// ==UserScript==
// @name Google Books Wiktionary Citation
// @version  1
// @include https://www.google.com/search*&tbm=bks&*
// @include https://www.google.com/search?tbm=bks&*
// @include https://www.google.com/books?*
// @include https://www.google.com/books/*
// @include https://books.google.com/books?*
// @include https://books.google.com/books/*
// @require https://cdn.jsdelivr.net/npm/citation-js@0.5
// @grant GM.xmlHttpRequest
// @grant GM_xmlhttpRequest
// ==/UserScript==
var Cite = require('citation-js');
var mode = "TM";

if (typeof GM_xmlhttpRequest == "undefined") {
    mode = "GM";
    GM_xmlhttpRequest = GM.xmlHttpRequest;
}

var viewType = "unknown";

function getURLFromSubframe() {
    try {
        var moreMenu = document.querySelector('img[src*="more_vert_black_24dp.png"]');
        moreMenu = moreMenu && moreMenu.parentNode.parentNode;
        mouseEvent(moreMenu, "mousedown");
        var shareButton = document.querySelector('.goog-menu.goog-menu-vertical > div.goog-control:nth-child(1)');
        mouseEvent(shareButton, "mousedown");
        mouseEvent(shareButton, "click");
        mouseEvent(shareButton, "mouseup");
        return document.querySelector('.popup-menu[style*="visible"] .linkto-popup-content input').value;
    } catch (error) {
        var id = /[?&]id=(.*?)(?:&|$)|\/books\/edition\/.*?\/([^?]+)/.exec(document.location);
        id = id && (id[2] || id[1]);
        return id && ("https://www.google.com/books?id=" + id) || document.querySelector('link[rel=canonical]').href;
    }
}

function getURLFromOldView() {
    var linkbar = document.getElementsByClassName("linkbar-panel-div");
    if (linkbar.length) return linkbar[0].getElementsByTagName("input")[0].value;
    var linkimg = document.querySelector("img[src*='insert_link.png']");
    mouseEvent(linkimg.parentNode, "mousedown");
    mouseEvent(linkimg.parentNode, "click");
    mouseEvent(linkimg.parentNode, "mouseup");
    linkbar = document.getElementsByClassName("linkbar-panel-div");
    return linkbar[0].getElementsByTagName("input")[0].value;
}

function getSnippet(page) {
    var snippets = document.querySelectorAll('body > div[style*="position: absolute; display: none; background-color"]');
    snippets = Array.from(snippets);
    if (!snippets.length) return;
    var snippet = page && snippets.find(function(x) {
        return x.children[0].textContent.match(RegExp("\\b" + page + "\\b"));
    });
    if (page && snippet) return snippet.children[1].textContent;
    snippet = snippets.map(function(x) {
        return x.children && x.children.length > 1 && ("[" + x.children[0].textContent + "] " + x.children[1].textContent) || "";
    }).join(" \n/// ");
    if (snippet.length < 2000) return snippet;
}

function addCiteLinksBooks() {
    var results = document.getElementsByClassName("Yr5TG");
    var button, buttonText;
    var tag = "button";
    for (var i = 0; i < results.length; i++) {
        viewType = "results";
        var line = results[i].getElementsByClassName("N96wpd")[0];
        if (!line.getElementsByClassName('wikt-cite-button').length) {
            button = document.createElement('button');
            button.classList.add('wikt-cite-button');
            buttonText = document.createTextNode("[cite]");
            button.appendChild(buttonText);
            button.onclick = displayCitationBooks;
            line.appendChild(button);
        }
    }
    var infobar = document.getElementsByClassName("gb-entity-page-toolbar-container");
    if (infobar.length) {
        viewType = "subframe";
        infobar = infobar[0];
    } else if (document.getElementById("volume-info-sidebar")) {
        viewType = "old";
        infobar = document.getElementById("volume-info-sidebar");
    } else {
        infobar = document.getElementById("bookinfo") || document.getElementById("bep-tab-selector");
    }
    if (infobar && !infobar.getElementsByClassName('wikt-cite-button').length) {
        var div = document.createElement('div');
        button = document.createElement(tag);
        button.classList.add('wikt-cite-button');
        buttonText = document.createTextNode("[cite]");
        button.appendChild(buttonText);
        button.onclick = displayCitationBooks;
        div.append(button);
        infobar.append(div);
    }

    var iframe = document.querySelector('iframe[src*="books.google.com/books"]');
    if (mode == "GM" && iframe) {
        var embed = document.createElement('embed');
        var attributes = iframe.attributes;
        for (i = 0; i < attributes.length; i++) {
            embed.setAttribute(attributes[i].nodeName, attributes[i].nodeValue);
        }
        iframe.replaceWith(embed);
    }
}

function displayCitationBooks() {
    var page = null;

    var result = this.closest(".Yr5TG");
    var that = this;

    var target = document.location;
    if (viewType == "results") target = result.getElementsByTagName("a")[0].href.split("&hl=")[0];
    else if (viewType == "subframe") target = getURLFromSubframe();
    else if (viewType == "old") target = getURLFromOldView();

    var id = /[?&]id=(.*?)(?:&|$)|\/books\/edition\/.*?\/([^?]+)/.exec(target);
    id = id && (id[2] || id[1]);

    page = /[?&]pg=PA(.*?)\b/.exec(target);
    page = page && page[1];

    var snippet;
    if (viewType == "results") {
        snippet = result.getElementsByClassName("ETWPw");
        snippet = snippet.length && snippet[0].getElementsByTagName("span")[0].textContent || null;
        page = result.getElementsByClassName("VNSPub");
        page = page.length && page[0].textContent || "";
        page = /(\d+)/.exec(page);
        if (page) page = page[1];
    } else snippet = getSnippet(page);

