const {
  Document, Packer, Paragraph, TextRun, Table, TableRow, TableCell,
  Header, Footer, AlignmentType, LevelFormat, HeadingLevel,
  BorderStyle, WidthType, ShadingType, VerticalAlign,
  PageNumber, PageBreak, TableOfContents
} = require('docx');
const fs = require('fs');

// ─── Color palette ────────────────────────────────────────────────────────────
const COLOR = {
  DARK_BLUE:   "1F3864",
  MED_BLUE:    "2E75B6",
  LIGHT_BLUE:  "D6E4F0",
  HEADER_BG:   "2E75B6",
  HEADER_FG:   "FFFFFF",
  ALT_ROW:     "EBF3FB",
  WHITE:       "FFFFFF",
  ALERT_RED:   "C0392B",
  ALERT_BG:    "FDEDEC",
  TIP_GREEN:   "1E8449",
  TIP_BG:      "EAFAF1",
  GRAY_TEXT:   "555555",
  BORDER:      "BBBBBB",
};

// ─── Reusable border helpers ─────────────────────────────────────────────────
const thinBorder = (color = COLOR.BORDER) => ({
  style: BorderStyle.SINGLE, size: 4, color
});
const cellBorders = (color = COLOR.BORDER) => ({
  top:    thinBorder(color),
  bottom: thinBorder(color),
  left:   thinBorder(color),
  right:  thinBorder(color),
});
const headerCellBorders = () => ({
  top:    thinBorder(COLOR.MED_BLUE),
  bottom: thinBorder(COLOR.MED_BLUE),
  left:   thinBorder(COLOR.MED_BLUE),
  right:  thinBorder(COLOR.MED_BLUE),
});

// ─── Cell factory ─────────────────────────────────────────────────────────────
function makeCell(text, width, opts = {}) {
  const {
    bold = false,
    isHeader = false,
    color = isHeader ? COLOR.HEADER_BG : COLOR.WHITE,
    textColor = isHeader ? COLOR.HEADER_FG : "000000",
    fontSize = 20,
    borders = isHeader ? headerCellBorders() : cellBorders(),
    vAlign = VerticalAlign.CENTER,
  } = opts;

  return new TableCell({
    borders,
    width: { size: width, type: WidthType.DXA },
    shading: { fill: color, type: ShadingType.CLEAR },
    margins: { top: 80, bottom: 80, left: 150, right: 150 },
    verticalAlign: vAlign,
    children: [new Paragraph({
      alignment: AlignmentType.LEFT,
      children: [new TextRun({
        text,
        bold: bold || isHeader,
        font: "Arial",
        size: fontSize,
        color: textColor,
      })]
    })]
  });
}

// ─── Paragraph helpers ────────────────────────────────────────────────────────
function para(text, opts = {}) {
  const { bold = false, italic = false, color = "000000", size = 22,
          spacing = { before: 80, after: 80 }, align = AlignmentType.LEFT } = opts;
  return new Paragraph({
    alignment: align,
    spacing,
    children: [new TextRun({ text, bold, italic, color, font: "Arial", size })]
  });
}

function heading1(text) {
  return new Paragraph({
    heading: HeadingLevel.HEADING_1,
    children: [new TextRun({ text, font: "Arial", bold: true, size: 36, color: COLOR.DARK_BLUE })]
  });
}

function heading2(text) {
  return new Paragraph({
    heading: HeadingLevel.HEADING_2,
    children: [new TextRun({ text, font: "Arial", bold: true, size: 28, color: COLOR.MED_BLUE })]
  });
}

function heading3(text) {
  return new Paragraph({
    heading: HeadingLevel.HEADING_3,
    children: [new TextRun({ text, font: "Arial", bold: true, size: 24, color: COLOR.DARK_BLUE })]
  });
}

function spacer(lines = 1) {
  return Array.from({ length: lines }, () => new Paragraph({
    children: [new TextRun("")],
    spacing: { before: 0, after: 0 }
  }));
}

function bullet(text, opts = {}) {
  return new Paragraph({
    numbering: { reference: "bullets", level: 0 },
    spacing: { before: 40, after: 40 },
    children: [new TextRun({ text, font: "Arial", size: 22, ...opts })]
  });
}

function numbered(text, opts = {}) {
  return new Paragraph({
    numbering: { reference: "numbers", level: 0 },
    spacing: { before: 40, after: 40 },
    children: [new TextRun({ text, font: "Arial", size: 22, ...opts })]
  });
}

function mixedPara(runs, opts = {}) {
  const { spacing = { before: 80, after: 80 }, align = AlignmentType.LEFT } = opts;
  return new Paragraph({ alignment: align, spacing, children: runs });
}

function tr(run, txt) {
  return new TextRun({ text: txt, font: "Arial", size: 22, ...run });
}

