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

OUTPUT = "/tmp/workspace/community-medicine/Community_Medicine_Quick_Reference.pdf"

doc = SimpleDocTemplate(
    OUTPUT,
    pagesize=A4,
    rightMargin=1.5*cm,
    leftMargin=1.5*cm,
    topMargin=1.8*cm,
    bottomMargin=1.8*cm,
    title="Community Medicine Quick Reference",
    author="Orris Study Companion"
)

# ── Colour Palette ──────────────────────────────────────────────────────────
TEAL       = colors.HexColor("#006d77")
TEAL_LIGHT = colors.HexColor("#83c5be")
CREAM      = colors.HexColor("#ffddd2")
ORANGE     = colors.HexColor("#e29578")
DARK       = colors.HexColor("#222222")
GREY_BG    = colors.HexColor("#f0f4f8")
WHITE      = colors.white
YELLOW_HL  = colors.HexColor("#fff3cd")
RED_LIGHT  = colors.HexColor("#fde8e8")
GREEN_LIGHT= colors.HexColor("#e8f5e9")

styles = getSampleStyleSheet()

# Custom styles
h_title = ParagraphStyle("h_title", parent=styles["Normal"],
    fontSize=22, textColor=WHITE, fontName="Helvetica-Bold",
    alignment=TA_CENTER, spaceAfter=4)

h_sub = ParagraphStyle("h_sub", parent=styles["Normal"],
    fontSize=11, textColor=TEAL_LIGHT, fontName="Helvetica",
    alignment=TA_CENTER, spaceAfter=2)

h1 = ParagraphStyle("h1", parent=styles["Normal"],
    fontSize=13, textColor=WHITE, fontName="Helvetica-Bold",
    alignment=TA_LEFT, spaceBefore=6, spaceAfter=4,
    leftIndent=6, borderPad=4)

h2 = ParagraphStyle("h2", parent=styles["Normal"],
    fontSize=11, textColor=TEAL, fontName="Helvetica-Bold",
    spaceBefore=6, spaceAfter=3)

body = ParagraphStyle("body", parent=styles["Normal"],
    fontSize=8.5, textColor=DARK, fontName="Helvetica",
    leading=12, spaceAfter=2)

bullet = ParagraphStyle("bullet", parent=styles["Normal"],
    fontSize=8.5, textColor=DARK, fontName="Helvetica",
    leading=12, leftIndent=10, bulletIndent=2, spaceAfter=1)

bold_kv = ParagraphStyle("bold_kv", parent=styles["Normal"],
    fontSize=8.5, textColor=DARK, fontName="Helvetica-Bold",
    leading=12, spaceAfter=1)

footer_style = ParagraphStyle("footer", parent=styles["Normal"],
    fontSize=7, textColor=colors.grey, alignment=TA_CENTER)

story = []

# ── Helper Functions ─────────────────────────────────────────────────────────

def section_header(text):
    """Teal banner section header."""
    tbl = Table([[Paragraph(text, h1)]], colWidths=[17.5*cm])
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), TEAL),
        ("ROUNDEDCORNERS", [4,4,4,4]),
        ("TOPPADDING",  (0,0),(-1,-1), 5),
        ("BOTTOMPADDING",(0,0),(-1,-1), 5),
        ("LEFTPADDING", (0,0),(-1,-1), 8),
    ]))
    story.append(tbl)
    story.append(Spacer(1, 4))

def subsection(text):
    story.append(Paragraph(text, h2))

def bp(text):
    story.append(Paragraph(f"• {text}", bullet))

def kv(key, val):
    story.append(Paragraph(f"<b>{key}:</b> {val}", body))

def note_box(text, bg=YELLOW_HL):
    tbl = Table([[Paragraph(f"⚡ {text}", body)]], colWidths=[17.5*cm])
    tbl.setStyle(TableStyle([
        ("BACKGROUND",(0,0),(-1,-1), bg),
        ("TOPPADDING",(0,0),(-1,-1), 5),
        ("BOTTOMPADDING",(0,0),(-1,-1), 5),
        ("LEFTPADDING",(0,0),(-1,-1), 8),
        ("GRID",(0,0),(-1,-1), 0.5, ORANGE),
    ]))
    story.append(tbl)
    story.append(Spacer(1,4))

