from docx import Document
from docx.shared import Pt, Inches, RGBColor
from docx.enum.text import WD_ALIGN_PARAGRAPH
from docx.oxml.ns import qn
from docx.oxml import OxmlElement
import datetime

doc = Document()

# ── Page margins ──────────────────────────────────────────────────────────────
section = doc.sections[0]
section.top_margin    = Inches(1.0)
section.bottom_margin = Inches(1.0)
section.left_margin   = Inches(1.15)
section.right_margin  = Inches(1.15)

# ── Base font ─────────────────────────────────────────────────────────────────
normal = doc.styles["Normal"]
normal.font.name = "Calibri"
normal.font.size = Pt(11)

# ── Helper: coloured heading ──────────────────────────────────────────────────
DARK_TEAL  = RGBColor(0x00, 0x6B, 0x6B)   # section headings
MID_TEAL   = RGBColor(0x00, 0x8B, 0x8B)   # sub-headings
ACCENT_RED = RGBColor(0xC0, 0x39, 0x2B)   # warning / avoid callouts
DARK_GREY  = RGBColor(0x33, 0x33, 0x33)

def add_heading(text, level=1, colour=DARK_TEAL):
    p = doc.add_heading(text, level=level)
    for run in p.runs:
        run.font.color.rgb = colour
        run.font.bold = True
    p.paragraph_format.space_before = Pt(14 if level == 1 else 8)
    p.paragraph_format.space_after  = Pt(4)
    return p

def add_body(text, bold=False, italic=False, colour=None, indent=False):
    p = doc.add_paragraph()
    p.paragraph_format.space_after = Pt(4)
    if indent:
        p.paragraph_format.left_indent = Inches(0.3)
    run = p.add_run(text)
    run.font.size = Pt(11)
    run.bold   = bold
    run.italic = italic
    if colour:
        run.font.color.rgb = colour
    return p

def add_bullet(text, level=0):
    p = doc.add_paragraph(style="List Bullet")
    p.paragraph_format.space_after = Pt(2)
    p.paragraph_format.left_indent = Inches(0.3 + level * 0.25)
    run = p.add_run(text)
    run.font.size = Pt(11)
    return p

def add_callout(label, text, label_colour=ACCENT_RED):
    p = doc.add_paragraph()
    p.paragraph_format.space_after  = Pt(4)
    p.paragraph_format.space_before = Pt(4)
    p.paragraph_format.left_indent  = Inches(0.3)
    r1 = p.add_run(f"{label}  ")
    r1.bold = True
    r1.font.color.rgb = label_colour
    r2 = p.add_run(text)
    r2.font.size = Pt(11)

def add_table_2col(headers, rows, col_widths=(2.8, 3.5)):
    table = doc.add_table(rows=1 + len(rows), cols=2)
    table.style = "Table Grid"
    # header row
    hdr = table.rows[0].cells
    for i, h in enumerate(headers):
        hdr[i].text = h
        run = hdr[i].paragraphs[0].runs[0]
        run.bold = True
        run.font.color.rgb = RGBColor(0xFF, 0xFF, 0xFF)
        tc = hdr[i]._tc
        tcPr = tc.get_or_add_tcPr()
        shd = OxmlElement("w:shd")
        shd.set(qn("w:val"), "clear")
        shd.set(qn("w:color"), "auto")
        shd.set(qn("w:fill"), "006B6B")
        tcPr.append(shd)
    # data rows
    for ri, row_data in enumerate(rows):
        cells = table.rows[ri + 1].cells
        for ci, val in enumerate(row_data):
            cells[ci].text = val
            cells[ci].paragraphs[0].runs[0].font.size = Pt(10.5)
    # column widths
    for row in table.rows:
        row.cells[0].width = Inches(col_widths[0])
        row.cells[1].width = Inches(col_widths[1])
    doc.add_paragraph()   # spacer after table

def hr():
    """Thin horizontal rule."""
    p = doc.add_paragraph()
    p.paragraph_format.space_before = Pt(2)
    p.paragraph_format.space_after  = Pt(2)
    pPr = p._p.get_or_add_pPr()
    pBdr = OxmlElement("w:pBdr")
    bottom = OxmlElement("w:bottom")
    bottom.set(qn("w:val"),   "single")
    bottom.set(qn("w:sz"),    "4")
    bottom.set(qn("w:space"), "1")
    bottom.set(qn("w:color"), "006B6B")
    pBdr.append(bottom)
    pPr.append(pBdr)

