// Balance simulation: seeded combat simulation to validate monster/zone balance.
// Creates a hero per class, auto-allocates points, hunts repeatedly, prints win rates and level-up metrics.
// Usage: node scripts/sim-balance.js

const { mulberry32, rngInt } = require('../src/utils/rng');
const { calcDerived } = require('../src/game/stats');
const { resolveCombat } = require('../src/game/combat');
const { calculateRewards, rollLoot } = require('../src/game/rewards');
const { applyXpGain, xpToNext } = require('../src/game/leveling');
const { getClass, getBaseStats, CLASS_KEYS } = require('../src/game/classes');
const { getEquipmentBonuses } = require('../src/game/equipment');

// ─── Seeded RNG ────────────────────────────────────────────────────────────
const SEED = 42;

// ─── Zone / monster definitions (mirrors DB via 008_balance.sql) ────────────
const ZONES = {
  meadows: { slug: 'whispering-meadows', minLevel: 1, energyCost: 5, monsters: [
    { name: 'Giant Rat', level: 1, hp: 120, attack: 11, defense: 40, speed: 12, xp: 20, goldMin: 3, goldMax: 7 },
    { name: 'Meadow Wolf', level: 2, hp: 150, attack: 12, defense: 40, speed: 16, xp: 30, goldMin: 5, goldMax: 12 },
    { name: 'Goblin Scrapper', level: 3, hp: 180, attack: 15, defense: 40, speed: 11, xp: 45, goldMin: 8, goldMax: 18 },
  ]},
  forest: { slug: 'gloomroot-forest', minLevel: 5, energyCost: 8, monsters: [
    { name: 'Webspinner', level: 5, hp: 200, attack: 28, defense: 30, speed: 15, xp: 50, goldMin: 12, goldMax: 24 },
    { name: 'Bandit Cutthroat', level: 6, hp: 250, attack: 33, defense: 30, speed: 14, xp: 70, goldMin: 18, goldMax: 36 },
    { name: 'Mossback Treant', level: 8, hp: 320, attack: 38, defense: 30, speed: 7, xp: 95, goldMin: 22, goldMax: 44 },
  ]},
  crags: { slug: 'ashfang-crag', minLevel: 10, energyCost: 12, monsters: [
    { name: 'Ember Imp', level: 10, hp: 300, attack: 45, defense: 40, speed: 20, xp: 120, goldMin: 30, goldMax: 55 },
    { name: 'Stone Golem', level: 12, hp: 600, attack: 48, defense: 40, speed: 5, xp: 170, goldMin: 40, goldMax: 75 },
    { name: 'Ashfang Drake', level: 14, hp: 850, attack: 55, defense: 40, speed: 18, xp: 260, goldMin: 55, goldMax: 110 },
  ]},
};

// Monster weights per zone
const MONSTER_WEIGHTS = { meadows: [30, 20, 15], forest: [25, 20, 10], crags: [25, 10, 5] };

// ─── Simulation helpers ────────────────────────────────────────────────────

function pickMonster(zoneKey, rng) {
  const zone = ZONES[zoneKey];
  const weights = MONSTER_WEIGHTS[zoneKey];
  const total = weights.reduce((a, b) => a + b, 0);
  let r = rng() * total;
  for (let i = 0; i < zone.monsters.length; i++) {
    r -= weights[i];
    if (r < 0) return zone.monsters[i];
  }
  return zone.monsters[zone.monsters.length - 1];
}

function simulateHunt(hero, monster, rng) {
  const equipBonuses = { bonus_str: 0, bonus_agi: 0, bonus_int: 0, bonus_vit: 0, bonus_attack: 0, bonus_defense: 0 };
  const fight = resolveCombat({
    class: hero.class, level: hero.level, hpCurrent: hero.hp,
    str: hero.str, agi: hero.agi, int: hero.int, vit: hero.vit,
    ...equipBonuses,
  }, monster, rng);

  let xpGained = 0, goldGained = 0;
  if (fight.winner === 'hero') {
    const rewards = calculateRewards(monster.xp, monster.goldMin, monster.goldMax, monster.level, hero.level, rng);
    xpGained = rewards.xp;
    goldGained = rewards.gold;
  }

  return { winner: fight.winner, hpRemaining: fight.hpRemaining, xpGained, goldGained };
}

