import { DAVClient } from 'tsdav';

// iCloud CalDAV Server URL
const ICLOUD_CALDAV_URL = 'https://caldav.icloud.com';

export interface AppleReminderList {
    id: string; // URL
    title: string;
    color?: string;
}

/**
 * Create a configured DAV client for Apple iCloud
 */
const createClient = (email: string, appSpecificPassword: string) => {
    return new DAVClient({
        serverUrl: ICLOUD_CALDAV_URL,
        credentials: {
            username: email,
            password: appSpecificPassword,
        },
        authMethod: 'Basic',
        defaultAccountType: 'caldav',
    });
};

/**
 * Fetch all reminder lists (VTODO collections)
 */
export const fetchAppleReminderLists = async (email: string, appSpecificPassword: string): Promise<AppleReminderList[]> => {
    try {
        const client = createClient(email, appSpecificPassword);
        await client.login();

        const calendars = await client.fetchCalendars();

        // Filter to VTODO collections (Reminders)
        const reminderLists = calendars.filter(cal => {
            const components: string[] = (cal as any).components || [];
            return components.includes('VTODO');
        });

        return reminderLists.map(cal => ({
            id: cal.url,
            title: (cal.displayName as string) || 'Untitled List',
            color: (cal as any).calendarColor,
        }));
    } catch (error) {
        console.error('Error fetching Apple reminder lists:', error);
        throw error;
    }
};

/**
 * Create a new reminder list (collection)
 */
export const createAppleReminderList = async (email: string, appSpecificPassword: string, title: string): Promise<AppleReminderList> => {
    try {
        const client = createClient(email, appSpecificPassword);
        await client.login();

        // tsdav's createDAVClient returns an object where we can use makeCalendar
        // First we need a base URL. We can derive it from existing calendars.
        const calendars = await client.fetchCalendars();
        if (calendars.length === 0) {
            throw new Error('No existing Apple calendars found to derive base URL');
        }

        // Deriving the base URL for new collections (usually parent of existing calendars)
        const firstCalUrl = calendars[0].url;
        const urlParts = firstCalUrl.split('/');
        // Remove the last part (and trailing slash if exists)
        if (firstCalUrl.endsWith('/')) urlParts.pop();
        urlParts.pop();
        const baseWebDavUrl = urlParts.join('/') + '/';

        const newId = crypto.randomUUID();
        const newCalendarUrl = `${baseWebDavUrl}${newId}/`;

        // Create the calendar (reminder list)
        await (client as any).makeCalendar({
            url: newCalendarUrl,
            props: {
                'displayname': title,
                'supported-calendar-component-set': {
                    'comp': { _attributes: { name: 'VTODO' } }
                }
            }
        });

        return {
            id: newCalendarUrl,
            title: title,
        };
    } catch (error) {
        console.error('Error creating Apple reminder list:', error);
        throw error;
    }
};