import '../../config/database.dart';

/// Data access layer for streaks and streak entries.
class StreakRepository {
  // ── Create ──────────────────────────────────────────────────────────

  Future<Map<String, dynamic>> create(Map<String, dynamic> data) async {
    final result = await Database.query(
      '''
      INSERT INTO streaks (
        id, user_id, name, description, frequency, grace_days,
        current_count, longest_count, frozen_until,
        created_at, updated_at
      ) VALUES (
        @id, @user_id, @name, @description, @frequency, @grace_days,
        0, 0, NULL,
        NOW(), NOW()
      )
      RETURNING *
      ''',
      parameters: data,
    );
    return _rowToMap(result.first);
  }

  // ── Read ────────────────────────────────────────────────────────────

  Future<Map<String, dynamic>?> findById(String id, String userId) async {
    final result = await Database.query(
      '''
      SELECT * FROM streaks
      WHERE id = @id AND user_id = @user_id
      ''',
      parameters: {'id': id, 'user_id': userId},
    );
    if (result.isEmpty) return null;
    return _rowToMap(result.first);
  }

  Future<List<Map<String, dynamic>>> findAll(String userId) async {
    final result = await Database.query(
      '''
      SELECT * FROM streaks
      WHERE user_id = @user_id
      ORDER BY created_at DESC
      ''',
      parameters: {'user_id': userId},
    );
    return result.map(_rowToMap).toList();
  }

  // ── Update ──────────────────────────────────────────────────────────

  Future<Map<String, dynamic>?> update(
    String id,
    String userId,
    Map<String, dynamic> data,
  ) async {
    final setClauses = <String>[];
    final params = <String, dynamic>{'id': id, 'user_id': userId};

    data.forEach((key, value) {
      setClauses.add('$key = @$key');
      params[key] = value;
    });
    setClauses.add('updated_at = NOW()');

    final result = await Database.query(
      '''
      UPDATE streaks SET ${setClauses.join(', ')}
      WHERE id = @id AND user_id = @user_id
      RETURNING *
      ''',
      parameters: params,
    );
    if (result.isEmpty) return null;
    return _rowToMap(result.first);
  }

  // ── Entries ─────────────────────────────────────────────────────────

  Future<void> addEntry(Map<String, dynamic> data) async {
    await Database.query(
      '''
      INSERT INTO streak_entries (id, streak_id, entry_date, entry_type, note, created_at)
      VALUES (@id, @streak_id, @entry_date, @entry_type, @note, NOW())
      ON CONFLICT (streak_id, entry_date) DO NOTHING
      ''',
      parameters: data,
    );
  }

  Future<List<Map<String, dynamic>>> getHistory(
    String streakId,
    String userId,
  ) async {
    final result = await Database.query(
      '''
      SELECT se.* FROM streak_entries se
      JOIN streaks s ON se.streak_id = s.id
      WHERE se.streak_id = @streak_id AND s.user_id = @user_id
      ORDER BY se.entry_date DESC
      LIMIT 90
      ''',
      parameters: {'streak_id': streakId, 'user_id': userId},
    );
    return result
        .map((row) => <String, dynamic>{
              'id': row[0],
              'streak_id': row[1],
              'entry_date': row[2] is DateTime
                  ? (row[2] as DateTime).toIso8601String()
                  : row[2],
              'entry_type': row[3],
              'note': row[4],
              'created_at': row[5] is DateTime
                  ? (row[5] as DateTime).toIso8601String()
                  : row[5],
            })
        .toList();
  }

  Future<DateTime?> lastCompletionDate(String streakId) async {
    final result = await Database.query(
      '''
      SELECT MAX(entry_date) FROM streak_entries
      WHERE streak_id = @streak_id AND entry_type = 'completion'
      ''',
      parameters: {'streak_id': streakId},
    );
    if (result.isEmpty || result.first[0] == null) return null;
    final val = result.first[0];
    if (val is DateTime) return val;
    return DateTime.tryParse(val.toString());
  }

  // ── Row mapper ──────────────────────────────────────────────────────

  Map<String, dynamic> _rowToMap(dynamic row) {
    final columns = [
      'id',
      'user_id',
      'name',
      'description',
      'frequency',
      'grace_days',
      'current_count',
      'longest_count',
      'frozen_until',
      'created_at',
      'updated_at',
    ];
    final map = <String, dynamic>{};
    for (var i = 0; i < columns.length; i++) {
      final value = row[i];
      map[columns[i]] = value is DateTime ? value.toIso8601String() : value;
    }
    return map;
  }
}