// Copyright (c) IPython Development Team.
// Distributed under the terms of the Modified BSD License.
/**
 *
 *
 * @module codecell
 * @namespace codecell
 * @class CodeCell
 */


define([
    'base/js/namespace',
    'jquery',
    'base/js/utils',
    'base/js/keyboard',
    'notebook/js/cell',
    'notebook/js/outputarea',
    'notebook/js/completer',
    'notebook/js/celltoolbar',
    'codemirror/lib/codemirror',
    'codemirror/mode/python/python',
    'notebook/js/codemirror-ipython'
], function(IPython, $, utils, keyboard, cell, outputarea, completer, celltoolbar, CodeMirror, cmpython, cmip) {
    "use strict";
    
    var Cell = cell.Cell;

    /* local util for codemirror */
    var posEq = function(a, b) {return a.line == b.line && a.ch == b.ch;};

    /**
     *
     * function to delete until previous non blanking space character
     * or first multiple of 4 tabstop.
     * @private
     */
    CodeMirror.commands.delSpaceToPrevTabStop = function(cm){
        var from = cm.getCursor(true), to = cm.getCursor(false), sel = !posEq(from, to);
        if (!posEq(from, to)) { cm.replaceRange("", from, to); return; }
        var cur = cm.getCursor(), line = cm.getLine(cur.line);
        var tabsize = cm.getOption('tabSize');
        var chToPrevTabStop = cur.ch-(Math.ceil(cur.ch/tabsize)-1)*tabsize;
        from = {ch:cur.ch-chToPrevTabStop,line:cur.line};
        var select = cm.getRange(from,cur);
        if( select.match(/^\ +$/) !== null){
            cm.replaceRange("",from,cur);
        } else {
            cm.deleteH(-1,"char");
        }
    };

    var keycodes = keyboard.keycodes;

    var CodeCell = function (kernel, options) {
        /**
         * Constructor
         *
         * A Cell conceived to write code.
         *
         * Parameters:
         *  kernel: Kernel instance
         *      The kernel doesn't have to be set at creation time, in that case
         *      it will be null and set_kernel has to be called later.
         *  options: dictionary
         *      Dictionary of keyword arguments.
         *          events: $(Events) instance 
         *          config: dictionary
         *          keyboard_manager: KeyboardManager instance 
         *          notebook: Notebook instance
         *          tooltip: Tooltip instance
         */
        this.kernel = kernel || null;
        this.notebook = options.notebook;
        this.collapsed = false;
        this.events = options.events;
        this.tooltip = options.tooltip;
        this.config = options.config;

        // create all attributed in constructor function
        // even if null for V8 VM optimisation
        this.input_prompt_number = null;
        this.celltoolbar = null;
        this.output_area = null;
        // Keep a stack of the 'active' output areas (where active means the 
        // output area that recieves output).  When a user activates an output
        // area, it gets pushed to the stack.  Then, when the output area is
        // deactivated, it's popped from the stack.  When the stack is empty,
        // the cell's output area is used.
        this.active_output_areas = [];
        var that = this;
        Object.defineProperty(this, 'active_output_area', {
            get: function() {
                if (that.active_output_areas && that.active_output_areas.length > 0) {
                    return that.active_output_areas[that.active_output_areas.length-1];
                } else {
                    return that.output_area;
                }
            },
        });

        this.last_msg_id = null;
        this.completer = null;
        this.widget_views = [];

        var config = utils.mergeopt(CodeCell, this.config);
        Cell.apply(this,[{
            config: config, 
            keyboard_manager: options.keyboard_manager, 
            events: this.events}]);

        // Attributes we want to override in this subclass.
        this.cell_type = "code";
        this.element.focusout(
            function() { that.auto_highlight(); }
        );
    };

    CodeCell.options_default = {
        cm_config : {
            extraKeys: {
                "Tab" :  "indentMore",
                "Shift-Tab" : "indentLess",
                "Backspace" : "delSpaceToPrevTabStop",
                "Cmd-/" : "toggleComment",
                "Ctrl-/" : "toggleComment"
            },
            mode: 'ipython',
            theme: 'ipython',
            matchBrackets: true
        }
    };

    CodeCell.msg_cells = {};

    CodeCell.prototype = Object.create(Cell.prototype);

    /**
     * @method push_output_area
     */
    CodeCell.prototype.push_output_area = function (output_area) {
        this.active_output_areas.push(output_area);
    };

    /**
     * @method pop_output_area
     */
    CodeCell.prototype.pop_output_area = function (output_area) {
        var index = this.active_output_areas.lastIndexOf(output_area);
        if (index > -1) {
            this.active_output_areas.splice(index, 1);
        }
    };

