import 'dart:io';

import 'package:drift/drift.dart';
import 'package:drift/native.dart';
import 'package:path/path.dart' as p;
import 'package:path_provider/path_provider.dart';

import '../../core/constants.dart';
import 'tables/catalog_tables.dart';
import 'tables/user_tables.dart';

part 'app_database.g.dart';

@DriftDatabase(tables: [
  // Catalog 8
  Protocols,
  BreakProtocols,
  CommonFrames,
  Methodologies,
  FramePatterns,
  RewardMenuItems,
  References,
  DietPatterns,
  // User 11 + 정규화 부속 1
  Users,
  Phases,
  Habits,
  HabitDoseVariants,
  IfThenRules,
  TrackerEntries,
  LapseLogs,
  UrgeLogs,
  RewardDeclarations,
  RewardClaims,
  Reflections,
  // Meta
  MetaKv,
])
class AppDatabase extends _$AppDatabase {
  AppDatabase(super.e);

  /// In-memory for tests.
  AppDatabase.memory() : super(NativeDatabase.memory());

  @override
  int get schemaVersion => 2;

  @override
  MigrationStrategy get migration => MigrationStrategy(
        onCreate: (m) async {
          await m.createAll();
          await _createIndexes(m);
        },
        onUpgrade: (m, from, to) async {
          // v1 → v2 (#226): Protocols.category CHECK 6 → 7 신 카테고리.
          // Read-only catalog 의 첫 마이그레이션. DROP + reseed 패턴 (ADR-0004).
          // user 테이블 (Habits, Phases, ...) 무변화.
          if (from == 1 && to >= 2) {
            await migrateV1ToV2(m, this);
          }
          if (from > to || to > schemaVersion) {
            assert(false,
                'Unknown upgrade path: from=$from to=$to (schemaVersion=$schemaVersion)');
          }
        },
      );

  Future<void> _createIndexes(Migrator m) async {
    // Catalog indexes
    await m.createIndex(Index('IDX_protocols_category',
        'CREATE INDEX IDX_protocols_category ON protocols(category)'));
    await m.createIndex(Index(
        'IDX_break_protocols_category',
        'CREATE UNIQUE INDEX IDX_break_protocols_category '
            'ON break_protocols(category)'));
    await m.createIndex(Index(
        'IDX_methodologies_core',
        'CREATE INDEX IDX_methodologies_core ON methodologies(is_core_engine) '
            'WHERE is_core_engine = 1'));
    await m.createIndex(Index(
        'IDX_frame_patterns_keyword',
        'CREATE INDEX IDX_frame_patterns_keyword '
            'ON frame_patterns(avoidance_keyword)'));
    await m.createIndex(Index(
        'IDX_reward_menu_tier',
        'CREATE INDEX IDX_reward_menu_tier '
            'ON reward_menu_items(tier_recommended)'));
    await m.createIndex(Index('IDX_references_kind',
        'CREATE INDEX IDX_references_kind ON "references"(kind)'));
    await m.createIndex(Index(
        'IDX_references_doi',
        'CREATE INDEX IDX_references_doi ON "references"(doi) '
            'WHERE doi IS NOT NULL'));
    await m.createIndex(Index(
        'IDX_diet_patterns_evidence',
        'CREATE INDEX IDX_diet_patterns_evidence '
            'ON diet_patterns(evidence_strength)'));
    await m.createIndex(Index(
        'IDX_diet_patterns_kfit',
        'CREATE INDEX IDX_diet_patterns_kfit '
            'ON diet_patterns(korean_context_fit) '
            'WHERE korean_context_fit IS NOT NULL'));

    // User indexes
    await m.createIndex(Index(
        'IDX_phases_user_status',
        'CREATE INDEX IDX_phases_user_status '
            'ON phases(user_id, status)'));
    await m.createIndex(Index(
        'IDX_habits_user_status_type',
        'CREATE INDEX IDX_habits_user_status_type '
            'ON habits(user_id, status, type)'));
    await m.createIndex(Index('IDX_habits_phase',
        'CREATE INDEX IDX_habits_phase ON habits(phase_id)'));
    await m.createIndex(Index(
        'IDX_habit_dose_variants_habit',
        'CREATE INDEX IDX_habit_dose_variants_habit '
            'ON habit_dose_variants(habit_id)'));
    await m.createIndex(Index(
        'IDX_habit_dose_variants_habit_min',
        'CREATE INDEX IDX_habit_dose_variants_habit_min '
            'ON habit_dose_variants(habit_id, is_minimum)'));
    await m.createIndex(Index('IDX_if_then_habit',
        'CREATE INDEX IDX_if_then_habit ON if_then_rules(habit_id)'));
    await m.createIndex(Index(
        'UQ_tracker_habit_date',
        'CREATE UNIQUE INDEX UQ_tracker_habit_date '
            'ON tracker_entries(habit_id, date)'));
    await m.createIndex(Index(
        'IDX_tracker_habit_date',
        'CREATE INDEX IDX_tracker_habit_date '
            'ON tracker_entries(habit_id, date)'));
    await m.createIndex(Index('IDX_tracker_date',
        'CREATE INDEX IDX_tracker_date ON tracker_entries(date)'));
    await m.createIndex(Index(
        'IDX_lapse_habit_date',
        'CREATE INDEX IDX_lapse_habit_date '
            'ON lapse_logs(habit_id, date)'));
    await m.createIndex(Index(
        'IDX_urge_habit_occurred',
        'CREATE INDEX IDX_urge_habit_occurred '
            'ON urge_logs(habit_id, occurred_at)'));
    await m.createIndex(Index(
        'IDX_reflections_user_scope',
        'CREATE INDEX IDX_reflections_user_scope '
            'ON reflections(user_id, scope)'));
  }
}

Future<File> appDatabaseFile() async {
  final dir = await getApplicationDocumentsDirectory();
  return File(p.join(dir.path, 'life_helper.sqlite'));
}

/// v1 → v2 마이그레이션. fn-migration_v1_to_v2.md 참고.
///
/// - Protocols 테이블 DROP + CREATE (v2 CHECK 적용) + 인덱스 재생성.
/// - `kSeededV1Flag` 클리어 → 다음 부팅이 SeedImporter.importIfNeeded() 호출 → 새 JSON 재시드.
/// - user 테이블 (Habits, Phases, TrackerEntries, ...) 무변화.
///
/// `onUpgrade` 에서 dispatch. 테스트는 직접 호출.
Future<void> migrateV1ToV2(Migrator m, AppDatabase db) async {
  await m.deleteTable(db.protocols.actualTableName);
  await m.createTable(db.protocols);
  await m.createIndex(Index('IDX_protocols_category',
      'CREATE INDEX IDX_protocols_category ON protocols(category)'));
  await (db.delete(db.metaKv)..where((t) => t.key.equals(kSeededV1Flag))).go();
}