# ══════════════════════════════════════════════════════════════════════════════
# TITLE BLOCK
# ══════════════════════════════════════════════════════════════════════════════
title_p = doc.add_paragraph()
title_p.alignment = WD_ALIGN_PARAGRAPH.CENTER
title_p.paragraph_format.space_before = Pt(6)
title_p.paragraph_format.space_after  = Pt(2)
tr = title_p.add_run("Chronic Gastritis: A Comprehensive Management Guide")
tr.font.name  = "Calibri"
tr.font.size  = Pt(20)
tr.font.bold  = True
tr.font.color.rgb = DARK_TEAL

sub_p = doc.add_paragraph()
sub_p.alignment = WD_ALIGN_PARAGRAPH.CENTER
sub_p.paragraph_format.space_after = Pt(2)
sr = sub_p.add_run("Diet  |  Stress Management  |  Medications")
sr.font.size  = Pt(13)
sr.font.color.rgb = MID_TEAL
sr.italic = True

date_p = doc.add_paragraph()
date_p.alignment = WD_ALIGN_PARAGRAPH.CENTER
date_p.paragraph_format.space_after = Pt(10)
dr = date_p.add_run(f"Prepared: {datetime.date.today().strftime('%B %d, %Y')}")
dr.font.size = Pt(10)
dr.font.color.rgb = RGBColor(0x88, 0x88, 0x88)

hr()

# ══════════════════════════════════════════════════════════════════════════════
# 1. WHAT IS CHRONIC GASTRITIS?
# ══════════════════════════════════════════════════════════════════════════════
add_heading("1. What Is Chronic Gastritis?", level=1)
add_body(
    "Chronic gastritis is persistent, long-term inflammation of the stomach lining (gastric mucosa). "
    "Unlike acute gastritis, which resolves quickly, chronic gastritis develops gradually over weeks to years "
    "and often causes little or no obvious pain - yet it can lead to serious complications such as peptic ulcer "
    "disease, gastric atrophy, vitamin B12 deficiency, and gastric cancer if left untreated."
)

add_heading("Common Causes", level=2, colour=MID_TEAL)
causes = [
    ("Helicobacter pylori (H. pylori) infection",
     "The dominant cause. Present in up to 90% of duodenal ulcer cases. Disrupts mucosal defence and triggers sustained inflammation."),
    ("Chronic NSAID / aspirin use",
     "Directly injures the gastric lining by inhibiting protective prostaglandins."),
    ("Autoimmune gastritis",
     "The body attacks parietal cells, causing B12 deficiency and pernicious anaemia."),
    ("Physiological stress",
     "Severe trauma, burns, sepsis - causes mucosal ischaemia and stress ulcers."),
    ("Psychological stress",
     "Increases acid secretion, reduces mucosal blood flow, lowers prostaglandin levels."),
    ("Alcohol, bile reflux, radiation",
     "Less common but clinically relevant contributors."),
]
add_table_2col(["Cause", "Mechanism / Notes"], causes, col_widths=(2.4, 3.9))

hr()

# ══════════════════════════════════════════════════════════════════════════════
# 2. DIETARY MANAGEMENT
# ══════════════════════════════════════════════════════════════════════════════
add_heading("2. Dietary Management", level=1)
add_body(
    "Diet does not cure chronic gastritis, but it significantly affects symptom severity. "
    "The goal is to reduce acid-related irritation, support the mucosal barrier, and avoid foods that "
    "directly inflame the stomach lining. An anti-inflammatory, low-fat, non-acidic eating pattern has the best evidence."
)

