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

OUTPUT = "/home/daytona/workspace/weight-loss-series/Meal_Sequence_Guide.pdf"

# ── Colours ──────────────────────────────────────────────────────────────────
GREEN_DARK  = colors.HexColor("#1B5E20")
GREEN_MED   = colors.HexColor("#2E7D32")
GREEN_LIGHT = colors.HexColor("#C8E6C9")
GREEN_PALE  = colors.HexColor("#F1F8E9")
ACCENT      = colors.HexColor("#558B2F")
TEXT_DARK   = colors.HexColor("#1A1A1A")
TEXT_MID    = colors.HexColor("#424242")
WHITE       = colors.white
GOLD        = colors.HexColor("#F9A825")

doc = SimpleDocTemplate(
    OUTPUT,
    pagesize=A4,
    leftMargin=18*mm, rightMargin=18*mm,
    topMargin=14*mm,  bottomMargin=14*mm,
)
W, H = A4
story = []

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

def S(name, **kw):
    return ParagraphStyle(name, **kw)

title_s = S("MainTitle",
    fontSize=26, leading=32, textColor=WHITE,
    fontName="Helvetica-Bold", alignment=TA_CENTER, spaceAfter=4)

subtitle_s = S("SubTitle",
    fontSize=12, leading=16, textColor=GREEN_LIGHT,
    fontName="Helvetica", alignment=TA_CENTER, spaceAfter=0)

section_h = S("SectionH",
    fontSize=13, leading=17, textColor=GREEN_DARK,
    fontName="Helvetica-Bold", spaceBefore=10, spaceAfter=4)

body_s = S("Body",
    fontSize=9.5, leading=14, textColor=TEXT_DARK,
    fontName="Helvetica", spaceAfter=4, alignment=TA_JUSTIFY)

bullet_s = S("Bullet",
    fontSize=9.5, leading=14, textColor=TEXT_DARK,
    fontName="Helvetica", leftIndent=12, spaceAfter=3,
    bulletIndent=4, alignment=TA_LEFT)

small_s = S("Small",
    fontSize=8, leading=11, textColor=TEXT_MID,
    fontName="Helvetica", spaceAfter=2)

cite_s = S("Cite",
    fontSize=7.5, leading=10, textColor=ACCENT,
    fontName="Helvetica-Oblique", spaceAfter=2)

step_label_s = S("StepLabel",
    fontSize=10, leading=13, textColor=WHITE,
    fontName="Helvetica-Bold", alignment=TA_CENTER)

step_body_s = S("StepBody",
    fontSize=9, leading=13, textColor=TEXT_DARK,
    fontName="Helvetica", alignment=TA_LEFT)

tag_s = S("Tag",
    fontSize=8, leading=11, textColor=WHITE,
    fontName="Helvetica-Bold", alignment=TA_CENTER)

# ─────────────────────────────────────────────────────────────────────────────
# HEADER BANNER
# ─────────────────────────────────────────────────────────────────────────────
banner_text = [
    [Paragraph("The Meal Sequence Method", title_s)],
    [Paragraph("Eat in the right order. Control your blood sugar. Lose weight.", subtitle_s)],
]
banner = Table(banner_text, colWidths=[W - 36*mm])
banner.setStyle(TableStyle([
    ("BACKGROUND", (0,0), (-1,-1), GREEN_DARK),
    ("TOPPADDING",    (0,0), (-1,0), 14),
    ("BOTTOMPADDING", (0,0), (-1,0), 4),
    ("TOPPADDING",    (0,1), (-1,1), 2),
    ("BOTTOMPADDING", (0,1), (-1,1), 14),
    ("LEFTPADDING",  (0,0), (-1,-1), 10),
    ("RIGHTPADDING", (0,0), (-1,-1), 10),
    ("ROUNDEDCORNERS", [6]),
]))
story.append(banner)
story.append(Spacer(1, 8*mm))

# ─────────────────────────────────────────────────────────────────────────────
# INTRO BLURB
# ─────────────────────────────────────────────────────────────────────────────
story.append(Paragraph(
    "Research shows that <b>the order you eat food within a meal</b> significantly affects "
    "your blood sugar response, insulin levels, and how full you feel - even when the total "
    "calories are identical. This simple strategy requires no calorie counting, no special "
    "foods, and works from your very next meal.",
    body_s))
story.append(Spacer(1, 5*mm))

