import { database } from '$lib/Database/activities';
import type { AniListAuthorisation, UserIdentity } from './identity';

export interface ActivityHistoryEntry {
	date: number;
	amount: number;
}

export const fillMissingDays = (
	inputActivities: ActivityHistoryEntry[],
	startOfYear = false
): ActivityHistoryEntry[] => {
	if (inputActivities.length === 0)
		return startOfYear
			? fillDateRange(
					new Date(new Date().getUTCFullYear(), 0, 1),
					new Date(new Date().getUTCFullYear() + 1, 0, 1)
			  )
			: [];

	const sortedActivities = [...inputActivities].sort((a, b) => a.date - b.date);
	const endDate = new Date(sortedActivities[sortedActivities.length - 1].date * 1000);

	endDate.setUTCDate(endDate.getUTCDate() + 1);

	return fillDateRange(
		startOfYear
			? new Date(new Date().getUTCFullYear(), 0, 1)
			: new Date(sortedActivities[0].date * 1000),
		endDate,
		sortedActivities
	);
};

const fillDateRange = (
	startDate: Date,
	endDate: Date,
	existingActivities: ActivityHistoryEntry[] = []
): ActivityHistoryEntry[] => {
	const outputActivities: ActivityHistoryEntry[] = [];

	for (let dt = new Date(startDate); dt < endDate; dt.setUTCDate(dt.getUTCDate() + 1)) {
		const dateString = dt.toDateString();

		if (
			!new Set(
				existingActivities.map((activity) => new Date(activity.date * 1000).toDateString())
			).has(dateString)
		) {
			outputActivities.push({ date: Math.floor(dt.getTime() / 1000), amount: 0 });
		} else {
			const activity = existingActivities.find(
				(activity) => new Date(activity.date * 1000).toDateString() === dateString
			);

			if (activity) outputActivities.push(activity);
		}
	}

	return outputActivities;
};

export const activityHistory = async (
	userIdentity: UserIdentity
): Promise<ActivityHistoryEntry[]> => {
	return (
		await (
			await fetch('https://graphql.anilist.co', {
				method: 'POST',
				headers: {
					'Content-Type': 'application/json',
					Accept: 'application/json'
				},
				body: JSON.stringify({
					query: `{ User(id: ${userIdentity.id}) {
					stats { activityHistory { date amount } }
        } }`
				})
			})
		).json()
	)['data']['User']['stats']['activityHistory'];
};

export const lastActivityDate = async (userIdentity: UserIdentity): Promise<Date> => {
	const history = await activityHistory(userIdentity);
	const date = new Date(
		Number(history[history.length - 1]['date']) * 1000 + new Date().getTimezoneOffset()
	);

	date.setDate(date.getDate() + 1);

	return date;
};

export interface ActivitiesPage {
	data: {
		Page: {
			pageInfo: {
				hasNextPage: boolean;
			};
			activities: {
				createdAt: number;
			}[];
		};
	};
}

const activitiesPage = async (
	page: number,
	anilistAuthorisation: AniListAuthorisation,
	userIdentity: UserIdentity
): Promise<ActivitiesPage> =>
	await (
		await fetch('https://graphql.anilist.co', {
			method: 'POST',
			headers: {
				Authorization: `${anilistAuthorisation.tokenType} ${anilistAuthorisation.accessToken}`,
				'Content-Type': 'application/json',
				Accept: 'application/json'
			},
			body: JSON.stringify({
				query: `{
					Page(page: ${page}) {
    				pageInfo { hasNextPage }
						activities(userId: ${userIdentity.id}, createdAt_greater: ${Math.floor(
					new Date(new Date().getFullYear(), 0, 1).getTime() / 1000
				)}, createdAt_lesser: ${Math.floor(
					new Date(new Date().getFullYear(), 6, 1).getTime() / 1000
				)}) {
							... on TextActivity    { createdAt }
							... on ListActivity    { createdAt }
							... on MessageActivity { createdAt }
						}
					}
				}`
			})
		})
	).json();

export const fullActivityHistory = async (
	anilistAuthorisation: AniListAuthorisation,
	userIdentity: UserIdentity
): Promise<ActivityHistoryEntry[]> => {
	const activities = [];
	let page = 1;
	let currentDatabasePage = await database.activities.get(page);
	let currentPage;

	if (currentDatabasePage) currentPage = currentDatabasePage.data;
	else {
		currentPage = await activitiesPage(page, anilistAuthorisation, userIdentity);
		database.activities.add({
			page,
			data: currentPage
		});
	}

	for (const activity of currentPage.data.Page.activities) activities.push(activity);

	while (currentPage['data']['Page']['pageInfo']['hasNextPage']) {
		for (const activity of currentPage.data.Page.activities) activities.push(activity);

		page += 1;
		currentDatabasePage = await database.activities.get(page);

		if (currentDatabasePage) currentPage = currentDatabasePage.data;
		else {
			currentPage = await activitiesPage(page, anilistAuthorisation, userIdentity);
			database.activities.add({
				page,
				data: currentPage
			});
		}
	}

	let fullLocalActivityHistory: ActivityHistoryEntry[] = [];

	for (const activity of activities) {
		const date = new Date(activity.createdAt * 1000);
		const dateString = date.toDateString();

		const activityHistoryEntry = fullLocalActivityHistory.find(
			(activityHistoryEntry) =>
				new Date(activityHistoryEntry.date * 1000).toDateString() === dateString
		);

		if (activityHistoryEntry) activityHistoryEntry.amount += 1;
		else fullLocalActivityHistory.push({ date: Math.floor(date.getTime() / 1000), amount: 1 });
	}

	fullLocalActivityHistory = fullLocalActivityHistory.filter((a) => !isNaN(a.date));

	fullLocalActivityHistory.push(...(await activityHistory(userIdentity)));

	fullLocalActivityHistory = fullLocalActivityHistory.filter(
		(activityHistoryEntry, index, self) =>
			self.findIndex(
				(a) =>
					new Date(a.date * 1000).toDateString() ===
					new Date(activityHistoryEntry.date * 1000).toDateString()
			) === index
	);

	fullLocalActivityHistory = fullLocalActivityHistory.filter(
		(activityHistoryEntry) =>
			new Date(activityHistoryEntry.date * 1000).getFullYear() === new Date().getFullYear()
	);

	return fullLocalActivityHistory;
};