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';

part 'database.g.dart';

// ── Tables ────────────────────────────────────────────────────────────────────

class Accounts extends Table {
  TextColumn get id => text()();
  TextColumn get displayName => text()();
  TextColumn get email => text()();
  TextColumn get imapHost => text()();
  IntColumn get imapPort => integer()();
  BoolColumn get imapSsl => boolean()();
  TextColumn get smtpHost => text()();
  IntColumn get smtpPort => integer()();
  BoolColumn get smtpSsl => boolean()();
  // Added in schema v2:
  TextColumn get accountType => text().withDefault(const Constant('imap'))();
  TextColumn get jmapUrl => text().nullable()();
  // Added in schema v3:
  TextColumn get username => text().withDefault(const Constant(''))();

  @override
  Set<Column> get primaryKey => {id};
}

@DataClassName('MailboxRow')
class Mailboxes extends Table {
  TextColumn get id => text()();
  TextColumn get accountId =>
      text().references(Accounts, #id, onDelete: KeyAction.cascade)();
  TextColumn get path => text()();
  TextColumn get name => text()();
  IntColumn get unreadCount => integer().withDefault(const Constant(0))();
  IntColumn get totalCount => integer().withDefault(const Constant(0))();
  // Added in schema v8: JMAP role (e.g. "inbox", "sent", "trash").
  TextColumn get role => text().nullable()();

  @override
  Set<Column> get primaryKey => {id};
}

class Emails extends Table {
  TextColumn get id => text()();
  TextColumn get accountId =>
      text().references(Accounts, #id, onDelete: KeyAction.cascade)();
  TextColumn get mailboxPath => text()();
  IntColumn get uid => integer()();
  TextColumn get subject => text().nullable()();
  DateTimeColumn get sentAt => dateTime().nullable()();
  DateTimeColumn get receivedAt => dateTime()();
  // JSON-encoded List<{name,email}>
  TextColumn get fromJson => text().withDefault(const Constant('[]'))();
  TextColumn get toAddresses => text().withDefault(const Constant('[]'))();
  TextColumn get ccJson => text().withDefault(const Constant('[]'))();
  TextColumn get preview => text().nullable()();
  BoolColumn get isSeen => boolean().withDefault(const Constant(false))();
  BoolColumn get isFlagged => boolean().withDefault(const Constant(false))();
  BoolColumn get hasAttachment =>
      boolean().withDefault(const Constant(false))();

  @override
  Set<Column> get primaryKey => {id};
}

class EmailBodies extends Table {
  TextColumn get emailId =>
      text().references(Emails, #id, onDelete: KeyAction.cascade)();
  TextColumn get textBody => text().nullable()();
  TextColumn get htmlBody => text().nullable()();
  // JSON-encoded List<{filename,contentType,size}>
  TextColumn get attachmentsJson => text().withDefault(const Constant('[]'))();
  // Added in schema v9: when the body was last fetched from the server.
  // Null for rows cached before this column was added (treated as expired).
  DateTimeColumn get cachedAt => dateTime().nullable()();

  @override
  Set<Column> get primaryKey => {emailId};
}

/// Protocol-agnostic outbound change queue.
/// Local mutations are written here before being sent to the server,
/// enabling offline-first behaviour and durable retries.
@DataClassName('PendingChangeRow')
class PendingChanges extends Table {
  IntColumn get id => integer().autoIncrement()();
  TextColumn get accountId =>
      text().references(Accounts, #id, onDelete: KeyAction.cascade)();
  TextColumn get resourceType => text()();
  TextColumn get resourceId => text()();
  // "flag_seen" | "flag_flagged" | "move" | "delete"
  TextColumn get changeType => text()();
  // JSON payload, e.g. {"seen": true} or {"dest": "Archive"}
  TextColumn get payload => text()();
  DateTimeColumn get createdAt => dateTime()();
  IntColumn get attempts => integer().withDefault(const Constant(0))();
  TextColumn get lastError => text().nullable()();
}

/// Sync checkpoint per (account, resource type).
/// Stores the server-side state token used for incremental sync.
/// For JMAP: the opaque `state` string from Mailbox/get or Email/get.
/// For IMAP: a JSON object with last-synced UID / MODSEQ per mailbox.
@DataClassName('SyncStateRow')
class SyncStates extends Table {
  TextColumn get accountId =>
      text().references(Accounts, #id, onDelete: KeyAction.cascade)();
  TextColumn get resourceType => text()();
  TextColumn get state => text()();
  DateTimeColumn get syncedAt => dateTime()();

  @override
  Set<Column> get primaryKey => {accountId, resourceType};
}

/// Lightweight audit trail for each sync cycle.
/// Useful for debugging and surfacing "last synced" timestamps in the UI.
@DataClassName('SyncLogRow')
class SyncLogs extends Table {
  IntColumn get id => integer().autoIncrement()();
  TextColumn get accountId =>
      text().references(Accounts, #id, onDelete: KeyAction.cascade)();
  // "ok" | "error"
  TextColumn get result => text()();
  TextColumn get errorMessage => text().nullable()();
  IntColumn get itemsSynced => integer().withDefault(const Constant(0))();
  DateTimeColumn get startedAt => dateTime()();
  DateTimeColumn get finishedAt => dateTime()();
}

/// Auto-saved compose drafts — persisted across app restarts.
class Drafts extends Table {
  IntColumn get id => integer().autoIncrement()();
  TextColumn get accountId => text().nullable()();

  /// Set for replies/reply-alls; null for new messages.
  TextColumn get replyToEmailId => text().nullable()();
  TextColumn get toText => text().withDefault(const Constant(''))();
  TextColumn get ccText => text().withDefault(const Constant(''))();
  TextColumn get subjectText => text().withDefault(const Constant(''))();
  TextColumn get bodyText => text().withDefault(const Constant(''))();
  DateTimeColumn get updatedAt => dateTime()();
}

// ── Database ──────────────────────────────────────────────────────────────────

@DriftDatabase(
  tables: [
    Accounts,
    Mailboxes,
    Emails,
    EmailBodies,
    Drafts,
    SyncStates,
    PendingChanges,
    SyncLogs,
  ],
)
class AppDatabase extends _$AppDatabase {
  AppDatabase([QueryExecutor? executor]) : super(executor ?? _openConnection());

  @override
  int get schemaVersion => 9;

  @override
  MigrationStrategy get migration => MigrationStrategy(
        onUpgrade: (m, from, to) async {
          if (from < 2) {
            await m.addColumn(accounts, accounts.accountType);
            await m.addColumn(accounts, accounts.jmapUrl);
          }
          if (from < 3) {
            await m.addColumn(accounts, accounts.username);
          }
          if (from < 4) {
            await m.createTable(drafts);
          }
          if (from < 5) {
            await m.createTable(syncStates);
          }
          if (from < 6) {
            await m.createTable(pendingChanges);
          }
          if (from < 7) {
            await m.createTable(syncLogs);
          }
          if (from < 8) {
            await m.addColumn(mailboxes, mailboxes.role);
          }
          if (from < 9) {
            await m.addColumn(emailBodies, emailBodies.cachedAt);
          }
        },
      );
}

LazyDatabase _openConnection() {
  return LazyDatabase(() async {
    final dir = await getApplicationSupportDirectory();
    final file = File(p.join(dir.path, 'sharedinbox.db'));
    return NativeDatabase.createInBackground(file);
  });
}