import 'dart:convert';
import 'package:sqflite/sqflite.dart';
import 'package:path/path.dart';
import '../models/models.dart';

class LocalStorage {
  static const _dbName = 'add_months.db';
  static const _tableName = 'user_data';
  static const _version = 1;

  static Database? _database;

  static Future<Database> get database async {
    if (_database != null) return _database!;
    _database = await _initDatabase();
    return _database!;
  }

  static Future<Database> _initDatabase() async {
    final dbPath = await getDatabasesPath();
    final path = join(dbPath, _dbName);

    return await openDatabase(
      path,
      version: _version,
      onCreate: (db, version) async {
        await db.execute('''
          CREATE TABLE $_tableName (
            key TEXT PRIMARY KEY,
            value TEXT NOT NULL,
            updated_at INTEGER NOT NULL
          )
        ''');
      },
    );
  }

  // Generic key-value operations
  static Future<void> _put(String key, Map<String, dynamic> value) async {
    final db = await database;
    await db.insert(
      _tableName,
      {
        'key': key,
        'value': jsonEncode(value),
        'updated_at': DateTime.now().millisecondsSinceEpoch,
      },
      conflictAlgorithm: ConflictAlgorithm.replace,
    );
  }

  static Future<Map<String, dynamic>?> _get(String key) async {
    final db = await database;
    final results = await db.query(
      _tableName,
      where: 'key = ?',
      whereArgs: [key],
    );

    if (results.isEmpty) return null;
    return jsonDecode(results.first['value'] as String) as Map<String, dynamic>;
  }

  // Profile operations
  static Future<void> saveProfile(UserProfile profile) async {
    await _put('profile', profile.toJson());
  }

  static Future<UserProfile?> getProfile() async {
    final json = await _get('profile');
    if (json == null) return null;
    return UserProfile.fromJson(json);
  }

  // Behavioral inputs operations
  static Future<void> saveBehaviors(BehavioralInputs behaviors) async {
    await _put('behaviors', behaviors.toJson());
  }

  static Future<BehavioralInputs?> getBehaviors() async {
    final json = await _get('behaviors');
    if (json == null) return null;
    return BehavioralInputs.fromJson(json);
  }

  // Result operations
  static Future<void> saveResult(CalculationResult result) async {
    await _put('lastResult', result.toJson());
  }

  static Future<CalculationResult?> getLastResult() async {
    final json = await _get('lastResult');
    if (json == null) return null;
    return CalculationResult.fromJson(json);
  }

  // Check if user has completed setup
  static Future<bool> hasCompletedSetup() async {
    final profile = await getProfile();
    final behaviors = await getBehaviors();
    return profile != null && behaviors != null;
  }

  // Delete all data
  static Future<void> deleteAllData() async {
    final db = await database;
    await db.delete(_tableName);
  }

  // Get last updated timestamp
  static Future<DateTime?> getLastUpdated() async {
    final db = await database;
    final results = await db.query(
      _tableName,
      columns: ['updated_at'],
      orderBy: 'updated_at DESC',
      limit: 1,
    );

    if (results.isEmpty) return null;
    return DateTime.fromMillisecondsSinceEpoch(
      results.first['updated_at'] as int,
    );
  }
}