import { __ID__, filePath } from "../consts.mjs";
import { getFile, lastModifiedAt } from "../utils/fs.mjs";
import { paginate } from "../utils/pagination.mjs";

const { HandlebarsApplicationMixin, ApplicationV2 } = foundry.applications.api;
const { FormDataExtended } = foundry.applications.ux;
const { deepClone } = foundry.utils;

const PAGE_SIZE = 8;

export class ArtistBrowser extends HandlebarsApplicationMixin(ApplicationV2) {
	// #region Options
	static DEFAULT_OPTIONS = {
		classes: [
			__ID__,
			`ArtistBrowser`,
			`data-browser`,
		],
		position: {},
		window: {},
		actions: {
			nextPage: this.#nextPage,
			prevPage: this.#prevPage,
		},
	};

	static PARTS = {
		sidebar: {
			template: filePath(`templates/ArtistBrowser/sidebar.hbs`),
		},
		list: {
			template: filePath(`templates/ArtistBrowser/list.hbs`),
			templates: [
				filePath(`templates/ArtistBrowser/artist.hbs`),
			],
		},
	};
	// #endregion Options

	// #region Instance Data
	#page = 1;
	filters = {
		name: ``,
		sortBy: `name-asc`,
	};

	constructor({ selectCount = 0, onSubmit = null, ...opts } = {}) {
		super(opts);
	};

	get page() {
		return this.#page;
	};

	async setPage(page) {
		if (this.#page == page) { return };
		this.#page = page;
		if (this.rendered) {
			await this.render({ parts: [`images`] });
			return;
		};
		return;
	};
	// #endregion Instance Data

	// #region Lifecycle
	#imagesDB = {
		lastModified: null,
		data: undefined,
	};
	async #getImages() {
		const newLastModified = await lastModifiedAt(`storage/db/images.json`);
		if (this.#imagesDB.lastModified && newLastModified === this.#imagesDB.lastModified) {
			return;
		};
		this.#imagesDB.lastModified = newLastModified;
		this.#imagesDB.data = await getFile(`storage/db/images.json`);
	};

	#artistDB = {
		lastModified: null,
		data: undefined,
	};
	async #getArtists() {
		const newLastModified = await lastModifiedAt(`storage/db/artists.json`);
		if (this.#artistDB.lastModified && newLastModified === this.#artistDB.lastModified) {
			return;
		};
		this.#artistDB.lastModified = newLastModified;
		this.#artistDB.data = await getFile(`storage/db/artists.json`);
	};

	async render(...args) {
		await this.#getArtists();
		await this.#getImages();
		return super.render(...args);
	};

	async _onRender(ctx, options) {
		if (options.parts?.includes(`sidebar`)) {
			this.element.querySelector(`form.filters`)?.addEventListener(
				`change`,
				this.#onFilterSubmit.bind(this),
			);
		};

		if (options.parts?.includes(`images`)) {
			this._updateSelectedCount();
		};
	};
	// #endregion Lifecycle

	// #region Data Prep
	_prepareContext() {
		return {
			meta: {
				idp: this.id,
			},
			can: {
				upload: game.user.can(`FILES_UPLOAD`),
			},
		};
	};

	_preparePartContext(partID, ctx) {
		switch (partID) {
			case `sidebar`: {
				this._prepareSidebarContext(ctx);
				break;
			};
			case `list`: {
				this._prepareListContext(ctx);
				break;
			};
		};

		return ctx;
	};

	_prepareSidebarContext(ctx) {
		ctx.name = this.filters.name;
		ctx.sortBy = this.filters.sortBy;
		ctx.sortOptions = [
			{ value: `name-asc`, label: `IT.apps.ArtistBrowser.sort-options.name-asc` },
			{ value: `name-desc`, label: `IT.apps.ArtistBrowser.sort-options.name-desc` },
			{ value: `image-count-asc`, label: `IT.apps.ArtistBrowser.sort-options.image-count-asc` },
			{ value: `image-count-desc`, label: `IT.apps.ArtistBrowser.sort-options.image-count-desc` },
		];
	};

	_prepareListContext(ctx) {
		const allArtists = Object.entries(deepClone(this.#artistDB.data));
		const allImages = Object.values(this.#imagesDB.data);

		const artists = [];
		for (const [id, artist] of allArtists) {
			// Check if it matches the required filters
			if (this.filters.name && !artist.name.includes(this.filters.name)) {
				continue;
			};

			// Populate ephemeral data for rendering
			artist.id = id;

			let imageCount = 0;
			let tags = {};

			for (const image of allImages) {
				if (!image.artists.includes(id)) continue;
				imageCount++;
				for (const tag of image.tags) {
					tags[tag] ??= { name: tag, count: 0 };
					tags[tag].count++;
				};
			};

			artist.imageCount = imageCount;
			artist.commonTags = Object.values(tags)
				.sort((a, b) => b.count - a.count)
				.slice(0, 5);

			artists.push(artist);
		};

		// Paginate after filtering and sorting to give page continuity
		artists.sort(compareArtists.bind(undefined, this.filters.sortBy));
		const paginated = paginate(artists, this.#page, PAGE_SIZE);
		ctx.artists = paginated.page;
		ctx.page = this.#page;
		ctx.pages = paginated.total;
		ctx.has = {
			prev: paginated.prev,
			next: paginated.next
		};
	};
	// #endregion Data Prep

	// #region Actions
	async #onFilterSubmit(event) {
		event.preventDefault();
		event.stopPropagation();
		const data = (new FormDataExtended(event.currentTarget)).object;
		this.filters = data;
		this.render({ parts: [`list`] });
	};

	/** @this {ArtistBrowser} */
	static async #nextPage() {
		this.setPage(this.#page + 1);
	};

	/** @this {ArtistBrowser} */
	static async #prevPage() {
		this.setPage(this.#page - 1);
	};
	// #endregion Actions
};

function compareArtists(mode, a, b) {
	switch (mode) {
		case `name-asc`: {
			return a.name.localeCompare(b.name);
		};
		case `name-desc`: {
			return b.name.localeCompare(a.name);
		};
		case `image-count-asc`: {
			return a.imageCount - b.imageCount;
		};
		case `image-count-desc`: {
			return b.imageCount - a.imageCount;
		};
	};
	return 0;
};