"""
1st Year MBBS Biochemistry Practical - Quick Reference Card (PDF)
A4 landscape, 2 columns, dense but readable layout
"""

from reportlab.lib.pagesizes import A4, landscape
from reportlab.lib.units import mm, cm
from reportlab.lib import colors
from reportlab.lib.styles import ParagraphStyle, getSampleStyleSheet
from reportlab.platypus import (
    BaseDocTemplate, PageTemplate, Frame, Paragraph, Table, TableStyle,
    Spacer, KeepTogether, HRFlowable
)
from reportlab.lib.enums import TA_CENTER, TA_LEFT

# ── Colour palette ──────────────────────────────────────────────────────────
DARK_BLUE   = colors.HexColor("#1a3a5c")
MED_BLUE    = colors.HexColor("#2563ab")
LIGHT_BLUE  = colors.HexColor("#dbeafe")
ACCENT_GREEN= colors.HexColor("#166534")
LIGHT_GREEN = colors.HexColor("#dcfce7")
ACCENT_RED  = colors.HexColor("#991b1b")
LIGHT_RED   = colors.HexColor("#fee2e2")
ACCENT_PURPLE=colors.HexColor("#5b21b6")
LIGHT_PURPLE= colors.HexColor("#ede9fe")
ORANGE      = colors.HexColor("#92400e")
LIGHT_ORANGE= colors.HexColor("#fef3c7")
GRAY_LIGHT  = colors.HexColor("#f1f5f9")
GRAY_MID    = colors.HexColor("#cbd5e1")
GRAY_DARK   = colors.HexColor("#334155")
WHITE       = colors.white
BLACK       = colors.black

# ── Page setup ───────────────────────────────────────────────────────────────
PAGE_W, PAGE_H = landscape(A4)
MARGIN = 8*mm
COL_GAP = 5*mm
COL_W = (PAGE_W - 2*MARGIN - COL_GAP) / 2
HEADER_H = 14*mm

# ── Styles ───────────────────────────────────────────────────────────────────
def make_styles():
    s = {}
    base = dict(fontName="Helvetica", leading=9)

    s["section_title"] = ParagraphStyle(
        "section_title", fontSize=7, fontName="Helvetica-Bold",
        textColor=WHITE, leading=9, spaceAfter=0, spaceBefore=0
    )
    s["col_header"] = ParagraphStyle(
        "col_header", fontSize=5.5, fontName="Helvetica-Bold",
        textColor=DARK_BLUE, leading=7
    )
    s["cell"] = ParagraphStyle(
        "cell", fontSize=5.5, fontName="Helvetica",
        textColor=GRAY_DARK, leading=7
    )
    s["cell_bold"] = ParagraphStyle(
        "cell_bold", fontSize=5.5, fontName="Helvetica-Bold",
        textColor=DARK_BLUE, leading=7
    )
    s["cell_red"] = ParagraphStyle(
        "cell_red", fontSize=5.5, fontName="Helvetica-Bold",
        textColor=ACCENT_RED, leading=7
    )
    s["cell_green"] = ParagraphStyle(
        "cell_green", fontSize=5.5, fontName="Helvetica-Bold",
        textColor=ACCENT_GREEN, leading=7
    )
    s["viva_q"] = ParagraphStyle(
        "viva_q", fontSize=5.5, fontName="Helvetica-Bold",
        textColor=DARK_BLUE, leading=7.5
    )
    s["viva_a"] = ParagraphStyle(
        "viva_a", fontSize=5.5, fontName="Helvetica",
        textColor=GRAY_DARK, leading=7.5
    )
    s["formula"] = ParagraphStyle(
        "formula", fontSize=6.5, fontName="Helvetica-Bold",
        textColor=ACCENT_PURPLE, leading=9, alignment=TA_CENTER
    )
    s["tiny"] = ParagraphStyle(
        "tiny", fontSize=4.8, fontName="Helvetica",
        textColor=GRAY_DARK, leading=6.5
    )
    return s

