import * as fs from 'fs';
import Manifest from './Manifest.js';
import Sequence from './Sequence.js';
import Canvas from './Canvas.js';
import Image from './Image.js';
const Common = {};

/**
 * @param {string} manifestId 
 */
Common.getImageList = async function (manifestId) {
    let folderName = manifestId.replace(/pherc-(\d+)-(\w+)$/, function (_match, g1, g2) {
        return `PHerc_${g1}_${g2.toUpperCase()}`;
    });

	folderName += '_iiif';

    return await fs.promises.readdir(`${process.env.IMAGES_DIR}/${folderName}`);
}
/**
 * @param {string} imageId The image's id as a URL to the image server
 * @returns {{width: number, height: number, thumb: {width: number, height: number}}}
 */
Common.getImageSize = async function (imageId) {
	let infoURL = imageId.replace(/full.*$/,'info.json');
	const res = await fetch(infoURL);

	let size = {};

	if (res.ok) {
		const infoJson = await res.json();
		const maxSize = infoJson.sizes[infoJson.sizes.length - 1];
		size.height = maxSize.height;
		size.width = maxSize.width;
		size.thumb = {
			width: infoJson.sizes[1].width,
			height: infoJson.sizes[1].height,
		}
	}

	return size;
}
/**
 * Get image name for given canvas
 * @param {Canvas} canvas
 */
Common.getImageName = async function (canvas) {
    const images = await this.getImageList(canvas.resourceId);
		
	return images.filter(i => i.includes(canvas.name))[0];
}
/**
 * @param {Manifest} manifest The manifest object
 * @param {string[]} images List of image filenames from folder
 * @returns {Manifest}
 */
Common.populateCanvases = async function (manifest, images) {
	const IIIF_API_VERSION = process.env.IIIF_API_VERSION;
	const BASE_URL = process.env.BASE_URL;
	const sequence = new Sequence(BASE_URL);
	// There's only one sequence
	sequence.generateID(manifest.resourceId, 0);

	for (let img of images) {
		let canvas = new Canvas(IIIF_API_VERSION, BASE_URL);
		const canvasName = img.split('_')[3].replace(/\.[\w\d]{2,3}$/,'');

		canvas.generateID(manifest.resourceId, canvasName);
		canvas.setLabel(`${manifest.resourceId}-${canvasName.toLowerCase()}`);

		let image = new Image(canvas.id);
		image.generateID(process.env.IMAGE_SERVER_URL, img);
		const imgSize = await this.getImageSize(image.id);
		image.setSize(imgSize.height, imgSize.width);

		canvas.setThumbnail(
			imgSize.thumb.height,
			imgSize.thumb.width,
			image.id
		);

		canvas.addImage(image);
		sequence.addCanvas(canvas);
	}

	manifest.addSequence(sequence);

	return manifest;
}

export default Common;