from reportlab.lib.pagesizes import A4
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.units import mm
from reportlab.lib import colors
from reportlab.platypus import (
    SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle,
    HRFlowable, PageBreak, KeepTogether
)
from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_JUSTIFY
from reportlab.pdfbase import pdfmetrics

# ── Output path ──────────────────────────────────────────────────────────────
OUTPUT = "/tmp/workspace/mitral-stenosis-pyq/Mitral_Stenosis_PYQ_Compilation.pdf"

# ── Document ─────────────────────────────────────────────────────────────────
doc = SimpleDocTemplate(
    OUTPUT,
    pagesize=A4,
    leftMargin=18*mm, rightMargin=18*mm,
    topMargin=20*mm, bottomMargin=20*mm,
    title="Mitral Stenosis PYQ Compilation",
    author="NEET PG | UPSC CMS | INICET",
    subject="Cardiology – Mitral Stenosis Previous Year Questions",
)

# ── Colour palette ────────────────────────────────────────────────────────────
DARK_BLUE   = colors.HexColor("#1A3A5C")
MED_BLUE    = colors.HexColor("#2E6DA4")
LIGHT_BLUE  = colors.HexColor("#D6E8F7")
ACCENT_GOLD = colors.HexColor("#E8A020")
ANS_GREEN   = colors.HexColor("#1B6E2E")
ANS_BG      = colors.HexColor("#EAF7EC")
OPT_WRONG   = colors.HexColor("#C0392B")
LIGHT_GRAY  = colors.HexColor("#F4F4F4")
HINT_BG     = colors.HexColor("#FFF8E1")
HINT_BORDER = colors.HexColor("#F0C040")

# ── Styles ────────────────────────────────────────────────────────────────────
base = getSampleStyleSheet()

COVER_TITLE = ParagraphStyle("CoverTitle",
    fontSize=28, leading=34, alignment=TA_CENTER,
    textColor=colors.white, fontName="Helvetica-Bold", spaceAfter=6)

COVER_SUB = ParagraphStyle("CoverSub",
    fontSize=13, leading=18, alignment=TA_CENTER,
    textColor=colors.HexColor("#D6E8F7"), fontName="Helvetica", spaceAfter=4)

SECTION_TITLE = ParagraphStyle("SectionTitle",
    fontSize=15, leading=20, alignment=TA_LEFT,
    textColor=colors.white, fontName="Helvetica-Bold",
    leftIndent=4*mm, spaceAfter=2*mm, spaceBefore=4*mm)

Q_NUM = ParagraphStyle("QNum",
    fontSize=9, leading=12, textColor=colors.HexColor("#666666"),
    fontName="Helvetica-BoldOblique", spaceAfter=1*mm)

Q_STEM = ParagraphStyle("QStem",
    fontSize=10.5, leading=15, textColor=DARK_BLUE,
    fontName="Helvetica-Bold", spaceAfter=2*mm, spaceBefore=1*mm)

OPT_STYLE = ParagraphStyle("Opt",
    fontSize=10, leading=14, textColor=colors.HexColor("#333333"),
    fontName="Helvetica", leftIndent=4*mm, spaceAfter=1.5*mm)

ANS_LABEL = ParagraphStyle("AnsLabel",
    fontSize=9.5, leading=13, textColor=ANS_GREEN,
    fontName="Helvetica-Bold", spaceAfter=1*mm)

ANS_BODY = ParagraphStyle("AnsBody",
    fontSize=9.5, leading=14, textColor=colors.HexColor("#1A3A1A"),
    fontName="Helvetica", leftIndent=4*mm, spaceAfter=0)

HINT_STYLE = ParagraphStyle("Hint",
    fontSize=9, leading=13, textColor=colors.HexColor("#5A4200"),
    fontName="Helvetica-Oblique", leftIndent=4*mm, spaceAfter=0)

TOPIC_HEAD = ParagraphStyle("TopicHead",
    fontSize=11, leading=15, textColor=MED_BLUE,
    fontName="Helvetica-Bold", spaceBefore=6*mm, spaceAfter=2*mm)

BULLET_STYLE = ParagraphStyle("Bullet",
    fontSize=9.5, leading=14, textColor=DARK_BLUE,
    fontName="Helvetica", leftIndent=6*mm, spaceAfter=1.5*mm,
    bulletIndent=2*mm)

TABLE_TITLE = ParagraphStyle("TableTitle",
    fontSize=10, leading=14, textColor=DARK_BLUE,
    fontName="Helvetica-Bold", spaceBefore=4*mm, spaceAfter=1*mm, alignment=TA_CENTER)

# ── Helper builders ───────────────────────────────────────────────────────────
def section_banner(text, color=MED_BLUE):
    """Returns a coloured banner row used as a section header."""
    tbl = Table([[Paragraph(text, SECTION_TITLE)]], colWidths=[174*mm])
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), color),
        ("BOTTOMPADDING", (0,0), (-1,-1), 4),
        ("TOPPADDING", (0,0), (-1,-1), 4),
        ("LEFTPADDING", (0,0), (-1,-1), 3),
        ("RIGHTPADDING", (0,0), (-1,-1), 3),
        ("ROUNDEDCORNERS", [4]),
    ]))
    return tbl

def answer_box(answer_text, explanation):
    data = [
        [Paragraph(f"Correct Answer: {answer_text}", ANS_LABEL)],
        [Paragraph(explanation, ANS_BODY)],
    ]
    tbl = Table(data, colWidths=[170*mm])
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), ANS_BG),
        ("BOX", (0,0), (-1,-1), 1, ANS_GREEN),
        ("TOPPADDING", (0,0), (-1,-1), 4),
        ("BOTTOMPADDING", (0,0), (-1,-1), 4),
        ("LEFTPADDING", (0,0), (-1,-1), 6),
        ("RIGHTPADDING", (0,0), (-1,-1), 6),
    ]))
    return tbl