// ─── Note/alert box using a border paragraph ─────────────────────────────────
function noteParagraph(text, type = "tip") {
  const bgColor   = type === "alert" ? COLOR.ALERT_BG : COLOR.TIP_BG;
  const textColor = type === "alert" ? COLOR.ALERT_RED : COLOR.TIP_GREEN;
  const prefix    = type === "alert" ? "ALERT: " : "TIP: ";
  return new Paragraph({
    spacing: { before: 120, after: 120 },
    border: {
      top:    { style: BorderStyle.SINGLE, size: 6, color: textColor },
      bottom: { style: BorderStyle.SINGLE, size: 6, color: textColor },
      left:   { style: BorderStyle.THICK,  size: 18, color: textColor },
      right:  { style: BorderStyle.SINGLE, size: 6, color: textColor },
    },
    shading: { fill: bgColor, type: ShadingType.CLEAR },
    indent: { left: 240, right: 240 },
    children: [
      new TextRun({ text: prefix, bold: true, font: "Arial", size: 22, color: textColor }),
      new TextRun({ text, font: "Arial", size: 22, color: "000000" })
    ]
  });
}

// ─── Divider line ─────────────────────────────────────────────────────────────
function divider() {
  return new Paragraph({
    spacing: { before: 120, after: 120 },
    border: { bottom: { style: BorderStyle.SINGLE, size: 6, color: COLOR.MED_BLUE, space: 1 } },
    children: [new TextRun("")]
  });
}

// ─── Page break ──────────────────────────────────────────────────────────────
function pageBreak() {
  return new Paragraph({ children: [new PageBreak()] });
}

// ─────────────────────────────────────────────────────────────────────────────
// COVER PAGE
// ─────────────────────────────────────────────────────────────────────────────
function buildCoverPage() {
  return [
    ...spacer(4),
    new Paragraph({
      alignment: AlignmentType.CENTER,
      spacing: { before: 0, after: 200 },
      children: [new TextRun({
        text: "PEDIATRICS FOR PHARMACISTS",
        font: "Arial", size: 56, bold: true, color: COLOR.DARK_BLUE
      })]
    }),
    new Paragraph({
      alignment: AlignmentType.CENTER,
      spacing: { before: 0, after: 160 },
      children: [new TextRun({
        text: "Complete MBBS-Level Course",
        font: "Arial", size: 36, bold: false, color: COLOR.MED_BLUE
      })]
    }),
    divider(),
    ...spacer(1),
    new Paragraph({
      alignment: AlignmentType.CENTER,
      spacing: { before: 120, after: 120 },
      children: [new TextRun({
        text: "CHAPTER 1",
        font: "Arial", size: 32, bold: true, color: COLOR.MED_BLUE
      })]
    }),
    new Paragraph({
      alignment: AlignmentType.CENTER,
      spacing: { before: 0, after: 200 },
      children: [new TextRun({
        text: "Introduction to Pediatrics & Child Growth / Development",
        font: "Arial", size: 28, bold: false, color: COLOR.DARK_BLUE
      })]
    }),
    ...spacer(3),
    new Paragraph({
      alignment: AlignmentType.CENTER,
      spacing: { before: 80, after: 80 },
      children: [new TextRun({
        text: "Pharmacist Training Series  |  MBBS-Level Curriculum",
        font: "Arial", size: 22, italic: true, color: COLOR.GRAY_TEXT
      })]
    }),
    ...spacer(2),
    new Paragraph({
      alignment: AlignmentType.CENTER,
      spacing: { before: 80, after: 80 },
      children: [new TextRun({
        text: "Reference Sources: The Harriet Lane Handbook 23rd Ed  |  Nelson Textbook of Pediatrics  |  WHO Child Growth Standards",
        font: "Arial", size: 18, italic: true, color: COLOR.GRAY_TEXT
      })]
    }),
    pageBreak()
  ];
}

// ─────────────────────────────────────────────────────────────────────────────
// CURRICULUM OVERVIEW
// ─────────────────────────────────────────────────────────────────────────────
function buildCurriculumOverview() {
  const chapters = [
    ["1",  "Introduction to Pediatrics & Age Groups"],
    ["2",  "Growth & Development (Milestones)"],
    ["3",  "Nutrition in Children (Breastfeeding, Weaning, Malnutrition)"],
    ["4",  "Immunization & Vaccines"],
    ["5",  "Neonatal Medicine (Newborn Care, Jaundice, Sepsis)"],
    ["6",  "Respiratory Diseases (ARI, Pneumonia, Asthma, Croup)"],
    ["7",  "Gastrointestinal Diseases (Diarrhea, Vomiting, GERD, Worm Infestations)"],
    ["8",  "Fever & Febrile Illnesses (Malaria, Typhoid, Dengue)"],
    ["9",  "Infectious Diseases (Measles, Chickenpox, Meningitis, TB)"],
    ["10", "Cardiovascular Diseases in Children (Congenital Heart Disease)"],
    ["11", "Hematological Disorders (Anemia, Thalassemia, Sickle Cell)"],
    ["12", "Neurological Disorders (Seizures, Cerebral Palsy, Meningitis)"],
    ["13", "Renal Diseases (UTI, Nephrotic Syndrome, Nephritic Syndrome)"],
    ["14", "Endocrine & Metabolic Disorders (Diabetes, Hypothyroidism)"],
    ["15", "Dermatological Conditions in Children"],
    ["16", "Pediatric Emergencies (Shock, Anaphylaxis, Status Asthmaticus)"],
    ["17", "Pediatric Pharmacology & Drug Dosing"],
  ];

