zoteroshortdoi.js

// Startup -- load Zotero and constants
if (typeof Zotero === 'undefined') {
    Zotero = {};
}

//const zotDOI_is7 = Zotero.platformMajorVersion >= 102;

function _create(doc, name) {
    const elt =
        Zotero.platformMajorVersion >= 102
            ? doc.createXULElement(name)
            : doc.createElementNS(
                "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul",
                name
            );
    return elt;
}

ShortDOI = {
    id: null,
    version: null,
    rootURI: null,
    addedElementIDs: [],
    notifierID: null,

    log(msg) {
        Zotero.debug("DOI Manager: " + msg);
    },

    // Preference managers

    getPref(pref) {
        return Zotero.Prefs.get("extensions.shortdoi." + pref, true);
    },

    setPref(pref, value) {
        return Zotero.Prefs.set("extensions.shortdoi." + pref, value, true);
    },

    // Startup - initialize plugin

    init({ id, version, rootURI } = {}) {
        ShortDOI.resetState("initial");

        this.id = id;
        this.version = version;
        this.rootURI = rootURI;

        // Register the callback in Zotero as an item observer
        notifierID = Zotero.Notifier.registerObserver(
            ShortDOI.notifierCallback,
            ["item"]
        );
    },

    // Overlay management

    addToWindow(window) {
        log("Updating window")

        let doc = window.document;

        // createElementNS() necessary in Zotero 6; createElement() defaults to HTML in Zotero 7
        //let HTML_NS = "http://www.w3.org/1999/xhtml";
        //let XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";

        let stringBundle = Services.strings.createBundle(
            "chrome://zoteroshortdoi/locale/zoteroshortdoi.properties"
        );

        // Item menu
        let itemmenu = _create(doc, "menu");
        itemmenu.id = "zotero-itemmenu-shortdoi-menu";
        itemmenu.setAttribute("class", "menu-iconic");
        //itemmenu.setAttribute('image', 'xxx');
        itemmenu.setAttribute(
            "label",
            stringBundle.GetStringFromName("shortdoi-menu-label")
        );

        let itemmenupopup = _create(doc, "menupopup");
        itemmenupopup.id = "zotero-itemmenu-shortdoi-menupopup";

        let updateShort = _create(doc, "menuitem");
        updateShort.id = "zotero-itemmenu-shortdoi-short";
        updateShort.setAttribute(
            "label",
            stringBundle.GetStringFromName("shortdoi-menu-short-label")
        );
        updateShort.addEventListener("command", () => {
            ShortDOI.updateSelectedItems("short");
        });

        let updateLong = _create(doc, "menuitem");
        updateLong.id = "zotero-itemmenu-shortdoi-long";
        updateLong.setAttribute(
            "label",
            stringBundle.GetStringFromName("shortdoi-menu-long-label")
        );
        updateLong.addEventListener("command", () => {
            ShortDOI.updateSelectedItems("long");
        });

        let updateCheck = _create(doc, "menuitem");
        updateCheck.id = "zotero-itemmenu-shortdoi-check";
        updateCheck.setAttribute(
            "label",
            stringBundle.GetStringFromName("shortdoi-menu-check-label")
        );
        updateCheck.addEventListener("command", () => {
            ShortDOI.updateSelectedItems("check");
        });

        itemmenupopup.appendChild(updateShort);
        itemmenupopup.appendChild(updateLong);
        itemmenupopup.appendChild(updateCheck);
        itemmenu.appendChild(itemmenupopup);
        doc.getElementById("zotero-itemmenu").appendChild(itemmenu);
        this.storeAddedElement(itemmenu);

        // Tools menu
        // Preferences
        // As they are now in the main Zotero preferences in Zotero 7, this is only for Zotero 6
        if (!(Zotero.platformMajorVersion >= 102)) {
            let menuitem = _create(doc, "menuitem");
            menuitem.id = "menu_Tools-shortdoi-preferences";
            menuitem.setAttribute(
                "label",
                stringBundle.GetStringFromName("shortdoi-preferences-label")
            );
            menuitem.addEventListener("command", () => {
                ShortDOI.openPreferenceWindow();
            });
            doc.getElementById("menu_ToolsPopup").appendChild(menuitem);
            this.storeAddedElement(menuitem);
        }

