import 'dart:async';
import 'dart:convert';
import 'dart:io';

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:path/path.dart' as p;
import 'package:path_provider/path_provider.dart';
import 'package:riverpod_annotation/riverpod_annotation.dart';

import '../providers/app_providers.dart';
import '../utils/debug_logger.dart';
import 'navigation_service.dart';
import '../../features/chat/providers/chat_providers.dart';
import '../../features/chat/providers/context_attachments_provider.dart';
import '../../features/auth/providers/unified_auth_providers.dart';
import '../../features/chat/views/voice_call_page.dart';
import '../../features/chat/services/file_attachment_service.dart';
import '../../shared/services/tasks/task_queue.dart';

part 'app_intents_service.g.dart';

const _askIntentId = 'app.cogwheel.conduit.ask_chat';
const _voiceCallIntentId = 'app.cogwheel.conduit.start_voice_call';
const _sendTextIntentId = 'app.cogwheel.conduit.send_text';
const _sendUrlIntentId = 'app.cogwheel.conduit.send_url';
const _sendImageIntentId = 'app.cogwheel.conduit.send_image';

/// Method channel for receiving App Intent invocations from native iOS code.
/// Native Swift code defines the intents with proper titles and metadata.
/// This Flutter code handles the business logic (navigation, state management).
const _appIntentsChannel = MethodChannel('conduit/app_intents');

/// Handles iOS App Intents for Siri/Shortcuts.
///
/// Native Swift code in AppDelegate.swift defines the App Intents with proper
/// titles, descriptions, and parameters. This coordinator sets up a method
/// channel to receive invocations and execute Flutter-side business logic.
@Riverpod(keepAlive: true)
class AppIntentCoordinator extends _$AppIntentCoordinator {
  @override
  FutureOr<void> build() {
    if (kIsWeb || defaultTargetPlatform != TargetPlatform.iOS) {
      return null;
    }
    _setupMethodChannel();
  }

  void _setupMethodChannel() {
    _appIntentsChannel.setMethodCallHandler(_handleMethodCall);
  }

  Future<Map<String, dynamic>> _handleMethodCall(MethodCall call) async {
    final parameters = (call.arguments as Map?)?.cast<String, dynamic>() ?? {};

    try {
      switch (call.method) {
        case _askIntentId:
          return await _handleAskIntent(parameters);
        case _voiceCallIntentId:
          return await _handleVoiceCallIntent(parameters);
        case _sendTextIntentId:
          return await _handleSendTextIntent(parameters);
        case _sendUrlIntentId:
          return await _handleSendUrlIntent(parameters);
        case _sendImageIntentId:
          return await _handleSendImageIntent(parameters);
        default:
          return {'success': false, 'error': 'Unknown intent: ${call.method}'};
      }
    } catch (error, stackTrace) {
      DebugLogger.error(
        'app-intents-dispatch',
        scope: 'siri',
        error: error,
        stackTrace: stackTrace,
      );
      return {'success': false, 'error': error.toString()};
    }
  }

  Future<Map<String, dynamic>> _handleAskIntent(
    Map<String, dynamic> parameters,
  ) async {
    final prompt = (parameters['prompt'] as String?)?.trim();

    try {
      await _prepareChat(prompt: prompt);
      final summary = prompt != null && prompt.isNotEmpty
          ? 'Opening chat for "$prompt"'
          : 'Opening Conduit chat';

      return {'success': true, 'value': summary};
    } catch (error, stackTrace) {
      DebugLogger.error(
        'app-intents-handle',
        scope: 'siri',
        error: error,
        stackTrace: stackTrace,
      );
      return {'success': false, 'error': 'Unable to open chat: $error'};
    }
  }

  Future<Map<String, dynamic>> _handleVoiceCallIntent(
    Map<String, dynamic> parameters,
  ) async {
    DebugLogger.log('Starting voice call from Siri/Shortcuts', scope: 'siri');

    if (!ref.mounted) {
      DebugLogger.log('Ref not mounted for voice call', scope: 'siri');
      return {'success': false, 'error': 'App not ready'};
    }

    // Check authentication state
    final navState = ref.read(authNavigationStateProvider);
    if (navState != AuthNavigationState.authenticated) {
      DebugLogger.log('Not authenticated for voice call', scope: 'siri');
      return {
        'success': false,
        'error': 'Please sign in to start a voice call',
      };
    }