def two_col_table(headers, rows, col_widths=None, bg=GREY_BG):
    if col_widths is None:
        col_widths = [5*cm, 12.5*cm]
    data = [headers] + rows
    tbl = Table(data, colWidths=col_widths, repeatRows=1)
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,0), TEAL),
        ("TEXTCOLOR",  (0,0), (-1,0), WHITE),
        ("FONTNAME",   (0,0), (-1,0), "Helvetica-Bold"),
        ("FONTSIZE",   (0,0), (-1,-1), 8),
        ("BACKGROUND", (0,1), (-1,-1), bg),
        ("ROWBACKGROUNDS",(0,1),(-1,-1),[WHITE, GREY_BG]),
        ("GRID",       (0,0), (-1,-1), 0.4, TEAL_LIGHT),
        ("TOPPADDING", (0,0), (-1,-1), 4),
        ("BOTTOMPADDING",(0,0),(-1,-1), 4),
        ("LEFTPADDING", (0,0),(-1,-1), 5),
        ("VALIGN",     (0,0),(-1,-1), "TOP"),
        ("FONTNAME",   (0,1),(-1,-1), "Helvetica"),
    ]))
    story.append(tbl)
    story.append(Spacer(1,5))

def spacer(h=5):
    story.append(Spacer(1, h))

# ─────────────────────────────────────────────────────────────────────────────
# TITLE PAGE BANNER
# ─────────────────────────────────────────────────────────────────────────────
title_data = [[
    Paragraph("COMMUNITY MEDICINE", h_title),
    ],[
    Paragraph("Quick Reference Guide  |  Based on Park's Textbook of Preventive & Social Medicine", h_sub),
    ],[
    Paragraph("Exam Prep Edition  •  2026", h_sub),
]]
title_tbl = Table([[Paragraph("COMMUNITY MEDICINE", h_title)],
                   [Paragraph("Quick Reference Guide  |  Park's Textbook of Preventive & Social Medicine", h_sub)],
                   [Paragraph("Exam Prep Edition  •  July 2026", h_sub)]],
                  colWidths=[17.5*cm])
title_tbl.setStyle(TableStyle([
    ("BACKGROUND",(0,0),(-1,-1), TEAL),
    ("TOPPADDING",(0,0),(-1,-1),8),
    ("BOTTOMPADDING",(0,0),(-1,-1),8),
    ("LEFTPADDING",(0,0),(-1,-1),10),
]))
story.append(title_tbl)
story.append(Spacer(1,12))

# ─────────────────────────────────────────────────────────────────────────────
# 1. CONCEPTS OF HEALTH & DISEASE
# ─────────────────────────────────────────────────────────────────────────────
section_header("1. CONCEPTS OF HEALTH & DISEASE")

subsection("Definitions of Health")
two_col_table(
    [Paragraph("<b>Source</b>",body), Paragraph("<b>Definition</b>",body)],
    [
        ["WHO 1948", "A state of complete physical, mental and social well-being, not merely absence of disease or infirmity."],
        ["WHO 1984 (revised)", "Extent to which an individual/group is able to realise aspirations, satisfy needs, cope with environment."],
        ["Positive health", "Physical fitness + mental well-being + social adjustment + spiritual health + high morale."],
    ]
)

subsection("Spectrum of Disease / Natural History")
bp("Stage 1 – Susceptibility (pre-pathogenesis): risk factors present, no disease yet")
bp("Stage 2 – Pre-symptomatic: pathological changes, no symptoms (ideal for screening)")
bp("Stage 3 – Clinical disease: symptoms appear")
bp("Stage 4 – Disability / Death: outcome stage")
note_box("Levels of Prevention: Primary (health promotion + specific protection) | Secondary (early diagnosis + treatment) | Tertiary (rehabilitation)")

subsection("Iceberg Phenomenon")
bp("Tip (visible): clinical cases")
bp("Submerged (invisible): subclinical, latent, carrier states")
bp("Importance: true disease burden is always underestimated")

spacer()

