import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import '../services/firebase_service.dart';

// ── Model ──────────────────────────────────────────────────────────────────
class AmorChatEntry {
  final String text;
  final bool isUser;
  final DateTime time;

  AmorChatEntry({
    required this.text,
    required this.isUser,
    required this.time,
  });

  Map<String, dynamic> toJson() => {
        'text': text,
        'isUser': isUser,
        'time': time.toIso8601String(),
      };

  factory AmorChatEntry.fromJson(Map<String, dynamic> json) => AmorChatEntry(
        text: json['text'] as String,
        isUser: json['isUser'] as bool,
        time: DateTime.parse(json['time'] as String),
      );
}

// ── State ──────────────────────────────────────────────────────────────────
class AmorChatState {
  final List<AmorChatEntry> messages;
  final bool isLoading;
  final bool isLoadedFromFirestore;

  const AmorChatState({
    this.messages = const [],
    this.isLoading = false,
    this.isLoadedFromFirestore = false,
  });

  AmorChatState copyWith({
    List<AmorChatEntry>? messages,
    bool? isLoading,
    bool? isLoadedFromFirestore,
  }) =>
      AmorChatState(
        messages: messages ?? this.messages,
        isLoading: isLoading ?? this.isLoading,
        isLoadedFromFirestore:
            isLoadedFromFirestore ?? this.isLoadedFromFirestore,
      );
}

// ── Notifier ───────────────────────────────────────────────────────────────
class AmorChatNotifier extends StateNotifier<AmorChatState> {
  final FirebaseFirestore _db = FirebaseFirestore.instance;
  static const String _chatCollection = 'amorChatHistory';
  static const int _maxMessages = 100; // batas simpan

  AmorChatNotifier() : super(const AmorChatState());

  String? get _uid => FirebaseService().currentUser?.uid;

  // ── Load riwayat dari Firestore ──────────────────────────────────────────
  Future<void> loadHistory() async {
    if (state.isLoadedFromFirestore) return; // sudah dimuat, skip
    final uid = _uid;
    if (uid == null) return;

    try {
      final doc = await _db.collection(_chatCollection).doc(uid).get();
      if (doc.exists && doc.data() != null) {
        final raw = doc.data()!['messages'] as List<dynamic>? ?? [];
        final msgs = raw
            .map((e) =>
                AmorChatEntry.fromJson(Map<String, dynamic>.from(e as Map)))
            .toList();
        state = state.copyWith(
          messages: msgs,
          isLoadedFromFirestore: true,
        );
      } else {
        state = state.copyWith(isLoadedFromFirestore: true);
      }
    } catch (e) {
      debugPrint('AmorChat loadHistory error: $e');
      state = state.copyWith(isLoadedFromFirestore: true);
    }
  }

  // ── Tambah pesan user ────────────────────────────────────────────────────
  void addUserMessage(String text) {
    final entry = AmorChatEntry(
      text: text,
      isUser: true,
      time: DateTime.now(),
    );
    state = state.copyWith(messages: [...state.messages, entry]);
  }

  // ── Tambah pesan AI & simpan ke Firestore ────────────────────────────────
  Future<void> addAIMessage(String text) async {
    final entry = AmorChatEntry(
      text: text,
      isUser: false,
      time: DateTime.now(),
    );
    final updated = [...state.messages, entry];
    state = state.copyWith(messages: updated);
    await _saveToFirestore(updated);
  }

  // ── Set loading ──────────────────────────────────────────────────────────
  void setLoading(bool v) => state = state.copyWith(isLoading: v);

  // ── Hapus semua riwayat ──────────────────────────────────────────────────
  Future<void> clearHistory() async {
    state = state.copyWith(messages: []);
    final uid = _uid;
    if (uid == null) return;
    try {
      await _db.collection(_chatCollection).doc(uid).delete();
    } catch (e) {
      debugPrint('AmorChat clearHistory error: $e');
    }
  }

  // ── Simpan ke Firestore ──────────────────────────────────────────────────
  Future<void> _saveToFirestore(List<AmorChatEntry> messages) async {
    final uid = _uid;
    if (uid == null) return;
    try {
      // Batasi ke _maxMessages terakhir agar tidak membengkak
      final limited = messages.length > _maxMessages
          ? messages.sublist(messages.length - _maxMessages)
          : messages;
      await _db.collection(_chatCollection).doc(uid).set({
        'messages': limited.map((m) => m.toJson()).toList(),
        'updatedAt': DateTime.now().toIso8601String(),
      });
    } catch (e) {
      debugPrint('AmorChat _saveToFirestore error: $e');
    }
  }

  // Kembalikan history dalam format yang dibutuhkan GeminiService
  List<Map<String, String>> get aiHistory => state.messages
      .map((m) => {
            'role': m.isUser ? 'user' : 'model',
            'text': m.text,
          })
      .toList();
}

// ── Provider ───────────────────────────────────────────────────────────────
final amorChatProvider =
    StateNotifierProvider<AmorChatNotifier, AmorChatState>(
  (ref) => AmorChatNotifier(),
);