  const tableWidth = 9360;
  const col1 = 900, col2 = 8460;

  const headerRow = new TableRow({
    tableHeader: true,
    children: [
      makeCell("Ch.", col1, { isHeader: true }),
      makeCell("Chapter Title", col2, { isHeader: true }),
    ]
  });

  const dataRows = chapters.map(([ch, title], i) => new TableRow({
    children: [
      makeCell(ch, col1, {
        color: i % 2 === 0 ? COLOR.WHITE : COLOR.ALT_ROW,
        bold: true,
        textColor: COLOR.MED_BLUE
      }),
      makeCell(title, col2, {
        color: i % 2 === 0 ? COLOR.WHITE : COLOR.ALT_ROW,
        bold: ch === "1"
      }),
    ]
  }));

  return [
    heading1("Full Curriculum Overview – All 17 Chapters"),
    ...spacer(1),
    para("This course covers the complete spectrum of pediatric medicine as applicable to pharmacists. Each chapter builds on the previous, progressing from foundational concepts to complex disease management.", { spacing: { before: 80, after: 160 } }),
    new Table({
      width: { size: tableWidth, type: WidthType.DXA },
      columnWidths: [col1, col2],
      rows: [headerRow, ...dataRows]
    }),
    ...spacer(1),
    pageBreak()
  ];
}

// ─────────────────────────────────────────────────────────────────────────────
// CHAPTER 1 BODY
// ─────────────────────────────────────────────────────────────────────────────

// 1.1  What is Pediatrics?
function section1_1() {
  return [
    heading2("1.1  What Is Pediatrics?"),
    para("Pediatrics is the branch of medicine concerned with the health, development, diseases, and care of children from birth to 18 years of age. The word comes from Greek: \"paidos\" (child) + \"iatros\" (physician).", { spacing: { before: 80, after: 120 } }),
    para("As a pharmacist working in pediatrics, you must understand:", { bold: true, spacing: { before: 80, after: 80 } }),
    bullet("Differences between children and adults (children are NOT just small adults)"),
    bullet("Age-based drug dosing"),
    bullet("Special physiological considerations"),
    bullet("Growth and developmental milestones"),
    ...spacer(1),
  ];
}

// 1.2  Age Groups
function section1_2() {
  const tableWidth = 9360;
  const cols = [2100, 2100, 5160];

  const header = new TableRow({
    tableHeader: true,
    children: [
      makeCell("Age Group",    cols[0], { isHeader: true }),
      makeCell("Age Range",    cols[1], { isHeader: true }),
      makeCell("Key Features", cols[2], { isHeader: true }),
    ]
  });

  const data = [
    ["Neonate / Newborn", "0–28 days",     "Most vulnerable; immature organ systems"],
    ["Infant",            "1–12 months",   "Rapid growth; breastfeeding period"],
    ["Toddler",           "1–3 years",     "Motor development; weaning period"],
    ["Preschool Child",   "3–6 years",     "Language development; vaccine boosters"],
    ["School-age Child",  "6–12 years",    "Cognitive development; increasing independence"],
    ["Adolescent",        "12–18 years",   "Puberty; adult-like physiology begins"],
  ];

  const rows = data.map(([grp, range, feat], i) => new TableRow({
    children: [
      makeCell(grp,   cols[0], { color: i % 2 === 0 ? COLOR.WHITE : COLOR.ALT_ROW, bold: true }),
      makeCell(range, cols[1], { color: i % 2 === 0 ? COLOR.WHITE : COLOR.ALT_ROW }),
      makeCell(feat,  cols[2], { color: i % 2 === 0 ? COLOR.WHITE : COLOR.ALT_ROW }),
    ]
  }));

  return [
    heading2("1.2  Age Groups in Pediatrics"),
    ...spacer(1),
    new Table({ width: { size: tableWidth, type: WidthType.DXA }, columnWidths: cols, rows: [header, ...rows] }),
    ...spacer(1),
    noteParagraph("Neonatal period (first 28 days) is the highest-risk period for childhood mortality. Particular care is required for drug dosing in neonates.", "alert"),
    ...spacer(1),
  ];
}