ST = make_styles()

# ── Helper builders ───────────────────────────────────────────────────────────
def section_header(title, bg_color=DARK_BLUE, star=""):
    label = f"{title}  {star}" if star else title
    tbl = Table([[Paragraph(label, ST["section_title"])]],
                colWidths=[COL_W], rowHeights=[9*mm])
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), bg_color),
        ("ROUNDEDCORNERS", [3]),
        ("LEFTPADDING", (0,0), (-1,-1), 4),
        ("TOPPADDING", (0,0), (-1,-1), 1),
        ("BOTTOMPADDING", (0,0), (-1,-1), 1),
    ]))
    return tbl

def data_table(headers, rows, col_widths, accent_col=MED_BLUE, row_colors=None):
    """Build a compact styled table."""
    p = lambda txt, style=ST["cell"]: Paragraph(str(txt), style)
    pb = lambda txt: Paragraph(str(txt), ST["cell_bold"])

    header_row = [pb(h) for h in headers]
    data_rows  = [[p(c) for c in row] for row in rows]
    all_rows   = [header_row] + data_rows

    style_cmds = [
        ("BACKGROUND", (0,0), (-1,0), accent_col),
        ("TEXTCOLOR",  (0,0), (-1,0), WHITE),
        ("FONTNAME",   (0,0), (-1,0), "Helvetica-Bold"),
        ("FONTSIZE",   (0,0), (-1,-1), 5.5),
        ("LEADING",    (0,0), (-1,-1), 7),
        ("LEFTPADDING",(0,0), (-1,-1), 3),
        ("RIGHTPADDING",(0,0),(-1,-1), 2),
        ("TOPPADDING", (0,0), (-1,-1), 1.5),
        ("BOTTOMPADDING",(0,0),(-1,-1), 1.5),
        ("GRID",       (0,0), (-1,-1), 0.3, GRAY_MID),
        ("ROWBACKGROUNDS", (0,1), (-1,-1), [WHITE, GRAY_LIGHT]),
    ]
    if row_colors:
        for row_idx, bg in row_colors:
            style_cmds.append(("BACKGROUND", (0,row_idx), (-1,row_idx), bg))

    tbl = Table(all_rows, colWidths=col_widths)
    tbl.setStyle(TableStyle(style_cmds))
    return tbl

def sp(h=2): return Spacer(1, h*mm)

# ── Content builders (return list of flowables) ────────────────────────────

def build_urine_analysis():
    items = []
    items.append(section_header("1. URINE ANALYSIS", DARK_BLUE, "★★★★★"))
    items.append(sp(1))

    # Physical
    phys_hdr = Paragraph("PHYSICAL EXAMINATION", ST["col_header"])
    phys_tbl = data_table(
        ["Parameter", "Normal", "Abnormal / Significance"],
        [
            ["Colour", "Pale–amber (urochrome)", "Dark=dehydration; Red=hematuria; Green=bile pigments"],
            ["Appearance", "Clear", "Turbid=pus/bacteria/phosphates"],
            ["Odour", "Faint aromatic", "Fruity=ketones(DM); Ammoniacal=UTI decomposition"],
            ["Sp. Gravity", "1.003–1.030", "Low=diabetes insipidus; High=DM, dehydration"],
            ["pH", "4.5–8.0 (avg 6.0)", "Acidic=DM/fever; Alkaline=UTI/vegetarians"],
        ],
        [22*mm, 30*mm, COL_W-52*mm-4],
        accent_col=MED_BLUE
    )
    items += [phys_hdr, sp(0.5), phys_tbl, sp(1.5)]

