#!/usr/bin/env python3
"""
DNB Anaesthesiology Diagram Question Bank PDF Builder
Generates a practice PDF with all 68 topics + textbook diagrams
"""

import requests
import os
from io import BytesIO
from reportlab.lib.pagesizes import A4
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.units import cm, mm
from reportlab.lib import colors
from reportlab.platypus import (
    SimpleDocTemplate, Paragraph, Spacer, Image, 
    HRFlowable, PageBreak, Table, TableStyle, KeepTogether
)
from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_JUSTIFY
from reportlab.pdfgen import canvas

OUTPUT_PATH = "/home/daytona/workspace/dnb-diagram-pdf/DNB_Anaesthesia_Diagram_Practice.pdf"

# ── Image data: topic -> list of (url, caption, source_book) ──────────────────
TOPIC_IMAGES = {
    "Oxygen Dissociation Curve": [
        (
            "https://cdn.orris.care/cdss_images/06488ee05723577b5793ee787ee9bff44f7308b7edd502a5f71edeff3943bf3a.png",
            "Fig 15-1: Oxygen dissociation curve — oxygen content vs PO2. Red=total O2, Blue=dissolved O2, P50 marked.",
            "Fishman's Pulmonary Diseases & Disorders"
        ),
        (
            "https://cdn.orris.care/cdss_images/33fd697d92ca94979c918d412923d4757cf71a8a5ef2dfe7497f75af01eb38a7.png",
            "Fig 15-2: Left shift (↓H⁺, ↓CO₂, ↓DPG, ↓temp) and right shift (↑H⁺, ↑CO₂, ↑DPG, ↑temp). Bohr effect illustrated.",
            "Fishman's Pulmonary Diseases & Disorders"
        ),
    ],
    "Mapleson D / Bain's Circuit": [
        (
            "https://cdn.orris.care/cdss_images/597a88f9632f79d89dce9fe45772844ba3e580fc9f02f1bf401657ba4972bc84.png",
            "Fig 20.38 (Miller's): Mapleson A–F breathing systems. D/E/F = T-piece group. FGF requirements labeled.",
            "Miller's Anesthesia, 10e"
        ),
        (
            "https://cdn.orris.care/cdss_images/23ed98aade1a7f7a6593eb1d84ddd5e499f55feec33cb7b2ece6cc42dc3a5932.png",
            "Fig 3-7 (Morgan): Bain circuit — Mapleson D with fresh gas tubing inside corrugated tube. APL valve labeled.",
            "Morgan & Mikhail's Clinical Anesthesiology, 7e"
        ),
    ],
    "Circle System": [
        (
            "https://cdn.orris.care/cdss_images/32cb98920d80b7065bad2bdc6736d7754993559d63a0b57824b2de34eda93bcc.png",
            "Fig 3-8 (Morgan): Complete circle system — mask, reservoir bag, unidirectional valves, CO₂ absorber, APL valve, FGI.",
            "Morgan & Mikhail's Clinical Anesthesiology, 7e"
        ),
    ],
    "BVM Self-Inflating Bag": [
        (
            "https://cdn.orris.care/cdss_images/557881ea3a0f3e78e677a3cbc2f67bf2702fa04cb5c212fe988b116c098e66fb.png",
            "Fig 20.40 (Miller's): Self-inflating manual resuscitator. (A) Inspiration flow. (B) Expiration flow. All components labeled.",
            "Miller's Anesthesia, 10e"
        ),
    ],
    "Rotameter (Flowmeter)": [
        (
            "https://cdn.orris.care/cdss_images/d3b48deae7545f01f1d359be29d9de453f5c97c15d5ea8d74c0b12d6ee0d1bcf.png",
            "Fig 25-9 (Barash): Oxygen flowmeter assembly — tapered Thorpe tube, flow control valve, float/bobbin, O₂ at 16 psig.",
            "Barash Clinical Anesthesia, 9e"
        ),
        (
            "https://cdn.orris.care/cdss_images/e9dd7f522f1bd43bbe90fb3cc605d144d92a036fbb8c22045446d8533717c5ff.png",
            "Fig 25-12 (Barash): Flow tube constriction — lower=tubular (viscosity dominant), upper=orificial (density dominant).",
            "Barash Clinical Anesthesia, 9e"
        ),
    ],
    "NMJ (Neuromuscular Junction)": [
        (
            "https://cdn.orris.care/cdss_images/3d10c92e62ae25b0389e570a30987e68e4485c6526cc87b1e05ec25ada709eef.png",
            "Fig 11.2 (Miller's): Motor nerve ending — ACh synthesis, vesicle transport, Ca²⁺-triggered release. SNARE proteins labeled.",
            "Miller's Anesthesia, 10e"
        ),
        (
            "https://cdn.orris.care/cdss_images/b056e2bfa1070a111a526f73941fbf9756b78a121f052eb9c9272a6b9c798f09.png",
            "Fig 21-1 (Morgan): NMJ schematic — ACh synthesis, release, receptor binding. Pre/post-synaptic membrane.",
            "Morgan & Mikhail's Clinical Anesthesiology, 7e"
        ),
    ],
    "NMJ Extended (Extrajunctional AChR)": [
        (
            "https://cdn.orris.care/cdss_images/1e39d5e93a4460dea5a3bef7ea97093d8091ab435f6460140edac72b7dc42636.png",
            "Fig 11.3 (Miller's): SNARE protein-mediated vesicle fusion. Botulinum toxin mechanism — cleaves SNARE to block ACh.",
            "Miller's Anesthesia, 10e"
        ),
    ],
    "Train-of-Four (TOF)": [
        (
            "https://cdn.orris.care/cdss_images/c93916980d950d2b9e2a6c1a4415ae1676fa281327bb2236601268f33e80ea65.png",
            "Fig 39.5 (Miller's): TOF nerve stimulation — evoked responses before and after non-depolarising vs depolarising NMBDs.",
            "Miller's Anesthesia, 10e"
        ),
        (
            "https://cdn.orris.care/cdss_images/18e7f95ec1a226cb0eb54cee7cac9f2a7948ba87c2b3412a49c756fd0d6bfce7.png",
            "Fig 39.6 (Miller's): TOF + Double-Burst Stimulation (DBS₃,₃) patterns during recovery from NMB. TOF ratio = T4/T1.",