// 1.3  Why Children Are NOT Small Adults
function section1_3() {
  return [
    heading2("1.3  Why Children Are NOT Small Adults – Key Physiological Differences"),
    para("Children differ from adults in every pharmacokinetic parameter. Understanding these differences is essential for safe drug prescribing and dispensing.", { spacing: { before: 80, after: 120 } }),

    heading3("A. Body Composition"),
    bullet("Higher percentage of total body water (TBW) in neonates (~75%) vs. adults (~60%)"),
    bullet("This affects the VOLUME OF DISTRIBUTION (Vd) of water-soluble drugs"),
    bullet("Less body fat in neonates → affects fat-soluble drug distribution"),
    ...spacer(1),

    heading3("B. Liver & Drug Metabolism"),
    bullet("Liver enzymes (CYP450 system) are immature at birth"),
    bullet("CYP3A4 reaches adult levels by approximately 6 months of age"),
    bullet("CYP1A2 reaches adult levels by approximately 1 year of age"),
    mixedPara([
      tr({ bold: true }, "RESULT: "),
      tr({}, "Some drugs have prolonged half-lives in neonates (e.g., morphine, phenobarbital)"),
    ], { spacing: { before: 60, after: 60 } }),
    mixedPara([
      tr({ bold: true }, "EXCEPTION: "),
      tr({}, "Some drugs are metabolized FASTER in children aged 2–6 years (e.g., theophylline)"),
    ], { spacing: { before: 60, after: 80 } }),
    ...spacer(1),

    heading3("C. Renal Function"),
    bullet("GFR at birth = ~20 mL/min/1.73 m\u00B2 (adult value = 120 mL/min/1.73 m\u00B2)"),
    bullet("Reaches adult levels by age 1–2 years"),
    mixedPara([
      tr({ bold: true }, "RESULT: "),
      tr({}, "Renally cleared drugs (aminoglycosides, vancomycin) require dose adjustment in neonates"),
    ], { spacing: { before: 60, after: 80 } }),
    ...spacer(1),

    heading3("D. Protein Binding"),
    bullet("Lower albumin levels in neonates → higher free (unbound) fraction of highly protein-bound drugs"),
    bullet("Examples: phenytoin, warfarin – risk of toxicity even at \"normal\" doses"),
    ...spacer(1),

    heading3("E. Gastric Absorption"),
    bullet("Gastric pH in neonates is HIGH (alkaline, ~6–8), which affects oral drug absorption"),
    bullet("Gastric emptying is slower in neonates"),
    bullet("Penicillin G has better bioavailability in neonates due to high gastric pH"),
    ...spacer(1),
  ];
}

// 1.4  Vital Signs
function section1_4() {
  const tableWidth = 9360;
  const cols = [1600, 1600, 2160, 2160, 1840];

  const header = new TableRow({
    tableHeader: true,
    children: [
      makeCell("Age Group",              cols[0], { isHeader: true }),
      makeCell("Heart Rate (bpm)",       cols[1], { isHeader: true }),
      makeCell("Respiratory Rate (/min)",cols[2], { isHeader: true }),
      makeCell("Systolic BP (mmHg)",     cols[3], { isHeader: true }),
      makeCell("",                       cols[4], { isHeader: true }),  // spacer for even col distribution
    ]
  });

  // re-define cols to 4 since we'll drop the last
  const cols4 = [1800, 1800, 2800, 2960];

  const header4 = new TableRow({
    tableHeader: true,
    children: [
      makeCell("Age Group",               cols4[0], { isHeader: true }),
      makeCell("Heart Rate (bpm)",        cols4[1], { isHeader: true }),
      makeCell("Resp. Rate (/min)",       cols4[2], { isHeader: true }),
      makeCell("Systolic BP (mmHg)",      cols4[3], { isHeader: true }),
    ]
  });

  const vitalData = [
    ["Neonate (0–28 d)",   "100–160", "40–60",  "60–90"],
    ["Infant (1–12 m)",    "100–150", "30–50",  "70–100"],
    ["Toddler (1–3 y)",    "90–140",  "24–40",  "80–110"],
    ["Preschool (3–6 y)",  "80–120",  "22–34",  "85–115"],
    ["School-age (6–12 y)","70–110",  "18–30",  "90–120"],
    ["Adolescent (12–18 y)","60–100", "12–16",  "100–130"],
  ];

  const vitalRows = vitalData.map(([age, hr, rr, bp], i) => new TableRow({
    children: cols4.map((w, ci) => makeCell([age, hr, rr, bp][ci], w, {
      color: i % 2 === 0 ? COLOR.WHITE : COLOR.ALT_ROW,
      bold: ci === 0
    }))
  }));

  return [
    heading2("1.4  Vital Signs by Age Group"),
    ...spacer(1),
    new Table({ width: { size: 9360, type: WidthType.DXA }, columnWidths: cols4, rows: [header4, ...vitalRows] }),
    ...spacer(1),
    noteParagraph("MEMORY TIP: Heart rate and respiratory rate DECREASE with age; blood pressure INCREASES with age.", "tip"),
    ...spacer(1),
  ];
}