// ─── Run simulation for one class ──────────────────────────────────────────

function simulateClass(className) {
  const cls = getClass(className);
  const base = getBaseStats(className);
  const rng = mulberry32(SEED + CLASS_KEYS.indexOf(className));

  // Hero state
  let hero = {
    class: className,
    level: 1,
    xp: 0,
    hp: 0, // set below after deriving maxHp
    maxHp: 0,
    str: base.str, agi: base.agi, int: base.int, vit: base.vit,
    gold: 50,
  };

  const derived = calcDerived({ str: hero.str, agi: hero.agi, int: hero.int, vit: hero.vit }, hero.level, className);
  hero.hp = derived.maxHp;
  hero.maxHp = derived.maxHp;

  // Track stats
  const results = { meadows: { wins: 0, total: 0 }, forest: { wins: 0, total: 0 }, crags: { wins: 0, total: 0 } };
  let totalHunts = 0;
  let consecutiveDefeats = 0;
  const MAX_DEFEATS = 50; // prevent infinite loops

  // Phase 1: Level 1 → 5 in Meadows
  while (hero.level < 5 && consecutiveDefeats < MAX_DEFEATS) {
    const monster = pickMonster('meadows', rng);
    const result = simulateHunt(hero, monster, rng);
    results.meadows.total++;
    if (result.winner === 'hero') {
      results.meadows.wins++;
      consecutiveDefeats = 0;
      const xpResult = applyXpGain(hero.level, hero.xp, 0, result.xpGained);
      if (xpResult.level > hero.level) {
        const newDerived = calcDerived({ str: hero.str, agi: hero.agi, int: hero.int, vit: hero.vit }, xpResult.level, className);
        hero.hp = newDerived.maxHp;
        hero.maxHp = newDerived.maxHp;
      }
      hero.xp = xpResult.xp;
      hero.level = xpResult.level;
      hero.gold += result.goldGained;
      // Recover some HP after victory (10% of maxHp)
      hero.hp = Math.min(hero.maxHp, hero.hp + Math.floor(hero.maxHp * 0.1));
    } else {
      hero.hp = 1;
      hero.gold = Math.max(0, hero.gold - Math.floor(hero.gold * 0.1));
      consecutiveDefeats++;
    }
    totalHunts++;
  }

  const huntsL1to5 = totalHunts;

  // Phase 2: Level 5 → 10 in Forest
  let huntsAtL5 = totalHunts;
  while (hero.level < 10 && consecutiveDefeats < MAX_DEFEATS) {
    const monster = pickMonster('forest', rng);
    const result = simulateHunt(hero, monster, rng);
    results.forest.total++;
    if (result.winner === 'hero') {
      results.forest.wins++;
      consecutiveDefeats = 0;
      const xpResult = applyXpGain(hero.level, hero.xp, 0, result.xpGained);
      if (xpResult.level > hero.level) {
        const newDerived = calcDerived({ str: hero.str, agi: hero.agi, int: hero.int, vit: hero.vit }, xpResult.level, className);
        hero.hp = newDerived.maxHp;
        hero.maxHp = newDerived.maxHp;
      }
      hero.xp = xpResult.xp;
      hero.level = xpResult.level;
      hero.gold += result.goldGained;
      hero.hp = Math.min(hero.maxHp, hero.hp + Math.floor(hero.maxHp * 0.1));
    } else {
      hero.hp = 1;
      hero.gold = Math.max(0, hero.gold - Math.floor(hero.gold * 0.1));
      consecutiveDefeats++;
    }
    totalHunts++;
  }

  const huntsL1to10 = totalHunts;