            "Miller's Anesthesia, 10e"
        ),
    ],
    "TOF All Patterns": [
        (
            "https://cdn.orris.care/cdss_images/bb30505da4a881a5f6ed3bab61f9f94c2192d7fc799d26c24301bb7601aa3e7a.png",
            "Fig 21-2 (Morgan): Dose-response curve for NMB — twitch depression vs dose. ED₅₀, ED₉₅ points marked.",
            "Morgan & Mikhail's Clinical Anesthesiology, 7e"
        ),
    ],
    "Pulse Oximetry": [
        (
            "https://cdn.orris.care/cdss_images/3180c140a515cb9d99d74f99f0994056d452e21b610a42f6185afeef58293db4.png",
            "Fig 37.3 (Miller's): Absorption spectra of Hb species — 660nm and 940nm wavelengths marked. Isobestic point ~805nm.",
            "Miller's Anesthesia, 10e"
        ),
        (
            "https://cdn.orris.care/cdss_images/b018cfb2b0f5fff8f2b93f01ff3ffd0f4be168f262b4e78879a85b861d91b3bf.png",
            "Fig 37.4 (Miller's): Pulse principle — AC (pulsatile arterial) vs DC (venous/tissue) absorption. Beer-Lambert basis.",
            "Miller's Anesthesia, 10e"
        ),
    ],
    "Capnography Waveform": [
        (
            "https://cdn.orris.care/cdss_images/435785a43c88683a112a9d5b1c83dd13b66e04d7d1580492ecf6c76e704d4629.png",
            "Fig 30-1 (Barash): Nasal cannula with O₂ tubing and ETCO₂ sampling port — sidestream capnography setup.",
            "Barash Clinical Anesthesia, 9e"
        ),
    ],
    "Brachial Plexus Anatomy": [
        (
            "https://cdn.orris.care/cdss_images/a290c7408736ae6b46f0923b60d589a609d499a3942f05ee65b238c13adf09d7.png",
            "Fig 36-9 (Barash): Brachial plexus schematic — Roots→Trunks→Divisions→Cords→Branches. Lateral, posterior, medial cords.",
            "Barash Clinical Anesthesia, 9e"
        ),
        (
            "https://cdn.orris.care/cdss_images/34752daac410d7591ca5589fe1c4bd7f11b8b962f5c10566bd87f3b56cc531c7.png",
            "Fig 36-10 (Barash): Terminal nerve courses of upper extremity. (A) Anterior view. (B) Posterior view — axillary & radial.",
            "Barash Clinical Anesthesia, 9e"
        ),
    ],
    "Cerebral Autoregulation Curve": [
        (
            "https://cdn.orris.care/cdss_images/6144a365e5722ef6ef1b077504d7222862dbb439596517a9bdf0dd05e8fcb214.png",
            "Fig 10.10 (Miller's): CBF autoregulation — plateau at MAP 70–150 mmHg. Hypertension right-shifts curve. CO₂/O₂ effects.",
            "Miller's Anesthesia, 10e"
        ),
    ],
    "TEG/ROTEM Trace": [
        (
            "https://cdn.orris.care/cdss_images/1ff3c174be945057b88cb8da3012fa84aed6f4747c0349cd17b452d7f7abe348.png",
            "Fig 17-5 (Barash): TEG vs ROTEM parameters — R/K/α-angle/MA/LY30 (TEG) vs CT/CFT/α/MCF/CLI30 (ROTEM).",
            "Barash Clinical Anesthesia, 9e"
        ),
        (
            "https://cdn.orris.care/cdss_images/676733cb56cff903e084519193a65c1f3dfbaadbf254f439a4e13e04e6bc3b72.png",
            "Fig 53-2 (Barash): TEG/ROTEM schematic tracing — clot initiation → propagation → clot strength → fibrinolysis phases.",
            "Barash Clinical Anesthesia, 9e"
        ),
    ],
    "TCI 3-Compartment Model": [
        (
            "https://cdn.orris.care/cdss_images/7393441d703cfd443c500f46305046cf257e935633300c113721e26875a59de6.png",
            "Fig 16.11 (Miller's): 1-, 2-, and 3-compartment models. V1 (central), V2 (rapid peripheral), V3 (slow peripheral). Rate constants.",
            "Miller's Anesthesia, 10e"
        ),
        (
            "https://cdn.orris.care/cdss_images/e17f6f4bb5b2fc9bb900a63f5583d2cc47e76175ac65a700a3f71b5e50b56c25.png",
            "Fig 11-13 (Barash): 3-compartment model with effect site. ke0 links central compartment to pharmacologic effect.",
            "Barash Clinical Anesthesia, 9e"
        ),
    ],
    "Dose-Response Curves": [
        (
            "https://cdn.orris.care/cdss_images/c89e184e336d1a8202ea9b6453bad0d52586b4b547cfbae5a14214b8d880dadb.png",
            "Fig 11-10 (Barash): Dose-response curve — linear scale (curvilinear) vs log scale (sigmoid). Linear region 20–80% Emax.",
            "Barash Clinical Anesthesia, 9e"
        ),
        (
            "https://cdn.orris.care/cdss_images/a974f56fe75dab13bf22c354d04baab78c57c0468f001b241e47f620ef697700.png",
            "Fig 11-11 (Barash): Full agonist (Drug A), partial agonist (Drug B), competitive & non-competitive antagonist (Drug C).",
            "Barash Clinical Anesthesia, 9e"
        ),
    ],
    "LA Ionisation": [
        (
            "https://cdn.orris.care/cdss_images/fa09944c98ce9f4973aecb111fa29933f9d404f732d9957dfb984558d7bf9573.png",
            "Fig 11-9 (Barash): 3-compartment pharmacokinetic model — deep, central, shallow compartments. Rate constants k12/k21/k13/k31.",
            "Barash Clinical Anesthesia, 9e"
        ),
    ],
    "Beer-Lambert Spectrophotometry": [
        (
            "https://cdn.orris.care/cdss_images/c1187fe04b8563d43d699e8a80c77147ae77dfeb2c40f8141ef2bec0c8c81528.png",
            "Fig 37.5 (Miller's): Pulse oximeter calibration curve — R value (AC/DC ratio) vs SpO₂. Developed from healthy volunteers.",
            "Miller's Anesthesia, 10e"
        ),
    ],
}