        // Auto-retrieve settings
        let submenu = _create(doc, "menu");
        submenu.id = "menu_Tools-shortdoi-menu";
        submenu.setAttribute(
            "label",
            stringBundle.GetStringFromName("shortdoi-autoretrieve-label")
        );
        let submenupopup = _create(doc, "menupopup");
        submenupopup.id = "menu_Tools-shortdoi-menu-popup";
        submenupopup.addEventListener("popupshowing", () => {
            ShortDOI.setCheck();
        });

        let itemShort = _create(doc, "menuitem");
        itemShort.id = "menu_Tools-shortdoi-menu-popup-short";
        itemShort.setAttribute("type", "checkbox");
        itemShort.setAttribute(
            "label",
            stringBundle.GetStringFromName("shortdoi-autoretrieve-short-label")
        );
        itemShort.addEventListener("command", () => {
            ShortDOI.changePref("short");
        });

        let itemLong = _create(doc, "menuitem");
        itemLong.id = "menu_Tools-shortdoi-menu-popup-long";
        itemLong.setAttribute("type", "checkbox");
        itemLong.setAttribute(
            "label",
            stringBundle.GetStringFromName("shortdoi-autoretrieve-long-label")
        );
        itemLong.addEventListener("command", () => {
            ShortDOI.changePref("long");
        });

        let itemCheck = _create(doc, "menuitem");
        itemCheck.id = "menu_Tools-shortdoi-menu-popup-check";
        itemCheck.setAttribute("type", "checkbox");
        itemCheck.setAttribute(
            "label",
            stringBundle.GetStringFromName("shortdoi-autoretrieve-check-label")
        );
        itemCheck.addEventListener("command", () => {
            ShortDOI.changePref("check");
        });

        let itemNone = _create(doc, "menuitem");
        itemNone.id = "menu_Tools-shortdoi-menu-popup-none";
        itemNone.setAttribute("type", "checkbox");
        itemNone.setAttribute(
            "label",
            stringBundle.GetStringFromName("shortdoi-autoretrieve-no-label")
        );
        itemNone.addEventListener("command", () => {
            ShortDOI.changePref("none");
        });

        submenupopup.appendChild(itemShort);
        submenupopup.appendChild(itemLong);
        submenupopup.appendChild(itemCheck);
        submenupopup.appendChild(itemNone);
        submenu.appendChild(submenupopup);
        doc.getElementById("menu_ToolsPopup").appendChild(submenu);
        this.storeAddedElement(submenu);

        // Use strings from make-it-red.ftl (Fluent) in Zotero 7
        /*if (is7) {
         window.MozXULElement.insertFTLIfNeeded("zoteroshortdoi.ftl");
         }
         // Use strings from make-it-red.properties (legacy properties format) in Zotero 6
         else {
         let stringBundle = Services.strings.createBundle(
         'chrome://zotero-shortdoi/locale/zoteroshortdoi.properties'
         );
         doc.getElementById('menu_Tools-shortdoi-preferences')
         .setAttribute('label', stringBundle.GetStringFromName('makeItGreenInstead.label'));
         }*/
    },

    addToAllWindows() {
        var windows = Zotero.getMainWindows();
        for (let win of windows) {
            if (!win.ZoteroPane) continue;
            this.addToWindow(win);
        }
    },

    storeAddedElement(elem) {
        if (!elem.id) {
            throw new Error("Element must have an id");
        }
        this.addedElementIDs.push(elem.id);
    },

    removeFromWindow(window) {
        var doc = window.document;
        // Remove all elements added to DOM
        for (let id of this.addedElementIDs) {
            // ?. (null coalescing operator) not available in Zotero 6
            let elem = doc.getElementById(id);
            if (elem) elem.remove();
        }
        //doc.querySelector('[href="zoteroshortdoi.ftl"]').remove();
    },

    removeFromAllWindows() {
        var windows = Zotero.getMainWindows();
        for (let win of windows) {
            if (!win.ZoteroPane) continue;
            this.removeFromWindow(win);
        }
    },