// 1.5  Drug Dosing Formulas
function section1_5() {
  return [
    heading2("1.5  Pediatric Drug Dosing Formulas (Pharmacist Essential)"),
    ...spacer(1),

    heading3("Weight-Based Dosing (Most Common)"),
    para("Dose = mg/kg/day   OR   mg/kg/dose", { bold: true }),
    para("Example: Amoxicillin 40 mg/kg/day in 3 divided doses for a 15 kg child:", { spacing: { before: 60, after: 40 } }),
    bullet("Total daily dose = 40 \u00D7 15 = 600 mg/day"),
    bullet("Per dose (TID) = 600 \u00F7 3 = 200 mg per dose"),
    ...spacer(1),

    heading3("Clark's Rule (Weight-Based)"),
    new Paragraph({
      spacing: { before: 60, after: 100 },
      children: [new TextRun({ text: "Child dose = (Weight in kg \u00F7 70) \u00D7 Adult dose", font: "Arial", size: 22, bold: true, color: COLOR.DARK_BLUE })]
    }),
    ...spacer(1),

    heading3("Young's Rule (Age-Based, for children > 2 years)"),
    new Paragraph({
      spacing: { before: 60, after: 100 },
      children: [new TextRun({ text: "Child dose = [Age \u00F7 (Age + 12)] \u00D7 Adult dose", font: "Arial", size: 22, bold: true, color: COLOR.DARK_BLUE })]
    }),
    ...spacer(1),

    heading3("Fried's Rule (for infants < 1 year)"),
    new Paragraph({
      spacing: { before: 60, after: 100 },
      children: [new TextRun({ text: "Child dose = [Age in months \u00F7 150] \u00D7 Adult dose", font: "Arial", size: 22, bold: true, color: COLOR.DARK_BLUE })]
    }),
    ...spacer(1),

    heading3("Body Surface Area (BSA) Method – Most Accurate"),
    para("Used primarily for chemotherapy agents and drugs with a narrow therapeutic index.", { spacing: { before: 40, after: 80 } }),
    new Paragraph({
      spacing: { before: 60, after: 60 },
      children: [new TextRun({ text: "Child dose = (BSA of child \u00F7 1.73 m\u00B2) \u00D7 Adult dose", font: "Arial", size: 22, bold: true, color: COLOR.DARK_BLUE })]
    }),
    new Paragraph({
      spacing: { before: 40, after: 100 },
      children: [new TextRun({ text: "BSA (m\u00B2) = \u221A[(Height in cm \u00D7 Weight in kg) \u00F7 3600]", font: "Arial", size: 22, bold: true, color: COLOR.DARK_BLUE })]
    }),
    noteParagraph("Weight-based dosing (mg/kg) is the most commonly used method in clinical practice. Always verify the child's current weight before dispensing.", "tip"),
    ...spacer(1),
  ];
}

// 1.6  Routes of Administration
function section1_6() {
  const tableWidth = 9360;
  const cols = [1800, 7560];

  const header = new TableRow({
    tableHeader: true,
    children: [
      makeCell("Route",          cols[0], { isHeader: true }),
      makeCell("Key Considerations", cols[1], { isHeader: true }),
    ]
  });

  const routeData = [
    ["Oral (PO)",          "Preferred route; syrups/suspensions for young children; always check if food affects absorption"],
    ["IV (Intravenous)",   "For emergencies; fast-acting; dilution and rate of infusion are critical"],
    ["IM (Intramuscular)", "Used for vaccines; painful; limited injection sites in infants"],
    ["Rectal (PR)",        "For vomiting children; diazepam rectal gel for acute seizures; paracetamol suppositories"],
    ["Inhalation",         "For asthma drugs (salbutamol, budesonide); spacer device required in young children and infants"],
    ["Topical",            "Limited routine use; absorption is higher in children due to thinner stratum corneum"],
    ["Nasogastric (NG)",   "For critically ill neonates who cannot feed or take oral medication"],
  ];

  const routeRows = routeData.map(([route, note], i) => new TableRow({
    children: [
      makeCell(route, cols[0], { color: i % 2 === 0 ? COLOR.WHITE : COLOR.ALT_ROW, bold: true }),
      makeCell(note,  cols[1], { color: i % 2 === 0 ? COLOR.WHITE : COLOR.ALT_ROW }),
    ]
  }));

  return [
    heading2("1.6  Common Routes of Drug Administration in Pediatrics"),
    ...spacer(1),
    new Table({ width: { size: tableWidth, type: WidthType.DXA }, columnWidths: cols, rows: [header, ...routeRows] }),
    ...spacer(1),
  ];
}

// 1.7  Normal Weight & Height
function section1_7() {
  return [
    heading2("1.7  Normal Weight & Height for Age (Reference Values)"),
    ...spacer(1),

    heading3("Weight Estimation Formulas"),
    bullet("Neonate at birth: ~3.0–3.5 kg (doubles by 5 months; triples by 1 year)"),
    bullet("Age 1 year: approximately 10 kg"),
    mixedPara([
      tr({ bold: true }, "Age 1–6 years:  "),
      tr({ bold: false }, "Weight (kg) = Age (years) \u00D7 2 + 8"),
    ], { spacing: { before: 40, after: 40 } }),
    mixedPara([
      tr({ bold: true }, "Age 7–12 years: "),
      tr({ bold: false }, "Weight (kg) = Age (years) \u00D7 3 + 3"),
    ], { spacing: { before: 40, after: 80 } }),
    ...spacer(1),

    heading3("Height Estimation"),
    bullet("Birth: ~50 cm"),
    bullet("1 year: ~75 cm"),
    bullet("2 years: ~87 cm"),
    bullet("After 2 years: +6 cm per year"),
    ...spacer(1),

    heading3("Head Circumference (Brain Growth Indicator)"),
    bullet("Birth: ~34 cm"),
    bullet("6 months: ~43 cm"),
    bullet("1 year: ~46 cm"),
    bullet("2 years: ~48 cm"),
    bullet("Adult: ~54–57 cm"),
    noteParagraph("Head circumference is a critical screening tool. Macrocephaly (>2 SD above mean) may indicate hydrocephalus; microcephaly (<2 SD below mean) may indicate brain growth restriction.", "alert"),
    ...spacer(1),
  ];
}