# ── All 68 topics with sections, frequency, key drawing points ─────────────────
ALL_TOPICS = [
    # SECTION, NUMBER, TOPIC NAME, FREQUENCY, KEY POINTS TO DRAW
    ("RESPIRATORY SYSTEM", 1, "Oxygen Dissociation Curve",
     "5×", "Sigmoid curve • P50 marked at 26.7 mmHg • Right shift (↑temp/H⁺/CO₂/DPG = Bohr effect) • Left shift (opposite) • Y-axis = % saturation, X-axis = PaO₂"),
    ("RESPIRATORY SYSTEM", 2, "ACLS Algorithms",
     "5×", "VF/pVT loop: CPR 2min → shock → epi q3-5min → amiodarone • PEA/Asystole: CPR 2min → epi → H's & T's • Bradycardia: atropine → pacing/dopamine/epi"),
    ("RESPIRATORY SYSTEM", 3, "Flow-Volume Loops",
     "4×", "Normal = elliptical • COPD = concave expiratory limb, increased RV • Restrictive = small loop, normal shape • Label: TLC, RV, FEF25-75, PEF"),
    ("RESPIRATORY SYSTEM", 4, "Oxygen Cascade",
     "3×", "Stepwise bar chart: Atmosphere (159) → Trachea (149) → Alveolar (100) → Arterial (95) → Mitochondria (<5) • A-a gradient • Pasteur point"),
    ("RESPIRATORY SYSTEM", 5, "V/Q West's Zones",
     "3×", "Zone I: PA>Pa>Pv (no flow) • Zone II: Pa>PA>Pv (waterfall) • Zone III: Pa>Pv>PA (flow) • Draw lung with gradient • V/Q values: apex >3, base <0.6"),
    ("RESPIRATORY SYSTEM", 6, "CO₂ Transport in Blood",
     "2×", "3 pathways: Dissolved 7% + Bicarbonate 70% + Carbamino 23% • Chloride shift (HCO₃⁻/Cl⁻ exchange) • Haldane effect (deoxy-Hb carries more CO₂)"),
    ("RESPIRATORY SYSTEM", 7, "Laryngeal Nerve Innervation",
     "2×", "SLN (internal = sensory above cords, external = cricothyroid motor) • RLN (all intrinsic muscles) • RLN palsy: unilateral = paramedian, bilateral = cadaveric/median"),
    ("RESPIRATORY SYSTEM", 8, "BVM Self-Inflating Bag",
     "1×", "Components: mask + non-rebreathing valve + bag + inlet valve + reservoir bag + O₂ port • FiO₂ without reservoir ~0.4, with reservoir ~0.9-1.0"),
    
    ("AIRWAY & BREATHING CIRCUITS", 9, "Difficult Airway Algorithm (AIDAA)",
     "4×", "Unanticipated: Plan A (direct laryngoscopy) → Plan B (video/supraglottic) → Plan C (face mask) → Plan D (FONA) • Can't intubate Can't Oxygenate → scalpel-bougie cricothyrotomy"),
    ("AIRWAY & BREATHING CIRCUITS", 10, "Mapleson D / Bain's Circuit",
     "4×", "Bain = Mapleson D coaxial • FGF for IPPV: ≥70 mL/kg/min • FGF for SV: ≥200 mL/kg/min • Pethick's test: flush O₂ → bag inflates if inner tube intact"),
    ("AIRWAY & BREATHING CIRCUITS", 11, "Circle System",
     "4×", "Components: inspiratory valve → Y-piece → expiratory valve → APL valve → reservoir bag → CO₂ absorber → FGI • O₂ analyser downstream of FGI • Unidirectional valves"),
    ("AIRWAY & BREATHING CIRCUITS", 12, "NMJ",
     "4×", "Pre-synaptic: ACh synthesis, vesicles, Ca²⁺ trigger • Synaptic cleft: AChE • Post-synaptic: nicotinic AChR (α₂βγδ or α₂βεδ) • NDNMBD blocks α-subunit • Suxamethonium = depolarising"),
    ("AIRWAY & BREATHING CIRCUITS", 13, "Desflurane Vaporiser (Tec 6)",
     "4×", "Heated sump at 39°C (SVP=2atm) • Injection valve injects vapour into fresh gas • Safety: no carrier gas enters sump • Resistance heater maintains constant vapour pressure"),
    ("AIRWAY & BREATHING CIRCUITS", 14, "Epidural Space",
     "4×", "Layers: skin → SC fat → supraspinous lig → interspinous lig → LF → epidural space → PLL → dura • Batson's plexus • Depth 4-6cm • LOR technique"),
    ("AIRWAY & BREATHING CIRCUITS", 15, "Capnography Waveform",
     "3×", "4 phases: I (dead space) → II (transition) → III (alveolar plateau, ETCO₂) → 0 (inspiration) • Abnormal: bronchospasm (slanted III), rebreathing (elevated I), VAE (sudden ↓), oesophageal (absent)"),
    ("AIRWAY & BREATHING CIRCUITS", 16, "Cormack-Lehane Grading",
     "2×", "Grade 1: full glottis • Grade 2a: partial glottis • Grade 2b: only arytenoids • Grade 3: epiglottis only • Grade 4: no structures • BURP: improves 3→2/1"),
    ("AIRWAY & BREATHING CIRCUITS", 17, "Spinal Cord Cross-Section",
     "2×", "Posterior columns: fine touch/vibration/proprioception (ipsilateral) • Lateral CST: motor (ipsilateral) • Spinothalamic: pain/temp (contralateral, 1-2 levels up) • ASA supplies anterior 2/3"),
    