# ─────────────────────────────────────────────────────────────────────────────
# THE 4-STEP SEQUENCE
# ─────────────────────────────────────────────────────────────────────────────
story.append(Paragraph("The 4-Step Eating Order", section_h))
story.append(HRFlowable(width="100%", thickness=1.5, color=GREEN_MED, spaceAfter=6))

steps = [
    ("1", "FIBRE FIRST",   "Vegetables, salad, greens, legumes",
     "Forms a physical mesh in your gut that slows carb absorption. "
     "Triggers GLP-1 (satiety hormone). Reduces blood sugar spike by up to 30%."),
    ("2", "PROTEIN SECOND","Chicken, fish, eggs, tofu, legumes, dairy",
     "Further boosts GLP-1 and PYY (fullness hormones). "
     "High thermic effect - burns 25-30% of its own calories in digestion. "
     "Preserves muscle while losing fat."),
    ("3", "FATS THIRD",    "Olive oil, avocado, nuts, oily fish",
     "Slows gastric emptying further. No blood sugar spike. "
     "Adds lasting satiety - keeps you full for 3-4 hours."),
    ("4", "CARBS LAST",    "Rice, bread, pasta, potato, fruit",
     "By now: fibre mesh is in place, stomach is partially full, GLP-1 is elevated. "
     "Glucose enters bloodstream gradually - lower spike, lower insulin, less fat storage."),
]

step_colors = [GREEN_DARK, GREEN_MED, ACCENT, colors.HexColor("#33691E")]

for num, title, examples, desc in steps:
    idx = int(num) - 1
    col = step_colors[idx]

    num_cell  = Paragraph(num, S(f"N{num}", fontSize=22, leading=26,
                                  textColor=WHITE, fontName="Helvetica-Bold",
                                  alignment=TA_CENTER))
    head_cell = Paragraph(f"<b>STEP {num}: {title}</b>",
                          S(f"H{num}", fontSize=11, leading=14,
                            textColor=WHITE, fontName="Helvetica-Bold"))
    ex_cell   = Paragraph(f"<i>e.g. {examples}</i>",
                          S(f"E{num}", fontSize=8.5, leading=12,
                            textColor=GREEN_LIGHT, fontName="Helvetica-Oblique"))
    desc_cell = Paragraph(desc,
                          S(f"D{num}", fontSize=9, leading=13,
                            textColor=TEXT_DARK, fontName="Helvetica"))

    inner = Table(
        [[head_cell], [ex_cell]],
        colWidths=[120*mm]
    )
    inner.setStyle(TableStyle([
        ("TOPPADDING",    (0,0), (-1,-1), 1),
        ("BOTTOMPADDING", (0,0), (-1,-1), 1),
        ("LEFTPADDING",   (0,0), (-1,-1), 0),
        ("RIGHTPADDING",  (0,0), (-1,-1), 0),
    ]))

    row = Table(
        [[num_cell, inner, desc_cell]],
        colWidths=[14*mm, 88*mm, 68*mm]
    )
    row.setStyle(TableStyle([
        ("BACKGROUND",    (0,0), (1,0), col),
        ("BACKGROUND",    (2,0), (2,0), GREEN_PALE),
        ("VALIGN",        (0,0), (-1,-1), "MIDDLE"),
        ("TOPPADDING",    (0,0), (-1,-1), 8),
        ("BOTTOMPADDING", (0,0), (-1,-1), 8),
        ("LEFTPADDING",   (0,0), (0,0), 4),
        ("LEFTPADDING",   (1,0), (1,0), 8),
        ("LEFTPADDING",   (2,0), (2,0), 10),
        ("RIGHTPADDING",  (2,0), (2,0), 8),
        ("ROUNDEDCORNERS", [4]),
        ("BOX", (0,0), (-1,-1), 0.5, colors.HexColor("#A5D6A7")),
    ]))
    story.append(KeepTogether([row, Spacer(1, 3*mm)]))

story.append(Spacer(1, 3*mm))