    # Chemical
    chem_hdr = Paragraph("CHEMICAL TESTS", ST["col_header"])
    chem_tbl = data_table(
        ["Test", "Reagent", "Positive", "Significance"],
        [
            ["Protein\n(Heat+AcOH)", "Heat + 1% acetic acid", "White ppt persists after acid", "Proteinuria – nephrotic sy., GN"],
            ["Glucose\n(Benedict's)", "Benedict's + heat", "Green→Yellow→Orange→Red ppt", "Glycosuria – DM, renal glycosuria"],
            ["Ketones\n(Rothera's)", "(NH₄)₂SO₄ + Na-nitroprusside + NH₃", "Purple/violet ring", "Ketonuria – DM, starvation"],
            ["Bile Salts\n(Hay's)", "Sprinkle sulphur powder", "Sulphur sinks", "Obstructive jaundice (↓surface tension)"],
            ["Bile Pigments\n(Fouchet's)", "BaCl₂ + Fouchet's reagent", "Green colour", "Jaundice – bilirubin in urine"],
            ["Blood\n(Orthotolidine)", "H₂O₂ + orthotolidine", "Blue/green colour", "Hematuria, hemoglobinuria"],
        ],
        [20*mm, 36*mm, 22*mm, COL_W-78*mm-4],
        accent_col=ACCENT_GREEN
    )
    items += [chem_hdr, sp(0.5), chem_tbl]
    return items


def build_carbohydrates():
    items = []
    items.append(section_header("2. QUALITATIVE CARBOHYDRATE TESTS", MED_BLUE, "★★★★★"))
    items.append(sp(1))
    tbl = data_table(
        ["Test", "Reagent", "Principle", "+ve Result", "Detects"],
        [
            ["Molisch", "α-naphthol + conc H₂SO₄", "Dehydration→furfural+α-naphthol", "Purple ring at interface", "ALL carbohydrates"],
            ["Benedict's", "CuSO₄+Na-citrate+Na₂CO₃", "Reducing sugars→Cu²⁺→Cu⁺(Cu₂O)", "Green/Yellow/Orange/Red ppt", "All reducing sugars"],
            ["Barfoed's", "Cu-acetate in acetic acid (acidic)", "Monosaccharides reduce Cu²⁺ faster", "Red ppt within 5 min", "Monosaccharides only"],
            ["Seliwanoff's", "Resorcinol + conc HCl", "Ketoses dehydrate faster than aldoses", "Cherry red <1 min", "Ketoses (fructose)"],
            ["Bial's", "Orcinol+FeCl₃+conc HCl", "Pentose→furfural+orcinol", "Blue-green colour", "Pentoses (ribose, arabinose)"],
            ["Iodine", "I₂/KI solution", "Iodine enters starch helical coils", "Blue-black", "Starch; Glycogen=reddish-brown"],
            ["Osazone", "Phenylhydrazine+NaOAc+AcOH", "Reducing sugar→osazone crystals", "Yellow crystals", "Glucose/Fructose/Lactose/Maltose"],
        ],
        [18*mm, 33*mm, 35*mm, 24*mm, COL_W-110*mm-4],
        accent_col=MED_BLUE
    )
    items.append(tbl)
    items.append(sp(1))

    # Crystal shapes box
    crystal_hdr = Paragraph("OSAZONE CRYSTAL SHAPES  (★ Viva favourite)", ST["col_header"])
    crystal_tbl = data_table(
        ["Sugar", "Crystal Shape", "Notes"],
        [
            ["Glucose / Fructose / Mannose", "Needle / sunflower / broomstick", "All three give SAME shape"],
            ["Lactose", "Mushroom / powder-puff", "Disc-shaped clumps"],
            ["Maltose", "Star / sea-urchin", "Spiky radiating needles"],
            ["Sucrose", "NO osazone", "Non-reducing – no free aldehyde/ketone"],
        ],
        [42*mm, 42*mm, COL_W-84*mm-4],
        accent_col=ORANGE,
        row_colors=[(4, LIGHT_RED)]
    )
    items += [crystal_hdr, sp(0.5), crystal_tbl]
    return items


