class Viewer {
	// Child components
	toolbar       = null;
	listNavigator = null;
	detailsWindow = null;

	divFilepreview = null;

	currentFile = "";
	title       = ""; // Contains either the file name or list title
	listId      = "";
	isList      = false;
	isFile      = false;
	initialized = false;

	constructor(type, data) {let v = this;
		if(v.initialized){
			return;
		}

		v.toolbar       = new Toolbar(v);
		v.detailsWindow = new DetailsWindow(v);

		v.divFilepreview = document.getElementById("filepreview");

		// On small screens the toolbar takes too much space, so it collapses
		// automatically
		if(v.divFilepreview.clientWidth > 600 && !v.toolbar.visible){
			v.toolbar.toggle();
		}

		// The close button only works if the window has an opener. So we hide
		// the button if it does not
		if (window.opener === null && window.history.length !== 1) {
			document.getElementById("button_close_file_viewer").remove()
		}


		if(type === "file"){
			v.isFile = true;
			v.currentFile = data.id;
			v.title = data.name;
			v.setFile(data);
		} else if (type === "list") {
			v.isList = true;
			v.listId = data.id;
			v.title = data.title;
			v.listNavigator = new ListNavigator(v, data.data);
		}

		v.renderSponsors();
		window.addEventListener("resize", e => { v.renderSponsors(e); });

		// Register keyboard shortcuts
		document.addEventListener("keydown", e => { v.keyboardEvent(e); });

		v.initialized = true;
	}

	setFile(file) {let v = this;
		v.currentFile = file.id;
		if (v.isList) {
			document.getElementById("file_viewer_headerbar_title").style.lineHeight = "1em";
			document.getElementById("file_viewer_list_title").innerText = this.title;
			document.getElementById("file_viewer_file_title").innerText = file.name;
			document.title = v.title + " ~ " + file.name + " ~ pixeldrain";
		} else {
			document.getElementById("file_viewer_file_title").innerText = file.name;
			document.title = file.name + " ~ pixeldrain";
		}

		// Update the file details
		v.detailsWindow.setDetails(file);

		// Clear the canvas
		v.divFilepreview.innerHTML = "";

		if (file.mime_type.startsWith("image")) {
			new ImageViewer(v, file).render(v.divFilepreview);
		} else if (file.mime_type.startsWith("video")) {
			new VideoViewer(v, file, () => {
				if (v.listNavigator !== null) {
					v.listNavigator.nextItem();
				}
			}).render(v.divFilepreview);
		} else if (file.mime_type.startsWith("audio") || file.mime_type === "application/ogg") {
			new AudioViewer(v, file, () => {
				if (v.listNavigator !== null) {
					v.listNavigator.nextItem();
				}
			}).render(v.divFilepreview);
		} else {
			fetch("/u/"+file.id+"/preview").then(resp => {
				if (!resp.ok) { return Promise.reject(resp.status); }
				return resp.text();
			}).then(resp => {
				v.divFilepreview.innerHTML = resp;
			}).catch(err => {
				v.divFilepreview.innerText = "Error loading file: "+err;
			});
		}
	}

	renderSponsors() {
		let scale = 1;
		let scaleWidth = 1;
		let scaleHeight = 1;
		let minWidth = 728;
		let minHeight = 800;

		if (window.innerWidth < minWidth) {
			scaleWidth = window.innerWidth/minWidth;
		}
		if (window.innerHeight < minHeight) {
			scaleHeight = window.innerHeight/minHeight;
		}
		scale = scaleWidth < scaleHeight ? scaleWidth : scaleHeight;

		// Because of the scale transformation the automatic margins don't work
		// anymore. So we have to maunally calculate the margin. Where we take the
		// width of the viewport - the width of the ad to calculate the amount of
		// pixels around the ad. We multiply the ad size by the scale we calcualted
		// to account for the smaller size.
		let offset = (window.innerWidth - (minWidth*scale)) / 2
		if (offset < 0) {
			offset = 0
		}
		document.querySelector(".sponsors > iframe").style.marginLeft = offset+"px";

		if (scale == 1) {
			document.querySelector(".sponsors > iframe").style.transform = "none";
			document.querySelector(".sponsors").style.height = "90px";
		} else {
			document.querySelector(".sponsors > iframe").style.transform = "scale("+scale+")";
			document.querySelector(".sponsors").style.height = (scale*90)+"px";
		}
	}

	keyboardEvent(evt) {let v = this;
		if (evt.ctrlKey || evt.altKey) {
			return // prevent custom shortcuts from interfering with system shortcuts
		}

		switch (evt.which) {
		case 65: // A or left arrow key go to previous file
		case 37:
			if (v.listNavigator != null) {
				v.listNavigator.previousItem();
			}
			break;
		case 68: // D or right arrow key go to next file
		case 39:
			if (v.listNavigator != null) {
				v.listNavigator.nextItem();
			}
			break;
		case 83:
			if (evt.shiftKey) {
				v.toolbar.downloadList(); // SHIFT + S downloads all files in list
			} else {
				v.toolbar.download(); // S to download the current file
			}
			break;
		case 82: // R to toggle list shuffle
			if (v.listNavigator != null) {
				v.listNavigator.toggleShuffle();
			}
			break;
		case 67: // C to copy to clipboard
			v.toolbar.copyUrl();
			break;
		case 73: // I to open the details window
			v.detailsWindow.toggle();
			break;
		case 81: // Q to close the window
			window.close();
			break;
		}
	}
};

// Against XSS attacks
function escapeHTML(str) {
    return String(str)
		.replace(/&/g, '&amp;')
		.replace(/</g, '&lt;')
		.replace(/>/g, '&gt;')
		.replace(/"/g, '&quot;');
}