~azzar1/unity/add-show-desktop-key

/* IVLE - Informatics Virtual Learning Environment

 * Copyright (C) 2007-2008 The University of Melbourne

 *

 * This program 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 2 of the License, or

 * (at your option) any later version.

 *

 * This program 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 this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

 *

 * Module: Console (Client-side JavaScript)

 * Author: Tom Conway, Matt Giuca

 * Date: 30/1/2008

 */

var server_key;

/* Begin religious debate (tabs vs spaces) here: */

/* (This string will be inserted in the console when the user presses the Tab

 * key) */

TAB_STRING = "    ";

/* Console DOM objects */

console_body = null;

console_filler = null;

windowpane_mode = false;

server_started = false;

/* Starts the console server, if it isn't already.

 * This can be called any number of times - it only starts the one server.

 * This is a separate step from console_init, as the server is only to be

 * started once the first command is entered.

 * Does not return a value. Writes to global variables

 * server_host, and server_port.

 */

function start_server()

{

    if (server_started) return;

    var xhr = ajax_call("consoleservice", "start", {}, "POST");

    var json_text = xhr.responseText;

    server_key = JSON.parse(json_text);

    server_started = true;

}

/** Initialises the console. All apps which import console are required to

 * call this function.

 * Optional "windowpane" (bool), if true, will cause the console to go into

 * "window pane" mode which will allow it to be opened and closed, and float

 * over the page.

 * (Defaults to closed).

 */

function console_init(windowpane)

{

    /* Set up the console as a floating pane */

    console_body = document.getElementById("console_body");

    /* If there is no console body, don't worry.

     * (This lets us import console.js even on pages without a console box */

    if (console_body == null) return;

    console_filler = document.getElementById("console_filler");

    if (windowpane)

    {

        windowpane_mode = true;

        console_minimize();

    }

    /* TEMP: Start the server now.

     * Ultimately we want the server to start only when a line is typed, but

     * it currently does it asynchronously and doesn't start in time for the

     * first line. */

    start_server();

}

/** Hide the main console panel, so the console minimizes to just an input box

 *  at the page bottom. */

function console_minimize()

{

    if (!windowpane_mode) return;

    console_body.setAttribute("class", "windowpane minimal");

    console_filler.setAttribute("class", "windowpane minimal");

}

/** Show the main console panel, so it enlarges out to its full size.

 */

function console_maximize()

{

    if (!windowpane_mode) return;

    console_body.setAttribute("class", "windowpane maximal");

    console_filler.setAttribute("class", "windowpane maximal");

    /* Focus the input box by default */

    document.getElementById("console_inputText").focus()

}

/* current_text is the string currently on the command line.

 * If non-empty, it will be stored at the bottom of the history.

 */

function historyUp(current_text)

{

    /* Remember the changes made to this item */

    this.edited[this.cursor] = current_text;

    if (this.cursor > 0)

    {

        this.cursor--;

    }

    this.earliestCursor = this.cursor;

}

function historyDown(current_text)

{

    /* Remember the changes made to this item */

    this.edited[this.cursor] = current_text;

    if (this.cursor < this.items.length - 1)

    {

        this.cursor++;

    }

}

function historyCurr()

{

    return this.edited[this.cursor];

}

function historySubmit(text)

{

    /* Copy the selected item's "edited" version over the permanent version of

     * the last item. */

    this.items[this.items.length-1] = text;

    /* Add a new blank item */

    this.items[this.items.length] = "";

    this.cursor = this.items.length-1;

    /* Blow away all the edited versions, replacing them with the existing

     * items set.

     * Not the whole history - just start from the earliest edited one.

     * (This avoids slowdown over extended usage time).

     */

    for (var i=this.earliestCursor; i<=this.cursor; i++)

        this.edited[i] = this.items[i];

    this.earliestCursor = this.cursor;

}

function historyShow()

{

    var res = "";

    for (var i = 0; i < this.items.length; i++)

    {

        if (i == this.cursor)

        {

            res += "["

        }

        res += this.items[i].toString();

        if (i == this.cursor)

        {

            res += "]"

        }

        res += " "

    }

    if (this.cursor == this.items.length)

    {

        res += "[]";

    }

    return res;

}

/* How history works

 * This is a fairly complex mechanism due to complications when editing

 * history items. We store two arrays. "items" is the permanent history of

 * each item. "edited" is a "volatile" version of items - the edits made to

 * the history between now and last time you hit "enter".

 * This is because the user can go back and edit any of the previous items,

 * and the edits are remembered until they hit enter.