add_heading("Foods to Include", level=2, colour=MID_TEAL)
include = [
    "Whole grains (oats, brown rice, soft bread) - high fibre, low irritation",
    "Lean proteins - boiled/grilled chicken, fish, eggs",
    "Non-acidic vegetables - carrots, broccoli, spinach, pumpkin",
    "Low-acid fruits - bananas, melons, pears (avoid citrus)",
    "Probiotic-rich foods - plain yogurt, kefir (may support mucosal health)",
    "Anti-bacterial foods - garlic, ginger, turmeric (evidence for H. pylori benefit)",
    "Herbal teas - chamomile, ginger tea (soothing, non-acidic)",
    "Plenty of water - aids digestion and mucosal hydration",
]
for item in include:
    add_bullet(item)

add_heading("Foods and Habits to Avoid", level=2, colour=ACCENT_RED)
avoid = [
    "Spicy foods - direct mucosal irritant",
    "Fatty and fried foods - delay gastric emptying, worsen bloating",
    "Acidic foods - citrus fruits, tomatoes, vinegar",
    "Caffeinated drinks - coffee (including decaf), energy drinks, cola",
    "Carbonated beverages - increase intragastric pressure",
    "Alcohol - major mucosal irritant; impairs healing",
    "Eating within 3 hours of bedtime - increases risk of acid reflux overnight",
    "Large, infrequent meals - cause excessive acid surges",
    "Irregular meal timing - associated with higher H. pylori risk and gastritis severity",
]
for item in avoid:
    add_bullet(item)

add_heading("Meal Timing and Frequency", level=2, colour=MID_TEAL)
add_body(
    "Small, regular meals every 3-4 hours help buffer resting gastric acid (2-5 mEq/hour even when fasting) "
    "and prevent the stomach from being completely empty for prolonged periods. This reduces fasting irritation "
    "and avoids the peak acid surge from a single large meal."
)
add_callout("Note:", 
    "Each meal triggers a new wave of acid secretion (the gastric phase = ~60% of total acid output). "
    "So frequent meals only help if the food is bland and non-irritating. Frequent snacking on "
    "spicy or fatty food will worsen symptoms.",
    label_colour=MID_TEAL)

hr()

# ══════════════════════════════════════════════════════════════════════════════
# 3. STRESS MANAGEMENT
# ══════════════════════════════════════════════════════════════════════════════
add_heading("3. Stress Management", level=1)
add_body(
    "Stress worsens gastritis through multiple physiological pathways. The brain and gut are directly "
    "connected via the brain-gut axis (enteric nervous system). Managing stress is a legitimate, "
    "evidence-based part of gastritis care - not merely a lifestyle suggestion."
)

add_heading("How Stress Harms the Stomach", level=2, colour=MID_TEAL)
mechanisms = [
    ("Increased acid secretion",
     "Stress activates the vagus nerve and raises acetylcholine + histamine levels, driving parietal cells to produce more acid."),
    ("Reduced mucosal blood flow",
     "Sympathetic (fight-or-flight) activation constricts gastric blood vessels, impairing the mucosa's ability to repair itself."),
    ("Decreased prostaglandins",
     "Stress lowers prostaglandins, weakening the protective mucus layer and reducing bicarbonate secretion."),
    ("Brain-gut hypersensitivity",
     "Chronic stress amplifies pain signals from the gut, making existing inflammation feel more severe."),
    ("Slowed gastric emptying",
     "Stress delays the stomach emptying, keeping acidic contents in contact with the inflamed lining longer."),
    ("Severe physiological stress",
     "Trauma, burns, sepsis cause mucosal ischaemia and frank stress ulcers (Curling's and Cushing's ulcers)."),
]
add_table_2col(["Mechanism", "Effect"], mechanisms, col_widths=(2.5, 3.8))

add_heading("Practical Stress-Reduction Strategies", level=2, colour=MID_TEAL)
strategies = [
    "Regular aerobic exercise (30 min, 5x/week) - reduces cortisol and sympathetic tone",
    "Mindfulness and breathing exercises - activate the parasympathetic ('rest and digest') system",
    "Adequate sleep (7-9 hours) - essential for mucosal repair and hormonal balance",
    "Limit alcohol and smoking - both amplify stress-related mucosal damage",
    "Cognitive Behavioural Therapy (CBT) - evidence-based for functional GI disorders",
    "Regular meals at consistent times - prevents irregular-meal-linked gastritis risk",
    "Seek support for untreated anxiety or depression - major psychiatric stressors are a recognised cause of stress gastritis",
]
for s in strategies:
    add_bullet(s)

hr()