# ─────────────────────────────────────────────────────────────────────────────
# WHY IT WORKS - TWO COLUMNS
# ─────────────────────────────────────────────────────────────────────────────
story.append(Paragraph("Why It Works for Weight Loss", section_h))
story.append(HRFlowable(width="100%", thickness=1.5, color=GREEN_MED, spaceAfter=6))

benefits = [
    ("Lower insulin spike",       "Insulin = fat-storage hormone. Flatten the spike, reduce fat storage."),
    ("More satiety hormones",     "GLP-1 and PYY rise earlier, so you eat less without feeling deprived."),
    ("Fewer cravings",            "Blood sugar crashes drive sweet cravings. A gradual rise = no crash."),
    ("Naturally smaller portions","You are already partially full before carbs arrive on your plate."),
    ("No calorie counting needed","The mechanism works passively - just change the order."),
    ("Reduces inflammation",      "Blunting glucose spikes lowers inflammatory immune activation over time."),
]

left_rows  = [[Paragraph(f"<b>{b[0]}</b>", S("BH", fontSize=9, leading=12,
               textColor=GREEN_DARK, fontName="Helvetica-Bold")),
               Paragraph(b[1], S("BD", fontSize=8.5, leading=12,
               textColor=TEXT_DARK, fontName="Helvetica"))]
              for b in benefits[:3]]
right_rows = [[Paragraph(f"<b>{b[0]}</b>", S("BH2", fontSize=9, leading=12,
               textColor=GREEN_DARK, fontName="Helvetica-Bold")),
               Paragraph(b[1], S("BD2", fontSize=8.5, leading=12,
               textColor=TEXT_DARK, fontName="Helvetica"))]
              for b in benefits[3:]]

def make_benefit_table(rows):
    t = Table(rows, colWidths=[42*mm, 43*mm])
    t.setStyle(TableStyle([
        ("BACKGROUND",    (0,0), (-1,-1), GREEN_PALE),
        ("VALIGN",        (0,0), (-1,-1), "TOP"),
        ("TOPPADDING",    (0,0), (-1,-1), 5),
        ("BOTTOMPADDING", (0,0), (-1,-1), 5),
        ("LEFTPADDING",   (0,0), (0,-1), 8),
        ("LEFTPADDING",   (1,0), (1,-1), 6),
        ("RIGHTPADDING",  (0,0), (-1,-1), 6),
        ("LINEBELOW",     (0,0), (-1,-2), 0.4, colors.HexColor("#A5D6A7")),
        ("BOX",           (0,0), (-1,-1), 0.5, colors.HexColor("#A5D6A7")),
    ]))
    return t

two_col = Table(
    [[make_benefit_table(left_rows), make_benefit_table(right_rows)]],
    colWidths=[(W - 36*mm)/2 - 2*mm, (W - 36*mm)/2 - 2*mm],
    hAlign="LEFT"
)
two_col.setStyle(TableStyle([
    ("LEFTPADDING",  (0,0), (-1,-1), 0),
    ("RIGHTPADDING", (0,0), (-1,-1), 0),
    ("TOPPADDING",   (0,0), (-1,-1), 0),
    ("BOTTOMPADDING",(0,0), (-1,-1), 0),
    ("VALIGN",       (0,0), (-1,-1), "TOP"),
]))
story.append(two_col)
story.append(Spacer(1, 5*mm))

# ─────────────────────────────────────────────────────────────────────────────
# PRACTICAL TIPS
# ─────────────────────────────────────────────────────────────────────────────
story.append(Paragraph("Practical Tips", section_h))
story.append(HRFlowable(width="100%", thickness=1.5, color=GREEN_MED, spaceAfter=6))

tips = [
    "Start every meal with a side salad, raw veggies, or cooked greens before anything else.",
    "At restaurants, order a soup or salad starter - it counts as your fibre first.",
    "Mixed meals (stir fry, curry, bowls)? Eat around the veggies first, finish with rice/noodles.",
    "A 5-10 min gap between fibre/protein and carbs makes a measurable difference.",
    "Pair this with adequate protein (1.6-2.2g per kg bodyweight) for best fat-loss results.",
    "Weigh yourself weekly (same time, same conditions) - trends matter, not daily numbers.",
]

tip_data = [[Paragraph(f"<b>{i+1}.</b>  {t}", S(f"T{i}", fontSize=9, leading=13,
             textColor=TEXT_DARK, fontName="Helvetica"))]
            for i, t in enumerate(tips)]