    // Notifications

    notifierCallback: {
        notify: function (event, type, ids, extraData) {
            if (event == "add") {
                switch (ShortDOI.getPref("autoretrieve")) {
                    case "short":
                        ShortDOI.updateItems(Zotero.Items.get(ids), "short");
                        break;
                    case "long":
                        ShortDOI.updateItems(Zotero.Items.get(ids), "long");
                        break;
                    case "check":
                        ShortDOI.updateItems(Zotero.Items.get(ids), "check");
                        break;
                    default:
                        break;
                }
            }
        },
    },

    // Controls for Tools menu

    // *********** Set the checkbox checks, frompref
    setCheck() {
        let document = Zotero.getMainWindow().document;

        var tools_short = document.getElementById(
            "menu_Tools-shortdoi-menu-popup-short"
        );
        var tools_long = document.getElementById(
            "menu_Tools-shortdoi-menu-popup-long"
        );
        var tools_check = document.getElementById(
            "menu_Tools-shortdoi-menu-popup-check"
        );
        var tools_none = document.getElementById(
            "menu_Tools-shortdoi-menu-popup-none"
        );
        var pref = ShortDOI.getPref("autoretrieve");
        tools_short.setAttribute("checked", Boolean(pref === "short"));
        tools_long.setAttribute("checked", Boolean(pref === "long"));
        tools_check.setAttribute("checked", Boolean(pref === "check"));
        tools_none.setAttribute("checked", Boolean(pref === "none"));
    },

    // *********** Change the checkbox, topref
    changePref(option) {
        ShortDOI.setPref("autoretrieve", option);
    },

    /**
     * Open shortdoi preference window
     */
    openPreferenceWindow(paneID, action) {
        log("Opening pref window for DOI");

        let window = Zotero.getMainWindow();
        var io = { pane: paneID, action: action };
        window.openDialog(
            "chrome://zoteroshortdoi/content/options.xul",
            "shortdoi-pref",
            "chrome,titlebar,toolbar,centerscreen" +
                Zotero.Prefs.get("browser.preferences.instantApply", true)
                ? "dialog=no"
                : "modal",
            io
        );
    },