  // Phase 3: Level 10+ in Crags (20 hunts)
  for (let i = 0; i < 20; i++) {
    const monster = pickMonster('crags', rng);
    const result = simulateHunt(hero, monster, rng);
    results.crags.total++;
    if (result.winner === 'hero') {
      results.crags.wins++;
      consecutiveDefeats = 0;
      const xpResult = applyXpGain(hero.level, hero.xp, 0, result.xpGained);
      if (xpResult.level > hero.level) {
        const newDerived = calcDerived({ str: hero.str, agi: hero.agi, int: hero.int, vit: hero.vit }, xpResult.level, className);
        hero.hp = newDerived.maxHp;
        hero.maxHp = newDerived.maxHp;
      }
      hero.xp = xpResult.xp;
      hero.level = xpResult.level;
      hero.gold += result.goldGained;
      hero.hp = Math.min(hero.maxHp, hero.hp + Math.floor(hero.maxHp * 0.1));
    } else {
      hero.hp = 1;
      hero.gold = Math.max(0, hero.gold - Math.floor(hero.gold * 0.1));
      consecutiveDefeats++;
    }
  }

  return { className, cls, results, huntsL1to5, huntsL1to10, finalLevel: hero.level, finalGold: hero.gold };
}

// ─── Level-1 zone win rates ────────────────────────────────────────────────

function simulateLevel1WinRate(zoneKey) {
  const rng = mulberry32(SEED + 999);
  let wins = 0;
  const rounds = 100;

  for (let r = 0; r < rounds; r++) {
    const classRng = mulberry32(SEED + r * 100);
    for (const className of CLASS_KEYS) {
      const cls = getClass(className);
      const base = getBaseStats(className);
      const derived = calcDerived({ str: base.str, agi: base.agi, int: base.int, vit: base.vit }, 1, className);

      const monster = pickMonster(zoneKey, classRng);
      const result = simulateHunt({
        class: className, level: 1, hp: derived.maxHp, maxHp: derived.maxHp,
        str: base.str, agi: base.agi, int: base.int, vit: base.vit,
      }, monster, classRng);

      if (result.winner === 'hero') wins++;
    }
  }

  return wins / (rounds * CLASS_KEYS.length) * 100;
}

// ─── Level-5 Forest win rate ───────────────────────────────────────────────

function simulateLevel5ForestWinRate() {
  const rng = mulberry32(SEED + 888);
  let wins = 0;
  const rounds = 100;

  for (let r = 0; r < rounds; r++) {
    for (const className of CLASS_KEYS) {
      const cls = getClass(className);
      const base = getBaseStats(className);
      // Auto-allocate 15 points to primary stat
      const primary = cls.primary;
      const stats = { ...base };
      stats[primary] += 15;
      const derived = calcDerived(stats, 5, className);

      const monster = pickMonster('forest', rng);
      const result = simulateHunt({
        class: className, level: 5, hp: derived.maxHp, maxHp: derived.maxHp,
        str: stats.str, agi: stats.agi, int: stats.int, vit: stats.vit,
      }, monster, rng);

      if (result.winner === 'hero') wins++;
    }
  }

  return wins / (rounds * CLASS_KEYS.length) * 100;
}

// ─── Main ──────────────────────────────────────────────────────────────────

function pct(n) {
  return `${Math.round(n * 100) / 100}%`;
}

function main() {
  console.log('='.repeat(80));
  console.log('Emberfall Balance Simulation (seed=' + SEED + ')');
  console.log('='.repeat(80));

  // Level-1 win rates
  const l1Meadows = simulateLevel1WinRate('meadows');
  const l1Crags = simulateLevel1WinRate('crags');

  console.log('\n--- Level-1 Win Rates ---');
  console.log(`  Meadows:  ${pct(l1Meadows)}  (target: 70–90%)`);
  console.log(`  Crags:    ${pct(l1Crags)}  (target: ≤15%)`);

  // Level-5 Forest win rate
  const l5Forest = simulateLevel5ForestWinRate();
  console.log(`  Forest L5: ${pct(l5Forest)}  (target: 50–75%)`);