# ─────────────────────────────────────────────────────────────────────────────
# 2. EPIDEMIOLOGY
# ─────────────────────────────────────────────────────────────────────────────
section_header("2. EPIDEMIOLOGY – METHODS & MEASURES")

subsection("Key Rates & Formulas")
two_col_table(
    [Paragraph("<b>Measure</b>",body), Paragraph("<b>Formula / Key Point</b>",body)],
    [
        ["Incidence Rate", "New cases / Population at risk × 1000 (per time period)"],
        ["Prevalence", "All existing cases / Total population × 100"],
        ["Prevalence vs Incidence", "Prevalence = Incidence × Duration of disease"],
        ["Attack Rate", "Cases during outbreak / Population exposed × 100"],
        ["Secondary Attack Rate (SAR)", "New cases among contacts / Susceptible contacts × 100"],
        ["CFR (Case Fatality Rate)", "Deaths from disease / Cases of disease × 100"],
        ["Proportional Mortality Rate", "Deaths from cause X / Total deaths × 100"],
        ["Infant Mortality Rate (IMR)", "Deaths <1 yr / Live births × 1000 (sensitive index of development)"],
        ["MMR", "Maternal deaths / Live births × 100,000"],
        ["NMR (Neonatal)", "Deaths <28 days / Live births × 1000"],
    ]
)

subsection("Study Designs (High-Yield)")
two_col_table(
    [Paragraph("<b>Study Type</b>",body), Paragraph("<b>Key Features</b>",body)],
    [
        ["Randomized Controlled Trial", "Gold standard for causation; experimental; prospective; minimises confounding"],
        ["Cohort Study", "Prospective; exposure → outcome; calculates RELATIVE RISK (RR); good for rare exposures"],
        ["Case-Control Study", "Retrospective; outcome → exposure; calculates ODDS RATIO (OR); good for rare diseases"],
        ["Cross-Sectional", "Prevalence study; one time point; calculates prevalence; quick & cheap"],
        ["Ecological Study", "Group level data; cannot infer individual causality (ecological fallacy)"],
        ["Systematic Review/Meta-analysis", "Highest level of evidence in hierarchy"],
    ]
)

subsection("Screening Criteria (Wilson & Jungner)")
bp("Disease should be an important health problem")
bp("Natural history well understood; recognisable latent stage")
bp("Acceptable, effective treatment available")
bp("Suitable test available: sensitive, specific, acceptable to population")
bp("Cost-effective and continuous process")

subsection("Sensitivity, Specificity & Predictive Values")
two_col_table(
    [Paragraph("<b>Term</b>",body), Paragraph("<b>Formula & Meaning</b>",body)],
    [
        ["Sensitivity (Se)", "TP / (TP+FN) × 100 — ability to detect TRUE positives (\"SnNout\" – sensitive test, negative result rules OUT)"],
        ["Specificity (Sp)", "TN / (TN+FP) × 100 — ability to identify TRUE negatives (\"SpPin\" – specific test, positive result rules IN)"],
        ["PPV", "TP / (TP+FP) × 100 — probability that positive test = true disease; rises with prevalence"],
        ["NPV", "TN / (TN+FN) × 100 — probability that negative test = truly disease-free"],
        ["Likelihood Ratio +ve", "Sensitivity / (1-Specificity)"],
    ]
)
note_box("High sensitivity → use for SCREENING. High specificity → use for CONFIRMATION/diagnosis.")

spacer()

# ─────────────────────────────────────────────────────────────────────────────
# 3. NUTRITION
# ─────────────────────────────────────────────────────────────────────────────
section_header("3. NUTRITION")

subsection("Protein-Energy Malnutrition (PEM)")
two_col_table(
    [Paragraph("<b>Condition</b>",body), Paragraph("<b>Features</b>",body)],
    [
        ["Kwashiorkor", "Protein deficiency dominant; oedema (hallmark); moon face; skin changes (flaky paint); growth retardation; fatty liver; age: 1–3 years"],
        ["Marasmus", "Calorie deficiency; severe wasting; no oedema; 'bag of bones' appearance; alert child; age: <1 year"],
        ["Marasmic Kwashiorkor", "Mixed features; worst prognosis"],
    ]
)