    /**
     * @method auto_highlight
     */
    CodeCell.prototype.auto_highlight = function () {
        this._auto_highlight(this.config.cell_magic_highlight);
    };

    /** @method create_element */
    CodeCell.prototype.create_element = function () {
        Cell.prototype.create_element.apply(this, arguments);

        var cell =  $('<div></div>').addClass('cell code_cell');
        cell.attr('tabindex','2');

        var input = $('<div></div>').addClass('input');
        var prompt = $('<div/>').addClass('prompt input_prompt');
        var inner_cell = $('<div/>').addClass('inner_cell');
        this.celltoolbar = new celltoolbar.CellToolbar({
            cell: this, 
            notebook: this.notebook});
        inner_cell.append(this.celltoolbar.element);
        var input_area = $('<div/>').addClass('input_area');
        this.code_mirror = new CodeMirror(input_area.get(0), this.cm_config);
        this.code_mirror.on('keydown', $.proxy(this.handle_keyevent,this))
        $(this.code_mirror.getInputField()).attr("spellcheck", "false");
        inner_cell.append(input_area);
        input.append(prompt).append(inner_cell);

        var widget_area = $('<div/>')
            .addClass('widget-area')
            .hide();
        this.widget_area = widget_area;
        var widget_prompt = $('<div/>')
            .addClass('prompt')
            .appendTo(widget_area);
        var widget_subarea = $('<div/>')
            .addClass('widget-subarea')
            .appendTo(widget_area);
        this.widget_subarea = widget_subarea;
        var that = this;
        var widget_clear_buton = $('<button />')
            .addClass('close')
            .html('&times;')
            .click(function() {
                widget_area.slideUp('', function(){ 
                    for (var i = 0; i < that.widget_views.length; i++) {
                        that.widget_views[i].remove();
                    }
                    that.widget_views = [];
                    widget_subarea.html(''); 
                });
            })
            .appendTo(widget_prompt);

        var output = $('<div></div>');
        cell.append(input).append(widget_area).append(output);
        this.element = cell;
        this.output_area = new outputarea.OutputArea({
            selector: output, 
            prompt_area: true, 
            events: this.events, 
            keyboard_manager: this.keyboard_manager});
        this.completer = new completer.Completer(this, this.events);
    };

    /**
    *  Display a widget view in the cell.
    */
    CodeCell.prototype.display_widget_view = function(view_promise) {
        
        // Display a dummy element
        var dummy = $('<div/>');
        this.widget_subarea.append(dummy);

        // Display the view.
        var that = this;
        return view_promise.then(function(view) {
            dummy.replaceWith(view.$el);
            this.widget_views.push(view);
            return view;
        });
    };

    /** @method bind_events */
    CodeCell.prototype.bind_events = function () {
        Cell.prototype.bind_events.apply(this);
        var that = this;

        this.element.focusout(
            function() { that.auto_highlight(); }
        );
    };


    /**
     *  This method gets called in CodeMirror's onKeyDown/onKeyPress
     *  handlers and is used to provide custom key handling. Its return
     *  value is used to determine if CodeMirror should ignore the event:
     *  true = ignore, false = don't ignore.
     *  @method handle_codemirror_keyevent
     */

    CodeCell.prototype.handle_codemirror_keyevent = function (editor, event) {

        var that = this;
        // whatever key is pressed, first, cancel the tooltip request before
        // they are sent, and remove tooltip if any, except for tab again
        var tooltip_closed = null;
        if (event.type === 'keydown' && event.which != keycodes.tab ) {
            tooltip_closed = this.tooltip.remove_and_cancel_tooltip();
        }

        var cur = editor.getCursor();
        if (event.keyCode === keycodes.enter){
            this.auto_highlight();
        }

        if (event.which === keycodes.down && event.type === 'keypress' && this.tooltip.time_before_tooltip >= 0) {
            // triger on keypress (!) otherwise inconsistent event.which depending on plateform
            // browser and keyboard layout !
            // Pressing '(' , request tooltip, don't forget to reappend it
            // The second argument says to hide the tooltip if the docstring
            // is actually empty
            this.tooltip.pending(that, true);
        } else if ( tooltip_closed && event.which === keycodes.esc && event.type === 'keydown') {
            // If tooltip is active, cancel it.  The call to
            // remove_and_cancel_tooltip above doesn't pass, force=true.
            // Because of this it won't actually close the tooltip
            // if it is in sticky mode. Thus, we have to check again if it is open
            // and close it with force=true.
            if (!this.tooltip._hidden) {
                this.tooltip.remove_and_cancel_tooltip(true);
            }
            // If we closed the tooltip, don't let CM or the global handlers
            // handle this event.
            event.codemirrorIgnore = true;
            event.preventDefault();
            return true;
        } else if (event.keyCode === keycodes.tab && event.type === 'keydown' && event.shiftKey) {
                if (editor.somethingSelected() || editor.getSelections().length !== 1){
                    var anchor = editor.getCursor("anchor");
                    var head = editor.getCursor("head");
                    if( anchor.line != head.line){
                        return false;
                    }
                }
                this.tooltip.request(that);
                event.codemirrorIgnore = true;
                event.preventDefault();
                return true;
        } else if (event.keyCode === keycodes.tab && event.type == 'keydown') {
            // Tab completion.
            this.tooltip.remove_and_cancel_tooltip();

