import 'dart:async';

import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:formz/formz.dart';
import 'package:equatable/equatable.dart';
import '../../../../data/network/api_exception.dart';
import '../../../../core/l10n/l10n.dart';
import '../../data/repositories/auth_repository.dart';
import '../../data/models/auth_response.dart';
import '../../../../shared/forms/inputs.dart';

class LoginState extends Equatable {
  static const defaultDialCode = '+86';
  static final _e164Regex = RegExp(r'^\+[1-9]\d{7,14}$');

  final String dialCode;
  final Phone phone;
  final VerificationCode code;
  final bool codeSent;
  final bool isSendingCode;
  final int resendCooldownSeconds;
  final FormzSubmissionStatus status;
  final String? errorMessage;

  const LoginState({
    this.dialCode = defaultDialCode,
    this.phone = const Phone.pure(),
    this.code = const VerificationCode.pure(),
    this.codeSent = false,
    this.isSendingCode = false,
    this.resendCooldownSeconds = 0,
    this.status = FormzSubmissionStatus.initial,
    this.errorMessage,
  });

  bool get isPhoneValidForApi =>
      phone.isValid && _e164Regex.hasMatch(e164Phone);
  bool get isValid => isPhoneValidForApi && code.isValid;
  String get e164Phone => '$dialCode${phone.value}';
  bool get canSendCode =>
      isPhoneValidForApi && !isSendingCode && resendCooldownSeconds == 0;

  LoginState copyWith({
    String? dialCode,
    Phone? phone,
    VerificationCode? code,
    bool? codeSent,
    bool? isSendingCode,
    int? resendCooldownSeconds,
    FormzSubmissionStatus? status,
    String? errorMessage,
  }) {
    return LoginState(
      dialCode: dialCode ?? this.dialCode,
      phone: phone ?? this.phone,
      code: code ?? this.code,
      codeSent: codeSent ?? this.codeSent,
      isSendingCode: isSendingCode ?? this.isSendingCode,
      resendCooldownSeconds:
          resendCooldownSeconds ?? this.resendCooldownSeconds,
      status: status ?? this.status,
      errorMessage: errorMessage,
    );
  }

  @override
  List<Object?> get props => [
    dialCode,
    phone,
    code,
    codeSent,
    isSendingCode,
    resendCooldownSeconds,
    status,
    errorMessage,
  ];
}

class LoginCubit extends Cubit<LoginState> {
  final AuthRepository _repository;
  Timer? _resendTimer;

  LoginCubit(this._repository) : super(const LoginState());

  void phoneChanged(String value) {
    final nextPhone = Phone.dirty(value);
    if (nextPhone.value == state.phone.value) {
      emit(state.copyWith(phone: nextPhone, errorMessage: null));
      return;
    }
    _resendTimer?.cancel();
    emit(
      state.copyWith(
        phone: nextPhone,
        code: const VerificationCode.pure(),
        codeSent: false,
        resendCooldownSeconds: 0,
        errorMessage: null,
      ),
    );
  }

  void dialCodeChanged(String value) {
    if (value == state.dialCode) {
      return;
    }
    _resendTimer?.cancel();
    emit(
      state.copyWith(
        dialCode: value,
        code: const VerificationCode.pure(),
        codeSent: false,
        resendCooldownSeconds: 0,
        errorMessage: null,
      ),
    );
  }

  void codeChanged(String value) {
    emit(state.copyWith(code: VerificationCode.dirty(value)));
  }

  Future<bool> sendCode() async {
    if (!state.phone.isValid) {
      emit(state.copyWith(errorMessage: L10n.current.authInvalidPhone));
      return false;
    }
    if (!state.canSendCode) {
      return false;
    }

    final requestPhone = state.e164Phone;
    emit(state.copyWith(isSendingCode: true, errorMessage: null));
    _startResendCooldown();
    try {
      await _repository.sendOtp(requestPhone);
      if (isClosed) {
        return false;
      }
      if (state.e164Phone != requestPhone) {
        emit(state.copyWith(isSendingCode: false));
        return false;
      }
      emit(
        state.copyWith(
          isSendingCode: false,
          codeSent: true,
          errorMessage: null,
        ),
      );
      return true;
    } catch (e) {
      if (isClosed) {
        return false;
      }
      final message = e is ApiException
          ? e.message
          : L10n.current.authSendCodeFailed;
      emit(state.copyWith(isSendingCode: false, errorMessage: message));
      return false;
    }
  }

  Future<AuthResponse?> submit() async {
    if (!state.isValid) return null;

    emit(state.copyWith(status: FormzSubmissionStatus.inProgress));

    try {
      final response = await _repository.createPhoneSession(
        phone: state.e164Phone,
        token: state.code.value,
      );
      if (isClosed) {
        return null;
      }
      emit(state.copyWith(status: FormzSubmissionStatus.success));
      return response;
    } catch (e) {
      if (isClosed) {
        return null;
      }
      final message = e is ApiException ? e.message : e.toString();
      emit(
        state.copyWith(
          status: FormzSubmissionStatus.failure,
          errorMessage: message,
        ),
      );
      return null;
    }
  }

  void _startResendCooldown() {
    _resendTimer?.cancel();
    emit(state.copyWith(resendCooldownSeconds: 60));
    _resendTimer = Timer.periodic(const Duration(seconds: 1), (timer) {
      if (isClosed) {
        timer.cancel();
        return;
      }
      if (state.resendCooldownSeconds <= 1) {
        timer.cancel();
        emit(state.copyWith(resendCooldownSeconds: 0));
        return;
      }
      emit(
        state.copyWith(resendCooldownSeconds: state.resendCooldownSeconds - 1),
      );
    });
  }

  @override
  Future<void> close() {
    _resendTimer?.cancel();
    return super.close();
  }
}