// 1.8  Pediatric Emergencies
function section1_8() {
  const tableWidth = 9360;
  const cols = [2200, 3260, 3900];

  const header = new TableRow({
    tableHeader: true,
    children: [
      makeCell("Drug",            cols[0], { isHeader: true }),
      makeCell("Dose",            cols[1], { isHeader: true }),
      makeCell("Indication",      cols[2], { isHeader: true }),
    ]
  });

  const emergencyDrugs = [
    ["Epinephrine (Adrenaline)", "0.01 mg/kg IV/IO (1:10,000 solution)",   "Cardiac arrest, anaphylaxis"],
    ["Atropine",                 "0.02 mg/kg IV (minimum 0.1 mg)",          "Symptomatic bradycardia"],
    ["Adenosine",                "0.1 mg/kg IV rapid push (max 6 mg)",      "SVT (supraventricular tachycardia)"],
    ["Glucose (Dextrose 10%)",   "2 mL/kg IV",                              "Hypoglycemia"],
    ["Normal Saline (0.9% NS)",  "20 mL/kg IV bolus",                       "Shock / hypovolemia"],
  ];

  const drugRows = emergencyDrugs.map(([drug, dose, ind], i) => new TableRow({
    children: [
      makeCell(drug, cols[0], { color: i % 2 === 0 ? COLOR.WHITE : COLOR.ALT_ROW, bold: true }),
      makeCell(dose, cols[1], { color: i % 2 === 0 ? COLOR.WHITE : COLOR.ALT_ROW }),
      makeCell(ind,  cols[2], { color: i % 2 === 0 ? COLOR.WHITE : COLOR.ALT_ROW }),
    ]
  }));

  return [
    heading2("1.8  Pediatric Emergencies – First Response (Introduction)"),
    ...spacer(1),
    para("The C-A-B approach (Compressions → Airway → Breathing) is used in pediatric basic life support:", { bold: true, spacing: { before: 80, after: 80 } }),
    bullet("If pulseless OR HR <60 bpm with poor perfusion → Start CPR immediately"),
    bullet("Chest compression rate: 100–120 per minute"),
    bullet("Compression depth: At least 1/3 of anteroposterior chest diameter"),
    bullet("Infant technique: 2 fingers OR 2-thumb encircling technique"),
    bullet("Child technique: 1 or 2 hands"),
    ...spacer(1),
    heading3("Key Emergency Drugs (Memorize These)"),
    ...spacer(1),
    new Table({ width: { size: tableWidth, type: WidthType.DXA }, columnWidths: cols, rows: [header, ...drugRows] }),
    ...spacer(1),
  ];
}

// 1.9  Summary
function section1_9() {
  return [
    heading2("1.9  Summary & Key Points for Pharmacists"),
    ...spacer(1),
    numbered("Pediatrics covers newborns (0 days) through adolescents (18 years)"),
    numbered("Neonates have immature liver, kidney, and enzyme systems → drug doses must be carefully calculated"),
    numbered("Children aged 2–6 years may metabolize some drugs FASTER than adults (CYP induction)"),
    numbered("Always use WEIGHT-BASED dosing; confirm actual weight before dispensing"),
    numbered("Know the common dosing formulas: Clark's, Young's, Fried's, and BSA method"),
    numbered("Age-appropriate formulations are critical (no aspirin in children <12 years due to Reye's syndrome)"),
    numbered("Monitor vital signs against age-appropriate reference ranges"),
    numbered("For oral suspensions: follow manufacturer reconstitution instructions; note expiry after reconstitution"),
    ...spacer(1),
  ];
}

// 1.10  Drug Safety Alerts
function section1_10() {
  const tableWidth = 9360;
  const cols = [2200, 4760, 2400];

  const header = new TableRow({
    tableHeader: true,
    children: [
      makeCell("Drug",                  cols[0], { isHeader: true }),
      makeCell("Reason Avoided",        cols[1], { isHeader: true }),
      makeCell("Age Restriction",       cols[2], { isHeader: true }),
    ]
  });

  const alertData = [
    ["Aspirin",                         "Reye's syndrome: fatal liver and brain damage",               "Avoid < 12 years"],
    ["Fluoroquinolones (Ciprofloxacin)","Cartilage damage (arthropathy) in growing joints",            "Avoid < 18 years*"],
    ["Tetracyclines (Doxycycline)",     "Tooth discoloration and bone growth inhibition",              "Avoid < 8 years"],
    ["Codeine",                         "Fatal respiratory depression in ultra-rapid CYP2D6 metabolizers","Avoid < 12 years"],
    ["Chloramphenicol",                 "Gray baby syndrome: cardiovascular collapse due to enzyme immaturity","Avoid in neonates"],
    ["Metoclopramide",                  "Extrapyramidal side effects (dystonia, tardive dyskinesia)",   "Caution < 1 year"],
    ["Benzyl alcohol (preservative)",   "Gasping syndrome in neonates (metabolic acidosis, CNS depression)","Avoid in neonates"],
  ];

