import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../core/api/api_client.dart';
import '../core/auth/auth_state.dart';
import '../core/config/app_constants.dart';
import '../core/models/page_result.dart';
import '../models/finance.dart';
import '../repositories/finance_repository.dart';

final financeRepositoryProvider = Provider<FinanceRepository>((ref) {
  return FinanceRepository(ref.watch(apiClientProvider));
});

final financeListProvider =
    AsyncNotifierProvider<FinanceListNotifier, PageResult<FinanceRecord>>(
  FinanceListNotifier.new,
);

class FinanceListNotifier extends AsyncNotifier<PageResult<FinanceRecord>> {
  int _page = 1;
  int _pageSize = AppConstants.defaultPageSize;
  String _type = '';
  String _month = '';
  String _startDate = '';
  String _endDate = '';

  @override
  Future<PageResult<FinanceRecord>> build() {
    ref.watch(authStateProvider.select((s) => s.user?.shopId));
    return _fetch();
  }

  Future<PageResult<FinanceRecord>> _fetch() {
    return ref.read(financeRepositoryProvider).listRecords(
          type: _type.isEmpty ? null : _type,
          month: _month.isEmpty ? null : _month,
          startDate: _startDate.isEmpty ? null : _startDate,
          endDate: _endDate.isEmpty ? null : _endDate,
          page: _page,
          pageSize: _pageSize,
        );
  }

  void setType(String type) {
    _type = type;
    _page = 1;
    reload();
  }

  void setMonth(String month) {
    _month = month;
    _startDate = '';
    _endDate = '';
    _page = 1;
    reload();
  }

  /// 日期区间（本季/自定义时间范围）；与 month 互斥。
  void setRange(String startDate, String endDate) {
    _startDate = startDate;
    _endDate = endDate;
    _month = '';
    _page = 1;
    reload();
  }

  void setPage(int page) {
    _page = page;
    reload();
  }

  void setPageSize(int pageSize) {
    _pageSize = pageSize;
    _page = 1;
    reload();
  }

  void reload() {
    // 保留上一次数据（isReloading）→ 屏幕渲染旧内容 + 半透明进度，不白屏。
    state = const AsyncValue<PageResult<FinanceRecord>>.loading()
        .copyWithPrevious(state);
    _fetch().then(
      (result) => state = AsyncValue.data(result),
      onError: (e, st) => state =
          AsyncValue<PageResult<FinanceRecord>>.error(e, st)
              .copyWithPrevious(state),
    );
  }
}

/// 收支趋势（近 6 个自然月，柱状图数据源）。
final financeTrendProvider = FutureProvider<List<TrendPoint>>((ref) async {
  ref.watch(authStateProvider.select((s) => s.user?.shopId));
  return ref.read(financeRepositoryProvider).trend(months: 6);
});

/// 应收/应付按往来单位汇总行（合并 /finance/summary 的 recv/pay 两类）。
class PartnerFinanceRow {
  final int? partnerId;
  final String name;
  final double recv;
  final double pay;
  final int openCount;
  const PartnerFinanceRow(
      {this.partnerId,
      required this.name,
      this.recv = 0,
      this.pay = 0,
      this.openCount = 0});

  double get net => recv - pay;
}

final financePartnerRowsProvider =
    FutureProvider<List<PartnerFinanceRow>>((ref) async {
  ref.watch(authStateProvider.select((s) => s.user?.shopId));
  final rows = await ref.read(financeRepositoryProvider).partnerSummary();
  final map = <String, PartnerFinanceRow>{};
  for (final r in rows) {
    final key = '${r.partnerId ?? 0}|${r.partnerName}';
    final cur = map[key] ??
        PartnerFinanceRow(
            partnerId: r.partnerId,
            name: r.partnerName.isEmpty ? '（未指定单位）' : r.partnerName);
    map[key] = PartnerFinanceRow(
      partnerId: cur.partnerId,
      name: cur.name,
      recv: cur.recv + (r.type == 'receivable' ? r.totalAmount : 0),
      pay: cur.pay + (r.type == 'payable' ? r.totalAmount : 0),
      openCount: cur.openCount + r.recordCount,
    );
  }
  final list = map.values.toList()
    ..sort((a, b) => (b.recv + b.pay).compareTo(a.recv + a.pay));
  return list;
});