def hint_box(hint_text):
    data = [[Paragraph(f"Exam Tip: {hint_text}", HINT_STYLE)]]
    tbl = Table(data, colWidths=[170*mm])
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), HINT_BG),
        ("BOX", (0,0), (-1,-1), 1, HINT_BORDER),
        ("TOPPADDING", (0,0), (-1,-1), 3),
        ("BOTTOMPADDING", (0,0), (-1,-1), 3),
        ("LEFTPADDING", (0,0), (-1,-1), 6),
        ("RIGHTPADDING", (0,0), (-1,-1), 6),
    ]))
    return tbl

def mcq_block(num, exam_tag, stem, options, answer, explanation, hint=None):
    """Full MCQ block with number, stem, options, answer, explanation."""
    items = []
    items.append(Paragraph(f"Q{num}  [{exam_tag}]", Q_NUM))
    items.append(Paragraph(stem, Q_STEM))
    for opt in options:
        items.append(Paragraph(opt, OPT_STYLE))
    items.append(Spacer(1, 2*mm))
    items.append(answer_box(answer, explanation))
    if hint:
        items.append(Spacer(1, 1.5*mm))
        items.append(hint_box(hint))
    items.append(Spacer(1, 4*mm))
    items.append(HRFlowable(width="100%", thickness=0.5, color=colors.HexColor("#CCCCCC")))
    items.append(Spacer(1, 3*mm))
    return KeepTogether(items)

# ══════════════════════════════════════════════════════════════════════════════
# DATA
# ══════════════════════════════════════════════════════════════════════════════

