// Bidirectional synchronization logic for calendars and tasks
import { CalendarEvent, getCalendarEvents, mergeWithTasks, filterEventsByDateRange } from './calendar-events';
import { Task } from '@/types/task';

export interface CalendarConnection {
  id: string;
  provider: 'google' | 'apple';
  accessToken: string;
  refreshToken?: string;
  expiresAt?: Date;
  calendars: Array<{
    id: string;
    title: string;
    isPrimary?: boolean;
  }>;
}

export interface SyncResult {
  syncedEvents: number;
  syncedTasks: number;
  conflicts: Array<{
    type: 'duplicate' | 'conflict';
    message: string;
  }>;
}

/**
 * Sync calendar events to tasks
 */
export const syncCalendarEvents = async (
  connections: CalendarConnection[],
  timeMin: string,
  timeMax: string,
  existingTasks: Task[]
): Promise<SyncResult> => {
  try {
    // Fetch events from all connected calendars
    const events = await getCalendarEvents(connections, timeMin, timeMax);

    // Filter events to the current week range
    const filteredEvents = filterEventsByDateRange(events, new Date(timeMin), new Date(timeMax));

    // Merge with existing tasks to avoid duplicates
    const uniqueEvents = mergeWithTasks(filteredEvents, existingTasks);

    // In a real implementation, this would create actual Task records in the DB
    // For now, we'll simulate this with a database operation
    // Assuming we have a function to create tasks in the database
    const createdTasks = await createTasksFromEvents(uniqueEvents);

    // Placeholder result - in a real implementation, this would sync with actual database
    return {
      syncedEvents: uniqueEvents.length,
      syncedTasks: createdTasks.length,
      conflicts: []
    };
  } catch (error) {
    console.error('Error syncing calendar events:', error);
    throw new Error('Failed to sync calendar events');
  }
};

/**
 * Helper function to create tasks from calendar events (placeholder implementation)
 */
const createTasksFromEvents = async (events: CalendarEvent[]): Promise<Task[]> => {
  // In a real implementation, this would connect to the database and create tasks
  // For now, just return an array with the same length as events
  return events.map(event => ({
    id: `task-${Date.now()}-${Math.random()}`,
    title: event.title,
    description: event.description,
    completed: false,
    startTime: event.start.dateTime,
    endTime: event.end.dateTime,
    dayOfWeek: event.start.dateTime ? new Date(event.start.dateTime).getDay() : undefined,
    createdAt: new Date(),
    updatedAt: new Date()
  }));
};

/**
 * Sync tasks to calendar events
 */
export const syncCalendarTasks = async (
  connections: CalendarConnection[],
  tasks: Task[],
  timeMin: string,
  timeMax: string
): Promise<SyncResult> => {
  try {
    // In a real implementation, this would convert tasks to calendar events
    // and update the connected calendars

    // In a real implementation, this would make API calls to calendar providers
    // For now, we'll simulate by just returning the count
    const syncedEvents = tasks.length;

    // Placeholder - in a real implementation, this would make API calls to calendar providers
    console.log(`Converting ${tasks.length} tasks to calendar events`);

    return {
      syncedEvents: syncedEvents,
      syncedTasks: tasks.length,
      conflicts: []
    };
  } catch (error) {
    console.error('Error syncing calendar tasks:', error);
    throw new Error('Failed to sync calendar tasks');
  }
};

/**
 * Full bidirectional sync operation
 */
export const syncCalendarBidirectional = async (
  connections: CalendarConnection[],
  timeMin: string,
  timeMax: string,
  existingTasks: Task[]
): Promise<SyncResult> => {
  try {
    // Sync calendar events to tasks
    const eventsResult = await syncCalendarEvents(connections, timeMin, timeMax, existingTasks);

    // Sync tasks to calendar events
    const tasksResult = await syncCalendarTasks(connections, existingTasks, timeMin, timeMax);

    // Combine results
    return {
      syncedEvents: eventsResult.syncedEvents,
      syncedTasks: tasksResult.syncedTasks,
      conflicts: [...eventsResult.conflicts, ...tasksResult.conflicts]
    };
  } catch (error) {
    console.error('Error performing bidirectional sync:', error);
    throw new Error('Failed to perform bidirectional sync');
  }
};