/* global Viewer */

var ListNavigator = {
	length: 0,
	position: 0,
	data: [],
	history: [],
	shuffle: false,

	nextItem: function(){
		if(!Viewer.isList){
			return;
		}
		if(this.shuffle){
			this.randItem();
			return;
		}

		if(this.position >= this.length){
			this.position = 0;
		}else{
			this.position++;
		}

		this.setItem(this.position);
	},

	previousItem: function(){
		if(!Viewer.isList){
			return;
		}

		if(this.position === 0){
			this.position = this.length - 1;
		}else{
			this.position--;
		}

		this.setItem(this.position);
	},

	randItem: function(){
		if(!Viewer.isList){
			return;
		}

		// Avoid viewing the same file multiple times
		var rand;
		do {
			rand = Math.round(Math.random() * this.length);
			console.log("rand is " + rand);
		} while(this.inHistory(rand));

		this.setItem(rand);
	},

	setItem: function(index){
		if(index >= this.length){
			this.position = 0;
		}else{
			this.position = index;
		}

		// Set the URL hash
		location.hash = "item=" + this.position;
		Viewer.setFile(this.data[this.position]);

		this.addToHistory(index);

		$("#list_navigator").find("*").removeClass("file_button_selected");
		var selectedItem = $("#list_navigator div").eq(this.position);
		selectedItem.addClass("file_button_selected");
		var itemWidth = selectedItem.outerWidth(true);

		// This centers the scroll bar exactly on the selected item
		$("#list_navigator").animate(
			{scrollLeft: ((this.position * itemWidth) + (itemWidth / 2)) - ($("#list_navigator").width() / 2)},
			{duration: 1000, queue: false}
		);

		this.loadThumbnails(index);
	},

	addToHistory: function(index){
		if(this.history.length >= (this.length - 6)){
			this.history.shift();
		}

		this.history.push(index);
	},

	inHistory: function(index){
		var i = $.inArray(index, this.history); // Returns -1 when the item is not found

		return (i !== -1); // Return false when it's not in the array
	},

	toggleShuffle: function(){
		this.shuffle = !this.shuffle; // :P

		if(this.shuffle){
			$("#btnShuffle > span").html(" Shuffle ☑"); // Check icon
			$("#btnShuffle").addClass("button_highlight");
		}else{
			$("#btnShuffle > span").html(" Shuffle ☐"); // Empty checkbox
			$("#btnShuffle").removeClass("button_highlight");
		}
	},

	loadThumbnails: function(index){
		var startPos = +index - 50;
		var endPos = +index + 50;
		// fyi, the + is to let javascript know it's actually a number instead of a string

		if(startPos < 0){
			startPos = 0;
		}

		if(endPos >= this.length){
			endPos = this.length - 1;
		}
		console.log(endPos);

		var navigatorItems = document.getElementById("list_navigator").children

		for (i = startPos; i <= endPos; i++){
			if (navigatorItems[i].innerHTML.includes("list_item_thumbnail")) {
				continue; // Thumbnail already loaded
			}

			var thumb = "/api/file/" + this.data[i].id + "/thumbnail?width=48&height=48";
			var name = this.data[i].name;

			var itemHtml = "<img src=\"" + thumb + "\" "
				+ "class=\"list_item_thumbnail\" alt=\"" + escapeHTML(name) + "\"/>"
				+ escapeHTML(name);

			navigatorItems[i].innerHTML = itemHtml;
		}
	},

	init: function(data){
		this.data = data;
		this.length = data.length;

		var listHTML = "";
		data.forEach(function(item, i){
			var filename;
			if(item.name !== "null"){
				filename = item.name;
			}else{
				filename = "Removed File";
			}

			listHTML += "<div class=\"file_button list_item\" "
				+ "onClick=\"ListNavigator.setItem('" + i + "')\">"
				+ escapeHTML(filename) + "<br>"
				+ "</div>";
		});
		document.getElementById("list_navigator").innerHTML = listHTML;

		var btnLastItem = document.createElement("button");
		btnLastItem.innerText = "◀";
		btnLastItem.setAttribute("id", "button_last_item");
		btnLastItem.setAttribute("class", "button_highlight");
		btnLastItem.setAttribute("onClick", "ListNavigator.previousItem();");

		var btnNextItem = document.createElement("button");
		btnNextItem.innerText = "▶";
		btnNextItem.setAttribute("id", "button_next_item");
		btnNextItem.setAttribute("class", "button_highlight");
		btnNextItem.setAttribute("onClick", "ListNavigator.nextItem();");

		var headerbar = document.getElementById("list_navigator_buttons");
		headerbar.appendChild(btnLastItem);
		headerbar.appendChild(btnNextItem);

		// Add the list download button to the toolbar
		var btnDownloadList = document.createElement("button");
		btnDownloadList.setAttribute("id", "btnDownloadList");
		btnDownloadList.setAttribute("class", "toolbar_button button_full_width");
		btnDownloadList.setAttribute("onClick", "Toolbar.downloadList();");

		var btnDownloadListImg = document.createElement("img");
		btnDownloadListImg.setAttribute("src", "{{template `floppy_small.png`}}");
		btnDownloadListImg.setAttribute("alt", "Download List");

		var btnDownloadListText = document.createElement("span");
		btnDownloadListText.innerHTML = "&nbsp;All Files";

		btnDownloadList.appendChild(btnDownloadListImg);
		btnDownloadList.appendChild(btnDownloadListText);
		document.getElementById("btnDownload").after(btnDownloadList);

		// Add the shuffle button to the toolbar
		var btnShuffle = document.createElement("button");
		btnShuffle.setAttribute("id", "btnShuffle");
		btnShuffle.setAttribute("class", "toolbar_button button_full_width");
		btnShuffle.setAttribute("onClick", "ListNavigator.toggleShuffle();");

		var btnShuffleImg = document.createElement("img");
		btnShuffleImg.setAttribute("src", "{{template `shuffle_small.png`}}");
		btnShuffleImg.setAttribute("alt", "Shuffle playback order");

		var btnShuffleText = document.createElement("span");
		btnShuffleText.innerHTML = "&nbsp;Shuffle&nbsp;&#x2610;";

		btnShuffle.appendChild(btnShuffleImg);
		btnShuffle.appendChild(btnShuffleText);
		document.getElementById("btnShare").after(btnShuffle);

		// Make the navigator visible
		document.getElementById("list_navigator").style.display = "inline-block";

		// Skip to the file defined in the link hash
		if(Number.isInteger(parseInt(getHashValue("item")))){
			this.setItem(parseInt(getHashValue("item")));
		}else{
			this.setItem(0);
		}
	}
};


// Misc function, don't really know where else to put it
function getHashValue(key) {
	var matches = location.hash.match(new RegExp(key + '=([^&]*)'));
	return matches ? matches[1] : null;
}