questions = [
    # ── ETIOLOGY & PATHOPHYSIOLOGY ──────────────────────────────────────────
    dict(
        num=1, exam_tag="NEET PG / UPSC CMS",
        stem="The most common cause of mitral stenosis (MS) in India is:",
        options=["A. Infective endocarditis",
                 "B. Rheumatic heart disease",
                 "C. Mitral annular calcification",
                 "D. Congenital mitral stenosis"],
        answer="B. Rheumatic heart disease",
        explanation=(
            "Rheumatic heart disease (RHD) accounts for the overwhelming majority of MS globally, "
            "especially in developing countries like India. It is 3x more common in women and "
            "typically presents in the 4th-5th decade. Mitral annular calcification is an "
            "increasingly recognised cause in elderly patients in developed nations. "
            "(Goldman-Cecil Medicine)"
        ),
        hint="In India context, always think Rheumatic MS first."
    ),
    dict(
        num=2, exam_tag="INICET",
        stem="Normal mitral valve area is approximately:",
        options=["A. 1-2 cm²",
                 "B. 2-3 cm²",
                 "C. 4-6 cm²",
                 "D. 6-8 cm²"],
        answer="C. 4-6 cm²",
        explanation=(
            "The normal mitral valve area is 4-6 cm². Symptoms generally appear when the area "
            "falls to about one third of normal (approx. 1.5-2.0 cm²). MS is classified as "
            "mild (>1.5 cm²), moderate (1.0-1.5 cm²), and severe (<1.0-1.5 cm²). "
            "(Goldman-Cecil Medicine; Braunwald's)"
        ),
        hint="MVA <1.5 cm² = significant MS; <1.0 cm² = very severe."
    ),
    dict(
        num=3, exam_tag="UPSC CMS",
        stem="In rheumatic mitral stenosis, which pathological change is the HALLMARK?",
        options=["A. Leaflet prolapse",
                 "B. Commissural fusion with diastolic doming",
                 "C. Chordal elongation",
                 "D. Papillary muscle rupture"],
        answer="B. Commissural fusion with diastolic doming",
        explanation=(
            "Rheumatic MS is characterised by commissural fusion, leaflet thickening, and "
            "chordal shortening/fusion. On 2D echo, the anterior mitral leaflet shows the "
            "classic 'hockey stick' or 'diastolic doming' deformity. This is also linked to "
            "the opening snap heard on auscultation. (Braunwald's; Fuster's Heart)"
        ),
        hint="'Hockey stick' deformity on echo = rheumatic MS."
    ),
    dict(
        num=4, exam_tag="NEET PG",
        stem=(
            "Which of the following correctly describes the pressure gradient in mitral stenosis?"
        ),
        options=["A. Elevated LV-to-LA gradient in diastole",
                 "B. Elevated LA-to-LV gradient in diastole",
                 "C. Elevated LA-to-LV gradient in systole",
                 "D. Elevated LV-to-Aorta gradient in systole"],
        answer="B. Elevated LA-to-LV gradient in diastole",
        explanation=(
            "In MS, the stenosed mitral valve impedes LV filling. A persistent diastolic "
            "pressure gradient exists from LA (high pressure) to LV (low pressure). This "
            "elevated LA pressure is transmitted back to the pulmonary veins causing "
            "pulmonary hypertension. (Goldman-Cecil; Tintinalli's)"
        ),
    ),
    # ── CLINICAL FEATURES ───────────────────────────────────────────────────
    dict(
        num=5, exam_tag="NEET PG / INICET",
        stem="The most common presenting symptom of mitral stenosis is:",
        options=["A. Palpitations",
                 "B. Exertional dyspnea",
                 "C. Hemoptysis",
                 "D. Chest pain"],
        answer="B. Exertional dyspnea",
        explanation=(
            "Exertional dyspnea is the most frequent presenting complaint in MS, resulting "
            "from elevated LA pressure and reduced cardiac output. Orthopnea and PND follow "
            "as disease progresses. Hemoptysis is characteristic but less common; it results "
            "from rupture of bronchial vein anastomoses under high LA pressure. "
            "(Goldman-Cecil; Tintinalli's)"
        ),
        hint="Dyspnea = #1 symptom. Hemoptysis = characteristic but not the most common."
    ),
    dict(
        num=6, exam_tag="UPSC CMS",
        stem=(
            "A patient with mitral stenosis develops hoarseness of voice. Which structure is "
            "compressed by the enlarged left atrium?"
        ),
        options=["A. Phrenic nerve",
                 "B. Recurrent laryngeal nerve (left)",
                 "C. Vagus nerve",
                 "D. Sympathetic chain"],
        answer="B. Recurrent laryngeal nerve (left)",
        explanation=(
            "Ortner syndrome (cardiovocal syndrome) occurs when a massively enlarged left "
            "atrium compresses the left recurrent laryngeal nerve as it loops under the "
            "aortic arch, causing hoarseness. The enlarged LA can also compress the esophagus "
            "causing dysphagia. (Goldman-Cecil Medicine)"
        ),
        hint="Ortner's syndrome = LA enlargement → Left RLN compression → hoarseness."
    ),
    dict(
        num=7, exam_tag="NEET PG",
        stem=(
            "Presystolic accentuation of the mid-diastolic murmur in mitral stenosis "
            "DISAPPEARS in:"
        ),
        options=["A. Sinus tachycardia",
                 "B. Atrial fibrillation",
                 "C. Complete heart block",
                 "D. Left bundle branch block"],
        answer="B. Atrial fibrillation",
        explanation=(
            "Presystolic accentuation results from atrial contraction pushing blood through "
            "the stenosed valve just before systole. When atrial fibrillation develops, "
            "there is no effective atrial contraction, so presystolic accentuation disappears. "
            "(Tintinalli's; Frameworks for Internal Medicine)"
        ),
        hint="Presystolic accentuation = atrial kick. AF = no atrial contraction = no accentuation."
    ),
    dict(
        num=8, exam_tag="INICET",
        stem=(
            "The opening snap (OS) in mitral stenosis is best described as:"
        ),
        options=[
            "A. Low-pitched, best heard at the apex during systole",
            "B. High-pitched early diastolic sound to the right of the apex",
            "C. Mid-systolic click heard at the left sternal border",
            "D. Late diastolic sound coinciding with P wave on ECG"
        ],
        answer="B. High-pitched early diastolic sound to the right of the apex",
        explanation=(
            "The opening snap is an early diastolic, high-pitched sound caused by sudden "
            "tensing of the abnormal mitral leaflets as the valve opens. It is best heard "
            "just to the right of the apex. It is analogous to the 'hockey stick' deformity "
            "seen on 2D echo. Disappears when valve is heavily calcified/fibrotic. "
            "(Fuster's Heart, 15th ed.)"
        ),
        hint="OS heard between apex and left sternal border; high-pitched; absent with heavily calcified valve."
    ),
    dict(
        num=9, exam_tag="NEET PG",
        stem=(
            "As mitral stenosis severity increases, the S2-OS interval:"
        ),
        options=["A. Increases",
                 "B. Decreases",
                 "C. Remains unchanged",
                 "D. First decreases then increases"],
        answer="B. Decreases",
        explanation=(
            "The S2-OS interval (A2-OS interval) reflects the time for LA pressure to fall "
            "from its systolic peak to the level at which the mitral valve pops open. In "
            "severe MS, LA pressure is very high, so it reaches valve opening pressure "
            "quickly after A2 → shorter A2-OS interval. Shorter interval = more severe MS."
        ),
        hint="Shorter A2-OS interval = more severe MS. (Mnemonic: More Severe = More Short)."
    ),
    dict(
        num=10, exam_tag="UPSC CMS / INICET",
        stem=(
            "The apical impulse in mitral stenosis is characteristically described as:"
        ),
        options=["A. Heaving, sustained, displaced outward",
                 "B. Small, tapping, non-displaced",
                 "C. Double apical impulse",
                 "D. Hyperdynamic, diffuse"],
        answer="B. Small, tapping, non-displaced",
        explanation=(
            "In MS, the LV is underfilled due to restricted mitral inflow. The LV is "
            "therefore small and the apical impulse is small and 'tapping'. It is NOT "
            "displaced (unlike in MR or DCM where LV is dilated). "
            "(Goldman-Cecil; Tintinalli's)"
        ),
        hint="Small tapping apex = underfilled LV in MS. Heaving apex = pressure overload (e.g. AS)."
    ),
    # ── INVESTIGATIONS ───────────────────────────────────────────────────────
    dict(
        num=11, exam_tag="NEET PG",
        stem="Investigation of choice for diagnosing and assessing severity of mitral stenosis is:",
        options=["A. Chest X-ray",
                 "B. ECG",
                 "C. 2D Echocardiography with Doppler",
                 "D. Cardiac catheterisation"],
        answer="C. 2D Echocardiography with Doppler",
        explanation=(
            "Transthoracic echocardiography (TTE) is the primary diagnostic tool, confirming "
            "diagnosis and assessing severity in nearly 100% of cases. It evaluates MVA by "
            "planimetry, pressure half-time (PHT) method, and Doppler gradients. Cardiac "
            "catheterisation is reserved for discordant clinical/echo findings or pre-operative "
            "coronary assessment. (Goldman-Cecil; Tintinalli's; Braunwald's)"