    ("REGIONAL ANAESTHESIA – USG BLOCKS", 18, "ESPB (Erector Spinae Plane Block)",
     "4×", "USG transverse at T5 • Probe: paramedian sagittal • Layers: skin → trapezius → rhomboid → erector spinae → transverse process tip • Needle in plane → below ESP → spread along TP"),
    ("REGIONAL ANAESTHESIA – USG BLOCKS", 19, "TAP Block",
     "3×", "USG lateral abdomen • 3 layers: external oblique → internal oblique → transversus abdominis • Needle between IO and TA • Subcostal variant for upper abdomen (T6-T9)"),
    ("REGIONAL ANAESTHESIA – USG BLOCKS", 20, "Adductor Canal Block",
     "3×", "USG mid-thigh: sartorius (superficial) / femoral artery (deep) / saphenous nerve (lateral to FA) • Needle lateral to medial under sartorius • Blocks saphenous nerve → sensory only"),
    ("REGIONAL ANAESTHESIA – USG BLOCKS", 21, "Stellate Ganglion Block",
     "2×", "C6 (Chassaignac's tubercle) or C7 level • USG anterior approach: CCA + thyroid lobe landmarks • 5mL LA anterior to longus colli • Horner's syndrome: ptosis/miosis/anhidrosis = success"),
    ("REGIONAL ANAESTHESIA – USG BLOCKS", 22, "Brachial Plexus Anatomy",
     "2×", "Roots (C5-T1) → Trunks (upper/middle/lower) → Divisions → Cords (lateral/posterior/medial) → Branches (5 terminal) • 4 approach levels: interscalene/supraclavicular/infraclavicular/axillary"),
    ("REGIONAL ANAESTHESIA – USG BLOCKS", 23, "Uteroplacental Circulation",
     "2×", "Spiral arteries → intervillous space → umbilical vein (SaO₂ ~80%) • Foetal shunts: FO (RA→LA), DA (PA→Ao), DV (UV→IVC) • Umbilical arteries (deoxygenated) → placenta"),
    ("REGIONAL ANAESTHESIA – USG BLOCKS", 24, "TEG/ROTEM Trace",
     "2×", "TEG spindle: R (clot initiation) → K (clot kinetics) → α-angle (fibrin) → MA (platelet strength) → LY30 (fibrinolysis) • Abnormal: hypercoag (↑MA), fibrinolysis (↑LY30), factor def (↑R)"),
    ("REGIONAL ANAESTHESIA – USG BLOCKS", 25, "Paravertebral Space",
     "1×", "Triangular cross-section: anterolateral (pleura) / posterior (SCTL) / medial (vertebra/IVF) • USG parasagittal view: probe lateral to spinous process • Pleura displaces anteriorly on injection"),
    ("REGIONAL ANAESTHESIA – USG BLOCKS", 26, "Sacral Hiatus",
     "1×", "Cornua (S4 remnants) flanking hiatus • Sacrococcygeal membrane covers hiatus • Canal contains: S4/S5 roots, filum terminale, epidural fat • USG: bowtie sign • Volumes: 15-20mL adults"),
    ("REGIONAL ANAESTHESIA – USG BLOCKS", 27, "Nerve Action Potential",
     "1×", "Phase 0: rapid depolarisation (Na⁺ in via VG-Na) • Phase 1-2: plateau • Phase 3: repolarisation (K⁺ out) • LA binds S6 helix of domain IV Na⁺ channel (inner surface) • Use-dependence: ↑freq = ↑block"),
    
    ("CARDIOVASCULAR SYSTEM", 28, "Coronary Circulation",
     "2×", "LMCA → LAD (anterior wall, septum) + LCx (lateral) • RCA (inferior/RV) • Coronary perfusion pressure = DBP − LVEDP • Coronary flow: 250mL/min at rest • ECG territories"),
    ("CARDIOVASCULAR SYSTEM", 29, "IABP Timing",
     "2×", "Inflation: at dicrotic notch (aortic valve closure) • Augmented diastolic peak (↑coronary perfusion) • Deflation: just before systole → ↓afterload, ↑CO • Ratio 1:1, 1:2, 1:3"),
    ("CARDIOVASCULAR SYSTEM", 30, "IVC Collapsibility Index",
     "2×", "USG subxiphoid: M-mode IVC • CI = (IVC max - IVC min)/IVC max × 100% • CI >50% = fluid responsive (spontaneous breathing) • DI >18% for ventilated patients • Normal IVC 1.5-2.5cm"),
    ("CARDIOVASCULAR SYSTEM", 31, "Cerebral Autoregulation Curve",
     "2×", "CBF constant (50 mL/100g/min) at CPP 50-150 mmHg • Chronic hypertension: right-shift of curve • Volatile agents (>1 MAC): impair autoregulation • CO₂: most potent vasodilator"),
    ("CARDIOVASCULAR SYSTEM", 32, "CSF Circulation",
     "2×", "Lateral ventricles → (Foramen of Monro) → 3rd ventricle → (Aqueduct of Sylvius) → 4th ventricle → (Foramen Magendie/Luschka) → Subarachnoid space → Arachnoid granulations → venous sinuses"),
    ("CARDIOVASCULAR SYSTEM", 33, "Pain Pathway",
     "1×", "Peripheral nociceptors (Aδ/C fibres) → dorsal horn (Rexed I,II,V) → decussate → spinothalamic tract → thalamus (VPL) → cortex • Descending inhibition: PAG → NRM → dorsal horn (enkephalin/serotonin)"),
    ("CARDIOVASCULAR SYSTEM", 34, "Coronary O₂ Supply/Demand",
     "1×", "Supply: CBF × CaO₂ • Determinants: DBP, diastolic time, coronary resistance • Demand: HR (most important), contractility, wall tension (Laplace: T=Pr/2h) • O₂ extraction ratio: 65-70% at rest"),
    