 *

 * When hitting enter, the "edited" version of the currently selected item

 * replaces the "item" version of the last item in the list.

 * Then a new blank item is created, for the new line of input.

 * Lastly, all the "edited" versions are replaced with their stable versions.

 *

 * Cursor never points to an invalid location.

 */

function History()

{

    this.items = new Array("");

    this.edited = new Array("");

    this.cursor = 0;

    this.earliestCursor = 0;

    this.up = historyUp;

    this.down = historyDown;

    this.curr = historyCurr;

    this.submit = historySubmit;

    this.show = historyShow;

}

var hist = new History();

/** Send a line of text to the Python server, wait for its return, and react

 * to its response by writing to the output box.

 * Also maximize the console window if not already.

 */

function console_enter_line(inputline, which)

{

    /* Start the server if it hasn't already been started */

    start_server();

    var args = {"key": server_key, "text":inputline};

    var xmlhttp = ajax_call("consoleservice", which, args, "POST");

    var res = JSON.parse(xmlhttp.responseText);

    var output = document.getElementById("console_output");

    {

        var pre = document.createElement("pre");

        pre.setAttribute("class", "inputMsg");

        pre.appendChild(document.createTextNode(inputline + "\n"));

        output.appendChild(pre);

    }

    if (res.hasOwnProperty('okay'))

    {

        // Success!

        // print out the output (res.okay[0])

        var pre = document.createElement("pre");

        pre.setAttribute("class", "outputMsg");

        pre.appendChild(document.createTextNode(res.okay[0]));

        output.appendChild(pre);

        // print out the return value (res.okay[1])

        if (res.okay[1])

        {

            var pre = document.createElement("pre");

            pre.setAttribute("class", "outputMsg");

            pre.appendChild(document.createTextNode(res.okay[1] + "\n"));

            output.appendChild(pre);

        }

        // set the prompt to >>>

        var prompt = document.getElementById("console_prompt");

        prompt.replaceChild(document.createTextNode(">>> "), prompt.firstChild);

    }

    else if (res.hasOwnProperty('exc'))

    {

        // Failure!

        // print out any output that came before the error

        if (res.exc[0].length > 0)

        {

            var pre = document.createElement("pre");

            pre.setAttribute("class", "outputMsg");

            pre.appendChild(document.createTextNode(res.exc[0]));

            output.appendChild(pre);

        }

        // print out the error message (res.exc)

        var pre = document.createElement("pre");

        pre.setAttribute("class", "errorMsg");

        pre.appendChild(document.createTextNode(res.exc[1]));

        output.appendChild(pre);

    }

    else if (res.hasOwnProperty('more'))

    {

        // Need more input, so set the prompt to ...

        var prompt = document.getElementById("console_prompt");

        prompt.replaceChild(document.createTextNode("... "), prompt.firstChild);

    }

    else {

        // assert res.hasOwnProperty('input')

        var prompt = document.getElementById("console_prompt");

        prompt.replaceChild(document.createTextNode("+++ "), prompt.firstChild);

    }

    /* Open up the console so we can see the output */

    console_maximize();

}

function catch_input(key)

{

    var inp = document.getElementById('console_inputText');

    switch (key)

    {

    case 9:                 /* Tab key */

        var selstart = inp.selectionStart;

        var selend = inp.selectionEnd;

        if (selstart == selend)

        {

            /* No selection, just a carat. Insert a tab here. */

            inp.value = inp.value.substr(0, selstart)

                + TAB_STRING + inp.value.substr(selstart);

        }

        else

        {

            /* Text is selected. Just indent the whole line

             * by inserting a tab at the start */

            inp.value = TAB_STRING + inp.value;

        }

        /* Update the selection so the same characters as before are selected

         */

        inp.selectionStart = selstart + TAB_STRING.length;

        inp.selectionEnd = inp.selectionStart + (selend - selstart);

        /* Cancel the event, so the TAB key doesn't move focus away from this

         * box */

        return false;

        /* Note: If it happens that some browsers don't support event

         * cancelling properly, this hack might work instead:

        setTimeout(

            "document.getElementById('console_inputText').focus()",

            0);

         */

        break;

    case 13:                /* Enter key */

        /* Send the line of text to the server */

        console_enter_line(inp.value, "chat");

        hist.submit(inp.value);

        inp.value = hist.curr();

        break;

    case 38:                /* Up arrow */

        hist.up(inp.value);

        inp.value = hist.curr();

        break;

    case 40:                /* Down arrow */

        hist.down(inp.value);

        inp.value = hist.curr();

        break;

    }

}