import { config } from "../config.mjs";
import { __ID__, devMode, filePath } from "../consts.mjs";

const { fetchJsonWithTimeout } = foundry.utils;

/**
 * Returns a pseudo-hash for a file. If the browser is in a secure
 * context this will return a true SHA-1 hash of the file, otherwise
 * a random ID is generated using the character set A-Za-z0-9.
 *
 * @param {File} file The file to hash
 */
export async function hashFile(file) {
	// Handle fallback when hashing isn't possible
	if (!window.isSecureContext || !crypto.subtle.digest) {
		return foundry.utils.randomID(40);
	};

	// Actually hash the file since we can
	const bytes = await file.arrayBuffer();
	const buffer = await crypto.subtle.digest(`SHA-1`, bytes);

	const intArray = new Uint8Array(buffer);
	if (Uint8Array.prototype.toHex) {
		return intArray.toHex();
	};
	return Array.from(intArray)
		.map(b => b.toString(16).padStart(2, `0`))
		.join(``);
};

/**
 * Converts an image file into a webp file unless it is already a webp file or
 * cannot be converted to a webp, in which case it doesn't modify the file at all.
 *
 * @param {File} file The file to convert
 * @returns {Promise<File>}
 */
export async function convertToWebp(file) {
	if (file.type === `image/webp`) { return null };
	if (config.WEBP_IGNORE.includes(file.type)) { return null };

	/** @type {HTMLImageElement} */
	const image = document.createElement(`img`);
	const url = URL.createObjectURL(file);
	image.src = url;
	await image.decode();

	/** @type {HTMLCanvasElement} */
	const canvas = document.createElement(`canvas`);
	canvas.width = image.naturalWidth;
	canvas.height = image.naturalHeight;
	canvas.getContext(`2d`).drawImage(image, 0, 0);

	return new Promise((resolve) => {
		canvas.toBlob(
			(blob) => {
				const name = file.name.split(`.`).slice(0, -1).join(`.`);
				const webp = new File([blob], `${name}.webp`, { type: blob.type });
				resolve(webp);
			},
			`image/webp`,
			config.WEBP_QUALITY,
		);
	});
};

export async function lastModifiedAt(path) {
	try {
		const response = await fetch(filePath(path), { method: `HEAD` });
		return response.headers.get(`Last-Modified`);
	} catch {
		return null;
	};
};

export async function getFileSize(path) {
	try {
		const response = await fetch(filePath(path), { method: `HEAD` });
		const bytes = response.headers.get(`Content-Length`);
		if (!bytes) { return null }

		// round the non-bytes to 2 decimal places
		const kilobytes = Math.floor(bytes / 10) / 100;
		const megabytes = Math.floor(bytes / 10_000) / 100;

		// determine the most appropriate unit to use
		let friendly = `${bytes} bytes`;
		if (megabytes > 0.25) {
			friendly = `${megabytes}MB`;
		} else if (kilobytes > 0) {
			friendly = `${kilobytes}KB`;
		};

		return { bytes, kilobytes, megabytes, friendly };
	} catch {
		return null;
	};
};

export async function getFile(path) {
	try {
		return fetchJsonWithTimeout(filePath(path));
	} catch {
		return undefined;
	};
};

/**
 * @param {string} path
 * @param {any} data
 */
export async function uploadJson(path, filename, data) {
	const content = JSON.stringify(
		data,
		undefined,
		devMode() ? `\t` : undefined,
	);
	try {
		const file = new File(
			[content],
			filename,
			{ type: `text/plain` },
		);
		await uploadFile(path, file);
	} catch {};
};

export async function uploadFile(path, file) {

	// uploadPersistent adds "storage" into the path automatically
	if (path.startsWith(`storage/`)) {
		path = path.slice(8);
	};
	if (path.endsWith(`/`)) {
		path = path.slice(0, -1);
	};

	const picker = foundry.applications.apps.FilePicker.implementation;
	try {
		await picker.uploadPersistent(
			__ID__,
			path,
			file,
		);
	} catch {};
};

export function determineFileExtension(file) {
	for (const [short, long] of Object.entries(CONST.IMAGE_FILE_EXTENSIONS)) {
		if (long === file.type) {
			return short;
		};
	};
	return null;
};