import 'chat_message.dart';

enum ChatType { general, jobSpecific }

class Chat {
  final String id;
  final String title;
  final String? receiver;
  final ChatType type;
  final String? jobId; // only for job-specific chats
  final String? jobNumber; // only for job-specific chats
  final List<ChatMessage> messages;
  final DateTime lastMessageTime;
  final String lastMessagePreview;

  Chat({
    required this.id,
    required this.title,
    this.receiver,
    required this.type,
    this.jobId,
    this.jobNumber,
    required this.messages,
    required this.lastMessageTime,
    required this.lastMessagePreview,
  });

  factory Chat.fromJson(Map<String, dynamic> json) {
    final messagesList = json['messages'] as List? ?? [];
    final messages =
        messagesList
            .map(
              (messageJson) =>
                  ChatMessage.fromJson(messageJson as Map<String, dynamic>),
            )
            .toList();

    return Chat(
      id: json['id']?.toString() ?? '',
      title: json['title']?.toString() ?? '',
      receiver: json['receiver']?.toString(),
      type:
          json['type'] == 'jobSpecific'
              ? ChatType.jobSpecific
              : ChatType.general,
      jobId: json['jobId']?.toString(),
      jobNumber: json['jobNumber']?.toString(),
      messages: messages,
      lastMessageTime: _resolveLastMessageTime(json, messages),
      lastMessagePreview: _resolveLastMessagePreview(json, messages),
    );
  }

  Map<String, dynamic> toJson() {
    return {
      'id': id,
      'title': title,
      'receiver': receiver,
      'type': type == ChatType.jobSpecific ? 'jobSpecific' : 'general',
      'jobId': jobId,
      'jobNumber': jobNumber,
      'messages': messages.map((message) => message.toJson()).toList(),
      'lastMessageTime': lastMessageTime.toIso8601String(),
      'lastMessagePreview': lastMessagePreview,
    };
  }

  // Factory constructor for general chat
  factory Chat.general({
    required String id,
    required String title,
    String? receiver,
    required List<ChatMessage> messages,
  }) {
    final lastMessage = messages.isNotEmpty ? messages.last : null;
    return Chat(
      id: id,
      title: title,
      receiver: receiver,
      type: ChatType.general,
      messages: messages,
      lastMessageTime: lastMessage?.createdAt ?? DateTime.now(),
      lastMessagePreview:
          lastMessage != null
              ? _previewForMessage(lastMessage)
              : 'Noch keine Nachrichten',
    );
  }

  // Factory constructor for job-specific chat
  factory Chat.jobSpecific({
    required String id,
    required String jobId,
    required String jobNumber,
    String? receiver,
    required List<ChatMessage> messages,
  }) {
    final lastMessage = messages.isNotEmpty ? messages.last : null;
    return Chat(
      id: id,
      title: 'Job $jobNumber',
      receiver: receiver,
      type: ChatType.jobSpecific,
      jobId: jobId,
      jobNumber: jobNumber,
      messages: messages,
      lastMessageTime: lastMessage?.createdAt ?? DateTime.now(),
      lastMessagePreview:
          lastMessage != null
              ? _previewForMessage(lastMessage)
              : 'Noch keine Nachrichten',
    );
  }

  static DateTime _resolveLastMessageTime(
    Map<String, dynamic> json,
    List<ChatMessage> messages,
  ) {
    if (messages.isNotEmpty) {
      return messages.last.createdAt;
    }
    final raw = json['lastMessageTime']?.toString();
    if (raw != null) {
      final parsed = DateTime.tryParse(raw);
      if (parsed != null) {
        return parsed;
      }
    }
    return DateTime.now();
  }

  static String _resolveLastMessagePreview(
    Map<String, dynamic> json,
    List<ChatMessage> messages,
  ) {
    if (messages.isNotEmpty) {
      return _previewForMessage(messages.last);
    }
    return json['lastMessagePreview']?.toString() ?? 'Noch keine Nachrichten';
  }

  static String _previewForMessage(ChatMessage message) {
    if (message.contentType == ChatContentType.image) {
      return '[Bild]';
    }
    return message.content;
  }

  @override
  String toString() {
    return 'Chat(id: $id, title: $title, type: $type, jobId: $jobId, messagesCount: ${messages.length})';
  }

  @override
  bool operator ==(Object other) {
    if (identical(this, other)) return true;
    return other is Chat && other.id == id;
  }

  @override
  int get hashCode => id.hashCode;
}