def build_proteins():
    items = []
    items.append(section_header("3. QUALITATIVE PROTEIN TESTS", ACCENT_GREEN, "★★★★★"))
    items.append(sp(1))
    tbl = data_table(
        ["Test", "Reagent", "Principle (group detected)", "+ve Result"],
        [
            ["Biuret", "NaOH + dilute CuSO₄", "Cu²⁺ complexes with peptide bonds (≥2 bonds)", "Violet/purple"],
            ["Ninhydrin", "Triketohydrindene hydrate", "Oxidative deamination of α-amino group", "Purple (Ruhemann's); Proline=YELLOW"],
            ["Xanthoproteic", "Conc HNO₃ then NH₄OH", "Nitration of aromatic rings (Phe,Tyr,Trp)", "Yellow→Orange on alkalinisation"],
            ["Millon's", "Hg-sulphate+HNO₃+NaNO₂", "Hg reacts with hydroxyphenyl group (Tyr)", "Brick red ppt"],
            ["Hopkins-Cole", "Glyoxylic acid+conc H₂SO₄", "Indole ring of Trp condenses with glyoxylate", "Violet ring at interface"],
            ["Sulphur test", "NaOH + lead acetate", "H₂S released from Cys/Cystine+Pb-acetate", "Black ppt (lead sulphide)"],
            ["Sakaguchi", "α-naphthol+NaOH+NaOBr", "Guanidinium group of Arginine", "Red/orange colour"],
        ],
        [22*mm, 36*mm, 44*mm, COL_W-102*mm-4],
        accent_col=ACCENT_GREEN
    )
    items.append(tbl)
    return items


def build_colorimetry():
    items = []
    items.append(section_header("4. COLORIMETRY & BEER-LAMBERT'S LAW", ACCENT_PURPLE, "★★★★"))
    items.append(sp(1))

    # Formula box
    formula_tbl = Table(
        [[Paragraph("A  =  ε × c × l", ST["formula"]),
          Paragraph("A = Absorbance  |  ε = Molar extinction coeff.  |  c = Concentration  |  l = Path length (1 cm cuvette)", ST["tiny"])]],
        colWidths=[38*mm, COL_W-38*mm-4]
    )
    formula_tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), LIGHT_PURPLE),
        ("LEFTPADDING",(0,0),(-1,-1), 4),
        ("TOPPADDING",(0,0),(-1,-1), 3),
        ("BOTTOMPADDING",(0,0),(-1,-1), 3),
        ("VALIGN",(0,0),(-1,-1),"MIDDLE"),
        ("BOX",(0,0),(-1,-1),0.5,ACCENT_PURPLE),
    ]))
    items += [formula_tbl, sp(1.5)]

    parts_hdr = Paragraph("PARTS OF COLORIMETER", ST["col_header"])
    parts_tbl = data_table(
        ["Part", "Function"],
        [
            ["Light source", "Tungsten bulb (visible light)"],
            ["Filter", "Selects wavelength complementary to solution colour"],
            ["Cuvette", "Holds sample (glass/plastic, 1 cm path)"],
            ["Photodetector", "Converts transmitted light → electrical signal"],
            ["Galvanometer/Display", "Reads absorbance or % transmittance"],
        ],
        [35*mm, COL_W-35*mm-4],
        accent_col=ACCENT_PURPLE
    )
    items += [parts_hdr, sp(0.5), parts_tbl, sp(1.5)]

    err_hdr = Paragraph("SOURCES OF ERROR", ST["col_header"])
    errors = ["Stray light | Dirty/scratched cuvette | Wrong wavelength | Solution too concentrated (non-linear) | Air bubbles | Temperature variation | Not zeroed with blank"]
    err_box = Table([[Paragraph(errors[0], ST["tiny"])]],
                    colWidths=[COL_W])
    err_box.setStyle(TableStyle([
        ("BACKGROUND",(0,0),(-1,-1), LIGHT_RED),
        ("LEFTPADDING",(0,0),(-1,-1),4),("TOPPADDING",(0,0),(-1,-1),2),
        ("BOTTOMPADDING",(0,0),(-1,-1),2),
        ("BOX",(0,0),(-1,-1),0.4,ACCENT_RED),
    ]))
    items += [err_hdr, sp(0.5), err_box]
    return items


