'use strict';

/* globals ePub, localforage, book, cacheId */

let _pagination_stored = 0;
let _last_position_sync = 0;
let _store_position = 0;

//const _is_ios = (/iPad|iPhone|iPod/).test(navigator.userAgent) && !window.MSStream;
const _res_data = [];

const DEFAULT_FONT_SIZE = 16;
const DEFAULT_FONT_FAMILY = "Georgia";
const DEFAULT_LINE_HEIGHT = 140;

function cacheId(suffix) {
	return "epube-book." + $.urlParam("b") + (suffix ? "." + suffix : "");
}

function init_loader() {
	// we need to preload resources for reader iframe because it can't utilize our
	// service worker because while offline it is created outside our base server context
	const res_names = [ "lib/bootstrap/v3/js/jquery.js", "lib/jquery.mobile-events.min.js",
		"css/transitions.css",
		"js/reader.js", "css/reader.css", "js/dict.js",
		"themes/default.css", "themes/mocca.css", "themes/night.css",
		"themes/plan9.css", "themes/gray.css" ];

	for (let i = 0; i < res_names.length; i++) {
		fetch(res_names[i], {credentials: 'same-origin'}).then(function(resp) {
			if (resp.status == 200) {
				resp.text().then(function(data) {
					const url = new URL(resp.url);
					url.searchParams.delete("ts");

					_res_data[url.toString()] = data;
				})
			} else {
				console.warn('loader failed for resource', res_names[i], resp);
			}
		});
	}

	check_resource_load(res_names, _res_data, 0);
}

function check_resource_load(res_names, res_data, attempt) {
	console.log("check_resource_load", attempt, res_names.length, Object.keys(res_data).length);

	if (attempt == 5) {
		$(".loading_message").html("Unable to load resources.");
		return;
	}

	if (res_names.length != Object.keys(res_data).length) {
		window.setTimeout(function() {
			check_resource_load(res_names, res_data, attempt+1);
		}, 250);
	} else {
		init_reader();
	}
}

function init_reader() {
	apply_theme();

	$(window).on('online', function() {
		console.log("we're online, storing lastread");

		const currentCfi = book.rendition.currentLocation().start.cfi;
		const currentPage = parseInt(book.locations.percentageFromCfi(currentCfi) * 100);

		$.post("backend.php", { op: "storelastread", id: $.urlParam("id"), page: currentPage,
			cfi: currentCfi }, function(data) {

				if (data.cfi) {
					_last_position_sync = new Date().getTime()/1000;
				}
			})
			.fail(function(e) {
				if (e && e.status == 401) {
					window.location = "index.php";
				}
			});
	});

	localforage.getItem(cacheId("book")).then(function(item) {

		// ios doesn't work with FileReader for whatever reason
		if (/*!_is_ios &&*/ item) {

			console.log("loading from local storage");

			const fileReader = new FileReader();

			fileReader.onload = function() {
				try {
					book.open(this.result);
				} catch (e) {
					$(".loading_message").html("Unable to load book (local).");
					console.log(e);
				}
			};

			fileReader.readAsArrayBuffer(item);

		} else {

			console.log("loading from network");

			if (navigator.onLine) {
				const book_url = "backend.php?op=download&id=" + $.urlParam("id");

				$(".loading_message").html("Downloading...");

				fetch(book_url, {credentials: 'same-origin'}).then(function(resp) {

					if (resp.status == 200) {
						const bookId = $.urlParam("b");

						resp.blob().then(function(blob) {

							// if there's no base information cached yet, let's do that too
							localforage.getItem(cacheId()).then(function(info) {
								if (!info) {
									$.post("backend.php", {op: "getinfo", id: bookId }, function(data) {
										if (data) {
											localforage.setItem(cacheId(), data);

											if (data.has_cover) {
												fetch("backend.php?op=cover&id=" + bookId, {credentials: 'same-origin'}).then(function(resp) {
													if (resp.status == 200) {
														localforage.setItem(cacheId('cover'), resp.blob());
													}
												});
											}
										}
									});
								}
							});

							const fileReader = new FileReader();

							fileReader.onload = function() {
								book.open(this.result).then(() => {

									// let's store this for later
									localforage.setItem(cacheId('book'), blob);

								}).catch((e) => {
									$(".loading_message").html("Unable to open book.<br/><small>" + e + "</small>");
								});
							};

							fileReader.onerror = function(e) {
								console.log('filereader error', e);
								$(".loading_message").html("Unable to open book.<br/><small>" + e + "</small>");
							}

							fileReader.readAsArrayBuffer(blob);