    ("EQUIPMENT & MONITORING", 35, "Rotameter",
     "4×", "Tapered tube: bobbin floats at equilibrium (viscosity at low flow, density at high flow) • O₂ downstream safety position • Hypoxic guard: linked O₂/N₂O flowmeters (min 25% O₂) • Calibrated for specific gas"),
    ("EQUIPMENT & MONITORING", 36, "Train-of-Four",
     "3×", "Ulnar nerve: electrodes 3-5cm apart at wrist • 5 patterns: normal (T1=T2=T3=T4) / TOF fade / post-tetanic / single twitch / DBS • PTC >15 = reversal with neostigmine • TOF ratio >0.9 = adequate reversal"),
    ("EQUIPMENT & MONITORING", 37, "BIS/Entropy",
     "2×", "EEG → filter → FFT → spectral edge → BIS: 100(awake)→60-40(GA)→0(EEG silence) • Entropy: SE (high freq, motor) vs RE (RE>SE = opioid effect) • Limitations: artifact, ketamine, paralysis"),
    ("EQUIPMENT & MONITORING", 38, "PiCCO",
     "2×", "Transpulmonary thermodilution: cold saline CVC → thermistor in femoral/axillary artery • Parameters: CO, EVLWI (<10mL/kg), PVPI (<3), GEDVI (680-800mL/m²), SVV (<10% = fluid unresponsive)"),
    ("EQUIPMENT & MONITORING", 39, "Neonatal Circulation Transition",
     "1×", "DA (PGE1 dependent): closes hours-days • FO (pressure-dependent): closes at birth (LA>RA) • DV: closes days-weeks • Triggers: ↑PaO₂, ↓PVR, ↑SVR, bradykinin • Transitional circulation can persist"),
    ("EQUIPMENT & MONITORING", 40, "Pulse Oximetry",
     "1×", "Beer-Lambert law • 660nm (R-Hb absorbs more) vs 940nm (OxyHb absorbs more) • Isobestic point 805nm • R = (AC660/DC660)/(AC940/DC940) • Limitations: MetHb, COHb, dark skin, motion, low flow"),
    ("EQUIPMENT & MONITORING", 41, "Volatile MAC",
     "1×", "Bar chart: Halothane=0.75 / Isoflurane=1.17 / Sevoflurane=2.0 / Desflurane=6.0 / N₂O=105 • ↓MAC: elderly, hypothermia, opioids, pregnancy, acute EtOH • ↑MAC: young age, hyperthermia, chronic EtOH"),
    ("EQUIPMENT & MONITORING", 42, "ECMO Circuit",
     "1×", "VV-ECMO: drainage (RIJ) → centrifugal pump → oxygenator → return (femoral) • VA-ECMO: femoral vein → pump → oxygenator → femoral artery • Harlequin: mixing zone in aorta → monitor right hand SpO₂"),
    