def build_instruments():
    items = []
    items.append(section_header("5. LABORATORY INSTRUMENTS", colors.HexColor("#0f766e"), "★★★★"))
    items.append(sp(1))
    tbl = data_table(
        ["Instrument", "Principle", "Key Points"],
        [
            ["Colorimeter", "Absorbance of complementary wavelength", "Filters; Visible light; Routine assays"],
            ["Spectrophotometer", "Prism/diffraction grating (continuous)", "UV+Vis+IR; More precise; Research use"],
            ["Centrifuge", "Centrifugal force separates by density", "Serum separation, urine sediment, cell fractionation"],
            ["Micropipette", "Air displacement (piston-driven)", "P20/P200/P1000; Use correct tips; Keep vertical when aspirating"],
            ["Water Bath", "Maintains constant temperature", "37°C = body temp; 56°C = complement inactivation"],
        ],
        [28*mm, 42*mm, COL_W-70*mm-4],
        accent_col=colors.HexColor("#0f766e")
    )
    items.append(tbl)
    return items


def build_blood_glucose():
    items = []
    items.append(section_header("6. BLOOD GLUCOSE – GOD-POD METHOD", colors.HexColor("#b45309"), "★★★★"))
    items.append(sp(1))

    rxn_hdr = Paragraph("REACTION STEPS", ST["col_header"])
    rxn_box = Table([
        [Paragraph("Step 1 (GOD): Glucose + O₂ + H₂O  →  Gluconic acid + H₂O₂", ST["tiny"])],
        [Paragraph("Step 2 (POD): H₂O₂ + 4-Aminoantipyrine + Phenol  →  Quinoneimine dye (PINK) + H₂O", ST["tiny"])],
        [Paragraph("Read at 505 nm. Colour intensity ∝ glucose concentration.", ST["tiny"])],
    ], colWidths=[COL_W])
    rxn_box.setStyle(TableStyle([
        ("BACKGROUND",(0,0),(-1,-1), LIGHT_ORANGE),
        ("LEFTPADDING",(0,0),(-1,-1),4),("TOPPADDING",(0,0),(-1,-1),1.5),
        ("BOTTOMPADDING",(0,0),(-1,-1),1.5),
        ("BOX",(0,0),(-1,-1),0.4, ORANGE),
    ]))
    items += [rxn_hdr, sp(0.5), rxn_box, sp(1.5)]

    val_hdr = Paragraph("NORMAL VALUES", ST["col_header"])
    val_tbl = data_table(
        ["State", "Value"],
        [
            ["Fasting blood glucose", "70–100 mg/dL"],
            ["Post-prandial (2 hr)", "< 140 mg/dL"],
            ["Random blood glucose", "< 200 mg/dL"],
            ["Impaired fasting", "100–125 mg/dL"],
            ["DM diagnosis (fasting)", "≥ 126 mg/dL"],
        ],
        [50*mm, COL_W-50*mm-4],
        accent_col=colors.HexColor("#b45309"),
        row_colors=[(5, LIGHT_RED)]
    )
    items += [val_hdr, sp(0.5), val_tbl]
    return items


def build_lft():
    items = []
    items.append(section_header("7. LIVER FUNCTION TESTS (LFT)", colors.HexColor("#7c3aed"), "★★★★"))
    items.append(sp(1))
    lft_tbl = data_table(
        ["Parameter", "Normal", "Elevated In"],
        [
            ["Total Bilirubin", "0.2–1.0 mg/dL", "All types of jaundice"],
            ["Direct (conjugated)", "0–0.3 mg/dL", "Obstructive / hepatic jaundice"],
            ["Indirect (unconjugated)", "0.1–0.8 mg/dL", "Haemolytic jaundice"],
            ["SGOT / AST", "10–40 U/L", "Hepatocellular damage, MI"],
            ["SGPT / ALT", "7–40 U/L", "Viral hepatitis (liver-specific)"],
            ["Alkaline Phosphatase", "40–125 U/L", "Obstructive jaundice, bone disease"],
            ["GGT", "10–66 U/L", "Alcoholic liver disease"],
            ["Total Protein", "6.0–8.0 g/dL", "↓ in liver failure, malnutrition"],
            ["Albumin", "3.5–5.0 g/dL", "↓ in cirrhosis, nephrotic syndrome"],
            ["Prothrombin Time", "11–13 sec", "Prolonged in liver disease"],
        ],
        [35*mm, 28*mm, COL_W-63*mm-4],
        accent_col=colors.HexColor("#7c3aed")
    )
    items += [lft_tbl, sp(1.5)]