subsection("Vitamin Deficiency Diseases")
two_col_table(
    [Paragraph("<b>Vitamin</b>",body), Paragraph("<b>Deficiency Disease / Features</b>",body)],
    [
        ["Vitamin A", "Night blindness → Bitot's spots → Xerophthalmia → Keratomalacia (preventable blindness). Treat: 2 lakh IU vitamin A"],
        ["Vitamin D", "Rickets (children) – bow legs, Harrison's sulcus. Osteomalacia (adults). Sunlight is key source."],
        ["Vitamin C (Ascorbic acid)", "Scurvy – bleeding gums, perifollicular haemorrhage, corkscrew hair, Fraenkel's sign"],
        ["Vitamin B1 (Thiamine)", "Beriberi – Wet (cardiac, oedema), Dry (peripheral neuropathy), Wernicke's encephalopathy"],
        ["Vitamin B2 (Riboflavin)", "Cheilosis, angular stomatitis, glossitis, corneal vascularisation"],
        ["Niacin (B3)", "Pellagra – 3 Ds: Dermatitis, Diarrhoea, Dementia (+Death = 4th D)"],
        ["Vitamin B12 / Folate", "Megaloblastic anaemia; B12 deficiency → subacute combined degeneration of spinal cord"],
        ["Iodine", "Goitre, cretinism, hypothyroidism. Universal Salt Iodisation: 15 ppm at retail level"],
        ["Iron", "IDA – most common nutritional deficiency globally. Koilonychia, pallor, fatigue"],
    ]
)

note_box("National Vitamin A Prophylaxis: 5 doses in first 5 years – 1 lakh IU at 9 months, then 2 lakh IU every 6 months up to 5 years.")

subsection("Anthropometric Indices (Malnutrition Classification)")
two_col_table(
    [Paragraph("<b>Index</b>",body), Paragraph("<b>Indicates</b>",body)],
    [
        ["Weight for Age (W/A)", "Overall nutritional status; used in Gomez classification (Grade I/II/III PEM)"],
        ["Height for Age (H/A)", "Chronic malnutrition → Stunting"],
        ["Weight for Height (W/H)", "Acute malnutrition → Wasting"],
        ["MUAC <12.5 cm (child)", "Severe acute malnutrition (SAM)"],
    ]
)
spacer()

# ─────────────────────────────────────────────────────────────────────────────
# 4. IMMUNIZATION
# ─────────────────────────────────────────────────────────────────────────────
section_header("4. IMMUNIZATION & NATIONAL IMMUNIZATION SCHEDULE")

subsection("Universal Immunization Programme (UIP) – India")
two_col_table(
    [Paragraph("<b>Age</b>",body), Paragraph("<b>Vaccines</b>",body)],
    [
        ["Birth", "BCG, OPV-0 (birth dose), Hepatitis B (birth dose)"],
        ["6 weeks", "OPV-1, IPV-1, Penta-1 (DPT+HepB+Hib), Rota-1, PCV-1"],
        ["10 weeks", "OPV-2, Penta-2, Rota-2, PCV-2"],
        ["14 weeks", "OPV-3, IPV-2, Penta-3, Rota-3, PCV-3"],
        ["9 months", "MR-1, JE-1 (endemic areas), Vitamin A-1 (1 lakh IU)"],
        ["12 months", "PCV Booster"],
        ["16–24 months", "MR-2, DPT Booster-1, OPV Booster, JE-2 (endemic), Vitamin A (2nd dose)"],
        ["5–6 years", "DPT Booster-2"],
        ["10 years & 16 years", "Td (Tetanus + diphtheria adult formulation)"],
        ["Pregnant women", "TT-1 (early pregnancy), TT-2 (4 wks after TT-1), TT Booster (if prev vaccinated within 3 yrs)"],
    ]
)

note_box("BCG – given at birth; protects against TB meningitis & miliary TB (not pulmonary TB in adults). Scar appears 2–6 weeks after vaccination.")

subsection("Cold Chain")
bp("Temperature: +2°C to +8°C for most vaccines (walk-in coolers, ice-lined refrigerators, cold boxes)")
bp("OPV: stored at -15°C to -25°C (freezer)")
bp("Walk-in Freezer (WIF): District level | Walk-in Cooler (WIC): District level | ILR: PHC level | Cold box/vaccine carrier: field level")
bp("Vaccine Vial Monitor (VVM): colour change indicates heat exposure — DO NOT USE if inner square = outer circle colour")

subsection("Types of Immunity")
two_col_table(
    [Paragraph("<b>Type</b>",body), Paragraph("<b>Examples</b>",body)],
    [
        ["Active Natural", "Recovery from infection (e.g., measles, chickenpox)"],
        ["Active Artificial", "Vaccination (e.g., OPV, BCG, DPT)"],
        ["Passive Natural", "Maternal antibodies via placenta (IgG) / breast milk (IgA)"],
        ["Passive Artificial", "Immunoglobulin injections, anti-tetanus serum (ATS)"],
    ]
)
spacer()

