// Writes the full lists (every library spell, weapon and monster, and every
// option the character builder offers) into the docs, straight from the data
// files the app itself uses, so the docs cannot drift from the app.
//
//   npm run docs:lists        (from /backend)
//
// Each list lives between a pair of markers in a doc:
//   <!-- BEGIN GENERATED: name -->  ...  <!-- END GENERATED: name -->
// Only the text between the markers is replaced; everything else in the docs
// is written by hand.
const fs = require('fs');
const path = require('path');
const { WEAPON_LIBRARY, SPELL_LIBRARY, MONSTER_LIBRARY } = require('../src/game/data/library');
const options = require('../src/game/data/characterOptions');
const { SPECIES } = require('../src/game/data/species');
const { CLASSES } = require('../src/game/data/classes');

const DOCS = path.join(__dirname, '..', '..', 'docs');

const cell = (value) => (value === null || value === undefined || value === '' ? '—' : String(value).replace(/\|/g, '\\|'));
const table = (headers, rows) =>
  [`| ${headers.join(' | ')} |`, `|${headers.map(() => '---').join('|')}|`, ...rows.map((r) => `| ${r.map(cell).join(' | ')} |`)].join('\n');
const signed = (n) => (n >= 0 ? `+${n}` : `${n}`);
const plural = (n, word) => `${n} ${word}${n === 1 ? '' : 's'}`;

function spellLibrary() {
  const levels = [...new Set(SPELL_LIBRARY.map((s) => s.level))].sort((a, b) => a - b);
  return levels
    .map((level) => {
      const spells = SPELL_LIBRARY.filter((s) => s.level === level).sort((a, b) => a.name.localeCompare(b.name));
      const heading = level === 0 ? `### Cantrips (${spells.length})` : `### Level ${level} (${plural(spells.length, 'spell')})`;
      const who = level === 0 ? 'Usable by any character.' : `Needs character level ${level}.`;
      return `${heading}\n\n${who}\n\n${table(['Spell', 'School', 'Damage', 'What it does'], spells.map((s) => [s.name, s.school, s.damageDice, s.description]))}`;
    })
    .join('\n\n');
}

const ATTACK_WITH = { STR: 'Strength', DEX: 'Dexterity', FINESSE: 'Strength or Dexterity (finesse)' };

function weaponLibrary() {
  const categories = [...new Set(WEAPON_LIBRARY.map((w) => w.category))];
  return categories
    .map((category) => {
      const weapons = WEAPON_LIBRARY.filter((w) => w.category === category);
      const rows = weapons.map((w) => [
        w.name,
        w.damageDice,
        w.damageType,
        ATTACK_WITH[w.attackAbility],
        w.properties.join(', '),
        w.rangeNormal ? `${w.rangeNormal}/${w.rangeLong} ft` : null,
      ]);
      return `### ${category} (${weapons.length})\n\n${table(['Weapon', 'Base damage', 'Type', 'Attacks with', 'Properties', 'Range'], rows)}`;
    })
    .join('\n\n');
}

function monsterLibrary() {
  const rows = MONSTER_LIBRARY.map((m) => [
    m.name,
    m.challengeRating,
    m.ac,
    m.maxHp,
    m.speed,
    signed(m.attackBonus),
    m.damageDice,
    [m.strScore, m.dexScore, m.conScore, m.intScore, m.wisScore, m.chaScore].join(' / '),
    m.specialTrait,
    m.notes,
  ]);
  return table(['Monster', 'CR', 'AC', 'HP', 'Speed', 'Attack', 'Damage', 'STR / DEX / CON / INT / WIS / CHA', 'Trait', 'Notes'], rows);
}

function builderLists() {
  const abilities = (list) => list.map((a) => `**${a.name}** — ${a.text}`).join('<br>');
  const groups = (list) =>
    list
      .map((g) => {
        const pick = g.min === g.max ? `pick ${g.min}` : `pick ${g.min} to ${g.max}`;
        return `**${g.label}** — ${g.prompt} (${pick})\n\n${table(['Option', 'What it adds'], g.options.map((o) => [o.label, o.text]))}`;
      })
      .join('\n\n');

  return [
    `### Motivations\n\n${options.MOTIVATIONS.map((m) => `- ${m.label}`).join('\n')}`,
    `### Special abilities granted by species\n\n${table(['Species', 'Abilities'], Object.keys(SPECIES).map((key) => [SPECIES[key].name, abilities(options.SPECIES_TRAITS[key])]))}`,
    `### Special abilities granted by class\n\n${table(['Class', 'Abilities'], Object.keys(CLASSES).sort().map((key) => [CLASSES[key].name, abilities(options.CLASS_FEATURES[key])]))}`,
    `### Talents (pick ${options.TALENT_PICKS})\n\n${table(['Talent', 'What it does'], options.TALENTS.map((t) => [t.name, t.text]))}`,
    `### Background questions\n\n${groups(options.BACKGROUND_GROUPS)}`,
    `### Appearance questions\n\n${groups(options.APPEARANCE_GROUPS)}`,
  ].join('\n\n');
}

const SECTIONS = {
  'SPELLS.md': { 'spell-library': spellLibrary },
  'WEAPONS.md': { 'weapon-library': weaponLibrary },
  'MONSTERS.md': { 'monster-library': monsterLibrary },
  'CHARACTERS.md': { 'builder-lists': builderLists },
};

for (const [file, sections] of Object.entries(SECTIONS)) {
  const filePath = path.join(DOCS, file);
  const original = fs.readFileSync(filePath, 'utf8');
  const newline = original.includes('\r\n') ? '\r\n' : '\n';
  let text = original.replace(/\r\n/g, '\n');
  for (const [name, render] of Object.entries(sections)) {
    const begin = `<!-- BEGIN GENERATED: ${name} -->`;
    const end = `<!-- END GENERATED: ${name} -->`;
    const from = text.indexOf(begin);
    const to = text.indexOf(end);
    if (from === -1 || to === -1 || to < from) throw new Error(`${file}: missing the "${name}" markers`);
    text = `${text.slice(0, from + begin.length)}\n${render()}\n${text.slice(to)}`;
  }
  const output = text.replace(/\n/g, newline);
  if (output !== original) fs.writeFileSync(filePath, output);
  console.log(`${output === original ? 'unchanged' : 'updated  '} docs/${file}`);
}