    jaund_hdr = Paragraph("JAUNDICE DIFFERENTIATOR", ST["col_header"])
    jaund_tbl = data_table(
        ["Feature", "Pre-hepatic", "Hepatic", "Post-hepatic"],
        [
            ["Urine bilirubin", "Absent", "Present", "Present"],
            ["Urine urobilinogen", "Increased", "Variable", "Absent"],
            ["Stool colour", "Normal/dark", "Pale", "Clay/pale"],
            ["ALP", "Normal", "Slight ↑", "Markedly ↑"],
        ],
        [28*mm, 24*mm, 22*mm, COL_W-74*mm-4],
        accent_col=colors.HexColor("#7c3aed")
    )
    items += [jaund_hdr, sp(0.5), jaund_tbl]
    return items


def build_kft():
    items = []
    items.append(section_header("8. KIDNEY FUNCTION TESTS (KFT)", colors.HexColor("#0369a1"), "★★★★"))
    items.append(sp(1))
    kft_tbl = data_table(
        ["Parameter", "Normal", "Method", "Elevated In"],
        [
            ["Serum Urea", "15–40 mg/dL", "Diacetyl monoxime (pink colour)", "Renal failure, high protein diet, dehydration"],
            ["Serum Creatinine", "M: 0.7–1.2\nF: 0.5–1.0 mg/dL", "Jaffe's reaction (picric acid, alkaline → orange-red)", "Renal failure (more specific than urea)"],
            ["Uric Acid", "M: 3.5–7.0\nF: 2.5–6.0 mg/dL", "Uricase / phosphotungstic acid", "Gout, renal failure, leukaemia, diuretics"],
            ["eGFR", "> 90 mL/min/1.73m²", "CKD-EPI formula (from creatinine)", "Decreased in CKD; <15 = ESRD"],
        ],
        [25*mm, 25*mm, 38*mm, COL_W-88*mm-4],
        accent_col=colors.HexColor("#0369a1")
    )
    items += [kft_tbl, sp(1)]

    note_box = Table([[Paragraph(
        "BUN:Creatinine ratio  Normal = 10:1–20:1  |  >20 = Pre-renal (dehydration/GI bleed)  |  <10 = Liver disease  |  "
        "GFR <60 for >3 months = CKD  |  GFR <15 = ESRD (dialysis)",
        ST["tiny"])]],
        colWidths=[COL_W])
    note_box.setStyle(TableStyle([
        ("BACKGROUND",(0,0),(-1,-1), LIGHT_BLUE),
        ("LEFTPADDING",(0,0),(-1,-1),4),("TOPPADDING",(0,0),(-1,-1),2),
        ("BOTTOMPADDING",(0,0),(-1,-1),2),
        ("BOX",(0,0),(-1,-1),0.4, MED_BLUE),
    ]))
    items.append(note_box)
    return items


def build_lipid():
    items = []
    items.append(section_header("9. LIPID PROFILE", colors.HexColor("#be185d"), "★★★"))
    items.append(sp(1))

