import Dexie, { type EntityTable } from 'dexie';
import type { Campaign } from '@/lib/schemas/campaign';
import type { Character } from '@/lib/schemas/character';
import type { Encounter } from '@/lib/schemas/encounter';
import type { DiceRoll } from '@/lib/schemas/dice';
import type { Note, Npc, Quest, Calendar, BattleMap, Homebrew } from '@/lib/schemas/world';
import { characterDefaults } from '@/lib/schemas/character';

/**
 * Single Dexie instance for the whole app. Dexie wraps IndexedDB transactions
 * correctly (commits before resolving), which removes the silent-data-loss
 * class of bugs the old hand-rolled adapter shipped with.
 *
 * Schema versions are additive: bump `version(n)` and add a `.upgrade()` when
 * the shape changes — never edit a past version in place.
 */
export class TtrpgDatabase extends Dexie {
  campaigns!: EntityTable<Campaign, 'id'>;
  characters!: EntityTable<Character, 'id'>;
  encounters!: EntityTable<Encounter, 'id'>;
  diceRolls!: EntityTable<DiceRoll, 'id'>;
  notes!: EntityTable<Note, 'id'>;
  npcs!: EntityTable<Npc, 'id'>;
  quests!: EntityTable<Quest, 'id'>;
  calendars!: EntityTable<Calendar, 'campaignId'>;
  maps!: EntityTable<BattleMap, 'id'>;
  homebrew!: EntityTable<Homebrew, 'id'>;

  constructor() {
    super('ttrpg-manager');
    this.version(1).stores({
      campaigns: 'id, updatedAt',
      characters: 'id, campaignId, kind',
      encounters: 'id, campaignId, status',
      diceRolls: 'id, campaignId, createdAt',
    });

    // v2 — Phase 1 character depth: backfill new fields on existing characters.
    this.version(2).stores({}).upgrade(async (tx) => {
      await tx
        .table('characters')
        .toCollection()
        .modify((c: Record<string, unknown>) => {
          for (const [key, value] of Object.entries(characterDefaults())) {
            if (c[key] === undefined) c[key] = value;
          }
        });
    });

    // v3 — Phase 3 combat depth: backfill the encounter event log.
    this.version(3).stores({}).upgrade(async (tx) => {
      await tx
        .table('encounters')
        .toCollection()
        .modify((e: Record<string, unknown>) => {
          if (e.log === undefined) e.log = [];
        });
    });

    // v4 — Phase 5 worldbuilding: notes, NPCs, quests, calendar.
    this.version(4).stores({
      notes: 'id, campaignId',
      npcs: 'id, campaignId',
      quests: 'id, campaignId, status',
      calendars: 'campaignId',
    });

    // v5 — Phase 7 maps/VTT.
    this.version(5).stores({ maps: 'id, campaignId' });

    // v6 — Phase 9 homebrew content.
    this.version(6).stores({ homebrew: 'id, campaignId, [campaignId+kind]' });

    // v7 — Phase 13 assistant: encounters gain optional partyLevelsSnapshot +
    // outcome. Both optional, so existing rows stay valid; no backfill needed.
    this.version(7).stores({});
  }
}

export const db = new TtrpgDatabase();
