import EventDay from '../model/eventDay.model';
import { IEvent } from '../model/event.model';
import cloudinary from './cloudinary.util';

/**
 * Generate EventDay records for each day between event's startDate and endDate
 */
export const generateEventDays = async (event: IEvent): Promise<void> => {
    const startDate = new Date(event.startDate);
    const endDate = new Date(event.endDate);

    // Set time to midnight for consistent date comparison
    startDate.setHours(0, 0, 0, 0);
    endDate.setHours(0, 0, 0, 0);

    const days: any[] = [];
    let currentDate = new Date(startDate);
    let dayNumber = 1;

    // Parse default time slots
    const [startHour, startMinute] = event.defaultStartTime.split(':').map(Number);
    const [endHour, endMinute] = event.defaultEndTime.split(':').map(Number);

    while (currentDate <= endDate) {
        // Create start and end times for this specific day
        const dayStartTime = new Date(currentDate);
        dayStartTime.setHours(startHour, startMinute, 0, 0);

        const dayEndTime = new Date(currentDate);
        dayEndTime.setHours(endHour, endMinute, 0, 0);

        days.push({
            event: event._id,
            date: new Date(currentDate),
            dayNumber: dayNumber,
            startTime: dayStartTime,
            endTime: dayEndTime,
            photos: [],
            attendance: [],
            hasStarted: false,
            isCompleted: false
        });

        currentDate.setDate(currentDate.getDate() + 1);
        dayNumber++;
    }

    // Bulk insert all days
    if (days.length > 0) {
        await EventDay.insertMany(days);
    }
};

/**
 * Upload event photo to Cloudinary with proper folder structure
 * Folder: events/{eventId}/day-{dayNumber}/{timestamp}-{random}
 */
export const uploadEventPhoto = async (
    file: any,
    eventId: string,
    dayNumber: number
): Promise<{ url: string; publicId: string }> => {
    return new Promise((resolve, reject) => {
        const timestamp = Date.now();
        const random = Math.random().toString(36).substring(7);
        const folder = `events/${eventId}/day-${dayNumber}`;
        const publicId = `${folder}/${timestamp}-${random}`;

        const uploadStream = cloudinary.uploader.upload_stream(
            {
                folder: folder,
                public_id: `${timestamp}-${random}`,
                resource_type: 'auto'
            },
            (error, result) => {
                if (error || !result) {
                    reject(error || new Error('Upload failed'));
                } else {
                    resolve({
                        url: result.secure_url,
                        publicId: result.public_id
                    });
                }
            }
        );

        uploadStream.end(file.buffer);
    });
};

/**
 * Delete event photo from Cloudinary
 */
export const deleteEventPhoto = async (publicId: string): Promise<void> => {
    await cloudinary.uploader.destroy(publicId);
};

/**
 * Calculate attendance statistics for an event
 */
export const calculateAttendanceStats = async (eventId: string): Promise<{
    totalDays: number;
    completedDays: number;
    averageAttendance: number;
    dailyStats: Array<{
        date: Date;
        dayNumber: number;
        attendanceCount: number;
        isCompleted: boolean;
    }>;
}> => {
    const eventDays = await EventDay.find({ event: eventId }).sort({ dayNumber: 1 });

    const totalDays = eventDays.length;
    const completedDays = eventDays.filter(day => day.isCompleted).length;

    const dailyStats = eventDays.map(day => ({
        date: day.date,
        dayNumber: day.dayNumber,
        attendanceCount: day.attendance.length,
        isCompleted: day.isCompleted
    }));

    const totalAttendance = dailyStats.reduce((sum, day) => sum + day.attendanceCount, 0);
    const averageAttendance = totalDays > 0 ? totalAttendance / totalDays : 0;

    return {
        totalDays,
        completedDays,
        averageAttendance: Math.round(averageAttendance * 100) / 100,
        dailyStats
    };
};

/**
 * Delete all EventDay records for an event (used when event is deleted)
 */
export const deleteEventDays = async (eventId: string): Promise<void> => {
    // Get all event days to delete their photos from Cloudinary
    const eventDays = await EventDay.find({ event: eventId });

    // Delete all photos from Cloudinary
    for (const day of eventDays) {
        for (const photo of day.photos) {
            try {
                await deleteEventPhoto(photo.publicId);
            } catch (err) {
                console.error(`Failed to delete photo ${photo.publicId}:`, err);
            }
        }
    }

    // Delete all EventDay records
    await EventDay.deleteMany({ event: eventId });
};

/**
 * Regenerate EventDay records if event dates are updated
 */
export const regenerateEventDays = async (event: IEvent): Promise<void> => {
    // Delete existing days (but preserve photos and attendance if possible)
    const existingDays = await EventDay.find({ event: event._id }).sort({ date: 1 });

    // Delete all existing days
    await EventDay.deleteMany({ event: event._id });

    // Generate new days
    await generateEventDays(event);

    // Try to restore data to matching dates
    const newDays = await EventDay.find({ event: event._id }).sort({ date: 1 });

    for (const existingDay of existingDays) {
        const matchingNewDay = newDays.find(
            newDay => newDay.date.toISOString().split('T')[0] === existingDay.date.toISOString().split('T')[0]
        );

        if (matchingNewDay) {
            matchingNewDay.photos = existingDay.photos;
            matchingNewDay.attendance = existingDay.attendance;
            matchingNewDay.notes = existingDay.notes;
            matchingNewDay.weatherCondition = existingDay.weatherCondition;
            matchingNewDay.activitiesConducted = existingDay.activitiesConducted;
            matchingNewDay.incidentsReported = existingDay.incidentsReported;
            matchingNewDay.equipmentUsed = existingDay.equipmentUsed;
            matchingNewDay.isCompleted = existingDay.isCompleted;
            matchingNewDay.completedAt = existingDay.completedAt;

            await matchingNewDay.save();
        }
    }
};