    formula_box = Table(
        [[Paragraph("Friedewald Formula:  LDL = Total Cholesterol − HDL − (Triglycerides ÷ 5)   [Valid when TG < 400 mg/dL]",
                    ST["formula"])]],
        colWidths=[COL_W]
    )
    formula_box.setStyle(TableStyle([
        ("BACKGROUND",(0,0),(-1,-1), LIGHT_PURPLE),
        ("LEFTPADDING",(0,0),(-1,-1),4),("TOPPADDING",(0,0),(-1,-1),3),
        ("BOTTOMPADDING",(0,0),(-1,-1),3),
        ("BOX",(0,0),(-1,-1),0.5, ACCENT_PURPLE),
    ]))
    items += [formula_box, sp(1)]

    lip_tbl = data_table(
        ["Parameter", "Desirable", "Borderline", "High Risk / Abnormal"],
        [
            ["Total Cholesterol", "< 200 mg/dL", "200–239 mg/dL", "≥ 240 mg/dL"],
            ["LDL  ('bad')", "< 100 mg/dL (optimal)", "130–159 mg/dL", "≥ 160 mg/dL"],
            ["HDL  ('good')", "> 60 mg/dL (protective)", "40–59 mg/dL", "< 40 mg/dL (RISK FACTOR)"],
            ["Triglycerides", "< 150 mg/dL", "150–199 mg/dL", "≥ 200 mg/dL"],
            ["VLDL", "2–30 mg/dL", "—", "> 30 mg/dL"],
        ],
        [25*mm, 30*mm, 26*mm, COL_W-81*mm-4],
        accent_col=colors.HexColor("#be185d")
    )
    items.append(lip_tbl)
    return items


def build_viva():
    items = []
    items.append(section_header("VIVA HOT QUESTIONS", ACCENT_RED, "★"))
    items.append(sp(1))

    qa = [
        ("Why add acetic acid in protein test?",
         "Dissolves phosphate precipitate; protein ppt persists after acidification"),
        ("Biuret +ve for amino acids?",
         "NO – needs ≥ 2 peptide bonds (tripeptides and above)"),
        ("Ninhydrin colour with proline?",
         "YELLOW (imino acid, not primary amino)"),
        ("GOD-POD wavelength?",
         "505 nm"),
        ("Sucrose in osazone test?",
         "NEGATIVE – non-reducing sugar (no free aldehyde/ketone)"),
        ("Beer-Lambert law formula?",
         "A = ε × c × l"),
        ("Jaffe's reaction is used for?",
         "Serum creatinine estimation"),
        ("ALT or AST – more liver specific?",
         "ALT (SGPT) is more liver-specific"),
        ("Why does sulphur sink in Hay's test?",
         "Bile salts reduce surface tension of urine"),
        ("Rothera's test detects?",
         "Acetoacetate + acetone (ketone bodies)"),
        ("Barfoed's – why acidic medium?",
         "Monosaccharides react in 5 min; disaccharides >10 min (differentiation)"),
        ("Seliwanoff's positive in 1 min means?",
         "Ketose (fructose); Aldoses give faint pink only after prolonged heating"),
    ]

    rows = []
    for q, a in qa:
        rows.append([
            Paragraph("Q: " + q, ST["viva_q"]),
            Paragraph("→ " + a, ST["viva_a"])
        ])

    viva_tbl = Table(rows, colWidths=[55*mm, COL_W-55*mm-4])
    viva_tbl.setStyle(TableStyle([
        ("FONTSIZE",(0,0),(-1,-1), 5.5),
        ("LEADING",(0,0),(-1,-1), 7.5),
        ("LEFTPADDING",(0,0),(-1,-1), 3),
        ("RIGHTPADDING",(0,0),(-1,-1), 3),
        ("TOPPADDING",(0,0),(-1,-1), 1.5),
        ("BOTTOMPADDING",(0,0),(-1,-1), 1.5),
        ("ROWBACKGROUNDS",(0,0),(-1,-1), [WHITE, LIGHT_RED]),
        ("GRID",(0,0),(-1,-1), 0.3, GRAY_MID),
        ("LINEAFTER",(0,0),(0,-1), 0.5, ACCENT_RED),
    ]))
    items.append(viva_tbl)
    return items