    resetState(operation) {
        if (operation == "initial") {
            if (ShortDOI.progressWindow) {
                ShortDOI.progressWindow.close();
            }
            ShortDOI.current = -1;
            ShortDOI.toUpdate = 0;
            ShortDOI.itemsToUpdate = null;
            ShortDOI.numberOfUpdatedItems = 0;
            ShortDOI.counter = 0;
            error_invalid = null;
            error_nodoi = null;
            error_multiple = null;
            error_invalid_shown = false;
            error_nodoi_shown = false;
            error_multiple_shown = false;
            final_count_shown = false;
            return;
        } else {
            if (error_invalid || error_nodoi || error_multiple) {
                ShortDOI.progressWindow.close();
                var icon = "chrome://zotero/skin/cross.png";
                if (error_invalid && !error_invalid_shown) {
                    var progressWindowInvalid = new Zotero.ProgressWindow({
                        closeOnClick: true,
                    });
                    progressWindowInvalid.changeHeadline("Invalid DOI");
                    if (ShortDOI.getPref("tag_invalid") !== "") {
                        progressWindowInvalid.progress = new progressWindowInvalid.ItemProgress(
                            icon,
                            "Invalid DOIs were found. These have been tagged with '" +
                            ShortDOI.getPref("tag_invalid") +
                            "'."
                        );
                    } else {
                        progressWindowInvalid.progress = new progressWindowInvalid.ItemProgress(
                            icon,
                            "Invalid DOIs were found."
                        );
                    }
                    progressWindowInvalid.progress.setError();
                    progressWindowInvalid.show();
                    progressWindowInvalid.startCloseTimer(8000);
                    error_invalid_shown = true;
                }
                if (error_nodoi && !error_nodoi_shown) {
                    var progressWindowNoDOI = new Zotero.ProgressWindow({
                        closeOnClick: true,
                    });
                    progressWindowNoDOI.changeHeadline("DOI not found");
                    if (ShortDOI.getPref("tag_nodoi") !== "") {
                        progressWindowNoDOI.progress = new progressWindowNoDOI.ItemProgress(
                            icon,
                            "No DOI was found for some items. These have been tagged with '" +
                            ShortDOI.getPref("tag_nodoi") +
                            "'."
                        );
                    } else {
                        progressWindowNoDOI.progress = new progressWindowNoDOI.ItemProgress(
                            icon,
                            "No DOI was found for some items."
                        );
                    }
                    progressWindowNoDOI.progress.setError();
                    progressWindowNoDOI.show();
                    progressWindowNoDOI.startCloseTimer(8000);
                    error_nodoi_shown = true;
                }
                if (error_multiple && !error_multiple_shown) {
                    var progressWindowMulti = new Zotero.ProgressWindow({
                        closeOnClick: true,
                    });
                    progressWindowMulti.changeHeadline(
                        "Multiple possible DOIs"
                    );
                    if (ShortDOI.getPref("tag_multiple") !== "") {
                        progressWindowMulti.progress = new progressWindowMulti.ItemProgress(
                            icon,
                            "Some items had multiple possible DOIs. Links to lists of DOIs have been added and tagged with '" +
                            ShortDOI.getPref("tag_multiple") +
                            "'."
                        );
                    } else {
                        progressWindowMulti.progress = new progressWindowMulti.ItemProgress(
                            icon,
                            "Some items had multiple possible DOIs."
                        );
                    }
                    progressWindow.progress.setError();
                    progressWindowMulti.show();
                    progressWindowMulti.startCloseTimer(8000);
                    error_multiple_shown = true;
                }
            } else {
                if (!final_count_shown) {
                    var icon = "chrome://zotero/skin/tick.png";
                    ShortDOI.progressWindow = new Zotero.ProgressWindow({
                        closeOnClick: true,
                    });
                    ShortDOI.progressWindow.changeHeadline("Finished");
                    ShortDOI.progressWindow.progress = new ShortDOI.progressWindow.ItemProgress(
                        icon
                    );
                    ShortDOI.progressWindow.progress.setProgress(100);
                    if (operation == "short") {
                        ShortDOI.progressWindow.progress.setText(
                            "shortDOIs updated for " +
                            ShortDOI.counter +
                            " items."
                        );
                    } else if (operation == "long") {
                        ShortDOI.progressWindow.progress.setText(
                            "Long DOIs updated for " +
                            ShortDOI.counter +
                            " items."
                        );
                    } else {
                        ShortDOI.progressWindow.progress.setText(
                            "DOIs verified for " + ShortDOI.counter + " items."
                        );
                    }
                    ShortDOI.progressWindow.show();
                    ShortDOI.progressWindow.startCloseTimer(4000);
                    final_count_shown = true;
                }
            }
            return;
        }
    },
};

ShortDOI.generateItemUrl = function (item, operation) {
    var doi = item.getField("DOI");
    if (!doi) {
        doi = ShortDOI.crossrefLookup(item, operation);
    } else {
        if (typeof doi === "string") {
            doi = Zotero.Utilities.cleanDOI(doi);
            if (doi) {
                if (operation === "short" && !doi.match(/10\/[^\s]*[^\s\.,]/)) {
                    var url =
                        "https://shortdoi.org/" +
                        encodeURIComponent(doi) +
                        "?format=json";
                    return url;
                } else {
                    var url =
                        "https://doi.org/api/handles/" +
                        encodeURIComponent(doi);
                    return url;
                }
            } else {
                return "invalid";
            }
        } else {
            return "invalid";
        }
    }

    return false;
};

ShortDOI.updateSelectedItems = function (operation) {
    ShortDOI.updateItems(
        Zotero.getActiveZoteroPane().getSelectedItems(),
        operation
    );
};

ShortDOI.updateItems = function (items, operation) {
    // For now, filter out non-journal article and conference paper items
    var items = items.filter(
        (item) =>
            item.itemTypeID == Zotero.ItemTypes.getID("journalArticle") ||
            item.itemTypeID == Zotero.ItemTypes.getID("conferencePaper")
    );
    var items = items.filter((item) => !item.isFeedItem);

    if (
        items.length === 0 ||
        ShortDOI.numberOfUpdatedItems < ShortDOI.toUpdate
    ) {
        return;
    }

