx in a cape-like (shawl) distribution, while <b>dorsal columns "
        "are spared</b> → called <b>dissociated sensory loss</b>. As the cavity enlarges, it eventually "
        "damages the dorsal columns and anterior horn cells.",
        S_BODY))
    story.append(Spacer(1, 6))

    # Lateral medullary
    story.append(Paragraph("<b>C. Lateral Medullary (Wallenberg) Syndrome</b>", S_H2))
    story.append(Paragraph(
        "Infarction of the posterolateral medulla (PICA territory) damages the <b>spinothalamic tract</b> "
        "after it has already crossed. This causes <b>contralateral loss of pain & temperature on the body</b> "
        "plus <b>ipsilateral loss of facial sensation</b> (via trigeminal nucleus also in the lateral medulla) "
        "— the classic <b>crossed sensory loss</b>.",
        S_BODY))
    story.append(Spacer(1, 6))

    # Anterolateral cordotomy
    story.append(Paragraph("<b>D. Anterolateral Cordotomy</b>", S_H2))
    story.append(Paragraph(
        "Surgical or percutaneous section of the spinothalamic tract is used for intractable pain. "
        "Because the tract has already crossed, the procedure relieves pain <b>contralateral</b> to and "
        "<b>below</b> the level of the cut. Pain relief may be temporary due to reorganization.",
        S_BODY))
    story.append(Spacer(1, 10))

    # ═══════════════════════════════════════════════════════
    # SECTION 10 — Key points box
    # ═══════════════════════════════════════════════════════
    story.append(SectionHeader("10.  KEY POINTS TO REMEMBER", C_NAVY, pw))
    story.append(Spacer(1, 6))

    key_pts = [
        "1. Spinothalamic tract = Pain, Temperature, Crude touch (NOT fine touch or proprioception)",
        "2. Fibers cross in the ANTERIOR COMMISSURE of spinal cord — 2-3 segments after entry",
        "3. Somatotopy: Sacral (lateral) → Lumbar → Thoracic → Cervical (medial) — 'SALT'",
        "4. Three tracts: Spinothalamic (VPL) | Spinoreticular (arousal) | Spinomesencephalic (PAG, modulation)",
        "5. Conduction velocity only 8–40 m/sec (slow, crude), poor localization, 10–20 intensity gradations",
        "6. Brown-Séquard: Contralateral pain/temp loss BELOW + Ipsilateral dorsal column loss",
        "7. Syringomyelia: Bilateral pain/temp loss at level (ant. commissure damage) = dissociated loss",
        "8. Wallenberg: Contralateral body pain/temp loss + Ipsilateral face loss (crossed pattern)",
    ]
    for pt in key_pts:
        col = C_LBLUE if int(pt[0]) % 2 == 1 else C_LGREEN
        kp_tbl = Table([[Paragraph(pt, S_BOX)]], colWidths=[pw])
        kp_tbl.setStyle(TableStyle([
            ("BACKGROUND",    (0,0), (-1,-1), col),
            ("LEFTPADDING",   (0,0), (-1,-1), 8),
            ("TOPPADDING",    (0,0), (-1,-1), 5),
            ("BOTTOMPADDING", (0,0), (-1,-1), 5),
            ("LINEBELOW",     (0,0), (-1,-1), 0.5, colors.HexColor("#bbdefb")),
        ]))
        story.append(kp_tbl)
        story.append(Spacer(1, 2))

    story.append(Spacer(1, 14))

    # References
    story.append(HRFlowable(width=pw, thickness=0.5, color=C_GRAY))
    story.append(Spacer(1, 4))
    story.append(Paragraph(
        "<b>References:</b> Guyton AC, Hall JE. <i>Textbook of Medical Physiology</i>, 14e — Chapters 48 & 49.  |  "
        "Blumenfeld H. <i>Neuroanatomy through Clinical Cases</i>, 3e — Chapter 7.",
        S_SMALL))

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

build()

Successfully replaced 1 instance(s) of the string in '/home/daytona/workspace/spinothalamic/make_pdf.py'

Successfully replaced 1 instance(s) of the string in '/home/daytona/workspace/spinothalamic/make_pdf.py'

Successfully replaced 1 instance(s) of the string in '/home/daytona/workspace/spinothalamic/make_pdf.py'