# ── Page template with header/footer ─────────────────────────────────────────
def on_page(canvas, doc):
    canvas.saveState()
    w, h = landscape(A4)

    # Top banner
    canvas.setFillColor(DARK_BLUE)
    canvas.rect(0, h - HEADER_H, w, HEADER_H, fill=1, stroke=0)
    canvas.setFillColor(WHITE)
    canvas.setFont("Helvetica-Bold", 9)
    canvas.drawCentredString(w/2, h - HEADER_H + 4.5*mm,
        "1st YEAR MBBS  –  BIOCHEMISTRY PRACTICAL  QUICK REFERENCE CARD")
    canvas.setFont("Helvetica", 6.5)
    canvas.setFillColor(colors.HexColor("#93c5fd"))
    canvas.drawString(MARGIN, h - HEADER_H + 4.5*mm,
        "Urine Analysis  •  Carbohydrates  •  Proteins  •  Colorimetry  •  Instruments")
    canvas.drawRightString(w - MARGIN, h - HEADER_H + 4.5*mm,
        "Blood Glucose  •  LFT  •  KFT  •  Lipid Profile")

    # Vertical divider
    canvas.setStrokeColor(GRAY_MID)
    canvas.setLineWidth(0.5)
    mid_x = MARGIN + COL_W + COL_GAP/2
    canvas.line(mid_x, MARGIN + 4*mm, mid_x, h - HEADER_H - 2*mm)

    # Footer
    canvas.setFillColor(GRAY_DARK)
    canvas.setFont("Helvetica", 5)
    footer = "Sources: Lippincott's Biochemistry 8e  |  Harper's Illustrated Biochemistry 32e  |  Basic Medical Biochemistry 6e"
    canvas.drawCentredString(w/2, 3*mm, footer)
    canvas.restoreState()


# ── Build document ────────────────────────────────────────────────────────────
def build():
    out = "/home/daytona/workspace/biochem-refcard/Biochem_Practical_QuickRef.pdf"

    doc = BaseDocTemplate(
        out,
        pagesize=landscape(A4),
        leftMargin=MARGIN, rightMargin=MARGIN,
        topMargin=HEADER_H + 2*mm, bottomMargin=6*mm,
        title="MBBS Biochemistry Practical Quick Reference",
        author="Orris"
    )

    left_frame = Frame(
        MARGIN, 6*mm,
        COL_W, PAGE_H - HEADER_H - 8*mm,
        leftPadding=0, rightPadding=0, topPadding=0, bottomPadding=0
    )
    right_frame = Frame(
        MARGIN + COL_W + COL_GAP, 6*mm,
        COL_W, PAGE_H - HEADER_H - 8*mm,
        leftPadding=0, rightPadding=0, topPadding=0, bottomPadding=0
    )

    doc.addPageTemplates([
        PageTemplate(id="TwoCol", frames=[left_frame, right_frame], onPage=on_page)
    ])

    # ── Page 1: Left col (topics 1–3), Right col (topics 4–6 + viva start) ──
    # ── Page 2: Left col (7–8), Right col (9 + viva) ──
    story = []

    # --- LEFT COLUMN PAGE 1 ---
    story += build_urine_analysis()
    story.append(sp(3))
    story += build_carbohydrates()
    story.append(sp(3))
    story += build_proteins()

    # --- RIGHT COLUMN PAGE 1 ---
    from reportlab.platypus import FrameBreak
    story.append(FrameBreak())

    story += build_colorimetry()
    story.append(sp(3))
    story += build_instruments()
    story.append(sp(3))
    story += build_blood_glucose()

    # --- PAGE 2 LEFT ---
    from reportlab.platypus import PageBreak
    story.append(PageBreak())

    story += build_lft()
    story.append(sp(3))
    story += build_kft()

    # --- PAGE 2 RIGHT ---
    story.append(FrameBreak())

    story += build_lipid()
    story.append(sp(3))
    story += build_viva()

    doc.build(story)
    print(f"PDF written to: {out}")
    return out


if __name__ == "__main__":
    build()