# ─────────────────────────────────────────────────────────────────────────────
# 5. COMMUNICABLE DISEASES
# ─────────────────────────────────────────────────────────────────────────────
section_header("5. COMMUNICABLE DISEASES – HIGH YIELD")

subsection("Tuberculosis")
two_col_table(
    [Paragraph("<b>Aspect</b>",body), Paragraph("<b>Details</b>",body)],
    [
        ["Causative agent", "Mycobacterium tuberculosis (acid-fast bacillus)"],
        ["Diagnosis", "Sputum smear (Ziehl-Neelsen stain), CBNAAT/GeneXpert (gold standard for drug resistance), Mantoux test"],
        ["Mantoux test", "5 TU PPD; read at 48–72 hrs; induration ≥10 mm = positive (≥5 mm in HIV/immunocompromised)"],
        ["DOTS", "Directly Observed Treatment Short-course; cornerstone of RNTCP/NikshayNi-kshay program"],
        ["RNTCP → NI-KSHAY", "Category I (new): 2HRZE / 4HR; Category II (retreatment): 2HRZES / 1HRZE / 5HRE"],
        ["Contact tracing", "All household contacts screened; children <6 yrs = Isoniazid prophylaxis"],
    ]
)

subsection("Malaria")
two_col_table(
    [Paragraph("<b>Aspect</b>",body), Paragraph("<b>Details</b>",body)],
    [
        ["Species", "P. falciparum (malignant tertian, severe, chloroquine resistance) | P. vivax (benign tertian, relapse due to hypnozoites)"],
        ["Vector", "Female Anopheles mosquito; bites at night; breeds in clean, stagnant water"],
        ["Incubation period", "P. vivax: 12–14 days | P. falciparum: 9–14 days"],
        ["Diagnosis", "Thick blood smear (most sensitive for parasitaemia) | RDT (antigen-based)"],
        ["Complications P.f.", "Cerebral malaria, blackwater fever, algid malaria, ARDS, DIC"],
        ["Treatment", "P. vivax: Chloroquine + Primaquine (14 days). P. falciparum: ACT (Artesunate-based) + Primaquine single dose"],
        ["API", "Annual Parasite Incidence = Positive blood slides / Population × 1000"],
        ["ABER", "Annual Blood Examination Rate (target ≥10%)"],
    ]
)

subsection("Leprosy")
two_col_table(
    [Paragraph("<b>Aspect</b>",body), Paragraph("<b>Details</b>",body)],
    [
        ["Causative agent", "Mycobacterium leprae (cannot be cultured in vitro)"],
        ["Classification", "Paucibacillary (PB): 1–5 skin lesions, slit skin smear negative | Multibacillary (MB): >5 lesions, smear positive"],
        ["MDT regimen", "PB (6 months): Dapsone + Rifampicin monthly. MB (12 months): Dapsone + Clofazimine daily + Rifampicin monthly"],
        ["Reactions", "Type 1 (reversal): CMI-mediated | Type 2 (ENL): immune complex"],
        ["Disability grading", "Grade 0: no anaesthesia, no deformity | Grade 1: anaesthesia, no visible deformity | Grade 2: visible deformity"],
        ["Elimination target", "Prevalence <1 per 10,000 population (India achieved 2005)"],
    ]
)
spacer(3)
story.append(PageBreak())

# ─────────────────────────────────────────────────────────────────────────────
# 6. NATIONAL HEALTH PROGRAMMES
# ─────────────────────────────────────────────────────────────────────────────
section_header("6. NATIONAL HEALTH PROGRAMMES – KEY TARGETS")