    ("PHARMACOLOGY & ADDITIONAL", 43, "NMJ Extended (Extrajunctional AChR)",
     "4×", "Burns/denervation → upregulation of extrajunctional fetal AChR (α₂βγδ) • Suxamethonium → massive K⁺ release → hyperkalaemic arrest • Safe period: 24-48h post-burn (peak risk 3 days–6 months)"),
    ("PHARMACOLOGY & ADDITIONAL", 44, "TOF All Patterns",
     "3×", "5 patterns: Normal / Deep block (PTC only) / Moderate (1-3 twitches) / Shallow (4 twitches with fade) / Recovered (TOF>0.9) • Sugammadex: 2mg/kg (TOF≥2), 4mg/kg (1-2 twitches), 16mg/kg (immediate reversal)"),
    ("PHARMACOLOGY & ADDITIONAL", 45, "LA Ionisation",
     "2×", "pKa diagram: % ionised (BH⁺, active on channel) vs unionised (B, membrane penetrant) • Henderson-Hasselbalch • Lidocaine pKa=7.9 → 25% unionised at pH 7.4 • NaHCO₃ → ↑pH → ↑unionised → faster onset"),
    ("PHARMACOLOGY & ADDITIONAL", 46, "Sugammadex Cyclodextrin",
     "2×", "γ-cyclodextrin donut structure: hydrophobic core encapsulates rocuronium (1:1 complex) • Vecuronium also encapsulated • Dose: 2/4/16 mg/kg • Renal excretion • No reversal of benzylisoquinoliniums"),
    ("PHARMACOLOGY & ADDITIONAL", 47, "Opioid Receptors",
     "1×", "Mu (μ): analgesia, euphoria, respiratory depression, constipation • Kappa (κ): analgesia, dysphoria, sedation • Delta (δ): analgesia, mood • All Gi-protein coupled → ↓cAMP, ↑K⁺, ↓Ca²⁺"),
    ("PHARMACOLOGY & ADDITIONAL", 48, "TCI 3-Compartment Model",
     "1×", "V1 (central/plasma) ↔ V2 (rapid: muscle) ↔ V3 (slow: fat) • ke0 = effect site equilibration • Marsh (propofol, weight-based) vs Schnider (age/height/weight) • Context-sensitive half-time ↑ with infusion duration"),
    ("PHARMACOLOGY & ADDITIONAL", 49, "CRRT Circuit",
     "2×", "CVVHDF: blood → pump → hemofilter → dialysate (diffusion) + ultrafiltrate (convection) • Pre-dilution (before filter): ↑filter life, ↓clearance • Post-dilution: ↑clearance • Anticoagulation: heparin/citrate/LMWH"),
    ("PHARMACOLOGY & ADDITIONAL", 50, "Dynamic Fluid Responsiveness",
     "2×", "PPV (>12%): ventilated, SR, no arrhythmia • SVV (>12%): similar limitations • IVC-DI (>18%): ventilated • PLR: autotransfusion ~300mL, respond within 90sec, cardiac output measurement required"),
    ("PHARMACOLOGY & ADDITIONAL", 51, "Ventilator P-V Loop",
     "1×", "Inflation limb: LIP (lower inflection = open alveoli) → linear portion → UIP (upper inflection = overdistension) • Hysteresis = difference between inflation/deflation • Driving pressure = Pplat − PEEP"),
    ("PHARMACOLOGY & ADDITIONAL", 52, "Oesophageal Doppler",
     "1×", "Probe at T5-T6 (25-35cm from teeth) • Velocity waveform: peak velocity + FTc (corrected flow time 330-360ms) • FTc <330ms = hypovolaemia • ↓peak velocity = ↓contractility"),
    ("PHARMACOLOGY & ADDITIONAL", 53, "Statistical Tests Decision Tree",
     "1×", "Parametric (normal distribution): 2 groups → t-test, >2 groups → ANOVA • Non-parametric: 2 groups → Mann-Whitney, >2 → Kruskal-Wallis • Categorical: Chi-square (expected>5) or Fisher's exact"),
    ("PHARMACOLOGY & ADDITIONAL", 54, "DLT vs Bronchial Blocker",
     "1×", "Left DLT: tracheal lumen (white) + bronchial lumen (blue) • FOB confirmation: view from tracheal = blue cuff below carina • BB types: Cohen (flexitip), Arndt (wire-guided) • DLT preferred for pus/bleeding"),
    ("PHARMACOLOGY & ADDITIONAL", 55, "Capnography Applications",
     "1×", "ETT confirmation (waveform) • CPR: ETCO₂>10 = adequate compressions, >35 = ROSC • VAE: sudden ↓ETCO₂ • PE: ↑A-a gap, ↓ETCO₂ • Colorimetric: yellow=CO₂, purple=no CO₂"),
    ("PHARMACOLOGY & ADDITIONAL", 56, "IABP Timing Errors",
     "1×", "Early inflation: before dicrotic notch → impede systole • Late inflation: after notch → ↓augmentation • Early deflation: before systole → diastolic pressure ↑ then ↓, no afterload reduction • Late deflation: into systole → ↑afterload"),
    ("PHARMACOLOGY & ADDITIONAL", 57, "Dose-Response Curves",
     "1×", "Full agonist: reaches Emax • Partial agonist: ceiling below Emax • Competitive antagonist: parallel rightward shift (surmountable) • Non-competitive: depresses Emax (insurmountable) • Inverse agonist: below baseline"),
    ("PHARMACOLOGY & ADDITIONAL", 58, "Volatile MAC Bar Chart",
     "1×", "Halothane 0.75 / Enflurane 1.63 / Isoflurane 1.17 / Sevoflurane 2.05 / Desflurane 6.0 / N₂O 105 • Second gas effect (N₂O + volatile) • MAC-awake ~0.3× MAC • MAC-BAR (block adrenergic response) ~1.5× MAC"),
    ("PHARMACOLOGY & ADDITIONAL", 59, "Opioid Routes",
     "1×", "Morphine routes: oral (30% bioavailability) / IV (100%) / epidural (10× less than IV) / intrathecal (10× less than epidural) / transdermal (slow onset 12-24h) • Fentanyl: highly lipophilic, fast epidural onset"),
    ("PHARMACOLOGY & ADDITIONAL", 60, "ECMO Harlequin Syndrome",
     "1×", "VA-ECMO: oxygenated blood from femoral → retrograde in aorta • Native heart: ejects desaturated blood antegrade • Mixing zone in distal aorta • Right hand (pre-mixing) may desaturate while ETCO₂ normal → monitor right hand SpO₂"),
    ("PHARMACOLOGY & ADDITIONAL", 61, "Passive Leg Raise Test",
     "1×", "45° leg elevation → autotransfusion ~300mL from lower limb/splanchnic • Measure CO within 90 seconds (reversible) • Advantages over PPV: works in AF, spontaneous breathing, low tidal volumes • Positive if CO↑>10%"),
    ("PHARMACOLOGY & ADDITIONAL", 62, "Normal Distribution Curve",
     "1×", "Bell-shaped curve • 68.2% within 1 SD • 95.4% within 2 SD • 99.7% within 3 SD • SEM = SD/√n (smaller than SD) • 95% CI = mean ± 1.96×SEM • Skewness: positive (tail right), negative (tail left)"),
    ("PHARMACOLOGY & ADDITIONAL", 63, "Beer-Lambert Spectrophotometry",
     "1×", "A = ε.c.l (absorbance = molar absorptivity × concentration × path length) • Isobestic point 805nm (OxyHb = DeoxyHb) • R = (AC660/DC660)/(AC940/DC940) • R=1 → SpO₂~85%, R=0.4 → SpO₂~100%"),
    ("PHARMACOLOGY & ADDITIONAL", 64, "Monroe-Kellie + ICP Waveforms",
     "1×", "Rigid skull: brain + blood + CSF = constant volume • Compensation: CSF displacement, venous drainage • Compliance curve: pressure rises steeply beyond threshold • Lundberg A (plateau, 50-100mmHg) / B (rhythmic) / C waves"),
    ("PHARMACOLOGY & ADDITIONAL", 65, "Epidural Approaches",
     "1×", "Midline: through supraspinous + interspinous ligament → LF → epidural space • Paramedian: avoids calcified SSL, 1cm lateral, angled 10-15° medially • LOR to saline preferred (air → pneumocephalus/patchy block)"),
    ("PHARMACOLOGY & ADDITIONAL", 66, "IABP Diastolic Augmentation Physiology",
     "1×", "80% coronary flow in diastole (unlike most organs) • IABP inflation in diastole → ↑coronary perfusion pressure • ↑myocardial O₂ supply while ↓O₂ demand (↓afterload) • Net: ↑CO by 0.5-1.0 L/min"),
    ("PHARMACOLOGY & ADDITIONAL", 67, "Alveolar Gas Equation",
     "1×", "PAO₂ = (PB − 47) × FiO₂ − PaCO₂/R • At sea level, FiO₂=0.21: PAO₂ ≈ 100 mmHg • A-a gradient = PAO₂ − PaO₂ (normal <10-15 on room air) • Pre-oxygenation: ↑FiO₂ → ↑PAO₂ → ↑apnoea time"),
    ("PHARMACOLOGY & ADDITIONAL", 68, "Uteroplacental Blood Flow",
     "1×", "UBF = (uterine artery P − uterine venous P) / uterine vascular resistance • Phenylephrine: ↑SVR → ↑BP → no ↓UBF (vasopressor of choice) • Ephedrine: ↑HR + ↑SVR, crosses placenta → foetal tachycardia • Oxytocin hyperstim → ↑uterine tone → ↓UBF"),
]