# ══════════════════════════════════════════════════════════════════════════════
# 4. MEDICATIONS
# ══════════════════════════════════════════════════════════════════════════════
add_heading("4. Medications", level=1)
add_body(
    "The right medication depends entirely on the underlying cause. Treating the root cause is the only "
    "way to cure chronic gastritis. Symptom-relief medications reduce discomfort but do not eliminate "
    "the source of inflammation on their own."
)

add_heading("4a. H. pylori Eradication (Most Important)", level=2, colour=MID_TEAL)
add_body(
    "H. pylori is the leading cause of chronic gastritis. Eradication reduces recurrent ulcer rate from "
    ">75% (acid suppression alone) to <20%, and reverses the gastric acid abnormalities caused by the infection. "
    "H. pylori eradication is the closest thing to a cure for H. pylori-associated chronic gastritis."
)

hpyl = [
    ("First-line: Clarithromycin Triple Therapy\n(low-resistance areas only)",
     "PPI (e.g. omeprazole 20 mg BD) + clarithromycin 500 mg BD + amoxicillin 1 g BD\n14 days. "
     "Use ONLY if local clarithromycin resistance is known to be low (<15%)."),
    ("First-line: Bismuth Quadruple Therapy\n(recommended universally)",
     "PPI (BD) + bismuth salt (QDS) + metronidazole (TDS/QDS) + tetracycline (QDS)\n14 days. "
     "Achieves eradication in 90%+ as first-line. Recommended by Maastricht V/Florence Consensus."),
    ("Second-line options",
     "Levofloxacin triple therapy; Rifabutin triple (PPI + amoxicillin + rifabutin); "
     "High-dose dual therapy (PPI + amoxicillin). Used after first-line failure."),
    ("Test of cure",
     "Urea breath test or stool antigen test at least 4 weeks after completing therapy. "
     "Do NOT use serology - it remains positive after eradication."),
]
add_table_2col(["Regimen", "Details"], hpyl, col_widths=(2.3, 4.0))

add_heading("4b. Acid-Suppressing Medications", level=2, colour=MID_TEAL)
acid_meds = [
    ("Proton Pump Inhibitors (PPIs)",
     "Omeprazole, esomeprazole, pantoprazole, lansoprazole.\n"
     "Most potent acid suppressants. Block the H+/K+-ATPase pump. "
     "First choice for erosive gastritis, NSAID-related gastritis, and stress ulcer prophylaxis. "
     "Oral preferred; IV pantoprazole available for those unable to eat."),
    ("H2 Receptor Antagonists (H2RAs)",
     "Ranitidine (now withdrawn in many countries), famotidine, cimetidine.\n"
     "Block histamine-stimulated acid. Less potent than PPIs but useful for mild symptoms "
     "and as an alternative in PPI-intolerant patients."),
    ("Antacids",
     "Aluminium/magnesium hydroxide, calcium carbonate.\n"
     "Provide rapid but short-lived symptom relief by neutralising existing acid. "
     "Not suitable for long-term management. Use as needed for breakthrough symptoms."),
    ("Sucralfate",
     "Forms a protective coating over the inflamed mucosa. "
     "Useful in erosive gastritis and as adjunct to PPIs. "
     "Take on an empty stomach 30-60 min before meals."),
]
add_table_2col(["Drug Class", "Details"], acid_meds, col_widths=(2.3, 4.0))

add_heading("4c. Other Specific Treatments", level=2, colour=MID_TEAL)
other_tx = [
    ("NSAID-induced gastritis",
     "Stop or reduce NSAID dose. Switch to a COX-2 selective inhibitor if pain relief still needed. "
     "Always co-prescribe a PPI with long-term NSAIDs."),
    ("Autoimmune gastritis",
     "No cure for the autoimmune process. Treat complications: B12 injections (cyanocobalamin/hydroxocobalamin) "
     "for pernicious anaemia. Monitor for gastric cancer. Iron supplementation if deficient."),
    ("Bile reflux gastritis",
     "Ursodiol (ursodeoxycholic acid) reduces bile toxicity. Surgery (Roux-en-Y diversion) "
     "for refractory cases."),
    ("Stress gastritis (ICU)",
     "PPI prophylaxis (oral or IV pantoprazole) in high-risk critically ill patients. "
     "Early enteral nutrition maintains gastric pH >3.5 and reduces bacterial translocation."),
]
add_table_2col(["Cause", "Treatment"], other_tx, col_widths=(2.3, 4.0))