two_col_table(
    [Paragraph("<b>Programme</b>",body), Paragraph("<b>Key Points</b>",body)],
    [
        ["RNTCP / Ni-kshay", "Detect ≥85% cases; DOTS treatment; cure rate ≥85%; Ni-kshay Poshan Yojana: ₹500/month to TB patient"],
        ["NMEP (Malaria)", "API <1 target for elimination by 2030; slide examination, DDT spraying, bed nets"],
        ["NLEP (Leprosy)", "MDT free of cost; elimination achieved 2005 (<1/10,000)"],
        ["NVBDCP", "National Vector Borne Disease Control Programme: Malaria, Dengue, Filaria, Kala-azar, JE, Chikungunya"],
        ["NPCB (Blindness)", "Reduce blindness to 0.3%; cataract surgery; school eye screening; Vit A prophylaxis"],
        ["NIDDCP (Iodine)", "Goitre control; iodised salt; target: USI"],
        ["NCD Mission (NPCDCS)", "Prevention of Cancer, Diabetes, CVD, Stroke; screening at 30+ yrs"],
        ["IDSP", "Integrated Disease Surveillance Programme: P (presumptive), L (lab-confirmed), S (syndromic) forms"],
        ["Ayushman Bharat – PMJAY", "₹5 lakh/family/yr; secondary & tertiary care; 107.4 crore beneficiaries"],
        ["NHM", "Rural + Urban Health Mission; strengthens PHC infrastructure; ASHA as key community link worker"],
        ["Janani Suraksha Yojana", "Cash incentive for institutional delivery; for BPL families"],
        ["PMMVY", "Pradhan Mantri Matru Vandana Yojana: ₹5000 for 1st live birth; conditional cash transfer"],
    ],
    col_widths=[5*cm, 12.5*cm]
)
spacer()

# ─────────────────────────────────────────────────────────────────────────────
# 7. FAMILY PLANNING & REPRODUCTIVE HEALTH
# ─────────────────────────────────────────────────────────────────────────────
section_header("7. FAMILY PLANNING & REPRODUCTIVE HEALTH")

subsection("Contraceptive Methods – Pearl Index (failures per 100 woman-years)")
two_col_table(
    [Paragraph("<b>Method</b>",body), Paragraph("<b>Pearl Index / Notes</b>",body)],
    [
        ["Combined OCP", "0.1–1; inhibits ovulation; taken Day 1–21; SE: nausea, DVT risk"],
        ["IUCD (Cu-T 380A)", "0.6–0.8; 10 years effective; MoA: spermicidal effect of copper ions; best: post-partum/post-abortion"],
        ["Condom", "2–15; also STI protection; female condom available"],
        ["DMPA (Depo-Provera)", "0.3; injection every 3 months; progestogen only"],
        ["Tubectomy (Minilap)", "<0.5; permanent; Pomeroy's technique most common; best: post-partum within 48 hrs or interval"],
        ["Vasectomy", "<0.15; permanent male sterilization; NSV (No-Scalpel Vasectomy) preferred in India"],
        ["Emergency Contraception", "Levonorgestrel 1.5 mg within 72 hrs (up to 120 hrs); Ulipristal up to 5 days; Cu-T within 5 days"],
        ["Lactational Amenorrhoea (LAM)", "<2; exclusive BF + amenorrhoea + <6 months postpartum (all 3 must be present)"],
    ]
)

subsection("Maternal & Child Health Targets (NHM)")
bp("MMR target: <100 per 100,000 live births by 2020 (current ~97 per NHM 2022)")
bp("IMR target: <25 per 1000 live births")
bp("NMR target: <10 per 1000 live births")
bp("TFR target: 2.1 (replacement level) — achieved nationally ~2.0 (NFHS-5)")
bp("Under-5 mortality target: <25 per 1000")
spacer()

# ─────────────────────────────────────────────────────────────────────────────
# 8. ENVIRONMENT & WATER
# ─────────────────────────────────────────────────────────────────────────────
section_header("8. ENVIRONMENT, WATER & SANITATION")

subsection("Water Quality Standards (BIS / WHO)")
two_col_table(
    [Paragraph("<b>Parameter</b>",body), Paragraph("<b>Standard</b>",body)],
    [
        ["Turbidity", "≤5 NTU (acceptable), ≤1 NTU (treated water)"],
        ["pH", "6.5 – 8.5"],
        ["Residual chlorine", "0.5 mg/L at source; 0.2 mg/L at tap (WHO)"],
        ["Fluoride", "0.5–1.5 mg/L (optimal 1 mg/L for dental health; >1.5 = dental fluorosis; >3 = skeletal fluorosis)"],
        ["Nitrate", "<45 mg/L (>45 = methaemoglobinaemia / blue baby syndrome)"],
        ["Coliforms", "0 per 100 mL in treated water (E. coli indicator of faecal contamination)"],
        ["Total Dissolved Solids", "<500 mg/L acceptable; <2000 permissible"],
    ]
)