        ),
        hint="Echo = investigation of choice for ALL valve lesions."
    ),
    dict(
        num=12, exam_tag="NEET PG / INICET",
        stem=(
            "Mitral valve area (MVA) by pressure half-time (PHT) method is calculated as:"
        ),
        options=["A. MVA = PHT × 220",
                 "B. MVA = 220 / PHT",
                 "C. MVA = PHT / 220",
                 "D. MVA = 440 / PHT"],
        answer="B. MVA = 220 / PHT",
        explanation=(
            "The empirical formula derived from catheterisation data is: MVA (cm²) = 220 / T½ "
            "where T½ is the pressure half-time in milliseconds. A PHT of 220 ms corresponds "
            "to a MVA of 1.0 cm² (severe MS). Normal T½ < 60 ms. "
            "(Textbook of Clinical Echocardiography; Fuster's Heart)"
        ),
        hint="MVA = 220/PHT. PHT ≥220 ms = severe MS (MVA ≤1.0 cm²)."
    ),
    dict(
        num=13, exam_tag="UPSC CMS",
        stem=(
            "On chest X-ray in mitral stenosis, which of the following is an EARLY finding?"
        ),
        options=["A. Cardiomegaly with left ventricular enlargement",
                 "B. Straightening of the left heart border",
                 "C. Right heart enlargement",
                 "D. Boot-shaped heart"],
        answer="B. Straightening of the left heart border",
        explanation=(
            "The left atrial appendage fills the concavity between the main pulmonary artery "
            "and the left ventricle on the CXR, causing 'straightening' or 'bulging' of the "
            "left heart border — an early and typical sign of left atrial enlargement in MS. "
            "Double density at the right heart border (double contour sign) is also a feature. "
            "Boot-shaped heart = Tetralogy of Fallot. (Goldman-Cecil; Tintinalli's)"
        ),
        hint="Left heart border straightening = LAE from MS. Double density = right heart border."
    ),
    dict(
        num=14, exam_tag="NEET PG",
        stem="Kerley B lines on chest X-ray in mitral stenosis represent:",
        options=["A. Dilated lymphatics in the lung parenchyma",
                 "B. Thickened pulmonary septa from chronic venous engorgement",
                 "C. Pulmonary artery dilatation",
                 "D. Pleural effusion"],
        answer="B. Thickened pulmonary septa from chronic venous engorgement",
        explanation=(
            "Kerley B lines are short (1-2 cm), horizontal lines at the lung bases on CXR, "
            "representing thickening of the interlobular septa secondary to chronic pulmonary "
            "venous hypertension. They indicate elevated LA pressure transmitted to the "
            "pulmonary vasculature, as seen in significant MS. (Goldman-Cecil Medicine)"
        ),
        hint="Kerley B lines = interlobular septal thickening = chronic pulmonary venous HTN."
    ),
    dict(
        num=15, exam_tag="INICET",
        stem=(
            "On ECG in a patient with mitral stenosis in sinus rhythm, which P-wave "
            "abnormality is expected?"
        ),
        options=["A. Tall peaked P waves (P pulmonale)",
                 "B. Notched or biphasic P waves (P mitrale)",
                 "C. Absent P waves",
                 "D. Delta waves"],
        answer="B. Notched or biphasic P waves (P mitrale)",
        explanation=(
            "Left atrial enlargement in MS produces broad, notched P waves in lead II "
            "(P mitrale) and a negative terminal component of the P wave in V1 (Morris index). "
            "If pulmonary hypertension develops, right axis deviation and right ventricular "
            "hypertrophy may appear. Atrial fibrillation is very common, especially >50 years. "
            "(Tintinalli's; Goldman-Cecil)"
        ),
        hint="P mitrale = LAE. P pulmonale = RAE. MS = P mitrale early."
    ),
    # ── SEVERITY CLASSIFICATION ──────────────────────────────────────────────
    dict(
        num=16, exam_tag="NEET PG / UPSC CMS",
        stem="Severe mitral stenosis is defined by a mitral valve area of:",
        options=["A. < 2.5 cm²",
                 "B. < 1.5 cm²",
                 "C. < 1.0 cm²",
                 "D. < 0.5 cm²"],
        answer="B. < 1.5 cm²",
        explanation=(
            "Classification of MS: Mild: MVA > 1.5 cm² | Moderate: MVA 1.0-1.5 cm² | "
            "Severe: MVA ≤ 1.5 cm² (AHA/ACC Stage C-D) | Very severe: MVA < 1.0 cm². "
            "Symptoms generally appear when MVA falls below 1.5 cm². Pressure half-time ≥ 150 ms "
            "corresponds to severe MS (PHT ≥ 220 ms = very severe). "
            "(Goldman-Cecil; Fuster's Heart; Harrison's)"
        ),
        hint="Severe MS = MVA ≤1.5 cm². Very severe = <1.0 cm²."
    ),
    dict(
        num=17, exam_tag="INICET",
        stem=(
            "The Wilkins echocardiographic scoring system for mitral stenosis assesses all "
            "of the following EXCEPT:"
        ),
        options=["A. Leaflet mobility",
                 "B. Leaflet thickening",
                 "C. Calcification",
                 "D. Severity of mitral regurgitation",
                 "(E. Subvalvular thickening)"],
        answer="D. Severity of mitral regurgitation",
        explanation=(
            "The Wilkins (echo) score grades: (1) Leaflet mobility, (2) Leaflet thickening, "
            "(3) Calcification, and (4) Subvalvular apparatus thickening — each scored 1-4 "
            "(total 4-16). Score ≤ 8 is ideal for PTMC/balloon valvotomy (>90% success). "
            "Score > 8 has lower success rates. MR degree is assessed separately as a "
            "contraindication (> moderate MR = relative contraindication to PTMC). "
            "(Textbook of Clinical Echocardiography; Braunwald's)"
        ),
        hint="Wilkins score: Mobility + Thickening + Calcification + Subvalvular. Max = 16. ≤8 = ideal for PTMC."
    ),
    # ── COMPLICATIONS ────────────────────────────────────────────────────────
    dict(
        num=18, exam_tag="NEET PG",
        stem=(
            "The most common complication of mitral stenosis is:"
        ),
        options=["A. Pulmonary hypertension",
                 "B. Atrial fibrillation",
                 "C. Infective endocarditis",
                 "D. Systemic thromboembolism"],
        answer="B. Atrial fibrillation",
        explanation=(
            "Atrial fibrillation is the most common complication of MS, occurring in up to "
            "40-75% of cases, especially in older patients. Chronic LA dilation from elevated "
            "pressure leads to fibrosis and electrophysiological changes favouring AF. AF "
            "further reduces cardiac output and greatly increases the risk of LA thrombus "
            "and systemic embolism including stroke. (Goldman-Cecil; Braunwald's; Harrison's)"
        ),
        hint="AF = most common complication. Endocarditis is actually uncommon in pure MS."
    ),
    dict(
        num=19, exam_tag="UPSC CMS / INICET",
        stem=(
            "A patient with severe MS develops sudden onset hemiplegia. The most likely "
            "underlying mechanism is:"
        ),
        options=["A. Hypertensive bleed",
                 "B. Cardioembolic stroke from left atrial thrombus",
                 "C. Venous thromboembolism",
                 "D. Carotid atherosclerosis"],
        answer="B. Cardioembolic stroke from left atrial thrombus",
        explanation=(
            "MS with AF leads to blood stasis in the LA (especially the left atrial appendage), "
            "promoting thrombus formation. Embolisation of LA thrombus causes ischaemic "
            "(cardioembolic) stroke. This is the most feared embolic complication. "
            "Anticoagulation with warfarin (target INR 2-3) is indicated in MS with AF, "
            "prior embolic event, or LA thrombus. (Tintinalli's; Creasy-Resnik)"
        ),
        hint="LA appendage thrombus in MS + AF → cardioembolic stroke. Always anticoagulate."
    ),
    dict(
        num=20, exam_tag="NEET PG",
        stem=(
            "Anticoagulation in mitral stenosis is INDICATED in which of the following?"
        ),
        options=[
            "A. Asymptomatic MS with sinus rhythm and MVA 2.0 cm²",
            "B. MS with atrial fibrillation",
            "C. MS with mild dyspnoea on exertion only",
            "D. MS post-PTMC with no residual stenosis"
        ],
        answer="B. MS with atrial fibrillation",
        explanation=(
            "Indications for anticoagulation in MS: (1) Atrial fibrillation, (2) Prior "
            "thromboembolic event, (3) LA thrombus, (4) LA diameter > 55 mm. "
            "Warfarin (INR 2-3) is standard. Asymptomatic MS with sinus rhythm and normal "
            "LA size does not require anticoagulation. (Tintinalli's; Goldman-Cecil)"
        ),
        hint="AF + MS = always anticoagulate. NOACs are NOT preferred in MS (valvular AF = warfarin)."
    ),
    # ── MANAGEMENT ──────────────────────────────────────────────────────────
    dict(
        num=21, exam_tag="NEET PG / UPSC CMS",
        stem=(
            "The treatment of choice for symptomatic severe mitral stenosis with a pliable, "
            "non-calcified valve and no significant MR is:"
        ),
        options=["A. Mitral valve replacement (MVR)",
                 "B. Open surgical commissurotomy",
                 "C. Percutaneous Transvenous Mitral Commissurotomy (PTMC) / balloon valvotomy",
                 "D. Medical management only"],
        answer="C. Percutaneous Transvenous Mitral Commissurotomy (PTMC) / balloon valvotomy",
        explanation=(
            "PTMC (Inoue balloon technique) is the preferred intervention for suitable "
            "candidates: symptomatic severe MS, pliable valve, low Wilkins score (≤8), "
