/*
 Copyright (c) 2011 Eli Grey, http://eligrey.com
 This file is based on:
 https://github.com/eligrey/FileSaver.js/blob/master/FileSaver.js ,
 licensed under X11/MIT.
 See https://github.com/eligrey/FileSaver.js/blob/master/LICENSE.md

 This file is part of SwitchySharp.
 SwitchySharp is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 SwitchySharp 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 General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with SwitchySharp.  If not, see <http://www.gnu.org/licenses/>.
 */

var saveAs = saveAs || (function (view) {
    "use strict";
    var
        doc = view.document
    // only get URL when necessary in case BlobBuilder.js hasn't overridden it yet
        , get_URL = function () {
            return view.URL || view.webkitURL || view;
        }
        , URL = view.URL || view.webkitURL || view
        , save_link = doc.createElementNS("http://www.w3.org/1999/xhtml", "a")
        , can_use_save_link = "download" in save_link
        , click = function (node) {
            var event = doc.createEvent("MouseEvents");
            event.initMouseEvent(
                "click", true, false, view, 0, 0, 0, 0, 0
                , false, false, false, false, 0, null
            );
            return node.dispatchEvent(event); // false if event was cancelled
        }
        , webkit_req_fs = view.webkitRequestFileSystem
        , req_fs = view.requestFileSystem || webkit_req_fs || view.mozRequestFileSystem
        , throw_outside = function (ex) {
            (view.setImmediate || view.setTimeout)(function () {
                throw ex;
            }, 0);
        }
        , force_saveable_type = "application/octet-stream"
        , fs_min_size = 0
        , deletion_queue = []
        , process_deletion_queue = function () {
            var i = deletion_queue.length;
            while (i--) {
                var file = deletion_queue[i];
                if (typeof file === "string") { // file is an object URL
                    URL.revokeObjectURL(file);
                } else { // file is a File
                    file.remove();
                }
            }
            deletion_queue.length = 0; // clear queue
        }
        , dispatch = function (filesaver, event_types, event) {
            event_types = [].concat(event_types);
            var i = event_types.length;
            while (i--) {
                var listener = filesaver["on" + event_types[i]];
                if (typeof listener === "function") {
                    try {
                        listener.call(filesaver, event || filesaver);
                    } catch (ex) {
                        throw_outside(ex);
                    }
                }
            }
        }
        , FileSaver = function (blob, name) {
            // First try a.download, then web filesystem, then object URLs
            var
                filesaver = this
                , type = blob.type
                , blob_changed = false
                , object_url
                , target_view
                , get_object_url = function (blob) {
                    var object_url = get_URL().createObjectURL(blob);
                    deletion_queue.push(object_url);
                    return object_url;
                }
                , dispatch_all = function () {
                    dispatch(filesaver, "writestart progress write writeend".split(" "));
                }
            // on any filesys errors revert to saving with object URLs
                , fs_error = function () {
                    // don't create more object URLs than needed
                    if (blob_changed || !object_url) {
                        object_url = get_object_url(blob);
                    }
                    target_view.location.href = object_url;
                    filesaver.readyState = filesaver.DONE;
                    dispatch_all();
                }
                , abortable = function (func) {
                    return function () {
                        if (filesaver.readyState !== filesaver.DONE) {
                            return func.apply(this, arguments);
                        }
                    };
                }
                , create_if_not_found = {create:true, exclusive:false}
                , slice
                ;
            filesaver.readyState = filesaver.INIT;
            if (!name) {
                name = "download";
            }
            if (can_use_save_link) {
                object_url = get_object_url(blob);
                save_link.href = object_url;
                save_link.download = name;
                if (click(save_link)) {
                    filesaver.readyState = filesaver.DONE;
                    dispatch_all();
                    return;
                }
            }
            // Object and web filesystem URLs have a problem saving in Google Chrome when
            // viewed in a tab, so I force save with application/octet-stream
            // http://code.google.com/p/chromium/issues/detail?id=91158
            if (view.chrome && type && type !== force_saveable_type) {
                slice = blob.slice || blob.webkitSlice;
                blob = slice.call(blob, 0, blob.size, force_saveable_type);
                blob_changed = true;
            }
            // Since I can't be sure that the guessed media type will trigger a download
            // in WebKit, I append .download to the filename.
            // https://bugs.webkit.org/show_bug.cgi?id=65440
            //if (webkit_req_fs && name !== "download") {
            //	name += ".download";
            //}
            if (type === force_saveable_type || webkit_req_fs) {
                target_view = view;
            } else {
                target_view = view.open();
            }
            if (!req_fs) {
                fs_error();
                return;
            }
            fs_min_size += blob.size;
            req_fs(view.TEMPORARY, fs_min_size, abortable(function (fs) {
                fs.root.getDirectory("saved", create_if_not_found, abortable(function (dir) {
                    var save = function () {
                        dir.getFile(name, create_if_not_found, abortable(function (file) {
                            file.createWriter(abortable(function (writer) {
                                writer.onwriteend = function (event) {
                                    target_view.location.href = file.toURL();
                                    deletion_queue.push(file);
                                    filesaver.readyState = filesaver.DONE;
                                    dispatch(filesaver, "writeend", event);
                                };
                                writer.onerror = function () {
                                    var error = writer.error;
                                    if (error.code !== error.ABORT_ERR) {
                                        fs_error();
                                    }
                                };
                                "writestart progress write abort".split(" ").forEach(function (event) {
                                    writer["on" + event] = filesaver["on" + event];
                                });
                                writer.write(blob);
                                filesaver.abort = function () {
                                    writer.abort();
                                    filesaver.readyState = filesaver.DONE;
                                };
                                filesaver.readyState = filesaver.WRITING;
                            }), fs_error);
                        }), fs_error);
                    };
                    dir.getFile(name, {create:false}, abortable(function (file) {
                        // delete file if it already exists
                        file.remove();
                        save();
                    }), abortable(function (ex) {
                        if (ex.code === ex.NOT_FOUND_ERR) {
                            save();
                        } else {
                            fs_error();
                        }
                    }));
                }), fs_error);
            }), fs_error);
        }
        , FS_proto = FileSaver.prototype
        , saveAs = function (blob, name) {
            return new FileSaver(blob, name);
        }
        ;
    FS_proto.abort = function () {
        var filesaver = this;
        filesaver.readyState = filesaver.DONE;
        dispatch(filesaver, "abort");
    };
    FS_proto.readyState = FS_proto.INIT = 0;
    FS_proto.WRITING = 1;
    FS_proto.DONE = 2;

    FS_proto.error =
        FS_proto.onwritestart =
            FS_proto.onprogress =
                FS_proto.onwrite =
                    FS_proto.onabort =
                        FS_proto.onerror =
                            FS_proto.onwriteend =
                                null;

    view.addEventListener("unload", process_deletion_queue, false);
    return saveAs;
}(self));