    ShortDOI.resetState("initial");
    ShortDOI.toUpdate = items.length;
    ShortDOI.itemsToUpdate = items;

    // Progress Windows
    ShortDOI.progressWindow = new Zotero.ProgressWindow({
        closeOnClick: false,
    });
    var icon =
        "chrome://zotero/skin/toolbar-advanced-search" +
        (Zotero.hiDPI ? "@2x" : "") +
        ".png";
    if (operation == "short") {
        ShortDOI.progressWindow.changeHeadline("Getting shortDOIs", icon);
    } else if (operation == "long") {
        ShortDOI.progressWindow.changeHeadline("Getting long DOIs", icon);
    } else {
        ShortDOI.progressWindow.changeHeadline(
            "Validating DOIs and removing extra text",
            icon
        );
    }
    let iconPath =
        Zotero.platformMajorVersion >= 102
            ? this.rootURI + "skin/doi"
            : "chrome://zoteroshortdoi/skin/doi";
    var doiIcon = iconPath + (Zotero.hiDPI ? "@2x" : "") + ".png";
    ShortDOI.progressWindow.progress = new ShortDOI.progressWindow.ItemProgress(
        doiIcon,
        "Checking DOIs."
    );

    ShortDOI.updateNextItem(operation);
};

ShortDOI.updateNextItem = function (operation) {
    ShortDOI.numberOfUpdatedItems++;

    if (ShortDOI.current == ShortDOI.toUpdate - 1) {
        ShortDOI.progressWindow.close();
        ShortDOI.resetState(operation);
        return;
    }

    ShortDOI.current++;

    // Progress Windows
    var percent = Math.round(
        (ShortDOI.numberOfUpdatedItems / ShortDOI.toUpdate) * 100
    );
    ShortDOI.progressWindow.progress.setProgress(percent);
    ShortDOI.progressWindow.progress.setText(
        "Item " + ShortDOI.current + " of " + ShortDOI.toUpdate
    );
    ShortDOI.progressWindow.show();

    ShortDOI.updateItem(ShortDOI.itemsToUpdate[ShortDOI.current], operation);
};

ShortDOI.updateItem = function (item, operation) {
    var url = ShortDOI.generateItemUrl(item, operation);

    if (!url) {
        if (item.hasTag(ShortDOI.getPref("tag_invalid"))) {
            item.removeTag(ShortDOI.getPref("tag_invalid"));
            item.saveTx();
        }
        ShortDOI.updateNextItem(operation);
    } else if (url == "invalid") {
        ShortDOI.invalidate(item, operation);
    } else {
        var oldDOI = item.getField("DOI");
        var req = new XMLHttpRequest();
        req.open("GET", url, true);
        req.responseType = "json";

        if (operation == "short") {
            req.onreadystatechange = function () {
                if (req.readyState == 4) {
                    if (req.status == 200) {
                        if (item.isRegularItem()) {
                            if (oldDOI.match(/10\/[^\s]*[^\s\.,]/)) {
                                if (req.response.responseCode == 1) {
                                    if (req.response.handle != oldDOI) {
                                        var shortDOI = req.response.handle.toLowerCase();
                                        item.setField("DOI", shortDOI);
                                        item.removeTag(
                                            ShortDOI.getPref("tag_invalid")
                                        );
                                        item.removeTag(
                                            ShortDOI.getPref("tag_multiple")
                                        );
                                        item.removeTag(
                                            ShortDOI.getPref("tag_nodoi")
                                        );
                                        item.saveTx();
                                        ShortDOI.counter++;
                                    } else if (
                                        item.hasTag(
                                            ShortDOI.getPref("tag_invalid")
                                        ) ||
                                        item.hasTag(
                                            ShortDOI.getPref("tag_multiple")
                                        ) ||
                                        item.hasTag(
                                            ShortDOI.getPref("tag_nodoi")
                                        )
                                    ) {
                                        item.removeTag(
                                            ShortDOI.getPref("tag_invalid")
                                        );
                                        item.removeTag(
                                            ShortDOI.getPref("tag_multiple")
                                        );
                                        item.removeTag(
                                            ShortDOI.getPref("tag_nodoi")
                                        );
                                        item.saveTx();
                                    }
                                } else {
                                    ShortDOI.invalidate(item, operation);
                                }
                            } else {
                                var shortDOI = req.response.ShortDOI.toLowerCase();
                                item.setField("DOI", shortDOI);
                                item.removeTag(ShortDOI.getPref("tag_invalid"));
                                item.removeTag(
                                    ShortDOI.getPref("tag_multiple")
                                );
                                item.removeTag(ShortDOI.getPref("tag_nodoi"));
                                item.saveTx();
                                ShortDOI.counter++;
                            }
                        }
                        ShortDOI.updateNextItem(operation);
                    } else if (req.status == 400 || req.status == 404) {
                        ShortDOI.invalidate(item, operation);
                    } else {
                        ShortDOI.updateNextItem(operation);
                    }
                }
            };

