/**
 * Copyright (C) 2014 KO GmbH <copyright@kogmbh.com>
 *
 * @licstart
 * This file is part of WebODF.
 *
 * WebODF is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Affero General Public License (GNU AGPL)
 * as published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * WebODF is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with WebODF.  If not, see <http://www.gnu.org/licenses/>.
 * @licend
 *
 * @source: http://www.webodf.org/
 * @source: https://github.com/kogmbh/WebODF/
 */

/*global document, window, runtime, FileReader, alert, Uint8Array, Blob, saveAs, Wodo*/

function createReviewEditor() {
    "use strict";

    var editor = null,
        editorOptions,
        loadedFilename;

    /*jslint emptyblock: true*/
    /**
     * @return {undefined}
     */
    function startEditing() {
    }
    /*jslint emptyblock: false*/

    /**
     * extract document url from the url-fragment
     *
     * @return {?string}
     */
    function guessDocUrl() {
        var pos, docUrl = String(document.location);
        // If the URL has a fragment (#...), try to load the file it represents
        pos = docUrl.indexOf('#');
        if (pos !== -1) {
            docUrl = docUrl.substr(pos + 1);
        } else {
            docUrl = "welcome.odt";
        }
        return docUrl || null;
    }

    function fileSelectHandler(evt) {
        var file, files, reader;
        files = (evt.target && evt.target.files) ||
            (evt.dataTransfer && evt.dataTransfer.files);
        function onLoadEnd() {
            if (reader.readyState === 2) {
                runtime.registerFile(file.name, reader.result);
                loadedFilename = file.name;
                editor.openDocumentFromUrl(loadedFilename, startEditing);
            }
        }
        if (files && files.length === 1) {
            if (!editor.isDocumentModified() ||
                window.confirm("There are unsaved changes to the file. Do you want to discard them?")) {
                editor.closeDocument(function() {
                    file = files[0];
                    reader = new FileReader();
                    reader.onloadend = onLoadEnd;
                    reader.readAsArrayBuffer(file);
                });
            }
        } else {
            alert("File could not be opened in this browser.");
        }
    }

    function enhanceRuntime() {
        var openedFiles = {},
            readFile = runtime.readFile;
        runtime.readFile = function (path, encoding, callback) {
            var array;
            if (openedFiles.hasOwnProperty(path)) {
                array = new Uint8Array(openedFiles[path]);
                callback(undefined, array);
            } else {
                return readFile(path, encoding, callback);
            }
        };
        runtime.registerFile = function (path, data) {
            openedFiles[path] = data;
        };
    }

    function createFileLoadForm() {
        var form = document.createElement("form"),
            input = document.createElement("input");

        function internalHandler(evt) {
            if (input.value !== "") {
                fileSelectHandler(evt);
            }
            // reset to "", so selecting the same file next time still trigger the change handler
            input.value = "";
        }
        form.appendChild(input);
        form.style.display = "none";
        input.id = "fileloader";
        input.setAttribute("type", "file");
        input.addEventListener("change", internalHandler, false);
        document.body.appendChild(form);
    }

    function load() {
        var form = document.getElementById("fileloader");
        if (!form) {
            enhanceRuntime();
            createFileLoadForm();
            form = document.getElementById("fileloader");
        }
        form.click();
    }

    function save() {
        function saveByteArrayLocally(err, data) {
            if (err) {
                alert(err);
                return;
            }
            // TODO: odfcontainer should have a property mimetype
            var mimetype = "application/vnd.oasis.opendocument.text",
                filename = loadedFilename || "doc.odt",
                blob = new Blob([data.buffer], {type: mimetype});
            saveAs(blob, filename);
            // TODO: hm, saveAs could fail or be cancelled
            editor.setDocumentModified(false);
        }

        editor.getDocumentAsByteArray(saveByteArrayLocally);
    }

    editorOptions = {
        loadCallback: load,
        saveCallback: save,
        modus: Wodo.MODUS_REVIEW,
        allFeaturesEnabled: true
    };

    function onEditorCreated(err, e) {
        var docUrl = guessDocUrl();

        if (err) {
            // something failed unexpectedly
            alert(err);
            return;
        }

        editor = e;
        editor.setUserData({
            fullName: "Curious WebODF-Reviewer",
            color:    "black"
        });

        window.addEventListener("beforeunload", function (e) {
            var confirmationMessage = "There are unsaved changes to the file.";

            if (editor.isDocumentModified()) {
                // Gecko + IE
                (e || window.event).returnValue = confirmationMessage;
                // Webkit, Safari, Chrome etc.
                return confirmationMessage;
            }
        });

        if (docUrl) {
            loadedFilename = docUrl;
            editor.openDocumentFromUrl(docUrl, startEditing);
        }
    }

    Wodo.createTextEditor('editorContainer', editorOptions, onEditorCreated);
}
