import 'package:flutter_riverpod/flutter_riverpod.dart';

import 'auth_provider.dart' show localDbProvider;

const aiConsentVersion = 'ai-data-consent-v1';

class AiConsentState {
  final bool isLoading;
  final bool isSaving;
  final bool granted;
  final String? userId;
  final String? error;

  const AiConsentState({
    this.isLoading = true,
    this.isSaving = false,
    this.granted = false,
    this.userId,
    this.error,
  });
}

final aiConsentProvider = NotifierProvider<AiConsentNotifier, AiConsentState>(
  AiConsentNotifier.new,
);

class AiConsentNotifier extends Notifier<AiConsentState> {
  @override
  AiConsentState build() => const AiConsentState();

  String _key(String userId) => '$aiConsentVersion:$userId';

  Future<void> load(String userId) async {
    state = AiConsentState(isLoading: true, userId: userId);
    try {
      final value = await ref.read(localDbProvider).read(_key(userId));
      state = AiConsentState(
        isLoading: false,
        granted: value == 'granted',
        userId: userId,
      );
    } catch (_) {
      state = AiConsentState(
        isLoading: false,
        userId: userId,
        error: '授权状态加载失败，请重试',
      );
    }
  }

  Future<bool> grant(String userId) async {
    state = AiConsentState(
      isLoading: false,
      isSaving: true,
      granted: state.granted,
      userId: userId,
    );
    try {
      await ref.read(localDbProvider).write(_key(userId), 'granted');
      state = AiConsentState(isLoading: false, granted: true, userId: userId);
      return true;
    } catch (_) {
      state = AiConsentState(
        isLoading: false,
        userId: userId,
        error: '授权保存失败，请稍后重试',
      );
      return false;
    }
  }

  Future<bool> revoke(String userId) async {
    state = AiConsentState(
      isLoading: false,
      isSaving: true,
      granted: state.granted,
      userId: userId,
    );
    try {
      await ref.read(localDbProvider).delete(_key(userId));
      state = AiConsentState(isLoading: false, granted: false, userId: userId);
      return true;
    } catch (_) {
      state = AiConsentState(
        isLoading: false,
        granted: true,
        userId: userId,
        error: '撤回授权失败，请稍后重试',
      );
      return false;
    }
  }
}