						}).catch((e) => {
							console.log('blob error', e);
							$(".loading_message").html("Unable to download book.<br/><small>" + e + "</small>");
						});
					} else {
						$(".loading_message").html("Unable to download book: " + resp.status + ".");
					}
				}).catch(function(e) {
					console.warn(e);

					if ($(".loading").is(":visible")) {
						$(".loading_message").html("Unable to load book (remote).<br/><small>" + e + "</small>");
					}
				});

			} else {
				$(".loading_message").html("This book is not available offline.");
			}
		}
	});

	const book = ePub();
	window.book = book;

	const rendition = book.renderTo("reader", {
		width: '100%',
		height: '100%',
		minSpreadWidth: 961
	});

	const displayed = rendition.display();

	// this sets default theme, then we apply CSS to already rendered content
	// with apply_styles()
	displayed.then(function () {

		let fontSize;
		let fontFamily;
		let lineHeight;
		//let themeName;

		Promise.all([
			localforage.getItem("epube.fontSize"),
			localforage.getItem("epube.fontFamily"),
			localforage.getItem("epube.lineHeight"),
			localforage.getItem("epube.theme")
		]).then(function(res) {
			fontSize = res[0] ? res[0] + "px" : DEFAULT_FONT_SIZE + "px";
			fontFamily = res[1] ? res[1] : DEFAULT_FONT_FAMILY;
			lineHeight = res[2] ? res[2] + "%" : DEFAULT_LINE_HEIGHT + "%";
			//themeName = res[3] ? res[3] : 'default';

			rendition.themes.default({
				html: {
					'font-size': fontSize,
					'font-family': "'" + fontFamily + "'",
					'line-height': lineHeight,
					'text-align': 'justify'
				}
			});

		});
	});

	rendition.hooks.content.register(function(contents) {

		contents.on("linkClicked", function(href) {
			console.log('linkClicked', href);

			if (href.indexOf("://") == -1) {
				$(".prev_location_btn")
					.attr("data-location-cfi", book.rendition.currentLocation().start.cfi)
					.show();

				window.setTimeout(function() {
					show_ui(true);
				}, 50);
			}

		});

		const base_url = window.location.href.match(/^.*\//)[0];
		const res_names = [ "lib/bootstrap/v3/js/jquery.js", "lib/jquery.mobile-events.min.js",
			"js/reader.js", "js/dict.js" ];
		const doc = contents.document;

		for (let i = 0; i < res_names.length; i++) {

			// we need to create script element with proper context, that is inside the iframe
			const elem = doc.createElement("script");
			elem.type = 'text/javascript';
			elem.text = _res_data[base_url + res_names[i]];

			doc.head.appendChild(elem);
		}

		$(contents.document.head)
			.append($("<style type='text/css'>")
			.text(_res_data[base_url + 'css/reader.css']));

		return localforage.getItem("epube.theme").then(function(theme) {
			if (!theme) theme = 'default';

			const theme_url = base_url + 'themes/' + theme + '.css';

			$(contents.document.head)
				.append($("<style type='text/css' id='theme_css'>")
				.text(_res_data[theme_url]));
		});

	});

	$('#settings-modal').on('shown.bs.modal', function() {

		localforage.getItem(cacheId("lastread")).then((item) => {
			if (item && item.cfi) {
				$(".lastread_input").val(item.page + '%');
			}

			$.post("backend.php", { op: "getlastread", id: $.urlParam("id") }, function(data) {
				$(".lastread_input").val(data.page + '%');
			});

		});

		localforage.getItem("epube.keep-ui-visible").then(function(keep) {
			$(".keep_ui_checkbox")
				.attr("checked", keep)
				.off("click")
				.on("click", function(evt) {
					localforage.setItem("epube.keep-ui-visible", evt.target.checked);
				});
		});

		localforage.getItem("epube.fontFamily").then(function(font) {
			if (!font) font = DEFAULT_FONT_FAMILY;

			$(".font_family").val(font);
		});

		localforage.getItem("epube.theme").then(function(theme) {
			$(".theme_name").val(theme);
		});

		localforage.getItem("epube.fontSize").then(function(size) {

			if (!size) size = DEFAULT_FONT_SIZE;

			const zoom = $(".font_size").html("");

			for (let i = 10; i <= 32; i++) {
				const opt = $("<option>").val(i).html(i + " px");
				zoom.append(opt);
			}

			zoom.val(size);