subsection("Disinfection Methods")
bp("Chlorination: most widely used; Breakpoint chlorination; Residual chlorine 0.5 mg/L")
bp("Boiling: 100°C for 1 minute; kills all pathogens; most reliable for household")
bp("UV radiation: effective, no residual; used for bottled water")
bp("Bleaching powder (CaOCl2): contains 25–33% available chlorine; dose 2–3 mg/L")

subsection("Air Pollution Standards – WHO 2021 (PM2.5)")
bp("Annual mean: 5 μg/m³ | 24-hr mean: 15 μg/m³")
bp("PM10: Annual 15 μg/m³ | 24-hr: 45 μg/m³")
bp("COPD, lung cancer, IHD are major outcomes of long-term exposure")
spacer()

# ─────────────────────────────────────────────────────────────────────────────
# 9. BIOSTATISTICS – MUST KNOW
# ─────────────────────────────────────────────────────────────────────────────
section_header("9. BIOSTATISTICS ESSENTIALS")

two_col_table(
    [Paragraph("<b>Term</b>",body), Paragraph("<b>Meaning / Formula</b>",body)],
    [
        ["Mean", "Sum of all values / n; affected by outliers"],
        ["Median", "Middle value; not affected by outliers; used for skewed data"],
        ["Mode", "Most frequent value"],
        ["Normal distribution", "Mean = Median = Mode; bell-shaped curve; ±1 SD = 68.2%, ±2 SD = 95.4%, ±3 SD = 99.7%"],
        ["Standard Deviation (SD)", "Measure of spread around mean"],
        ["Standard Error (SE)", "SD / √n ; measures precision of sample mean"],
        ["95% CI", "Mean ± 1.96 SE; if CI does not include null = statistically significant"],
        ["p-value", "<0.05 = statistically significant (5% chance results due to chance)"],
        ["Relative Risk (RR)", "Incidence in exposed / Incidence in unexposed; used in cohort studies"],
        ["Odds Ratio (OR)", "Odds of exposure in cases / Odds of exposure in controls; case-control studies"],
        ["Attributable Risk (AR)", "Incidence exposed – Incidence unexposed; disease burden due to exposure"],
        ["NNT", "1 / Absolute Risk Reduction; number needed to treat"],
        ["Chi-square test", "Comparison of proportions / categorical data"],
        ["Student's t-test", "Comparison of means; 2 groups"],
        ["ANOVA", "Comparison of means; >2 groups"],
        ["Pearson's r", "Linear correlation; r=+1 perfect positive, r=-1 perfect negative, r=0 no correlation"],
    ]
)

note_box("Type I error (α): Rejecting a true null hypothesis (false positive). Type II error (β): Accepting a false null hypothesis (false negative). Power = 1 – β.")
spacer()

# ─────────────────────────────────────────────────────────────────────────────
# 10. HEALTH SYSTEM & ADMINISTRATION
# ─────────────────────────────────────────────────────────────────────────────
section_header("10. HEALTH SYSTEM & ADMINISTRATION")

subsection("Primary Health Care (Alma Ata Declaration, 1978)")
bp("Essential health care; first level of contact; universally accessible; affordable")
bp("8 components: Education, Nutrition, Safe water & sanitation, MCH & FP, Immunisation, Endemic disease control, Essential drugs, Treatment of common diseases")
bp("Principles: Equitable distribution, Community participation, Intersectoral coordination, Appropriate technology")

subsection("Rural Health Infrastructure (India)")
two_col_table(
    [Paragraph("<b>Level</b>",body), Paragraph("<b>Population Served / Details</b>",body)],
    [
        ["Sub-Centre (SC)", "5000 plains / 3000 hilly; ANM + Male Health Worker (MPW-M); first contact point"],
        ["Primary Health Centre (PHC)", "30,000 plains / 20,000 hilly; 1 MO + 14 paramedical staff; 6-bed facility; ESSENTIAL health services"],
        ["Community Health Centre (CHC)", "1,20,000 population; 30 beds; 4 specialists (surgeon, physician, OBG, paeds)"],
        ["District Hospital", "District HQ; 100–500 beds; all specialities"],
        ["Sub-Divisional Hospital", "Between CHC and District hospital"],
    ]
)

