import generatedLootCatalog from "./generated/lootCatalog.json";
import type { ContentCategoryId } from "../app/contentCategories";
import {
  itemStatsFor,
  type SourceItemStats,
  type WeaponStats,
} from "./itemStats";
import type { InventoryItem, ItemQuality } from "./lootTypes";
import { rollRunewakerBossLoot, runewakerBossHasLoot } from "./runewakerLootCatalog";
import { allowedLootDrops } from "./lootPolicy";

export interface LootCatalogItem {
  readonly itemId: number;
  readonly itemKey: string;
  readonly itemName: string;
  readonly quality: ItemQuality;
  readonly inventorySlot: string;
  readonly armorType: string | null;
  readonly weaponType: string | null;
  readonly sourceItemLevel: number;
  readonly scalable: boolean;
  readonly weight: number;
  readonly minQuantity: number;
  readonly maxQuantity: number;
  readonly sourceUrl: string | null;
  readonly sourceStats: SourceItemStats;
  readonly sourceWeapon: WeaponStats | null;
}

export interface BossLootTable {
  readonly bossKey: string;
  readonly creatureEntry: number;
  readonly bossName: string;
  readonly dungeonId: string;
  readonly lootTableId: string;
  readonly rollsMin: number;
  readonly rollsMax: number;
  readonly items: readonly LootCatalogItem[];
}

export interface LootCatalog {
  readonly schemaVersion: 2;
  readonly generatedFrom: readonly string[];
  readonly bosses: readonly BossLootTable[];
}

export interface LootRollOptions {
  readonly random?: () => number;
  readonly now?: number;
  /** A single additional weighted item roll after the authored boss rolls. */
  readonly bonusItemChance?: number;
  /** Saved character/party category; source identity is never inferred from dungeon. */
  readonly ownerCategory?: ContentCategoryId;
}

export const LOOT_CATALOG = generatedLootCatalog as LootCatalog;

const bossLootByKey = new Map(LOOT_CATALOG.bosses.map((boss) => [boss.bossKey, boss]));
let itemInstanceSequence = 0;

export function bossLootTable(bossKey: string): BossLootTable | null {
  return bossLootByKey.get(bossKey) ?? null;
}

export function bossHasLoot(bossKey: string): boolean {
  return (bossLootByKey.get(bossKey)?.items.length ?? 0) > 0
    || runewakerBossHasLoot(bossKey);
}

function boundedRandom(random: () => number): number {
  const value = random();
  if (!Number.isFinite(value)) return 0;
  return Math.max(0, Math.min(0.999999999999, value));
}

function randomInteger(minimum: number, maximum: number, random: () => number): number {
  if (maximum <= minimum) return minimum;
  return minimum + Math.floor(boundedRandom(random) * (maximum - minimum + 1));
}

function chooseWeightedItem(items: readonly LootCatalogItem[], random: () => number): LootCatalogItem | null {
  const totalWeight = items.reduce((total, item) => total + Math.max(0, item.weight), 0);
  if (totalWeight <= 0) return null;
  let cursor = boundedRandom(random) * totalWeight;
  for (const item of items) {
    cursor -= Math.max(0, item.weight);
    if (cursor < 0) return item;
  }
  return items.at(-1) ?? null;
}

export function scaledLootItemLevel(playerLevel: number): number {
  const level = Math.max(1, Math.min(80, Math.trunc(Number.isFinite(playerLevel) ? playerLevel : 1)));
  return level >= 80 ? 85 : level;
}

/**
 * Rolls a SQL-authored boss table and creates concrete inventory items.
 * Item level is captured now, before any XP from the killing blow changes it.
 */
export function rollBossLoot(
  bossKey: string,
  playerLevel: number,
  options: LootRollOptions = {},
): readonly InventoryItem[] {
  const table = bossLootTable(bossKey);
  if (!table?.items.length) {
    return rollRunewakerBossLoot(bossKey, playerLevel, options);
  }
  if (options.ownerCategory !== undefined && options.ownerCategory !== "wow") return [];
  const random = options.random ?? Math.random;
  const acquiredAt = options.now ?? Date.now();
  const rolls = randomInteger(table.rollsMin, table.rollsMax, random);
  const itemLevel = scaledLootItemLevel(playerLevel);
  const drops: InventoryItem[] = [];

  const addWeightedDrop = () => {
    const template = chooseWeightedItem(table.items, random);
    if (!template) return;
    const quantity = randomInteger(template.minQuantity, template.maxQuantity, random);
    itemInstanceSequence += 1;
    const scaledItemLevel = template.scalable ? itemLevel : template.sourceItemLevel;
    drops.push({
      contentCategory: "wow",
      instanceId: `${bossKey}:${acquiredAt}:${itemInstanceSequence}`,
      itemId: template.itemId,
      itemKey: template.itemKey,
      name: template.itemName,
      quality: template.quality,
      inventorySlot: template.inventorySlot,
      armorType: template.armorType,
      weaponType: template.weaponType,
      itemLevel: scaledItemLevel,
      sourceItemLevel: template.sourceItemLevel,
      stats: itemStatsFor({
        itemId: template.itemId,
        quality: template.quality,
        inventorySlot: template.inventorySlot,
        armorType: template.armorType,
        weaponType: template.weaponType,
        itemLevel: scaledItemLevel,
        sourceItemLevel: template.sourceItemLevel,
        sourceStats: template.sourceStats,
        sourceWeapon: template.sourceWeapon,
      }),
      quantity,
      sourceBossKey: table.bossKey,
      sourceBossName: table.bossName,
      acquiredAt,
    });
  };

  for (let roll = 0; roll < rolls; roll += 1) {
    addWeightedDrop();
  }

  const bonusItemChance = Math.max(0, Math.min(1, options.bonusItemChance ?? 0));
  if (bonusItemChance > 0 && boundedRandom(random) < bonusItemChance) {
    addWeightedDrop();
  }

  return allowedLootDrops(drops, playerLevel, options.ownerCategory);
}