import 'package:riverpod_annotation/riverpod_annotation.dart';

part 'payment_draft_provider.g.dart';

/// Session mode the customer is paying for. Mirrors backend `SessionMode`
/// (chat | call). Phase 4 introduces `call` as a future option — pricing config
/// supplies the call tier list, but no functional voice feature is built yet.
enum PaymentMode {
  chat('chat'),
  call('call');

  final String value;
  const PaymentMode(this.value);

  static PaymentMode fromString(String? v) =>
      values.firstWhere((e) => e.value == v, orElse: () => PaymentMode.chat);
}

/// Draft state shared across the multi-screen payment flow:
/// discount-paywall / method-pick / duration-pick / method / waiting / expired.
///
/// The state is deliberately minimal — the *source of truth* for amount and
/// duration is always the backend (server-validated tier or first-session
/// discount). The draft only carries the customer's in-flight intent across
/// the screen graph.
class PaymentDraft {
  final PaymentMode mode;
  final String? durationId;
  final int? durationMinutes;
  final int? priceIDR;
  final String? paymentId;
  final bool isFirstSessionDiscount;

  const PaymentDraft({
    this.mode = PaymentMode.chat,
    this.durationId,
    this.durationMinutes,
    this.priceIDR,
    this.paymentId,
    this.isFirstSessionDiscount = false,
  });

  PaymentDraft copyWith({
    PaymentMode? mode,
    String? durationId,
    int? durationMinutes,
    int? priceIDR,
    String? paymentId,
    bool? isFirstSessionDiscount,
  }) {
    return PaymentDraft(
      mode: mode ?? this.mode,
      durationId: durationId ?? this.durationId,
      durationMinutes: durationMinutes ?? this.durationMinutes,
      priceIDR: priceIDR ?? this.priceIDR,
      paymentId: paymentId ?? this.paymentId,
      isFirstSessionDiscount: isFirstSessionDiscount ?? this.isFirstSessionDiscount,
    );
  }
}

@Riverpod(keepAlive: true)
class PaymentDraftNotifier extends _$PaymentDraftNotifier {
  @override
  PaymentDraft build() => const PaymentDraft();

  void setMode(PaymentMode mode) {
    // Switching mode resets the previously-picked tier — chat and call
    // tier lists are independent.
    state = state.copyWith(
      mode: mode,
      durationId: null,
      durationMinutes: null,
      priceIDR: null,
    );
  }

  void setTier({
    required String durationId,
    required int durationMinutes,
    required int priceIDR,
  }) {
    state = state.copyWith(
      durationId: durationId,
      durationMinutes: durationMinutes,
      priceIDR: priceIDR,
    );
  }

  void setDiscountPlan({
    required int durationMinutes,
    required int priceIDR,
  }) {
    state = state.copyWith(
      mode: PaymentMode.chat,
      durationMinutes: durationMinutes,
      priceIDR: priceIDR,
      isFirstSessionDiscount: true,
    );
  }

  void setPaymentId(String paymentId) {
    state = state.copyWith(paymentId: paymentId);
  }

  /// Wipe the draft when entering the flow fresh (e.g. tapping "Mulai Curhat"
  /// from home). Keeping it across back-nav inside the flow is the default.
  void reset() {
    state = const PaymentDraft();
  }
}