import 'package:flutter/foundation.dart';
import 'package:path/path.dart';
import 'package:sqflite/sqflite.dart';
import 'package:sqflite_common_ffi/sqflite_ffi.dart';

import '../log/log.dart';

class Db {
  late Database _db;

  void init() async {
    if (kIsWeb) {
      Log.i("Database on web is not supported");
      return;
    }
    String dbpath = 'previews.db';
    if (defaultTargetPlatform == TargetPlatform.android ||
        defaultTargetPlatform == TargetPlatform.iOS) {
      dbpath = join(await getDatabasesPath(), dbpath);
    } else {
      // Initialize FFI
      sqfliteFfiInit();
      // Change the default factory
      databaseFactory = databaseFactoryFfi;
    }

    _db = await openDatabase(
      // Set the path to the database. Note: Using the `join` function from the
      // `path` package is best practice to ensure the path is correctly
      // constructed for each platform.
      dbpath,
      onCreate: (db, version) {
        // Run the CREATE TABLE statement on the database.
        return db.execute(
          'CREATE TABLE previews(id INTEGER PRIMARY KEY, thumbnail BLOB)',
        );
      },
      // Set the version. This executes the onCreate function and provides a
      // path to perform database upgrades and downgrades.
      version: 1,
    );
  }

  /// delete all data but keep structure
  Future<void> clear() async {
    await _db.delete("previews");
    // shrink the db file size
    await _db.execute("VACUUM");
  }

  /// get db size in bytes
  Future<int> getDbSize() async {
    final int cnt = (await Db().db().rawQuery("pragma page_count;"))[0]
        ["page_count"] as int;
    final int pagesize =
        (await Db().db().rawQuery("pragma page_size;"))[0]["page_size"] as int;
    return cnt * pagesize;
  }

  Database db() {
    return _db;
  }

  static final Db _singleton = Db._internal();

  factory Db() {
    return _singleton;
  }

  Db._internal();
}