  const alertRows = alertData.map(([drug, reason, age], i) => new TableRow({
    children: [
      makeCell(drug,   cols[0], { color: i % 2 === 0 ? COLOR.WHITE : COLOR.ALERT_BG, bold: true, textColor: COLOR.ALERT_RED }),
      makeCell(reason, cols[1], { color: i % 2 === 0 ? COLOR.WHITE : COLOR.ALERT_BG }),
      makeCell(age,    cols[2], { color: i % 2 === 0 ? COLOR.WHITE : COLOR.ALERT_BG, bold: true }),
    ]
  }));

  return [
    heading2("1.10  Important Drug Safety Alerts in Pediatrics"),
    noteParagraph("These contraindications are high-yield exam and clinical practice topics. Memorize each drug and its corresponding risk.", "alert"),
    ...spacer(1),
    new Table({ width: { size: tableWidth, type: WidthType.DXA }, columnWidths: cols, rows: [header, ...alertRows] }),
    para("* Fluoroquinolones may be used in children for specific indications (e.g., complicated UTI, anthrax exposure) when no safe alternative exists.", { italic: true, color: COLOR.GRAY_TEXT, spacing: { before: 80, after: 120 } }),
    ...spacer(1),
  ];
}

// Practice Questions
function buildPracticeQuestions() {
  const qaData = [
    {
      q: "Q1. A 20 kg child requires amoxicillin 40 mg/kg/day in 3 divided doses. What is the dose per administration?",
      a: "Total daily dose = 40 \u00D7 20 = 800 mg/day. Per dose = 800 \u00F7 3 \u2248 267 mg. Round to nearest available strength (250 mg or 500 mg tablet)."
    },
    {
      q: "Q2. Which drug is absolutely contraindicated in children under 12 years due to Reye's syndrome?",
      a: "Aspirin (Acetylsalicylic acid) – causes fatal hepatic and cerebral encephalopathy, especially following viral illnesses."
    },
    {
      q: "Q3. Why does chloramphenicol cause 'Gray baby syndrome' in neonates?",
      a: "Neonates lack sufficient glucuronyl transferase enzyme and cannot adequately conjugate (glucuronidate) chloramphenicol. This leads to toxic drug accumulation, causing cardiovascular collapse, ashen-grey skin colour, abdominal distension, and respiratory failure."
    },
    {
      q: "Q4. A neonate has bradycardia (HR 50 bpm) with poor perfusion. What is the immediate action?",
      a: "Start CPR immediately using the 2-thumb encircling technique at a rate of 100–120 compressions per minute. Call for emergency support."
    },
    {
      q: "Q5. What is the estimated weight of a 4-year-old child using the standard formula?",
      a: "Weight = (Age \u00D7 2) + 8 = (4 \u00D7 2) + 8 = 16 kg"
    },
  ];

  const items = [];
  items.push(heading2("Practice Questions – Self-Assessment"));
  items.push(...spacer(1));

  qaData.forEach((qa, i) => {
    items.push(new Paragraph({
      spacing: { before: 120, after: 60 },
      children: [new TextRun({ text: qa.q, font: "Arial", size: 22, bold: true, color: COLOR.DARK_BLUE })]
    }));
    items.push(new Paragraph({
      spacing: { before: 40, after: 120 },
      indent: { left: 360 },
      children: [
        new TextRun({ text: "Answer: ", font: "Arial", size: 22, bold: true, color: COLOR.TIP_GREEN }),
        new TextRun({ text: qa.a, font: "Arial", size: 22, bold: false })
      ]
    }));
  });

  items.push(...spacer(1));
  return items;
}

// References
function buildReferences() {
  const refs = [
    "The Harriet Lane Handbook, 23rd Edition, Johns Hopkins Hospital",
    "Red Book 2021, AAP Committee on Infectious Diseases",
    "WHO Child Growth Standards – WHO Press, Geneva",
    "Nelson Textbook of Pediatrics, 21st Edition – Kliegman et al.",
  ];
  return [
    heading2("References"),
    ...refs.map(r => bullet(r)),
    ...spacer(2),
  ];
}

// Next Chapter teaser
function buildNextChapter() {
  return [
    divider(),
    new Paragraph({
      alignment: AlignmentType.CENTER,
      spacing: { before: 160, after: 80 },
      children: [new TextRun({ text: "NEXT: Chapter 2 – Growth & Development (Developmental Milestones)", font: "Arial", size: 24, bold: true, color: COLOR.MED_BLUE })]
    }),
  ];
}

