import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'expense_model.dart';
import 'expense_api.dart';

class ExpenseApplyState {
  final ExpenseModel expense;
  final bool isSubmitting;

  const ExpenseApplyState({required this.expense, this.isSubmitting = false});

  ExpenseApplyState copyWith({ExpenseModel? expense, bool? isSubmitting}) {
    return ExpenseApplyState(
      expense: expense ?? this.expense,
      isSubmitting: isSubmitting ?? this.isSubmitting,
    );
  }
}

class ExpenseApplyController extends StateNotifier<ExpenseApplyState> {
  final ExpenseApi _api;

  ExpenseApplyController(this._api, {ExpenseModel? initial})
    : super(
        ExpenseApplyState(
          expense:
              initial ??
              ExpenseModel(
                id: '',
                reportNo: '',
                applicantId: '',
                applicantName: '',
                deptId: '',
                deptName: '',
                expenseType: '',
                totalAmount: 0.0,
                purpose: '',
                createTime: DateTime.now(),
                updateTime: DateTime.now(),
              ),
        ),
      );

  void updatePurpose(String purpose) {
    state = state.copyWith(expense: state.expense.copyWith(purpose: purpose));
  }

  void addDetail(ExpenseDetailModel detail) {
    final details = [...state.expense.details, detail];
    state = state.copyWith(expense: state.expense.copyWith(details: details));
  }

  void removeDetail(int index) {
    final details = [...state.expense.details]..removeAt(index);
    state = state.copyWith(expense: state.expense.copyWith(details: details));
  }

  void recalculateAmount() {
    final total = state.expense.details.fold<double>(
      0,
      (sum, d) => sum + d.totalAmount,
    );
    state = state.copyWith(expense: state.expense.copyWith(totalAmount: total));
  }

  Future<bool> submit() async {
    state = state.copyWith(isSubmitting: true);
    try {
      await _api.submit(state.expense.copyWith(status: 'pending'));
      return true;
    } catch (_) {
      return false;
    } finally {
      state = state.copyWith(isSubmitting: false);
    }
  }

  Future<bool> saveDraft() async {
    state = state.copyWith(isSubmitting: true);
    try {
      await _api.saveDraft(state.expense);
      return true;
    } catch (_) {
      return false;
    } finally {
      state = state.copyWith(isSubmitting: false);
    }
  }
}

final expenseApplyProvider = StateNotifierProvider.autoDispose
    .family<ExpenseApplyController, ExpenseApplyState, String?>((ref, editId) {
      final api = ref.watch(expenseApiProvider);
      return ExpenseApplyController(api);
    });