		});

		localforage.getItem("epube.lineHeight").then(function(height) {

			if (!height) height = DEFAULT_LINE_HEIGHT;

			const zoom = $(".line_height").html("");

			for (let i = 100; i <= 220; i += 10) {
				const opt = $("<option>").val(i).html(i + "%");
				zoom.append(opt);
			}

			zoom.val(height);

		});
	});

	$('#dict-modal').on('shown.bs.modal', function() {
		$(".dict_result").scrollTop(0);
	})

	// TODO: make configurable
	$(".dict_search_btn").on("click", function() {
		$("#dict-modal").modal('hide');
		window.open("https://duckduckgo.com/?q=" + $(".dict_query").val());
	});

	$(".wiki_search_btn").on("click", function() {
		$(".dict_result").html("Loading, please wait...");

		$.post("backend.php", {op: "wikisearch", query: $(".dict_query").val()})
			.then((resp) => {
				try {
					let tmp = "";

					$.each(resp.query.pages, (i,p) => {
						tmp += p.extract;
					});

					$(".dict_result").html(tmp && tmp != "undefined" ? tmp : "No definition found for " + $(".dict_query").val() + ".");
				} catch (e) {
					console.error(e);
					$(".dict_result").text("Error while processing data: " + e);
				}
			})
			.fail((e) => {
				console.error(e);
				$(".dict_result").text("Error while retrieving data.");
			})
	});

	function toc_loc_msg(href) {
		try {
			const cfiBase = book.spine.get(href).cfiBase;

			const loc = book.locations._locations.find(function(k) {
				return k.indexOf(cfiBase) != -1
				});

			return window.book.locations.locationFromCfi(loc);

		} catch (e) {
			console.warn(e);
		}

		return "";
	}

	function process_toc_sublist(row, list, nest) {

		if (nest == 3) return false;

		if (row.subitems) {

			const sublist = $("<ul class='toc_sublist list-unstyled'>");

			$.each(row.subitems, function(i, row) {

				const a = $("<a>")
					.attr('href', '#')
					.html("<b class='pull-right'>" + toc_loc_msg(row.href) + "</b>" + row.label)
					.attr('data-href', row.href)
					.click(function() {
						book.rendition.display(a.attr('data-href'));
					});

				sublist.append($("<li>").append(a));

				process_toc_sublist(row, sublist, nest + 1);

			});

			list.append(sublist);
		}
	}

	$('#toc-modal').on('shown.bs.modal', function() {

		const toc = book.navigation.toc;

		const list = $(".toc_list");
		list.html("");

		$.each(toc, function(i, row) {

			// if anything fails here the toc entry is likely useless anyway (i.e. no cfi)
			try {
				const a = $("<a>")
					.attr('href', '#')
					.html("<b class='pull-right'>" + toc_loc_msg(row.href) + "</b>" + row.label)
					.attr('data-href', row.href)
					.click(function() {
						book.rendition.display(a.attr('data-href'));
					});

				list.append($("<li>").append(a));

				process_toc_sublist(row, list, 0);

			} catch (e) {
				console.warn(e);
			}
		});

		// well the toc didn't work out, might as well generate one
		if (list.children().length <= 1) {

			list.html("");

			$.each(book.spine.items, function (i, row) {

				const a = $("<a>")
					.attr('href', '#')
					.attr('title', row.url)
					.html("Section " + (i+1))
					.attr('data-href', row.href)
					.click(function() {
						book.rendition.display(a.attr('data-href'));
					});

				list.append($("<li>").append(a));

			});
		}

	});

	book.ready.then(function() {

		const meta = book.package.metadata;

		document.title = meta.title + " – " + meta.creator + " – The Epube";
		$(".title").text(meta.title);

		return localforage.getItem(cacheId("locations")).then(function(locations) {

			console.log('stored pagination', locations != null);