def download_image(url, max_width, max_height):
    """Download image from URL and return a ReportLab Image object or None."""
    try:
        resp = requests.get(url, timeout=15)
        resp.raise_for_status()
        img_data = BytesIO(resp.content)
        img = Image(img_data)
        # Scale to fit
        ratio = min(max_width / img.drawWidth, max_height / img.drawHeight)
        img.drawWidth *= ratio
        img.drawHeight *= ratio
        return img
    except Exception as e:
        print(f"  ✗ Failed to download {url[:60]}... → {e}")
        return None

def build_pdf():
    doc = SimpleDocTemplate(
        OUTPUT_PATH,
        pagesize=A4,
        rightMargin=1.5*cm,
        leftMargin=1.5*cm,
        topMargin=1.8*cm,
        bottomMargin=1.8*cm,
        title="DNB Anaesthesiology – Diagram Practice Bank",
        author="Medical Library"
    )

    W, H = A4
    usable_w = W - 3*cm
    usable_h = H - 3.6*cm

    styles = getSampleStyleSheet()

    # Custom styles
    title_style = ParagraphStyle(
        'BookTitle', parent=styles['Title'],
        fontSize=22, textColor=colors.HexColor('#1a3a5c'),
        spaceAfter=6, spaceBefore=6, alignment=TA_CENTER,
        fontName='Helvetica-Bold'
    )
    subtitle_style = ParagraphStyle(
        'Subtitle', parent=styles['Normal'],
        fontSize=12, textColor=colors.HexColor('#4a4a4a'),
        spaceAfter=4, alignment=TA_CENTER
    )
    section_style = ParagraphStyle(
        'SectionHead', parent=styles['Heading1'],
        fontSize=14, textColor=colors.white,
        spaceAfter=0, spaceBefore=16,
        fontName='Helvetica-Bold',
        backColor=colors.HexColor('#1a3a5c'),
        leftIndent=-8, rightIndent=-8,
        borderPad=5
    )
    topic_style = ParagraphStyle(
        'TopicHead', parent=styles['Heading2'],
        fontSize=12, textColor=colors.HexColor('#1a3a5c'),
        spaceAfter=2, spaceBefore=10,
        fontName='Helvetica-Bold',
        borderPad=3
    )
    freq_style = ParagraphStyle(
        'Freq', parent=styles['Normal'],
        fontSize=9, textColor=colors.HexColor('#cc4400'),
        spaceAfter=2, fontName='Helvetica-Bold'
    )
    keypoints_style = ParagraphStyle(
        'KeyPoints', parent=styles['Normal'],
        fontSize=9, textColor=colors.HexColor('#2a2a2a'),
        spaceAfter=6, leading=13,
        leftIndent=8, fontName='Helvetica'
    )
    caption_style = ParagraphStyle(
        'Caption', parent=styles['Normal'],
        fontSize=8, textColor=colors.HexColor('#555555'),
        spaceAfter=4, alignment=TA_CENTER,
        fontName='Helvetica-Oblique'
    )
    source_style = ParagraphStyle(
        'Source', parent=styles['Normal'],
        fontSize=7.5, textColor=colors.HexColor('#1a3a5c'),
        spaceAfter=8, alignment=TA_CENTER,
        fontName='Helvetica-BoldOblique'
    )
    note_style = ParagraphStyle(
        'Note', parent=styles['Normal'],
        fontSize=8.5, textColor=colors.HexColor('#555555'),
        spaceAfter=4, alignment=TA_CENTER,
        fontName='Helvetica-Oblique'
    )

    story = []

    # ── Cover Page ────────────────────────────────────────────────────────────
    story.append(Spacer(1, 2*cm))
    story.append(Paragraph("DNB ANAESTHESIOLOGY", title_style))
    story.append(Paragraph("Diagram Practice Bank", ParagraphStyle(
        'T2', parent=styles['Title'], fontSize=18,
        textColor=colors.HexColor('#cc4400'), alignment=TA_CENTER,
        fontName='Helvetica-Bold', spaceAfter=8
    )))
    story.append(HRFlowable(width="100%", thickness=2, color=colors.HexColor('#1a3a5c')))
    story.append(Spacer(1, 0.5*cm))
    story.append(Paragraph("68 High-Yield Topics with Standard Textbook Diagrams", subtitle_style))
    story.append(Paragraph("Complete 2021–2025 DNB Exam Analysis", subtitle_style))
    story.append(Spacer(1, 0.4*cm))