subsection("ASHA (Accredited Social Health Activist)")
bp("1 per 1000 rural population; link between community and health system")
bp("Minimum: 8th std pass, married/widow/divorced, 25–45 yrs (18 yrs in some states)")
bp("Incentive-based (not salaried); trained for 23 days + 4 rounds refresher")
bp("Key roles: JSY facilitation, immunisation tracking, DOTS, FP counselling, IMNCI")

subsection("Millennium Development Goals → Sustainable Development Goals")
bp("SDGs (2015–2030): 17 goals, 169 targets. SDG 3 = Ensure healthy lives & well-being for all at all ages")
bp("Key SDG 3 targets: End AIDS/TB/malaria; reduce NMR to ≤12; MMR to <70; UHC; road traffic injury reduction")
spacer()

# ─────────────────────────────────────────────────────────────────────────────
# MNEMONICS PAGE
# ─────────────────────────────────────────────────────────────────────────────
section_header("⚡ QUICK MNEMONICS & MEMORY HOOKS")

mnemonic_data = [
    ["Pellagra (4 Ds)", "Dermatitis, Diarrhoea, Dementia, Death (Niacin deficiency)"],
    ["Primary Health Care components (8)", "\"Every Nation Should Make Immunization Everyone's Duty True\" → Education, Nutrition, Safe water, MCH-FP, Immunization, Endemic disease, Essential drugs, Treatment"],
    ["Wilson-Jungner criteria (10)", "Important condition | Known natural history | Recognisable latent stage | Acceptable test | Acceptable treatment | Agreed policy | Facilities available | Recognisable early symptoms | Cost-effective | Continuous process"],
    ["Tetrad of malaria", "Fever, Chills, Rigors, Diaphoresis (sweating cycle)"],
    ["Leprosy disability grades", "0 = No problem, 1 = Anaesthesia, 2 = Deformity visible"],
    ["ASHA eligibility", "Married/Widow/Divorced, 25–45 yrs, 8th pass, local resident"],
    ["Kwashiorkor vs Marasmus", "Kwashiorkor = K for K (protein), has oedema | Marasmus = M for More calorie deficit, wasting"],
    ["CHC specialists (4)", "SOMP → Surgeon, Obstetrician, Medicine physician, Paediatrician"],
]

tbl = Table(
    [[Paragraph("<b>Concept</b>", body), Paragraph("<b>Mnemonic / Hook</b>", body)]] +
    [[Paragraph(r[0], body), Paragraph(r[1], body)] for r in mnemonic_data],
    colWidths=[5*cm, 12.5*cm], repeatRows=1
)
tbl.setStyle(TableStyle([
    ("BACKGROUND", (0,0), (-1,0), ORANGE),
    ("TEXTCOLOR",  (0,0), (-1,0), WHITE),
    ("FONTNAME",   (0,0), (-1,0), "Helvetica-Bold"),
    ("FONTSIZE",   (0,0), (-1,-1), 8),
    ("ROWBACKGROUNDS",(0,1),(-1,-1),[CREAM, WHITE]),
    ("GRID",       (0,0), (-1,-1), 0.4, ORANGE),
    ("TOPPADDING", (0,0), (-1,-1), 4),
    ("BOTTOMPADDING",(0,0),(-1,-1), 4),
    ("LEFTPADDING", (0,0),(-1,-1), 5),
    ("VALIGN",     (0,0),(-1,-1), "TOP"),
    ("FONTNAME",   (0,1),(-1,-1), "Helvetica"),
]))
story.append(tbl)
spacer(8)

# ─────────────────────────────────────────────────────────────────────────────
# FOOTER NOTE
# ─────────────────────────────────────────────────────────────────────────────
story.append(HRFlowable(width="100%", thickness=0.5, color=TEAL_LIGHT))
spacer(4)
story.append(Paragraph(
    "Prepared by Orris Study Companion  •  Based on Park's Textbook of Preventive & Social Medicine  •  July 2026  •  For exam revision use only",
    footer_style
))

# ─────────────────────────────────────────────────────────────────────────────
# BUILD
# ─────────────────────────────────────────────────────────────────────────────
doc.build(story)
print(f"PDF saved to: {OUTPUT}")