    // Check if a model is selected
    final model = ref.read(selectedModelProvider);
    if (model == null) {
      DebugLogger.log('No model selected for voice call', scope: 'siri');
      return {'success': false, 'error': 'Please select a model first'};
    }

    try {
      await _startVoiceCall();
      DebugLogger.log('Voice call launched from Siri/Shortcuts', scope: 'siri');
      return {'success': true, 'value': 'Starting Conduit voice call'};
    } catch (error, stackTrace) {
      DebugLogger.error(
        'app-intents-voice',
        scope: 'siri',
        error: error,
        stackTrace: stackTrace,
      );
      return {'success': false, 'error': 'Unable to start voice call: $error'};
    }
  }

  Future<Map<String, dynamic>> _handleSendTextIntent(
    Map<String, dynamic> parameters,
  ) async {
    final text = (parameters['text'] as String?)?.trim();
    if (text == null || text.isEmpty) {
      return {'success': false, 'error': 'No text provided.'};
    }

    try {
      await _prepareChatWithOptions(
        prompt: text,
        focusComposer: true,
        resetChat: true,
      );
      return {'success': true, 'value': 'Sent to Conduit'};
    } catch (error, stackTrace) {
      DebugLogger.error(
        'app-intents-text',
        scope: 'siri',
        error: error,
        stackTrace: stackTrace,
      );
      return {'success': false, 'error': 'Unable to send text: $error'};
    }
  }

  Future<Map<String, dynamic>> _handleSendUrlIntent(
    Map<String, dynamic> parameters,
  ) async {
    final url = (parameters['url'] as String?)?.trim();
    if (url == null || url.isEmpty) {
      return {'success': false, 'error': 'No URL provided.'};
    }

    try {
      // Determine if this is a YouTube URL
      final isYoutube =
          url.startsWith('https://www.youtube.com') ||
          url.startsWith('https://youtu.be') ||
          url.startsWith('https://youtube.com') ||
          url.startsWith('https://m.youtube.com');

      // Try to fetch the URL content first
      String? content;
      String? name;
      String? collectionName;
      final api = ref.read(apiServiceProvider);
      if (api != null) {
        final result = isYoutube
            ? await api.processYoutube(url: url)
            : await api.processWebpage(url: url);

        final file = (result?['file'] as Map?)?.cast<String, dynamic>();
        final fileData = (file?['data'] as Map?)?.cast<String, dynamic>();
        content = fileData?['content']?.toString() ?? '';
        final meta = (file?['meta'] as Map?)?.cast<String, dynamic>();
        name = meta?['name']?.toString() ?? Uri.parse(url).host;
        collectionName = result?['collection_name']?.toString();
      }

      final prompt = isYoutube
          ? 'Please summarize or analyze this video:'
          : 'Please summarize or analyze this page:';

      // Reset chat first, then add attachments (startNewChat clears attachments)
      await _prepareChatWithOptions(
        prompt: prompt,
        focusComposer: true,
        resetChat: true,
      );

      // Add attachments after reset so they aren't cleared
      final bool contentAttached = content != null && content.isNotEmpty;
      if (contentAttached) {
        final notifier = ref.read(contextAttachmentsProvider.notifier);
        if (isYoutube) {
          notifier.addYoutube(
            displayName: name ?? Uri.parse(url).host,
            content: content,
            url: url,
            collectionName: collectionName,
          );
        } else {
          notifier.addWeb(
            displayName: name ?? Uri.parse(url).host,
            content: content,
            url: url,
            collectionName: collectionName,
          );
        }
      }

      if (contentAttached) {
        return {
          'success': true,
          'value': isYoutube
              ? 'YouTube video attached in Conduit'
              : 'Webpage attached in Conduit',
        };
      } else {
        return {
          'success': true,
          'value': 'Opening Conduit with URL (content could not be fetched)',
        };
      }
    } catch (error, stackTrace) {
      DebugLogger.error(
        'app-intents-url',
        scope: 'siri',
        error: error,
        stackTrace: stackTrace,
      );
      return {'success': false, 'error': 'Unable to send URL: $error'};
    }
  }

  Future<Map<String, dynamic>> _handleSendImageIntent(
    Map<String, dynamic> parameters,
  ) async {
    final base64 = parameters['bytes'] as String?;
    if (base64 == null || base64.isEmpty) {
      return {'success': false, 'error': 'No image data provided.'};
    }
    final filenameRaw = (parameters['filename'] as String?)?.trim();

    try {
      final file = await _materializeTempFile(
        base64,
        preferredName: filenameRaw,
      );
      await _attachFiles([file]);
      await _prepareChatWithOptions(focusComposer: true, resetChat: true);
      return {'success': true, 'value': 'Image attached in Conduit'};
    } catch (error, stackTrace) {
      DebugLogger.error(
        'app-intents-image',
        scope: 'siri',
        error: error,
        stackTrace: stackTrace,
      );
      return {'success': false, 'error': 'Unable to send image: $error'};
    }
  }