// ─────────────────────────────────────────────────────────────────────────────
// ASSEMBLE DOCUMENT
// ─────────────────────────────────────────────────────────────────────────────
const allContent = [
  // Cover
  ...buildCoverPage(),

  // TOC section heading
  heading1("Table of Contents"),
  new TableOfContents("Table of Contents", { hyperlink: true, headingStyleRange: "1-3" }),
  pageBreak(),

  // Curriculum overview
  ...buildCurriculumOverview(),

  // Chapter 1 main heading
  heading1("Chapter 1: Introduction to Pediatrics"),
  ...spacer(1),

  // Sections
  ...section1_1(),
  divider(),
  ...section1_2(),
  divider(),
  ...section1_3(),
  divider(),
  ...section1_4(),
  divider(),
  ...section1_5(),
  divider(),
  ...section1_6(),
  divider(),
  ...section1_7(),
  divider(),
  ...section1_8(),
  divider(),
  ...section1_9(),
  divider(),
  ...section1_10(),
  divider(),
  ...buildPracticeQuestions(),
  divider(),
  ...buildReferences(),
  ...buildNextChapter(),
];

// ─────────────────────────────────────────────────────────────────────────────
// BUILD & SAVE
// ─────────────────────────────────────────────────────────────────────────────
const doc = new Document({
  numbering: {
    config: [
      {
        reference: "bullets",
        levels: [{
          level: 0,
          format: LevelFormat.BULLET,
          text: "\u2022",
          alignment: AlignmentType.LEFT,
          style: { paragraph: { indent: { left: 720, hanging: 360 } } }
        }]
      },
      {
        reference: "numbers",
        levels: [{
          level: 0,
          format: LevelFormat.DECIMAL,
          text: "%1.",
          alignment: AlignmentType.LEFT,
          style: { paragraph: { indent: { left: 720, hanging: 360 } } }
        }]
      },
    ]
  },
  styles: {
    default: {
      document: { run: { font: "Arial", size: 22 } }
    },
    paragraphStyles: [
      {
        id: "Heading1", name: "Heading 1",
        basedOn: "Normal", next: "Normal", quickFormat: true,
        run:       { size: 36, bold: true, font: "Arial", color: COLOR.DARK_BLUE },
        paragraph: { spacing: { before: 360, after: 200 }, outlineLevel: 0,
                     border: { bottom: { style: BorderStyle.SINGLE, size: 8, color: COLOR.MED_BLUE, space: 4 } } }
      },
      {
        id: "Heading2", name: "Heading 2",
        basedOn: "Normal", next: "Normal", quickFormat: true,
        run:       { size: 28, bold: true, font: "Arial", color: COLOR.MED_BLUE },
        paragraph: { spacing: { before: 280, after: 140 }, outlineLevel: 1 }
      },
      {
        id: "Heading3", name: "Heading 3",
        basedOn: "Normal", next: "Normal", quickFormat: true,
        run:       { size: 24, bold: true, font: "Arial", color: COLOR.DARK_BLUE },
        paragraph: { spacing: { before: 200, after: 100 }, outlineLevel: 2 }
      },
    ]
  },
  sections: [{
    properties: {
      page: {
        size: { width: 12240, height: 15840 },
        margin: { top: 1440, right: 1440, bottom: 1440, left: 1440 }
      }
    },
    headers: {
      default: new Header({
        children: [new Paragraph({
          spacing: { before: 0, after: 0 },
          border: { bottom: { style: BorderStyle.SINGLE, size: 6, color: COLOR.MED_BLUE, space: 4 } },
          children: [
            new TextRun({ text: "Pediatrics for Pharmacists – Complete MBBS-Level Course", font: "Arial", size: 18, color: COLOR.GRAY_TEXT }),
            new TextRun({ text: "   |   Chapter 1: Introduction to Pediatrics", font: "Arial", size: 18, color: COLOR.MED_BLUE }),
          ]
        })]
      })
    },
    footers: {
      default: new Footer({
        children: [new Paragraph({
          spacing: { before: 0, after: 0 },
          border: { top: { style: BorderStyle.SINGLE, size: 4, color: COLOR.MED_BLUE, space: 4 } },
          children: [
            new TextRun({ text: "Pharmacist Pediatrics Training  |  Page ", font: "Arial", size: 18, color: COLOR.GRAY_TEXT }),
            new TextRun({ children: [PageNumber.CURRENT], font: "Arial", size: 18, color: COLOR.MED_BLUE }),
            new TextRun({ text: "  |  For educational use only", font: "Arial", size: 18, color: COLOR.GRAY_TEXT }),
          ]
        })]
      })
    },
    children: allContent
  }]
});

const outputPath = "/home/daytona/workspace/pediatrics-notes/Chapter1_Introduction_to_Pediatrics.docx";

Packer.toBuffer(doc).then(buffer => {
  fs.writeFileSync(outputPath, buffer);
  console.log("SUCCESS: Document written to " + outputPath);
}).catch(err => {
  console.error("ERROR:", err);
  process.exit(1);
});

Successfully replaced 1 instance(s) of the string in '/home/daytona/workspace/pediatrics-notes/generate_chapter1.js'