import 'package:dio/dio.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../core/network/api_exception.dart';
import '../core/network/dio_client.dart';
import '../models/bill.dart';
import '../models/bill_request.dart';

final billApiProvider = Provider<BillApi>((ref) => BillApi(ref.watch(dioProvider)));

class BillApi {
  final Dio _dio;

  BillApi(this._dio);

  /// 账单列表，可选日期区间（yyyy-MM-dd）。
  /// 后端返回裸数组，无分页。
  Future<List<Bill>> getBills({String? startDate, String? endDate}) async {
    try {
      final params = <String, dynamic>{};
      if (startDate != null) params['startDate'] = startDate;
      if (endDate != null) params['endDate'] = endDate;
      final res = await _dio.get('/bills', queryParameters: params);
      return _parseList(res.data).map(Bill.fromJson).toList();
    } on DioException catch (e) {
      throw _unwrap(e);
    }
  }

  /// 账单详情
  Future<Bill> getBill(int id) async {
    try {
      final res = await _dio.get('/bills/$id');
      return Bill.fromJson(_parseObject(res.data));
    } on DioException catch (e) {
      throw _unwrap(e);
    }
  }

  /// 创建账单
  Future<void> createBill(BillRequest bill) async {
    try {
      await _dio.post('/bills', data: bill.toJson());
    } on DioException catch (e) {
      throw _unwrap(e);
    }
  }

  /// 批量创建账单（OCR 直接存储）
  Future<void> createBillsBatch(List<BillRequest> bills) async {
    try {
      await _dio.post('/bills/batch', data: {
        'bills': bills.map((b) => b.toJson()).toList(),
      });
    } on DioException catch (e) {
      throw _unwrap(e);
    }
  }

  /// 更新账单
  ///
  /// 注意：后端对 description 为 null 会覆盖成 null，所以必须回传全部字段
  /// （BillRequest.toJson 不含 imageUrl，后端按「null 保留原值」处理，正好保留原图）。
  Future<Bill> updateBill(int id, BillRequest bill) async {
    try {
      final res = await _dio.put('/bills/$id', data: bill.toJson());
      return Bill.fromJson(_parseObject(res.data));
    } on DioException catch (e) {
      throw _unwrap(e);
    }
  }

  /// 删除账单（后端为物理删除，不可恢复）
  Future<void> deleteBill(int id) async {
    try {
      await _dio.delete('/bills/$id');
    } on DioException catch (e) {
      throw _unwrap(e);
    }
  }

  /// 兼容裸数组与 {code,data:[...]} 两种形态
  List<Map<String, dynamic>> _parseList(Object? data) {
    if (data is List) {
      return data.whereType<Map<String, dynamic>>().toList();
    }
    if (data is Map && data['data'] is List) {
      return (data['data'] as List).whereType<Map<String, dynamic>>().toList();
    }
    throw ApiException(-1, '响应格式异常');
  }

  Map<String, dynamic> _parseObject(Object? data) {
    if (data is Map<String, dynamic>) return data;
    if (data is Map && data['data'] is Map) return Map<String, dynamic>.from(data['data'] as Map);
    throw ApiException(-1, '响应格式异常');
  }

  Never _unwrap(DioException e) {
    final err = e.error;
    if (err is ApiException) throw err;
    throw ApiException(-1, '请求失败');
  }
}