// Copyright (C) 2025, uvok cheetah
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

import 'dart:convert';

import 'package:universal_ble/universal_ble.dart';
import 'package:uvok_epaper_badge/string_ext.dart';
import 'package:uvok_epaper_badge/badge_exception.dart';
import 'package:uvok_epaper_badge/model/badge_motive.dart';
import 'package:uvok_epaper_badge/model/device/universal_ble_device.dart';
import 'package:uvok_epaper_badge/model/motive_selection/badge_motive_selection.dart';

class UniversalBlueMotiveSelection implements BadgeMotiveSelection {
  final UniversalBleDevice _device;
  final String _badgeService = "ca260000-b4bb-46b2-bd06-b7b7a61ea990";
  final String _currentMotiveCharacteristic =
      "ca260001-b4bb-46b2-bd06-b7b7a61ea990";
  final String _availableMotivesCharacteristic =
      "ca260002-b4bb-46b2-bd06-b7b7a61ea990";

  List<BadgeMotive> _cachedMotives = [];

  UniversalBlueMotiveSelection({required UniversalBleDevice device})
    : _device = device;

  @override
  Future<BadgeMotive> getCurrentMotive() async {
    await _ensureConnected();

    if (_cachedMotives.isEmpty) {
      await getMotives();
    }
    if (_cachedMotives.isEmpty) {
      throw BadgeException(
        "No motives available, so there's no current motive",
      );
    }

    try {
      var c = await _device.device.getCharacteristic(
        _currentMotiveCharacteristic,
        service: _badgeService,
      );

      var val = await c.read();
      int? currentMotive = int.tryParse(ascii.decode(val));
      if (currentMotive == null) {
        throw BadgeException("Error reading current motive.");
      }
      return _cachedMotives.singleWhere(
        (bm) => bm.id == currentMotive,
        orElse: () => throw BadgeException("Selected motive not in templates"),
      );
    } on NotFoundException {
      throw BadgeException("Characeristic/Service not found.");
    }
  }

  @override
  Future<List<BadgeMotive>> getMotives() async {
    await _ensureConnected();

    try {
      var c = await _device.device.getCharacteristic(
        _availableMotivesCharacteristic,
        service: _badgeService,
      );
      var val = await c.read();
      var templates = ascii.decode(val);
      _cachedMotives = templates
          .split(";")
          .where((s) => s.isNotEmpty)
          .map((String s) {
            List<String> parts = s.splitFirst("-");
            if (parts.length != 2) {
              return BadgeMotive(-1, "Invalid value");
            }
            return BadgeMotive(int.tryParse(parts[0]) ?? -1, parts[1]);
          })
          .toList(growable: false);
    } on NotFoundException {
      throw BadgeException("Characeristic/Service not found.");
    }

    return _cachedMotives;
  }

  Future<void> _ensureConnected() async {
    if (await _device.device.connectionState != BleConnectionState.connected) {
      throw BadgeException("Not connected");
    }
  }

  @override
  Future<void> setCurrentMotive(BadgeMotive motive) async {
    await _ensureConnected();
    try {
      var c = await _device.device.getCharacteristic(
        _currentMotiveCharacteristic,
        service: _badgeService,
      );

      await c.write(ascii.encode(motive.id.toString()), withResponse: true);
    } on NotFoundException {
      throw BadgeException("Characeristic/Service not found.");
    }
  }
}