			// legacy format is array of objects {cfi: ..., page: ...}
			if (locations && typeof locations[0] == "string") {
				_pagination_stored = 1;
				return book.locations.load(locations);
			} else {
				console.log("requesting pagination...");

				const url = "backend.php?op=getpagination&id=" + encodeURIComponent($.urlParam("id"));

				return fetch(url, {credentials:'same-origin'}).then(function(resp) {

					if (resp.ok) {
						return resp.json().then(function(locations) {
							if (locations && typeof locations[0] == "string") {
								_pagination_stored = 1;
								return book.locations.load(locations);
							} else {
								$(".loading_message").html("Paginating...");
								return book.locations.generate(1600);
							}
						});
					} else {
						$(".loading_message").html("Paginating...");
						return book.locations.generate(1600);
					}
				}).catch(function() {
					$(".loading_message").html("Paginating...");
					return book.locations.generate(1600);
				});
			}

		});

	}).then(function(locations) {

		console.log("locations ready, stored=", _pagination_stored);

		if (locations) {
			if (navigator.onLine && !_pagination_stored) {
				$.post("backend.php", { op: "storepagination", id: $.urlParam("id"),
					payload: JSON.stringify(locations), total: 100});
			}

			// store if needed
			localforage.getItem(cacheId("locations")).then(function(item) {
				if (!item) localforage.setItem(cacheId("locations"), locations);
			});

		} else {
			$(".loading_message").html("Pagination failed.");
			return;
		}

		$(".location").click(function() {
			const current = book.rendition.currentLocation().start.location;
			const total = book.locations.length();

			const page = prompt("Jump to location [1-" + total + "]", current);

			if (page) {
				book.rendition.display(book.locations._locations[page]);
			}
		});

		open_lastread();

		window.setTimeout(function() {
			open_lastread();

			$(".loading").hide();
		}, 250);
	});

	rendition.on("keyup", hotkey_handler);

	rendition.on('resized', function() {
		console.log('resized');

		$(".loading").show();
		$(".loading_message").html("Opening chapter...");

		window.setTimeout(function() {
			open_lastread();

			$(".loading").hide();
		}, 250);
	});

	rendition.on('rendered', function(/*chapter*/) {
		$(".chapter").html($("<span>").addClass("glyphicon glyphicon-th-list"));

		resize_side_columns();

		try {
			const location = book.rendition.currentLocation();

			if (location.start) {
				const cur_href = book.canonical(location.start.href);
				let toc_entry = false;

				/* eslint-disable no-inner-declarations */
				function iterate_sublist(row, nest) {
					if (nest == 2) return false;

					if (row.subitems) {
						$.each(row.subitems, function (i, r) {

							if (book.spine.get(r.href).canonical == cur_href) {
								toc_entry = r;
								return true;
							}

							if (iterate_sublist(r, nest + 0))
								return true;
						});
					}

					return false;
				}
				/* eslint-enable no-inne-declarations */

				$.each(book.navigation.toc, function(i, a) {
					if (book.spine.get(a.href).canonical == cur_href) {
						toc_entry = a;
						return;
					}

					if (iterate_sublist(a, 0)) return;

				});

				if (toc_entry && toc_entry.label.trim())
					$(".chapter").append("&nbsp;" + toc_entry.label);
			}

		} catch (e) {
			console.warn(e);
		}
	});

	rendition.on('relocated', function(location) {

		// locations not generated yet
		if (book.locations.length() == 0)
			return;

		const currentCfi = location.start.cfi;
		const currentPage = parseInt(book.locations.percentageFromCfi(currentCfi) * 100);
		const pct = book.locations.percentageFromCfi(currentCfi);

		$("#cur_page").html(location.start.location);
		$("#total_pages").html(book.locations.length());

		$("#page_pct").html(parseInt(pct*100) + '%');

		if (_store_position && new Date().getTime()/1000 - _last_position_sync > 15) {
			console.log("storing lastread", currentPage, currentCfi);

			if (navigator.onLine) {

				$.post("backend.php", { op: "storelastread", id: $.urlParam("id"), page: currentPage,
					cfi: currentCfi }, function(data) {

					if (data.cfi) {
						_last_position_sync = new Date().getTime()/1000;
					}

				})
				.fail(function(e) {
					if (e && e.status == 401) {
						window.location = "index.php";
					}
				});

				_store_position = 0;
			} else {
				_last_position_sync = 0;
			}

			localforage.setItem(cacheId("lastread"),
				{cfi: currentCfi, page: currentPage, total: 100});

		}
	});