            "no significant MR (≤ mild-moderate), no LA thrombus. Produces commissurotomy "
            "by splitting the fused leaflets, substantially increasing MVA. "
            "(Goldman-Cecil; Tintinalli's; Braunwald's)"
        ),
        hint="Pliable valve + low Wilkins score = PTMC. Heavy calcification / significant MR = MVR."
    ),
    dict(
        num=22, exam_tag="INICET",
        stem=(
            "PTMC (Percutaneous Transvenous Mitral Commissurotomy) is CONTRAINDICATED in:"
        ),
        options=["A. Rheumatic MS with MVA 1.2 cm² in sinus rhythm",
                 "B. MS with left atrial thrombus on TEE",
                 "C. MS with mild mitral regurgitation",
                 "D. Pregnant patient with severe MS"],
        answer="B. MS with left atrial thrombus on TEE",
        explanation=(
            "Absolute contraindications to PTMC: (1) LA thrombus (risk of embolisation during "
            "transseptal puncture), (2) More than moderate MR (would worsen MR). "
            "Pregnancy with severe MS is actually an indication for PTMC (procedure of choice "
            "in pregnancy to avoid teratogenic surgery). A TEE must be done before PTMC to "
            "rule out LA thrombus. (Goldman-Cecil; Textbook of Clinical Echocardiography)"
        ),
        hint="ALWAYS do TEE before PTMC to exclude LA thrombus. LA thrombus = absolute contraindication."
    ),
    dict(
        num=23, exam_tag="UPSC CMS",
        stem=(
            "Rate control in mitral stenosis with atrial fibrillation is best achieved with:"
        ),
        options=["A. Digoxin alone",
                 "B. Beta-blockers or non-dihydropyridine calcium channel blockers",
                 "C. Amiodarone",
                 "D. Flecainide"],
        answer="B. Beta-blockers or non-dihydropyridine calcium channel blockers",
        explanation=(
            "Heart rate control is essential in MS with AF because tachycardia shortens "
            "diastolic filling time, worsening the gradient and symptoms. "
            "Beta-blockers (metoprolol, bisoprolol) or non-DHP CCBs (verapamil, diltiazem) "
            "are first-line for rate control. Digoxin can be used as an adjunct. "
            "(Tintinalli's; Goldman-Cecil)"
        ),
        hint="Slower HR = longer diastole = better LV filling in MS. Beta-blocker = first-line rate control."
    ),
    dict(
        num=24, exam_tag="NEET PG",
        stem=(
            "A 28-year-old pregnant woman at 20 weeks gestation is found to have severe "
            "mitral stenosis with dyspnoea at rest. The preferred intervention is:"
        ),
        options=["A. Mitral valve replacement under cardiopulmonary bypass",
                 "B. Medical management until delivery",
                 "C. Percutaneous balloon mitral valvotomy (PBMV)",
                 "D. Surgical commissurotomy"],
        answer="C. Percutaneous balloon mitral valvotomy (PBMV)",
        explanation=(
            "PBMV/PTMC is the procedure of choice for severe symptomatic MS in pregnancy. "
            "It avoids the risks of cardiopulmonary bypass (which carries high fetal "
            "mortality) and teratogenic exposure. It should be performed after 20 weeks "
            "(organogenesis complete) and with radiation shielding. AHA guidelines recommend "
            "valvuloplasty prior to conception for women with moderate-severe MS planning "
            "pregnancy. (Harrison's 22e; Creasy-Resnik Maternal-Fetal Medicine)"
        ),
        hint="Pregnant + severe MS = PTMC (avoid CPB). Perform after organogenesis (>20 wks)."
    ),
    # ── HIGH-YIELD SPECIAL TOPICS ────────────────────────────────────────────
    dict(
        num=25, exam_tag="INICET",
        stem=(
            "Which of the following physical signs suggests very severe / tight mitral stenosis?"
        ),
        options=["A. Long A2-OS interval",
                 "B. Short A2-OS interval with long diastolic murmur",
                 "C. Soft S1 with absent opening snap",
                 "D. Only A2 if valve is calcified"],
        answer="B. Short A2-OS interval with long diastolic murmur",
        explanation=(
            "In severe/tight MS: (1) A2-OS interval is SHORT (high LA pressure opens valve "
            "quickly after A2). (2) The diastolic murmur occupies most of diastole (longer). "
            "(3) S1 is loud (pliable valve). When the valve becomes heavily calcified, S1 "
            "softens and OS disappears. (Fuster's Heart; Goldman-Cecil)"
        ),
        hint="Short A2-OS + long diastolic murmur = tight MS. Calcified valve = soft S1, no OS."
    ),
    dict(
        num=26, exam_tag="NEET PG",
        stem=(
            "The 'double density' sign on PA chest X-ray in mitral stenosis indicates:"
        ),
        options=["A. Right ventricular enlargement",
                 "B. Left atrial enlargement producing a second right heart border shadow",
                 "C. Aortic knuckle prominence",
                 "D. Pulmonary artery dilatation"],
        answer="B. Left atrial enlargement producing a second right heart border shadow",
        explanation=(
            "The enlarged LA projects beyond the right border of the heart on the PA CXR, "
            "creating a 'double density' or 'double contour' sign at the right heart border "
            "(right and left atrial silhouettes overlapping). Straightening of the left heart "
            "border (LAA prominence) + double density at right = classic MS CXR. "
            "(Goldman-Cecil Medicine)"
        ),
        hint="Double density = right border. Straightening = left border. Both from LAE in MS."
    ),
    dict(
        num=27, exam_tag="UPSC CMS / INICET",
        stem=(
            "In mitral stenosis, which of the following is NOT a feature of pulmonary "
            "hypertension developing as a complication?"
        ),
        options=["A. Right ventricular hypertrophy",
                 "B. Tricuspid regurgitation",
                 "C. Left ventricular hypertrophy",
                 "D. Loud P2"],
        answer="C. Left ventricular hypertrophy",
        explanation=(
            "Pulmonary hypertension in MS causes RIGHT-sided pressure overload. Features "
            "include: RVH, loud P2, parasternal heave, tricuspid regurgitation, pulmonary "
            "regurgitation (Graham-Steell murmur), and eventually RV failure. LVH does NOT "
            "occur because MS actually reduces LV preload (inflow obstruction). "
            "(Tintinalli's; Goldman-Cecil; Fuster's Heart)"
        ),
        hint="MS → RV pressure overload (not LV). LVH is absent; RVH is the finding."
    ),
    dict(
        num=28, exam_tag="NEET PG",
        stem=(
            "Graham-Steell murmur, heard in mitral stenosis with severe pulmonary hypertension, is:"
        ),
        options=["A. Pansystolic murmur at apex",
                 "B. Early diastolic, high-pitched murmur at left sternal border",
                 "C. Mid-systolic click",
                 "D. Low-pitched mid-diastolic murmur"],
        answer="B. Early diastolic, high-pitched murmur at left sternal border",
        explanation=(
            "Graham-Steell murmur is an early diastolic, high-pitched, decrescendo murmur "
            "heard at the left sternal border. It results from pulmonary regurgitation (PR) "
            "secondary to severe pulmonary hypertension in MS. It must be differentiated from "
            "aortic regurgitation (AR) which is also early diastolic but radiates to apex. "
        ),
        hint="Graham-Steell = PR from PHT in MS. Mimics AR but pulmonary in origin."
    ),
    dict(
        num=29, exam_tag="INICET",
        stem=(
            "Trans-septal puncture is performed as part of PTMC to access the:"
        ),
        options=["A. Right atrium from the aorta",
                 "B. Left atrium from the right atrium via the interatrial septum",
                 "C. Left ventricle from the right ventricle",
                 "D. Pulmonary artery from the right ventricle"],
        answer="B. Left atrium from the right atrium via the interatrial septum",
        explanation=(
            "In PTMC (Inoue balloon technique), the catheter is advanced from the femoral "
            "vein → inferior vena cava → right atrium. A trans-septal puncture is made at "
            "the fossa ovalis to enter the left atrium. The balloon catheter then crosses "
            "the stenosed mitral valve into the LV and is inflated to perform commissurotomy. "
            "TEE guidance reduces complications (cardiac tamponade in ~5%). (Braunwald's)"
        ),
        hint="PTMC = transseptal approach via fossa ovalis (RA→LA). TEE guided."
    ),
    dict(
        num=30, exam_tag="NEET PG / UPSC CMS",
        stem=(
            "What is the most common cause of restenosis after successful PTMC for rheumatic "
            "mitral stenosis?"
        ),
        options=["A. Calcification of the mitral ring",
                 "B. Re-fusion of commissures",
                 "C. Papillary muscle dysfunction",
                 "D. Valve thrombosis"],
        answer="B. Re-fusion of commissures",
        explanation=(
            "After PTMC, the commissures have been split. If rheumatic activity continues "
            "(recurrent streptococcal pharyngitis without prophylaxis), progressive inflammatory "
            "changes can lead to re-fusion of the commissures and restenosis. This is why "
            "secondary prophylaxis with benzathine penicillin is mandatory after rheumatic "
            "fever. Rate of restenosis is ~5-7% at 7 years in ideal candidates. (Braunwald's)"
        ),
        hint="Restenosis after PTMC = re-fusion of commissures. Prevent with penicillin prophylaxis."
    ),
]