            req.send(null);
        } else if (operation == "long") {
            req.onreadystatechange = function () {
                if (req.readyState == 4) {
                    if (req.status == 200) {
                        if (req.response.responseCode == 1) {
                            if (oldDOI.match(/10\/[^\s]*[^\s\.,]/)) {
                                if (item.isRegularItem()) {
                                    var longDOI = req.response.values[
                                        "1"
                                    ].data.value.toLowerCase();
                                    item.setField("DOI", longDOI);
                                    item.removeTag(
                                        ShortDOI.getPref("tag_invalid")
                                    );
                                    item.removeTag(
                                        ShortDOI.getPref("tag_multiple")
                                    );
                                    item.removeTag(
                                        ShortDOI.getPref("tag_nodoi")
                                    );
                                    item.saveTx();
                                    ShortDOI.counter++;
                                }
                            } else {
                                if (req.response.handle != oldDOI) {
                                    var longDOI = req.response.handle.toLowerCase();
                                    item.setField("DOI", longDOI);
                                    item.removeTag(
                                        ShortDOI.getPref("tag_invalid")
                                    );
                                    item.removeTag(
                                        ShortDOI.getPref("tag_multiple")
                                    );
                                    item.removeTag(
                                        ShortDOI.getPref("tag_nodoi")
                                    );
                                    item.saveTx();
                                    ShortDOI.counter++;
                                } else if (
                                    item.hasTag(
                                        ShortDOI.getPref("tag_invalid")
                                    ) ||
                                    item.hasTag(
                                        ShortDOI.getPref("tag_multiple")
                                    ) ||
                                    item.hasTag(ShortDOI.getPref("tag_nodoi"))
                                ) {
                                    item.removeTag(
                                        ShortDOI.getPref("tag_invalid")
                                    );
                                    item.removeTag(
                                        ShortDOI.getPref("tag_multiple")
                                    );
                                    item.removeTag(
                                        ShortDOI.getPref("tag_nodoi")
                                    );
                                    item.saveTx();
                                }
                            }
                            ShortDOI.updateNextItem(operation);
                        } else {
                            ShortDOI.invalidate(item, operation);
                        }
                    } else if (req.status == 404) {
                        ShortDOI.invalidate(item, operation);
                    } else {
                        ShortDOI.updateNextItem(operation);
                    }
                }
            };

            req.send(null);
        } else {
            //operation == "check"

            req.onreadystatechange = function () {
                if (req.readyState == 4) {
                    if (req.status == 404) {
                        ShortDOI.invalidate(item, operation);
                    } else if (req.status == 200) {
                        if (req.response.responseCode == 200) {
                            ShortDOI.invalidate(item, operation);
                        } else {
                            if (req.response.handle != oldDOI) {
                                var newDOI = req.response.handle.toLowerCase();
                                item.setField("DOI", newDOI);
                                item.removeTag(ShortDOI.getPref("tag_invalid"));
                                item.removeTag(
                                    ShortDOI.getPref("tag_multiple")
                                );
                                item.removeTag(ShortDOI.getPref("tag_nodoi"));
                                item.saveTx();
                            } else if (
                                item.hasTag(ShortDOI.getPref("tag_invalid")) ||
                                item.hasTag(ShortDOI.getPref("tag_multiple")) ||
                                item.hasTag(ShortDOI.getPref("tag_nodoi"))
                            ) {
                                item.removeTag(ShortDOI.getPref("tag_invalid"));
                                item.removeTag(
                                    ShortDOI.getPref("tag_multiple")
                                );
                                item.removeTag(ShortDOI.getPref("tag_nodoi"));
                                item.saveTx();
                            }
                            ShortDOI.counter++;
                            ShortDOI.updateNextItem(operation);
                        }
                    } else {
                        ShortDOI.updateNextItem(operation);
                    }
                }
            };

            req.send(null);
        }
    }
};