}

/* exported toggle_fullscreen */
function toggle_fullscreen() {
	const element = document.documentElement;
	const isFullscreen = document.webkitIsFullScreen || document.mozFullScreen || false;

	element.requestFullScreen = element.requestFullScreen || element.webkitRequestFullScreen || element.mozRequestFullScreen ||
		function () { return false; };

	document.cancelFullScreen = document.cancelFullScreen || document.webkitCancelFullScreen || document.mozCancelFullScreen ||
		function () { return false; };

	isFullscreen ? document.cancelFullScreen() : element.requestFullScreen();
}

function show_ui(show) {
	if (show)
		$(".header,.footer").fadeIn();
	else
		$(".header,.footer").fadeOut();
}

/* exported toggle_ui */
function toggle_ui() {
	if ($(".header").is(":visible"))
		$(".header,.footer").fadeOut();
	else
		$(".header,.footer").fadeIn();
}

function open_lastread() {
	localforage.getItem(cacheId("lastread")).then(function(item) {
		console.log('lr local', item);

		item = item || {};

		// CFI missing or w/e
		try {

			// this is ridiculous tbh
			if (item.cfi) book.rendition.display(item.cfi).then(() => {
				book.rendition.display(item.cfi);
			});

		} catch (e) {
			console.warn(e);
		}

		if (navigator.onLine) {

			$.post("backend.php", { op: "getlastread", id: $.urlParam("id") }, function(data) {
				console.log('lr remote', data);

				if (navigator.onLine && data) {
					localforage.setItem(cacheId("lastread"),
						{cfi: data.cfi, page: data.page, total: data.total});

					try {
						if (item.cfi != data.cfi && (!item.page || data.page >= item.page))
							console.log('using remote lastread...');

							book.rendition.display(data.cfi).then(() => {
								book.rendition.display(data.cfi);
							});
					} catch (e) {
						console.warn(e);
					}

				}
			})
			.fail(function(e) {
				if (e && e.status == 401) {
					window.location = "index.php";
				}
			});
		}

	});
}

function next_page() {
	_store_position = 1;

	window.book.rendition.next();

	localforage.getItem("epube.keep-ui-visible").then(function(keep) {
		if (!keep) show_ui(false);
	});
}

function prev_page() {
	window.book.rendition.prev();

	localforage.getItem("epube.keep-ui-visible").then(function(keep) {
		if (!keep) show_ui(false);
	});
}

function hotkey_handler(e) {
	try {
		//console.log('K3:' + e.which, e);

		if ($(".modal").is(":visible"))
			return;

		// right or space
		if (e.which == 39 || e.which == 32) {
			e.preventDefault();
			next_page();
		}

		// left
		if (e.which == 37) {
			e.preventDefault();
			prev_page();
		}

		// esc
		if (e.which == 27) {
			e.preventDefault();
			show_ui(true);
		}
	} catch (e) {
		console.warn(e);
	}
}

function resize_side_columns() {
	let width = $("#reader").position().left;
	const iframe = $("#reader iframe")[0];

	if (iframe && iframe.contentWindow.$)
		width += parseInt(iframe.contentWindow.$("body").css("padding-left"));

	$("#left, #right").width(width);
}

$(document).ready(function() {
	if ('serviceWorker' in navigator) {
		navigator.serviceWorker
        .register('worker.js')
        .then(function() {
				console.log("service worker registered");

				init_loader();
			});
	} else {
		alert("Service worker support missing in browser (are you using plain HTTP?).");
	}

	$(document).on("keyup", function(e) {
		hotkey_handler(e);
	});

	$("#left").on("mouseup", function() {
		prev_page();
	});

	$("#right").on("mouseup", function() {
		next_page();
	});
});

/* exported apply_line_height */
function apply_line_height(elem) {
	const height = $(elem).val();

	localforage.setItem("epube.lineHeight", height).then(function() {
		apply_styles();
	});
}

/* exported apply_font */
function apply_font(elem) {
	const font = $(elem).val();

	localforage.setItem("epube.fontFamily", font).then(function() {
		apply_styles();
	});

}

/* exported apply_font_size */
function apply_font_size(elem) {
	const size = $(elem).val();

	localforage.setItem("epube.fontSize", size).then(function() {
		apply_styles();
	});
}

function apply_styles() {

	Promise.all([
		localforage.getItem("epube.fontSize"),
		localforage.getItem("epube.fontFamily"),
		localforage.getItem("epube.lineHeight"),
		localforage.getItem("epube.theme")
	]).then(function(res) {
		const fontSize = res[0] ? res[0] + "px" : DEFAULT_FONT_SIZE + "px";
		const fontFamily = res[1] ? res[1] : DEFAULT_FONT_FAMILY;
		const lineHeight = res[2] ? res[2] + "%" : DEFAULT_LINE_HEIGHT + "%";
		//const themeName = res[3] ? res[3] : false;

		console.log('style', fontFamily, fontSize, lineHeight);