            // completion does not work on multicursor, it might be possible though in some cases
            if (editor.somethingSelected() || editor.getSelections().length > 1) {
                return false;
            }
            var pre_cursor = editor.getRange({line:cur.line,ch:0},cur);
            if (pre_cursor.trim() === "") {
                // Don't autocomplete if the part of the line before the cursor
                // is empty.  In this case, let CodeMirror handle indentation.
                return false;
            } else {
                event.codemirrorIgnore = true;
                event.preventDefault();
                this.completer.startCompletion();
                return true;
            }
        } 
        
        // keyboard event wasn't one of those unique to code cells, let's see
        // if it's one of the generic ones (i.e. check edit mode shortcuts)
        return Cell.prototype.handle_codemirror_keyevent.apply(this, [editor, event]);
    };

    // Kernel related calls.

    CodeCell.prototype.set_kernel = function (kernel) {
        this.kernel = kernel;
    };

    /**
     * Execute current code cell to the kernel
     * @method execute
     */
    CodeCell.prototype.execute = function () {
        if (!this.kernel || !this.kernel.is_connected()) {
            console.log("Can't execute, kernel is not connected.");
            return;
        }

        this.active_output_area.clear_output();
        
        // Clear widget area
        for (var i = 0; i < this.widget_views.length; i++) {
            this.widget_views[i].remove();
        }
        this.widget_views = [];
        this.widget_subarea.html('');
        this.widget_subarea.height('');
        this.widget_area.height('');
        this.widget_area.hide();

        this.set_input_prompt('*');
        this.element.addClass("running");
        if (this.last_msg_id) {
            this.kernel.clear_callbacks_for_msg(this.last_msg_id);
        }
        var callbacks = this.get_callbacks();
        
        var old_msg_id = this.last_msg_id;
        this.last_msg_id = this.kernel.execute(this.get_text(), callbacks, {silent: false, store_history: true});
        if (old_msg_id) {
            delete CodeCell.msg_cells[old_msg_id];
        }
        CodeCell.msg_cells[this.last_msg_id] = this;
        this.render();
        this.events.trigger('execute.CodeCell', {cell: this});
    };
    
    /**
     * Construct the default callbacks for
     * @method get_callbacks
     */
    CodeCell.prototype.get_callbacks = function () {
        var that = this;
        return {
            shell : {
                reply : $.proxy(this._handle_execute_reply, this),
                payload : {
                    set_next_input : $.proxy(this._handle_set_next_input, this),
                    page : $.proxy(this._open_with_pager, this)
                }
            },
            iopub : {
                output : function() { 
                    that.active_output_area.handle_output.apply(that.active_output_area, arguments);
                }, 
                clear_output : function() { 
                    that.active_output_area.handle_clear_output.apply(that.active_output_area, arguments);
                }, 
            },
            input : $.proxy(this._handle_input_request, this)
        };
    };
    
    CodeCell.prototype._open_with_pager = function (payload) {
        this.events.trigger('open_with_text.Pager', payload);
    };

    /**
     * @method _handle_execute_reply
     * @private
     */
    CodeCell.prototype._handle_execute_reply = function (msg) {
        this.set_input_prompt(msg.content.execution_count);
        this.element.removeClass("running");
        this.events.trigger('set_dirty.Notebook', {value: true});
    };

    /**
     * @method _handle_set_next_input
     * @private
     */
    CodeCell.prototype._handle_set_next_input = function (payload) {
        var data = {'cell': this, 'text': payload.text, replace: payload.replace};
        this.events.trigger('set_next_input.Notebook', data);
    };

    /**
     * @method _handle_input_request
     * @private
     */
    CodeCell.prototype._handle_input_request = function (msg) {
        this.active_output_area.append_raw_input(msg);
    };


    // Basic cell manipulation.

