define(function(require, exports, module) {
"use strict";
/** simple statusbar **/
var dom = require("ace/lib/dom");
var lang = require("ace/lib/lang");

var commands = [{
    name: "leftToRight",
    bindKey: { win: "Ctrl-Alt-Shift-L", mac: "Command-Alt-Shift-L" },
    exec: function(editor) {
        editor.session.$bidiHandler.setRtlDirection(editor, false);
    },
    readOnly: true
}, {
    name: "rightToLeft",
    bindKey: { win: "Ctrl-Alt-Shift-R",  mac: "Command-Alt-Shift-R" },
    exec: function(editor) {
        editor.session.$bidiHandler.setRtlDirection(editor, true);
    },
    readOnly: true
}];

var Editor = require("../editor").Editor;
require("../config").defineOptions(Editor.prototype, "editor", {
    rtlText: {
        set: function(val) {
            if (val) {
                this.on("session", onChange);
                this.on("changeSelection", onChangeSelection);
                this.renderer.on("afterRender", updateLineDirection);
                this.commands.on("exec", onCommandEmitted);
                this.commands.addCommands(commands);
            } else {
                this.off("session", onChange);
                this.off("changeSelection", onChangeSelection);
                this.renderer.off("afterRender", updateLineDirection);
                this.commands.off("exec", onCommandEmitted);
                this.commands.removeCommands(commands);
                clearTextLayer(this.renderer);
            }
            this.renderer.updateFull();
        }
    }
});

/**
 * Whenever the selection is changed, prevent cursor (lead) to be positioned at
 * position 0 of right-to-left line in order to maintain the RLE marker at this position.
 * When cursor reaches position 0, either advance it to position 1 of current line (default) 
 * or to last position of previous line (if it comes from position 1 as the result of commands
 * mentioned in 'onCommandEmitted' event handler).
 * This serves few purposes:
 * - ensures cursor visual movement as if RLE mark doesn't exist.
 * - prevents character insertion before RLE mark.
 * - prevents RLE mark removal when 'delete' is pressed when cursot stays at position 0.         
 * - ensures RLE mark removal on line merge, when 'delete' is pressed and cursor stays 
 *   at last position of previous line and when 'backspace' is pressed and cursor  stays at
 *   first position of current line. This is achived by hacking range boundaries on 'remove' operation.
 **/
function onChangeSelection(e, editor) {
    var lead = editor.getSelection().lead;
    if (editor.session.$bidiHandler.isRtlLine(lead.row)) {
        if (lead.column === 0) {
            if (editor.session.$bidiHandler.isMoveLeftOperation && lead.row > 0) {
                editor.getSelection().moveCursorTo(lead.row - 1, editor.session.getLine(lead.row - 1).length);
            } else {
                if (editor.getSelection().isEmpty())
                    lead.column += 1;
                else
                    lead.setPosition(lead.row, lead.column + 1);
            }
        }
    }
}

function onCommandEmitted(commadEvent) {
    commadEvent.editor.session.$bidiHandler.isMoveLeftOperation = /gotoleft|selectleft|backspace|removewordleft/.test(commadEvent.command.name);
}

/**
 * Whenever the document is changed make sure that line break operatin
 * on right-to-left line (like pressing Enter or pasting multi-line text)
 * produces new right-to-left lines
 **/
function onChange(delta, session) {
    session.$bidiHandler.currentRow = null;
    if (session.$bidiHandler.isRtlLine(delta.start.row) && delta.action === 'insert' && delta.lines.length > 1) {
        for (var row = delta.start.row; row < delta.end.row; row++) {
            if (session.getLine(row + 1).charAt(0) !== session.$bidiHandler.RLE)
                session.getDocument().$lines[row + 1] = session.$bidiHandler.RLE + session.getLine(row + 1);
        }
    }
}

function updateLineDirection(e, renderer) {
    var session = renderer.session;
    var $bidiHandler = session.$bidiHandler;
    var cells = renderer.$textLayer.$lines.cells;
    var width = renderer.layerConfig.width - renderer.layerConfig.padding + "px";
    cells.forEach(function(cell) {
        var style = cell.element.style;
        if ($bidiHandler && $bidiHandler.isRtlLine(cell.row)) {
            style.direction = "rtl";
            style.textAlign = "right";
            style.width = width;
        } else {
            style.direction = "";
            style.textAlign = "";
            style.width = "";
        }
    });
}

function clearTextLayer(renderer) {
    var lines = renderer.$textLayer.$lines;
    lines.cells.forEach(clear);
    lines.cellCache.forEach(clear);
    function clear(cell) {
        var style = cell.element.style;
        style.direction = style.textAlign = style.width = "";
    }
}

});
