import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../api/bill_api.dart';
import '../core/network/api_exception.dart';
import '../models/bill_request.dart';
import '../models/ocr_result.dart';
import '../utils/date_util.dart';
import 'bill_refresh.dart';

/// 手动记账表单状态
class AddBillFormState {
  final int type; // 1=支出 2=收入
  final int? categoryId;
  final double? amount;
  final String billDate; // yyyy-MM-dd
  final String description;
  final bool submitting;
  final int revision; // 每次 fillFromOcr 外部填充时 +1，供 UI 同步非受控输入框

  const AddBillFormState({
    this.type = 1,
    this.categoryId,
    this.amount,
    required this.billDate,
    this.description = '',
    this.submitting = false,
    this.revision = 0,
  });

  AddBillFormState copyWith({
    int? type,
    int? categoryId,
    Object? amount = _sentinel,
    String? billDate,
    String? description,
    bool? submitting,
    int? revision,
  }) {
    return AddBillFormState(
      type: type ?? this.type,
      categoryId: categoryId ?? this.categoryId,
      amount: amount == _sentinel ? this.amount : amount as double?,
      billDate: billDate ?? this.billDate,
      description: description ?? this.description,
      submitting: submitting ?? this.submitting,
      revision: revision ?? this.revision,
    );
  }

  static const _sentinel = Object();
}

class AddBillFormNotifier extends Notifier<AddBillFormState> {
  @override
  AddBillFormState build() => AddBillFormState(billDate: formatDate(DateTime.now()));

  void setType(int type) {
    if (type == state.type) return;
    // 类型切换后分类需重选（对齐 uniApp watch 行为）
    state = state.copyWith(type: type, categoryId: null);
  }

  void setCategory(int id) => state = state.copyWith(categoryId: id);

  void setAmount(double? value) => state = state.copyWith(amount: value);

  void setDate(String date) => state = state.copyWith(billDate: date);

  void setDescription(String desc) => state = state.copyWith(description: desc);

  /// 保存账单，成功返回 true
  Future<bool> submit() async {
    final s = state;
    if (s.categoryId == null) throw ApiException(-1, '请选择分类');
    if (s.amount == null || s.amount! <= 0) throw ApiException(-1, '请输入有效金额');
    state = state.copyWith(submitting: true);
    try {
      await ref.read(billApiProvider).createBill(BillRequest(
            categoryId: s.categoryId!,
            amount: s.amount!,
            description: s.description,
            billDate: s.billDate,
            type: s.type,
          ));
      // 让首页列表与统计页重新取数
      invalidateBillData(ref);
      _resetAfterSubmit();
      return true;
    } finally {
      state = state.copyWith(submitting: false);
    }
  }

  void _resetAfterSubmit() {
    state = AddBillFormState(
      type: state.type,
      billDate: formatDate(DateTime.now()),
    );
  }

  /// OCR「选择此条」：按金额正负推断类型并填充表单
  void fillFromOcr(OcrResult ocr) {
    state = AddBillFormState(
      type: ocr.isExpense ? 1 : 2,
      amount: ocr.absAmount,
      description: ocr.merchant ?? '',
      billDate: parseBillDate(ocr.date),
      revision: state.revision + 1,
    );
  }
}

final addBillFormProvider =
    NotifierProvider<AddBillFormNotifier, AddBillFormState>(AddBillFormNotifier.new);