    CodeCell.prototype.select = function () {
        var cont = Cell.prototype.select.apply(this);
        if (cont) {
            this.code_mirror.refresh();
            this.auto_highlight();
        }
        return cont;
    };

    CodeCell.prototype.render = function () {
        var cont = Cell.prototype.render.apply(this);
        // Always execute, even if we are already in the rendered state
        return cont;
    };
    
    CodeCell.prototype.select_all = function () {
        var start = {line: 0, ch: 0};
        var nlines = this.code_mirror.lineCount();
        var last_line = this.code_mirror.getLine(nlines-1);
        var end = {line: nlines-1, ch: last_line.length};
        this.code_mirror.setSelection(start, end);
    };


    CodeCell.prototype.collapse_output = function () {
        this.output_area.collapse();
    };


    CodeCell.prototype.expand_output = function () {
        this.output_area.expand();
        this.output_area.unscroll_area();
    };

    CodeCell.prototype.scroll_output = function () {
        this.output_area.expand();
        this.output_area.scroll_if_long();
    };

    CodeCell.prototype.toggle_output = function () {
        this.output_area.toggle_output();
    };

    CodeCell.prototype.toggle_output_scroll = function () {
        this.output_area.toggle_scroll();
    };


    CodeCell.input_prompt_classical = function (prompt_value, lines_number) {
        var ns;
        if (prompt_value === undefined || prompt_value === null) {
            ns = "&nbsp;";
        } else {
            ns = encodeURIComponent(prompt_value);
        }
        return 'In&nbsp;[' + ns + ']:';
    };

    CodeCell.input_prompt_continuation = function (prompt_value, lines_number) {
        var html = [CodeCell.input_prompt_classical(prompt_value, lines_number)];
        for(var i=1; i < lines_number; i++) {
            html.push(['...:']);
        }
        return html.join('<br/>');
    };

    CodeCell.input_prompt_function = CodeCell.input_prompt_classical;


    CodeCell.prototype.set_input_prompt = function (number) {
        var nline = 1;
        if (this.code_mirror !== undefined) {
           nline = this.code_mirror.lineCount();
        }
        this.input_prompt_number = number;
        var prompt_html = CodeCell.input_prompt_function(this.input_prompt_number, nline);
        // This HTML call is okay because the user contents are escaped.
        this.element.find('div.input_prompt').html(prompt_html);
    };


    CodeCell.prototype.clear_input = function () {
        this.code_mirror.setValue('');
    };


    CodeCell.prototype.get_text = function () {
        return this.code_mirror.getValue();
    };


    CodeCell.prototype.set_text = function (code) {
        return this.code_mirror.setValue(code);
    };


    CodeCell.prototype.clear_output = function (wait) {
        this.active_output_area.clear_output(wait);
        this.set_input_prompt();
    };


    // JSON serialization

    CodeCell.prototype.fromJSON = function (data) {
        Cell.prototype.fromJSON.apply(this, arguments);
        if (data.cell_type === 'code') {
            if (data.source !== undefined) {
                this.set_text(data.source);
                // make this value the starting point, so that we can only undo
                // to this state, instead of a blank cell
                this.code_mirror.clearHistory();
                this.auto_highlight();
            }
            this.set_input_prompt(data.execution_count);
            this.output_area.trusted = data.metadata.trusted || false;
            this.output_area.fromJSON(data.outputs);
            if (data.metadata.collapsed !== undefined) {
                if (data.metadata.collapsed) {
                    this.collapse_output();
                } else {
                    this.expand_output();
                }
            }
        }
    };


    CodeCell.prototype.toJSON = function () {
        var data = Cell.prototype.toJSON.apply(this);
        data.source = this.get_text();
        // is finite protect against undefined and '*' value
        if (isFinite(this.input_prompt_number)) {
            data.execution_count = this.input_prompt_number;
        } else {
            data.execution_count = null;
        }
        var outputs = this.output_area.toJSON();
        data.outputs = outputs;
        data.metadata.trusted = this.output_area.trusted;
        data.metadata.collapsed = this.output_area.collapsed;
        return data;
    };

    /**
     * handle cell level logic when a cell is unselected
     * @method unselect
     * @return is the action being taken
     */
    CodeCell.prototype.unselect = function () {
        var cont = Cell.prototype.unselect.apply(this);
        if (cont) {
            // When a code cell is usnelected, make sure that the corresponding
            // tooltip and completer to that cell is closed.
            this.tooltip.remove_and_cancel_tooltip(true);
            if (this.completer !== null) {
                this.completer.close();
            }
        }
        return cont;
    };

    // Backwards compatability.
    IPython.CodeCell = CodeCell;

    return {'CodeCell': CodeCell};
});