		$.each(window.book.rendition.getContents(), function(i, c) {
			c.css("font-size", fontSize);
			c.css("font-family", "'" + fontFamily + "'");
			c.css("line-height", lineHeight);
		});

		apply_theme();
	});

}

/* exported clear_lastread */
function clear_lastread() {
	if (confirm("Clear stored last read location?")) {
		const total = window.book.locations.length();

		if (navigator.onLine) {
			$.post("backend.php", { op: "storelastread", page: -1, cfi: "", id: $.urlParam("id") }, function(data) {
				$(".lastread_input").val(data.page + '%');
			});
		}

		localforage.setItem(cacheId("lastread"),
			{cfi: "", page: 0, total: total});

	}
}

/* exported mark_as_read */
function mark_as_read() {
	if (confirm("Mark book as read?")) {
		const total = 100;
		const lastCfi = window.book.locations.cfiFromPercentage(1);

		if (navigator.onLine) {
			$.post("backend.php", { op: "storelastread", page: total, cfi: lastCfi, id: $.urlParam("id") }, function(data) {
				$(".lastread_input").val(data.page + '%');
			});
		}

		localforage.setItem(cacheId("lastread"),
			{cfi: lastCfi, page: total, total: total});

	}
}

/* exported save_and_close */
function save_and_close() {
	const location = window.book.rendition.currentLocation();

	const currentCfi = location.start.cfi;
	const currentPage = parseInt(window.book.locations.percentageFromCfi(currentCfi) * 100);
	const totalPages = 100;

	localforage.setItem(cacheId("lastread"),
		{cfi: currentCfi, page: currentPage, total: totalPages});

	if (navigator.onLine) {
		$.post("backend.php", { op: "storelastread", id: $.urlParam("id"), page: currentPage,
			cfi: currentCfi }, function() {
				window.location = $.urlParam("rt") ? "index.php?mode=" + $.urlParam("rt") : "index.php";
			})
			.fail(function() {
				window.location = "index.php";
			});
	} else {
		window.location = "index.php";
	}
}

/* exported change_theme */
function change_theme(elem) {
	const theme = $(elem).val();

	localforage.setItem("epube.theme", theme).then(function() {
		apply_styles();
	});
}

function apply_theme() {
	localforage.getItem("epube.theme").then(function(theme) {
		console.log('theme', theme);

		const base_url = window.location.href.match(/^.*\//)[0];

		if (!theme) theme = 'default';
		const theme_url = base_url + "themes/" + theme + ".css";

		$("#theme_css").attr("href", theme_url);

		$.each(window.book.rendition.getContents(), function(i,c) {
			$(c.document).find("#theme_css").text(_res_data[theme_url])
		});

	});
}

/* exported search */
function search() {
	const query = $(".search_input").val();
	const list = $(".search_results");

	list.html("");

	if (query) {

		/* eslint-disable prefer-spread */
		Promise.all(
			book.spine.spineItems.map(
				(item) => item.load(book.load.bind(book))
				.then(item.find.bind(item, query))
				.finally(item.unload.bind(item)))
			)
		.then((results) => Promise.resolve([].concat.apply([], results)))
		.then(function(results) {
			$.each(results, function (i, row) {
				const a = $("<a>")
					.attr('href', '#')
					.html("<b class='pull-right'>" + window.book.locations.locationFromCfi(row.cfi) + "</b>" + row.excerpt)
					.attr('data-cfi', row.cfi)
					.attr('data-id', row.id)
					.click(function() {
							window.book.rendition.display(a.attr('data-cfi'));
					});

				list.append($("<li>").append(a));
			});
		});
	}
}

/* exported dict_lookup */
function dict_lookup(word, callback) {
	$.post("backend.php", {op: 'define', word: word}, function(data) {
		if (data) {

			$(".dict_result").html(data.result.join("<br/>"));
			$(".dict_query").val(word);
			$("#dict-modal").modal('show');

			if (callback) callback();
		}
	});
}

/* exported open_previous_location */
function open_previous_location(elem) {
	const cfi = $(elem).attr("data-location-cfi");

	if (cfi) {
		window.book.rendition.display(cfi);
	}

	$(elem).fadeOut();
}