    # Summary table
    table_data = [
        ["📚 Sources", "Miller's Anesthesia 10e  |  Barash 9e  |  Morgan & Mikhail 7e\nFishman's Pulmonary  |  Guyton & Hall Physiology"],
        ["📋 Topics", "68 diagram-critical topics across 6 major systems"],
        ["🖼 Diagrams", "Textbook-sourced images for 15 high-frequency topics"],
        ["⭐ High Priority", "5× topics: ODC, ACLS, Flow-Volume, ACLS algorithms, Mapleson"],
    ]
    cover_table = Table(table_data, colWidths=[3.5*cm, usable_w-3.5*cm])
    cover_table.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (0,-1), colors.HexColor('#1a3a5c')),
        ('TEXTCOLOR', (0,0), (0,-1), colors.white),
        ('FONTNAME', (0,0), (0,-1), 'Helvetica-Bold'),
        ('FONTSIZE', (0,0), (-1,-1), 9),
        ('BACKGROUND', (1,0), (1,-1), colors.HexColor('#f0f4f8')),
        ('GRID', (0,0), (-1,-1), 0.5, colors.HexColor('#cccccc')),
        ('VALIGN', (0,0), (-1,-1), 'MIDDLE'),
        ('TOPPADDING', (0,0), (-1,-1), 6),
        ('BOTTOMPADDING', (0,0), (-1,-1), 6),
        ('LEFTPADDING', (0,0), (-1,-1), 8),
    ]))
    story.append(cover_table)
    story.append(Spacer(1, 0.5*cm))
    story.append(Paragraph(
        "FREQUENCY LEGEND: 5× = Asked Every Year  |  4× = Exam Staple  |  3× = High Priority  |  2× = Asked Twice  |  1× = Classic Topic",
        ParagraphStyle('Legend', parent=styles['Normal'], fontSize=8,
                      textColor=colors.HexColor('#666666'), alignment=TA_CENTER)
    ))
    story.append(PageBreak())

    # ── Topics ────────────────────────────────────────────────────────────────
    current_section = None

    for (section, num, topic, freq, keypoints) in ALL_TOPICS:
        # Section header
        if section != current_section:
            current_section = section
            story.append(Spacer(1, 0.3*cm))
            story.append(Paragraph(f"  {section}", section_style))
            story.append(Spacer(1, 0.2*cm))

        # Topic header
        topic_content = []
        topic_content.append(
            Paragraph(f"{num}. {topic}", topic_style)
        )
        topic_content.append(
            Paragraph(f"DNB Frequency: {freq}", freq_style)
        )
        topic_content.append(
            Paragraph(f"<b>Key drawing points:</b> {keypoints}", keypoints_style)
        )
        topic_content.append(
            HRFlowable(width="100%", thickness=0.5, color=colors.HexColor('#cccccc'))
        )

        # Images for this topic
        images_added = 0
        # Match by topic name (try partial match)
        matched_key = None
        for key in TOPIC_IMAGES:
            if key.lower() in topic.lower() or topic.lower() in key.lower():
                matched_key = key
                break
        # Also try exact match
        if topic in TOPIC_IMAGES:
            matched_key = topic

        if matched_key and images_added < 2:
            for (img_url, caption, source) in TOPIC_IMAGES[matched_key][:2]:
                print(f"  Downloading image for [{topic}]...")
                img_obj = download_image(img_url, max_width=usable_w*0.92, max_height=10*cm)
                if img_obj:
                    topic_content.append(Spacer(1, 0.2*cm))
                    topic_content.append(img_obj)
                    topic_content.append(Paragraph(caption, caption_style))
                    topic_content.append(Paragraph(f"Source: {source}", source_style))
                    images_added += 1

        if images_added == 0:
            topic_content.append(
                Paragraph(
                    "[ Draw this diagram from memory — refer to the key points above ]",
                    note_style
                )
            )

        topic_content.append(Spacer(1, 0.4*cm))
        story.extend(topic_content)

    # ── Back page ─────────────────────────────────────────────────────────────
    story.append(PageBreak())
    story.append(Spacer(1, 3*cm))
    story.append(Paragraph("QUICK REFERENCE", title_style))
    story.append(HRFlowable(width="100%", thickness=2, color=colors.HexColor('#1a3a5c')))
    story.append(Spacer(1, 0.5*cm))

    # Top 10 most frequent
    top_topics = [(num, name, freq) for (_, num, name, freq, _) in ALL_TOPICS if '5×' in freq or '4×' in freq]
    story.append(Paragraph("<b>HIGHEST FREQUENCY TOPICS (5× and 4× asked)</b>", 
                          ParagraphStyle('RefHead', parent=styles['Normal'],
                                        fontSize=11, textColor=colors.HexColor('#1a3a5c'),
                                        fontName='Helvetica-Bold', spaceAfter=6)))
    ref_data = [["#", "Topic", "Frequency"]]
    for (num, name, freq) in top_topics:
        ref_data.append([str(num), name, freq])
    ref_table = Table(ref_data, colWidths=[1*cm, usable_w-3*cm, 2*cm])
    ref_table.setStyle(TableStyle([
        ('BACKGROUND', (0,0), (-1,0), colors.HexColor('#1a3a5c')),
        ('TEXTCOLOR', (0,0), (-1,0), colors.white),
        ('FONTNAME', (0,0), (-1,0), 'Helvetica-Bold'),
        ('FONTSIZE', (0,0), (-1,-1), 9),
        ('ROWBACKGROUNDS', (0,1), (-1,-1), [colors.HexColor('#f0f4f8'), colors.white]),
        ('GRID', (0,0), (-1,-1), 0.5, colors.HexColor('#cccccc')),
        ('VALIGN', (0,0), (-1,-1), 'MIDDLE'),
        ('TOPPADDING', (0,0), (-1,-1), 5),
        ('BOTTOMPADDING', (0,0), (-1,-1), 5),
        ('LEFTPADDING', (0,0), (-1,-1), 6),
        ('ALIGN', (2,0), (2,-1), 'CENTER'),
    ]))
    story.append(ref_table)

    print("\nBuilding PDF...")
    doc.build(story)
    print(f"✓ PDF saved to: {OUTPUT_PATH}")

if __name__ == "__main__":
    build_pdf()