add_callout("Important:",
    "Always confirm H. pylori status before starting long-term acid suppression. "
    "PPIs mask symptoms but do not treat the underlying bacterial infection.",
    label_colour=ACCENT_RED)

hr()

# ══════════════════════════════════════════════════════════════════════════════
# 5. INTEGRATED MANAGEMENT PLAN
# ══════════════════════════════════════════════════════════════════════════════
add_heading("5. Integrated Management Plan at a Glance", level=1)

summary_rows = [
    ("Test for H. pylori",
     "Urea breath test, stool antigen, or endoscopic biopsy. This is the single most important first step."),
    ("Eradicate H. pylori if positive",
     "14-day bismuth quadruple therapy (preferred) or clarithromycin triple therapy."),
    ("Acid suppression",
     "PPI (omeprazole 20 mg once or twice daily) for 4-8 weeks. Reduces mucosal irritation while healing occurs."),
    ("Stop/adjust NSAIDs",
     "Switch to paracetamol if possible. If NSAIDs are essential, co-prescribe a PPI."),
    ("Dietary adjustments",
     "Small meals every 3-4 hours; bland, low-fat, non-acidic foods. Stop eating 3 hours before bedtime."),
    ("Stress management",
     "Regular exercise, consistent sleep, mindfulness. Address anxiety/depression with appropriate support."),
    ("Avoid mucosal irritants",
     "No alcohol, smoking, or caffeinated drinks during active gastritis."),
    ("B12 / iron supplementation",
     "If autoimmune gastritis or nutritional deficiencies are identified."),
    ("Follow-up",
     "Confirm H. pylori eradication 4+ weeks after therapy. Endoscopy if symptoms persist or alarm features present."),
]
add_table_2col(["Step", "Action"], summary_rows, col_widths=(2.3, 4.0))

add_callout("When to seek urgent medical attention:",
    "Blood in vomit or black/tarry stools (bleeding) | Unintentional weight loss | "
    "Severe or worsening abdominal pain | Difficulty swallowing | Persistent vomiting. "
    "These are alarm features requiring immediate evaluation.",
    label_colour=ACCENT_RED)

hr()

# ══════════════════════════════════════════════════════════════════════════════
# FOOTER / DISCLAIMER
# ══════════════════════════════════════════════════════════════════════════════
doc.add_paragraph()
disc = doc.add_paragraph()
disc.alignment = WD_ALIGN_PARAGRAPH.CENTER
dr2 = disc.add_run(
    "This document is for educational purposes only and does not constitute medical advice. "
    "Always consult a qualified healthcare professional for diagnosis and treatment."
)
dr2.font.size = Pt(9)
dr2.italic = True
dr2.font.color.rgb = RGBColor(0x88, 0x88, 0x88)

src_p = doc.add_paragraph()
src_p.alignment = WD_ALIGN_PARAGRAPH.CENTER
src_r = src_p.add_run(
    "Sources: Harrison's Principles of Internal Medicine 22e (2025) | Schwartz's Principles of Surgery 11e | "
    "Yamada's Textbook of Gastroenterology 7e | Robbins & Kumar Basic Pathology | "
    "Mulholland & Greenfield's Surgery 7e | Sleisenger & Fordtran's GI & Liver Disease"
)
src_r.font.size = Pt(8.5)
src_r.font.color.rgb = RGBColor(0xAA, 0xAA, 0xAA)

# ── Save ───────────────────────────────────────────────────────────────────────
out_path = "/tmp/workspace/gastritis-summary/Gastritis_Management_Guide.docx"
doc.save(out_path)
print(f"Saved: {out_path}")