tip_table = Table(tip_data, colWidths=[W - 36*mm])
tip_table.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (-1,-1), WHITE),
    ("BACKGROUND",    (0,0), (-1,0), GREEN_PALE),
    ("BACKGROUND",    (0,2), (-1,2), GREEN_PALE),
    ("BACKGROUND",    (0,4), (-1,4), GREEN_PALE),
    ("TOPPADDING",    (0,0), (-1,-1), 6),
    ("BOTTOMPADDING", (0,0), (-1,-1), 6),
    ("LEFTPADDING",   (0,0), (-1,-1), 10),
    ("LINEBELOW",     (0,0), (-1,-2), 0.4, colors.HexColor("#C8E6C9")),
    ("BOX",           (0,0), (-1,-1), 0.5, colors.HexColor("#A5D6A7")),
]))
story.append(tip_table)
story.append(Spacer(1, 5*mm))

# ─────────────────────────────────────────────────────────────────────────────
# SOURCES
# ─────────────────────────────────────────────────────────────────────────────
story.append(Paragraph("Evidence & Sources", section_h))
story.append(HRFlowable(width="100%", thickness=1.5, color=GREEN_MED, spaceAfter=5))

sources = [
    ("1", "Sun L et al.",
     "Postprandial glucose, insulin and incretin responses differ by test meal macronutrient "
     "ingestion sequence (PATTERN study). Clinical Nutrition, 2020.",
     "PMID: 31053510"),
    ("2", "Higuchi Y et al.",
     "Dietary Modification with Food Order and Divided Carbohydrate Intake Improves Glycemic "
     "Excursions in Healthy Young Women. Nutrients, 2025.",
     "PMID: 41156447"),
    ("3", "Shukla AP et al.",
     "A Randomized Controlled Pilot Study of the Food Order Behavioral Intervention in "
     "Prediabetes. Nutrients, 2023.",
     "PMID: 37892527"),
    ("4", "Imai S et al.",
     "A Review of Recent Findings on Meal Sequence: An Attractive Dietary Approach to "
     "Prevention and Management of Type 2 Diabetes. PMC, 2020.",
     "PMC7551485"),
]

for num, author, title_txt, pid in sources:
    row = Table(
        [[Paragraph(f"<b>[{num}]</b>", S(f"SN{num}", fontSize=8.5, leading=12,
                    textColor=ACCENT, fontName="Helvetica-Bold")),
          Paragraph(f"<b>{author}</b> {title_txt} "
                    f"<font color='#558B2F'><i>{pid}</i></font>",
                    S(f"ST{num}", fontSize=8, leading=12,
                      textColor=TEXT_MID, fontName="Helvetica"))]],
        colWidths=[10*mm, W - 46*mm]
    )
    row.setStyle(TableStyle([
        ("VALIGN",        (0,0), (-1,-1), "TOP"),
        ("TOPPADDING",    (0,0), (-1,-1), 3),
        ("BOTTOMPADDING", (0,0), (-1,-1), 3),
        ("LEFTPADDING",   (0,0), (0,0), 0),
        ("LEFTPADDING",   (1,0), (1,0), 4),
    ]))
    story.append(row)

story.append(Spacer(1, 4*mm))

# ─────────────────────────────────────────────────────────────────────────────
# FOOTER
# ─────────────────────────────────────────────────────────────────────────────
footer_data = [[
    Paragraph("This guide is for informational purposes only. Consult a registered dietitian "
              "or healthcare professional before making significant dietary changes.",
              S("Disc", fontSize=7.5, leading=11, textColor=WHITE,
                fontName="Helvetica-Oblique", alignment=TA_CENTER)),
]]
footer = Table(footer_data, colWidths=[W - 36*mm])
footer.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (-1,-1), GREEN_MED),
    ("TOPPADDING",    (0,0), (-1,-1), 7),
    ("BOTTOMPADDING", (0,0), (-1,-1), 7),
    ("LEFTPADDING",   (0,0), (-1,-1), 10),
    ("RIGHTPADDING",  (0,0), (-1,-1), 10),
    ("ROUNDEDCORNERS", [4]),
]))
story.append(footer)

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