import 'package:relationship_saver/features/local/local_models.dart';
import 'package:relationship_saver/features/share_intake/domain/signal_share_parser.dart';
import 'package:relationship_saver/features/share_intake/whatsapp_share_parser.dart';

class SharePayloadParser {
  const SharePayloadParser._();

  static final RegExp _urlPattern = RegExp(
    r'(https?:\/\/[^\s]+|www\.[^\s]+)',
    caseSensitive: false,
  );

  static SharedPayload parse({
    required String rawText,
    required String sourceApp,
    required String platform,
    DateTime? createdAt,
    DateTime? receivedAt,
  }) {
    final DateTime now = DateTime.now();
    final String normalizedSourceApp = _normalizeSourceApp(sourceApp);
    final String trimmed = rawText.trim();
    final _ParsedSourceMetadata? sourceMetadata = _parseSourceMetadata(
      sourceApp: normalizedSourceApp,
      rawText: trimmed,
    );
    final String candidateText = sourceMetadata?.messageText.trim() ?? trimmed;
    final RegExpMatch? urlMatch = _urlPattern.firstMatch(candidateText);
    final String? url = urlMatch == null
        ? null
        : _normalizeUrl(urlMatch.group(0));
    final String cleanedText = url == null
        ? candidateText
        : candidateText.replaceFirst(urlMatch!.group(0)!, '').trim();
    final SharedPayloadType payloadType;
    if (url != null && cleanedText.isNotEmpty) {
      payloadType = SharedPayloadType.textWithUrl;
    } else if (url != null) {
      payloadType = SharedPayloadType.url;
    } else {
      payloadType = SharedPayloadType.text;
    }

    return SharedPayload(
      sourceApp: normalizedSourceApp,
      payloadType: payloadType,
      rawText: cleanedText,
      url: url,
      createdAt: createdAt ?? now,
      receivedAt: receivedAt ?? now,
      platform: platform,
      sourceDisplayName: sourceMetadata?.sourceDisplayName,
      sourceUserId: sourceMetadata?.sourceUserId,
      sourceThreadId: sourceMetadata?.sourceThreadId,
      parsingHints: <String>[
        if (normalizedSourceApp != 'share_sheet')
          'source_app_$normalizedSourceApp',
        if (url != null) 'contains_url',
        if (sourceMetadata?.sourceDisplayName case final String _)
          'sender_detected',
      ],
      metadata: <String, String>{
        if (url case final String value) 'primaryUrl': value,
      },
    );
  }

  static String detectSourceApp({
    required String rawText,
    String? sourceAppHint,
  }) {
    final String normalizedHint = _normalizeSourceApp(sourceAppHint);
    if (normalizedHint != 'share_sheet') {
      return normalizedHint;
    }

    final String trimmed = rawText.trim();
    if (_shouldUseWhatsAppParser(normalizedHint, trimmed)) {
      return 'whatsapp';
    }

    return 'share_sheet';
  }

  static bool _shouldUseWhatsAppParser(String sourceApp, String rawText) {
    if (sourceApp.contains('whatsapp')) {
      return true;
    }
    if (sourceApp != 'share_sheet') {
      return false;
    }
    if (rawText.contains(': ') && rawText.length < 4000) {
      return WhatsAppShareParser.looksLikeWhatsAppMessage(rawText);
    }
    return false;
  }

  static bool _shouldUseSignalParser(String sourceApp) {
    return sourceApp.contains('signal');
  }

  static _ParsedSourceMetadata? _parseSourceMetadata({
    required String sourceApp,
    required String rawText,
  }) {
    if (_shouldUseWhatsAppParser(sourceApp, rawText)) {
      final WhatsAppSharePayload payload = WhatsAppShareParser.parse(rawText);
      return _ParsedSourceMetadata(
        messageText: payload.messageText,
        sourceDisplayName: payload.sourceDisplayName,
        sourceUserId: payload.sourceUserId,
        sourceThreadId: payload.sourceThreadId,
      );
    }

    if (_shouldUseSignalParser(sourceApp) &&
        SignalShareParser.looksLikeSignalMessage(rawText)) {
      final SignalSharePayload payload = SignalShareParser.parse(rawText);
      return _ParsedSourceMetadata(
        messageText: payload.messageText,
        sourceDisplayName: payload.sourceDisplayName,
        sourceUserId: payload.sourceUserId,
        sourceThreadId: payload.sourceThreadId,
      );
    }

    return null;
  }

  static String _normalizeSourceApp(String? raw) {
    final String value = raw?.trim().toLowerCase() ?? '';
    if (value.isEmpty ||
        value == 'generic' ||
        value == 'text' ||
        value == 'share sheet') {
      return 'share_sheet';
    }
    if (value.contains('whatsapp')) {
      return 'whatsapp';
    }
    if (value.contains('signal')) {
      return 'signal';
    }
    if (value.contains('note')) {
      return 'notes';
    }
    return value;
  }

  static String? _normalizeUrl(String? raw) {
    if (raw == null) {
      return null;
    }
    final String value = raw.trim();
    if (value.isEmpty) {
      return null;
    }
    if (value.toLowerCase().startsWith('http://') ||
        value.toLowerCase().startsWith('https://')) {
      return value;
    }
    return 'https://$value';
  }
}

class _ParsedSourceMetadata {
  const _ParsedSourceMetadata({
    required this.messageText,
    this.sourceDisplayName,
    this.sourceUserId,
    this.sourceThreadId,
  });

  final String messageText;
  final String? sourceDisplayName;
  final String? sourceUserId;
  final String? sourceThreadId;
}