  // Per-class progression
  console.log('\n--- Per-Class Progression ---');
  console.log('Class        Hunts L1→5   Hunts L1→10   Crags Win%   Final Lv   Gold');
  console.log('-'.repeat(70));

  const targets = {
    l1Meadows: [0.70, 0.90],
    l1Crags: [0, 0.15],
    l5Forest: [0.50, 0.75],
    l1to5Hunts: [40, 70],
    l1to10Hunts: [150, 300],
  };

  let allMet = true;

  const classResults = [];
  for (const className of CLASS_KEYS) {
    const sim = simulateClass(className);
    classResults.push(sim);
    const meadowsRate = sim.results.meadows.total > 0 ? sim.results.meadows.wins / sim.results.meadows.total : 0;
    const cragsRate = pct(sim.results.crags.wins / Math.max(1, sim.results.crags.total));
    console.log(className + '  L1->5: ' + String(sim.huntsL1to5).padStart(8) + '  L1->10: ' + String(sim.huntsL1to10).padStart(8) + '  Crags: ' + cragsRate.padStart(9) + '  Lv' + String(sim.finalLevel).padStart(6) + '  ' + String(sim.finalGold).padStart(6) + 'g');

    // Check L1→5 hunts (use the first class's value as representative)
  }

  // Use the average of all classes for progression metrics
  const avgL1to5 = Math.round(classResults.reduce((s, c) => s + c.huntsL1to5, 0) / classResults.length);
  const avgL1to10 = Math.round(classResults.reduce((s, c) => s + c.huntsL1to10, 0) / classResults.length);

  console.log('\n--- Aggregate Targets ---');
  console.log(`  L1→5 hunts:    ${avgL1to5}  (target: 40–70) ${avgL1to5 >= 40 && avgL1to5 <= 70 ? '✓' : '✗'}`);
  console.log(`  L1→10 hunts:   ${avgL1to10}  (target: 150–300) ${avgL1to10 >= 150 && avgL1to10 <= 300 ? '✓' : '✗'}`);

  if (l1Meadows < targets.l1Meadows[0] || l1Meadows > targets.l1Meadows[1]) { console.log(`  L1 Meadows:    ${pct(l1Meadows)}  ✗`); allMet = false; } else { console.log(`  L1 Meadows:    ${pct(l1Meadows)}  ✓`); }
  if (l1Crags < targets.l1Crags[0] || l1Crags > targets.l1Crags[1]) { console.log(`  L1 Crags:      ${pct(l1Crags)}  ✗`); allMet = false; } else { console.log(`  L1 Crags:      ${pct(l1Crags)}  ✓`); }
  if (l5Forest < targets.l5Forest[0] || l5Forest > targets.l5Forest[1]) { console.log(`  L5 Forest:     ${pct(l5Forest)}  ✗`); allMet = false; } else { console.log(`  L5 Forest:     ${pct(l5Forest)}  ✓`); }

  // Check class spread (no class > 15pp above another in any zone)
  console.log('\n--- Class Spread (max 15pp gap) ---');
  for (const zone of ['meadows', 'forest', 'crags']) {
    const rates = classResults.map(c => zone === 'crags' ? c.results.crags.wins / Math.max(1, c.results.crags.total) : 0);
    // For meadows/forest, compute from the full sim (all hunts in that zone)
    if (zone === 'meadows') {
      const rates2 = classResults.map(c => c.results.meadows.total > 0 ? c.results.meadows.wins / c.results.meadows.total : 0);
      const max = Math.max(...rates2);
      const min = Math.min(...rates2);
      const gap = (max - min) * 100;
      console.log(`  Meadows: gap ${pct(gap / 100)}  ${gap <= 15 ? '✓' : '✗'}`);
      if (gap > 15) allMet = false;
    }
  }

  console.log('\n' + '='.repeat(80));
  console.log(allMet ? 'ALL TARGETS MET ✓' : 'SOME TARGETS NOT MET ✗ — tune monster stats in a NEW migration');
  console.log('='.repeat(80));
}

main();