# ── QUICK REVISION TABLE ───────────────────────────────────────────────────────
def quick_reference_table():
    items = []
    items.append(Spacer(1, 4*mm))
    items.append(section_banner("QUICK REVISION: Key Facts at a Glance", DARK_BLUE))
    items.append(Spacer(1, 3*mm))

    data = [
        ["Parameter", "Value / Feature"],
        ["Normal MVA", "4-6 cm²"],
        ["Mild MS (MVA)", "> 1.5 cm²"],
        ["Moderate MS (MVA)", "1.0-1.5 cm²"],
        ["Severe MS (MVA)", "≤ 1.5 cm² (AHA/ACC Stage C-D)"],
        ["Very Severe MS (MVA)", "< 1.0 cm²"],
        ["PHT in severe MS", "≥ 150 ms  (very severe ≥ 220 ms)"],
        ["MVA by PHT formula", "MVA (cm²) = 220 / PHT (ms)"],
        ["Wilkins Score ideal for PTMC", "≤ 8 (max possible = 16)"],
        ["S2-OS interval in severe MS", "Shortened (< 0.08 s)"],
        ["Most common cause (India)", "Rheumatic heart disease"],
        ["Most common complication", "Atrial fibrillation"],
        ["Most common presenting symptom", "Exertional dyspnea"],
        ["ECG finding (sinus rhythm)", "P mitrale (broad, notched P waves)"],
        ["CXR early sign", "Straightening of left heart border (LAE)"],
        ["Murmur character", "Low-pitched mid-diastolic rumble with presystolic accentuation"],
        ["Presystolic accentuation absent", "Atrial fibrillation"],
        ["Opening snap absent", "Calcified/fibrotic valve"],
        ["Ortner syndrome", "LA enlargement → Left RLN compression → hoarseness"],
        ["Graham-Steell murmur", "Pulmonary regurgitation from pulmonary hypertension in MS"],
        ["Treatment of choice", "PTMC (pliable valve, Wilkins ≤ 8, no LA thrombus, ≤ mild MR)"],
        ["Contraindication to PTMC", "LA thrombus, > moderate MR"],
        ["Anticoagulation indication", "AF, prior embolism, LA thrombus, LA diameter > 55 mm"],
        ["MS in pregnancy", "PTMC is preferred (after 20 wks; avoid CPB)"],
        ["Kerley B lines", "Interlobular septal thickening from pulmonary venous HTN"],
    ]