  Future<void> _prepareChat({String? prompt}) async {
    await _prepareChatWithOptions(
      prompt: prompt,
      focusComposer: false,
      resetChat: false,
    );
  }

  Future<void> openChatFromExternal({
    String? prompt,
    bool focusComposer = false,
    bool resetChat = false,
  }) {
    return _prepareChatWithOptions(
      prompt: prompt,
      focusComposer: focusComposer,
      resetChat: resetChat,
    );
  }

  Future<void> startVoiceCallFromExternal() => _startVoiceCall();

  Future<void> _prepareChatWithOptions({
    String? prompt,
    bool focusComposer = false,
    bool resetChat = false,
  }) async {
    if (!ref.mounted) return;

    NavigationService.navigateToChat();

    final navState = ref.read(authNavigationStateProvider);
    if (prompt != null && prompt.isNotEmpty) {
      ref.read(prefilledInputTextProvider.notifier).set(prompt);
    }

    if (navState == AuthNavigationState.authenticated && resetChat) {
      startNewChat(ref);
    }

    if (focusComposer) {
      final tick = ref.read(inputFocusTriggerProvider);
      ref.read(inputFocusTriggerProvider.notifier).set(tick + 1);
    }
  }

  Future<void> _startVoiceCall() async {
    if (!ref.mounted) return;

    // Validate authentication state
    final navState = ref.read(authNavigationStateProvider);
    if (navState != AuthNavigationState.authenticated) {
      throw StateError('Sign in to start a voice call.');
    }

    // Validate model selection
    final model = ref.read(selectedModelProvider);
    if (model == null) {
      throw StateError('Choose a model before starting a voice call.');
    }

    // Pre-warm socket connection before navigating to voice call.
    // This reduces the chance of "websocket not connected" errors when
    // opening voice call right after app start or from Siri/Shortcuts.
    final socketService = ref.read(socketServiceProvider);
    if (socketService != null && !socketService.isConnected) {
      // Start connection attempt in parallel, don't wait for full connection
      // The VoiceCallService.startCall() will wait with extended timeout
      unawaited(socketService.connect());
    }

    // Navigate to chat first if not already there
    final isOnChatRoute = NavigationService.currentRoute == Routes.chat;
    if (!isOnChatRoute) {
      await NavigationService.navigateToChat();
    }

    // Wait a tick for navigation to settle so navigator/context are present.
    await Future<void>.delayed(const Duration(milliseconds: 50));

    final context = NavigationService.navigatorKey.currentContext;
    if (context == null) {
      throw StateError('Navigation context not available.');
    }

    // Dismiss keyboard before navigating
    FocusScope.of(context).unfocus();

    // Navigate to voice call page with new conversation flag
    await Navigator.of(context).push(
      MaterialPageRoute(
        builder: (_) => const VoiceCallPage(startNewConversation: true),
        fullscreenDialog: true,
      ),
    );
  }

  Future<File> _materializeTempFile(
    String base64Data, {
    String? preferredName,
  }) async {
    final bytes = base64Decode(base64Data);
    const maxBytes = 20 * 1024 * 1024; // 20 MB guardrail
    if (bytes.length > maxBytes) {
      throw StateError('Image too large (max 20 MB).');
    }

    final tempDir = await getTemporaryDirectory();
    final safeName = (preferredName != null && preferredName.isNotEmpty)
        ? preferredName
        : 'conduit_image_${DateTime.now().millisecondsSinceEpoch}.jpg';
    final sanitizedName = safeName.replaceAll(RegExp(r'[^\w\.\-]'), '_');
    final file = File(p.join(tempDir.path, sanitizedName));
    await file.writeAsBytes(bytes, flush: true);
    return file;
  }

  Future<void> _attachFiles(List<File> files) async {
    if (files.isEmpty) return;
    // Warm the attachment service to ensure dependencies are ready.
    final _ = ref.read(fileAttachmentServiceProvider);
    final notifier = ref.read(attachedFilesProvider.notifier);
    final taskQueue = ref.read(taskQueueProvider.notifier);
    final activeConv = ref.read(activeConversationProvider);

    final attachments = files
        .map((f) => LocalAttachment(file: f, displayName: p.basename(f.path)))
        .toList();

    notifier.addFiles(attachments);

    for (final attachment in attachments) {
      try {
        await taskQueue.enqueueUploadMedia(
          conversationId: activeConv?.id,
          filePath: attachment.file.path,
          fileName: attachment.displayName,
          fileSize: await attachment.file.length(),
        );
      } catch (error, stackTrace) {
        DebugLogger.error(
          'app-intents-upload',
          scope: 'siri',
          error: error,
          stackTrace: stackTrace,
        );
      }
    }
  }
}