    var oclc = document.querySelector('a[href*="worldcat.org/oclc/"]');
    oclc = oclc && /worldcat\.org\/oclc\/([0-9]+)/.exec(oclc)[1];

    var volumeInfo = null,
        cite = null,
        lccn = null;

    var request = GM_xmlhttpRequest({
        method: "GET",
        url: "https://www.googleapis.com/books/v1/volumes/" + id,
        onload: function(response) {
            volumeInfo = JSON.parse(response.responseText).volumeInfo;
            request = GM_xmlhttpRequest({
                method: "GET",
                url: "https://books.google.com/books?id=" + id + "&output=ris",
                onload: function(response) {
                    cite = new Cite(response.responseText).data[0];
                    request = GM_xmlhttpRequest({
                        method: "GET",
                        url: "https://books.google.com/books?id=" + id + "&output=bibtex",
                        onload: function(response) {
                            lccn = /\blccn={(.*?)}/.exec(response.responseText);
                            lccn = lccn && lccn[1];
                            if (oclc || (viewType != "results" && viewType != "subframe")) displayCitationsBooks2(that, result, page, target, id, snippet, volumeInfo, cite, lccn, oclc);
                            else {
                                request = GM_xmlhttpRequest({
                                    method: "GET",
                                    url: "https://www.google.com/books/?id=" + id,
                                    onload: function(response) {
                                        var el = document.createElement('html');
                                        el.innerHTML = response.responseText;
                                        oclc = el.querySelector('a[href*="worldcat.org/oclc/"]');
                                        oclc = oclc && /worldcat\.org\/oclc\/([0-9]+)/.exec(oclc)[1];
                                        displayCitationsBooks2(that, result, page, target, id, snippet, volumeInfo, cite, lccn, oclc);
                                    }
                                });
                            }
                        }
                    });
                }
            });
        }
    });
}

function displayCitationsBooks2(that, result, page, target, id, snippet, volumeInfo, cite, lccn, oclc) {
    var title = volumeInfo.title && (volumeInfo.title + (volumeInfo.subtitle && (": " + volumeInfo.subtitle) || "")).replace("|", "&#124;");

    var publisher = volumeInfo.publisher && volumeInfo.publisher.replace("|", "&#124;");

    var date = volumeInfo.publishedDate;
    var dateType = date && date.includes("-") && "date" || "year";

    var lang = volumeInfo.language;

    var volume = /\bv\. (.*?)(?:,|$)/.exec(cite.issue || "");
    volume = volume && volume[1];
    var issue = /\bnos?\. (.*?)(?:,|$)/.exec(cite.issue || "");
    issue = issue && issue[1];
    var part = /\bpts?\. (.*?)(?:,|$)/.exec(cite.issue || "");
    part = part && part[1];
    var series = cite["collection-title"];
    if (series == title) series = null;

    var isbn, issn;
    var identifiers = volumeInfo.industryIdentifiers;
    if (identifiers) {
        isbn = identifiers.find(function(x) {
            return x.type == "ISBN_13"
        }) || identifiers.find(function(x) {
            return x.type == "ISBN_10"
        });
        issn = identifiers.find(function(x) {
            return x.type == "ISSN"
        });
        if (isbn) isbn = isbn.identifier;
        if (issn) issn = issn.identifier;
    }

    var author = volumeInfo.authors && volumeInfo.authors.join(", ").replace("|", "&#124;");

    var citation = "{{quote-book|" +
        lang +
        (target && ("\n|url=" + target) || "") +
        (title && ("\n|title=" + title) || "") +
        (author && ("\n|author=" + author) || "") +
        (publisher && ("\n|publisher=" + publisher) || "") +
        (series && ("\n|series=" + series) || "") +
        (isbn && ("\n|isbn=" + isbn) || "") +
        (issn && ("\n|issn=" + issn) || "") +
        (lccn && ("\n|lccn=" + lccn) || "") +
        (oclc && ("\n|oclc=" + oclc) || "") +
        (date && ("\n|" + dateType + "=" + date) || "") +
        (volume && ("\n|volume=" + volume) || "") +
        (issue && ("\n|issue=" + issue) || "") +
        (part && ("\n|other=part " + part) || "") +
        (page && ("\n|page=" + page) || "") +
        (snippet && ("\n|passage=" + snippet) || "") +
        (snippet && (lang != "en") && ("\n|t=") || "") +
        "\n}}";

    var textarea = document.createElement("textarea");
    var button = document.createElement('button');
    var buttonText = document.createTextNode("[minify]");
    button.appendChild(buttonText);
    button.onclick = minify;
    textarea.setAttribute('rows', 10);
    textarea.setAttribute('cols', (viewType == "results") && 80 || (viewType == "old") && 25 || (viewType == "subframe") && 200);
    textarea.value = citation;

    if (viewType == "results") {
        var line = result.getElementsByClassName("N96wpd")[0];
        line.insertBefore(button, this.nextSibling);
        line.insertBefore(textarea, button);
    } else {
        that.parentNode.append(textarea);
        that.parentNode.append(button);
    }
}

function minify() {
    var textarea = this.parentNode.getElementsByTagName('textarea')[0];
    textarea.value = textarea.value.replace(/\n/g, "");
}

function mouseEvent(element, eventType) {
    var event = document.createEvent("MouseEvents");
    event.initEvent(eventType, true, true);
    element.dispatchEvent(event);
}

addCiteLinksBooks();

var observer = new MutationObserver(addCiteLinksBooks);

observer.observe(document.body, {
    childList: true,
    subtree: true,
    attributes: false,
    characterData: false
});