    col_widths = [70*mm, 100*mm]
    tbl = Table(data, colWidths=col_widths, repeatRows=1)
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,0), DARK_BLUE),
        ("TEXTCOLOR", (0,0), (-1,0), colors.white),
        ("FONTNAME", (0,0), (-1,0), "Helvetica-Bold"),
        ("FONTSIZE", (0,0), (-1,0), 9.5),
        ("BACKGROUND", (0,1), (-1,-1), colors.white),
        ("ROWBACKGROUNDS", (0,1), (-1,-1), [colors.white, LIGHT_BLUE]),
        ("FONTNAME", (0,1), (-1,-1), "Helvetica"),
        ("FONTSIZE", (0,1), (-1,-1), 9),
        ("FONTNAME", (0,1), (0,-1), "Helvetica-Bold"),
        ("TEXTCOLOR", (0,1), (0,-1), DARK_BLUE),
        ("GRID", (0,0), (-1,-1), 0.5, colors.HexColor("#AAAAAA")),
        ("TOPPADDING", (0,0), (-1,-1), 4),
        ("BOTTOMPADDING", (0,0), (-1,-1), 4),
        ("LEFTPADDING", (0,0), (-1,-1), 5),
        ("RIGHTPADDING", (0,0), (-1,-1), 5),
        ("ALIGN", (0,0), (-1,-1), "LEFT"),
        ("VALIGN", (0,0), (-1,-1), "MIDDLE"),
    ]))
    items.append(tbl)
    return items