ShortDOI.invalidate = function (item, operation) {
    if (item.isRegularItem()) {
        error_invalid = true;
        if (ShortDOI.getPref("tag_invalid") !== "")
            item.addTag(ShortDOI.getPref("tag_invalid"), 1);
        item.saveTx();
    }
    ShortDOI.updateNextItem(operation);
};

if (typeof window !== "undefined") {
    window.addEventListener(
        "load",
        function (e) {
            ShortDOI.init();
        },
        false
    );
}

ShortDOI.crossrefLookup = function (item, operation) {
    var crossrefOpenURL =
        "https://www.crossref.org/openurl?pid=zoteroDOI@wiernik.org&";
    var ctx = Zotero.OpenURL.createContextObject(item, "1.0");
    if (ctx) {
        var url = crossrefOpenURL + ctx + "&multihit=true";
        var req = new XMLHttpRequest();
        req.open("GET", url, true);

        req.onreadystatechange = function () {
            if (req.readyState == 4) {
                if (req.status == 200) {
                    var response = req.responseXML.getElementsByTagName(
                        "query"
                    )[0];
                    var status = response.getAttribute("status");
                    if (status === "resolved") {
                        var doi = response.getElementsByTagName("doi")[0]
                            .childNodes[0].nodeValue;
                        if (operation === "short") {
                            item.setField("DOI", doi);
                            ShortDOI.updateItem(item, operation);
                        } else {
                            item.setField("DOI", doi);
                            item.removeTag(ShortDOI.getPref("tag_invalid"));
                            item.removeTag(ShortDOI.getPref("tag_multiple"));
                            item.removeTag(ShortDOI.getPref("tag_nodoi"));
                            item.saveTx();
                            ShortDOI.counter++;
                            ShortDOI.updateNextItem(operation);
                        }
                    } else if (status === "unresolved") {
                        error_nodoi = true;
                        item.removeTag(ShortDOI.getPref("tag_invalid"));
                        item.removeTag(ShortDOI.getPref("tag_multiple"));
                        item.removeTag(ShortDOI.getPref("tag_nodoi"));
                        if (ShortDOI.getPref("tag_nodoi") !== "")
                            item.addTag(ShortDOI.getPref("tag_nodoi"), 1);
                        item.saveTx();
                        ShortDOI.updateNextItem(operation);
                    } else if (status === "multiresolved") {
                        error_multiple = true;
                        Zotero.Attachments.linkFromURL({
                            url: crossrefOpenURL + ctx,
                            parentItemID: item.id,
                            contentType: "text/html",
                            title: "Multiple DOIs found",
                        });
                        if (
                            item.hasTag(ShortDOI.getPref("tag_invalid")) ||
                            item.hasTag(ShortDOI.getPref("tag_nodoi"))
                        ) {
                            item.removeTag(ShortDOI.getPref("tag_invalid"));
                            item.removeTag(ShortDOI.getPref("tag_nodoi"));
                        }
                        // TODO: Move this tag to the attachment link
                        if (ShortDOI.getPref("tag_multiple") !== "")
                            item.addTag(ShortDOI.getPref("tag_multiple"), 1);
                        item.saveTx();
                        ShortDOI.updateNextItem(operation);
                    } else {
                        Zotero.debug(
                            "Zotero DOI Manager: CrossRef lookup: Unknown status code: " +
                            status
                        );
                        ShortDOI.updateNextItem(operation);
                    }
                } else {
                    ShortDOI.updateNextItem(operation);
                }
            }
        };

        req.send(null);
    }

    return false;
};