# ══════════════════════════════════════════════════════════════════════════════
# COVER PAGE
# ══════════════════════════════════════════════════════════════════════════════

def cover_page():
    items = []
    # top banner
    cover_data = [
        [Paragraph("MITRAL STENOSIS", COVER_TITLE)],
        [Paragraph("Previous Year Questions Compilation", COVER_SUB)],
        [Paragraph("NEET PG  ·  UPSC CMS  ·  INICET", COVER_SUB)],
    ]
    cover_tbl = Table(cover_data, colWidths=[174*mm])
    cover_tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), DARK_BLUE),
        ("TOPPADDING", (0,0), (-1,-1), 10),
        ("BOTTOMPADDING", (0,0), (-1,-1), 10),
        ("LEFTPADDING", (0,0), (-1,-1), 8),
        ("RIGHTPADDING", (0,0), (-1,-1), 8),
        ("ROUNDEDCORNERS", [8]),
    ]))
    items.append(cover_tbl)
    items.append(Spacer(1, 8*mm))

    # Info box
    info_data = [
        [Paragraph("Topic", ParagraphStyle("lbl", fontSize=9, fontName="Helvetica-Bold", textColor=DARK_BLUE)),
         Paragraph("Mitral Stenosis — Cardiology", ParagraphStyle("val", fontSize=9, fontName="Helvetica"))],
        [Paragraph("Exams Covered", ParagraphStyle("lbl", fontSize=9, fontName="Helvetica-Bold", textColor=DARK_BLUE)),
         Paragraph("NEET PG, UPSC CMS, INICET", ParagraphStyle("val", fontSize=9, fontName="Helvetica"))],
        [Paragraph("Total Questions", ParagraphStyle("lbl", fontSize=9, fontName="Helvetica-Bold", textColor=DARK_BLUE)),
         Paragraph("30 MCQs + Quick Revision Table", ParagraphStyle("val", fontSize=9, fontName="Helvetica"))],
        [Paragraph("Topics", ParagraphStyle("lbl", fontSize=9, fontName="Helvetica-Bold", textColor=DARK_BLUE)),
         Paragraph("Etiology · Pathophysiology · Clinical Features · Investigations · Severity · Complications · Management",
                   ParagraphStyle("val", fontSize=9, fontName="Helvetica"))],
        [Paragraph("Sources", ParagraphStyle("lbl", fontSize=9, fontName="Helvetica-Bold", textColor=DARK_BLUE)),
         Paragraph("Harrison's 22e · Braunwald's Heart Disease · Goldman-Cecil Medicine · Fuster's Heart 15e · Tintinalli's EM",
                   ParagraphStyle("val", fontSize=9, fontName="Helvetica"))],
    ]
    info_tbl = Table(info_data, colWidths=[40*mm, 130*mm])
    info_tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), LIGHT_GRAY),
        ("BOX", (0,0), (-1,-1), 1, MED_BLUE),
        ("INNERGRID", (0,0), (-1,-1), 0.3, colors.HexColor("#CCCCCC")),
        ("TOPPADDING", (0,0), (-1,-1), 5),
        ("BOTTOMPADDING", (0,0), (-1,-1), 5),
        ("LEFTPADDING", (0,0), (-1,-1), 6),
        ("RIGHTPADDING", (0,0), (-1,-1), 6),
    ]))
    items.append(info_tbl)
    items.append(Spacer(1, 6*mm))

    # How to use
    items.append(Paragraph("How to Use This Compilation", TOPIC_HEAD))
    for bullet in [
        "Each MCQ is labelled with the exam it is commonly asked in.",
        "Read the stem carefully — pay attention to the clinical scenario.",
        "The answer box shows the correct option with a concise explanation.",
        "Exam Tips highlight high-yield patterns frequently tested.",
        "Use the Quick Revision Table at the end for last-minute review.",
    ]:
        items.append(Paragraph(f"• {bullet}", BULLET_STYLE))
    items.append(Spacer(1, 4*mm))
    items.append(PageBreak())
    return items

# ══════════════════════════════════════════════════════════════════════════════
# SECTION HEADERS PER TOPIC
# ══════════════════════════════════════════════════════════════════════════════

section_markers = {
    1:  ("SECTION 1: Etiology & Pathophysiology", MED_BLUE),
    5:  ("SECTION 2: Clinical Features", colors.HexColor("#1B6E2E")),
    11: ("SECTION 3: Investigations & Diagnosis", colors.HexColor("#7B3F00")),
    16: ("SECTION 4: Severity Classification & Echo Score", colors.HexColor("#5B2D8E")),
    18: ("SECTION 5: Complications", colors.HexColor("#B8390E")),
    21: ("SECTION 6: Management", colors.HexColor("#1A5276")),
    25: ("SECTION 7: High-Yield Special Topics", DARK_BLUE),
}

# ══════════════════════════════════════════════════════════════════════════════
# BUILD STORY
# ══════════════════════════════════════════════════════════════════════════════

story = []
story.extend(cover_page())

for q in questions:
    n = q["num"]
    if n in section_markers:
        title, col = section_markers[n]
        story.append(section_banner(title, col))
        story.append(Spacer(1, 3*mm))
    story.append(mcq_block(
        num=q["num"],
        exam_tag=q["exam_tag"],
        stem=q["stem"],
        options=q["options"],
        answer=q["answer"],
        explanation=q["explanation"],
        hint=q.get("hint"),
    ))

story.extend(quick_reference_table())

# ── Build ─────────────────────────────────────────────────────────────────────
doc.build(story)
print(f"PDF written to {OUTPUT}")