/*\
title: $:/plugins/tiddlywiki/codemirror/engine.js
type: application/javascript
module-type: library

Text editor engine based on a CodeMirror instance

\*/
(function(){

/*jslint node: true, browser: true */
/*global $tw: false */
"use strict";

var CODEMIRROR_OPTIONS = "$:/config/CodeMirror",
	HEIGHT_VALUE_TITLE = "$:/config/TextEditor/EditorHeight/Height"

// Install CodeMirror
if($tw.browser && !window.CodeMirror) {
	window.CodeMirror = require("$:/plugins/tiddlywiki/codemirror/lib/codemirror.js");
	// Install required CodeMirror plugins
	var configOptions = $tw.wiki.getTiddlerData(CODEMIRROR_OPTIONS,{}),
		req = configOptions.require;
	if(req) {
		if($tw.utils.isArray(req)) {
			for(var index=0; index<req.length; index++) {
				require(req[index]);
			}
		} else {
			require(req);
		}
	}
}

function CodeMirrorEngine(options) {
	// Save our options
	var self = this;
	options = options || {};
	this.widget = options.widget;
	this.value = options.value;
	this.parentNode = options.parentNode;
	this.nextSibling = options.nextSibling;
	// Create the wrapper DIV
	this.domNode = this.widget.document.createElement("div");
	if(this.widget.editClass) {
		this.domNode.className = this.widget.editClass;
	}
	this.domNode.style.display = "inline-block";
	this.parentNode.insertBefore(this.domNode,this.nextSibling);
	this.widget.domNodes.push(this.domNode);
	// Get the configuration options for the CodeMirror object
	var config = $tw.wiki.getTiddlerData(CODEMIRROR_OPTIONS,{}).configuration || {};
	if(!("lineWrapping" in config)) {
		config.lineWrapping = true;
	}
	if(!("lineNumbers" in config)) {
		config.lineNumbers = true;
	}
	config.mode = options.type;
	config.value = options.value;
	// Create the CodeMirror instance
	this.cm = window.CodeMirror(function(cmDomNode) {
		// Note that this is a synchronous callback that is called before the constructor returns
		self.domNode.appendChild(cmDomNode);
	},config);
	// Set up a change event handler
	this.cm.on("change",function() {
		self.widget.saveChanges(self.getText());
	});
	this.cm.on("drop",function(cm,event) {
		event.stopPropagation(); // Otherwise TW's dropzone widget sees the drop event
		return false;
	});
	this.cm.on("keydown",function(cm,event) {
		return self.widget.handleKeydownEvent.call(self.widget,event);
	});
}

/*
Set the text of the engine if it doesn't currently have focus
*/
CodeMirrorEngine.prototype.setText = function(text,type) {
	this.cm.setOption("mode",type);
	if(!this.cm.hasFocus()) {
		this.cm.setValue(text);
	}
};

/*
Get the text of the engine
*/
CodeMirrorEngine.prototype.getText = function() {
	return this.cm.getValue();
};

/*
Fix the height of textarea to fit content
*/
CodeMirrorEngine.prototype.fixHeight = function() {
	if(this.widget.editAutoHeight) {
		// Resize to fit
		this.cm.setSize(null,null);
	} else {
		var fixedHeight = parseInt(this.widget.wiki.getTiddlerText(HEIGHT_VALUE_TITLE,"400px"),10);
		fixedHeight = Math.max(fixedHeight,20);
		this.cm.setSize(null,fixedHeight);
	}
};

/*
Focus the engine node
*/
CodeMirrorEngine.prototype.focus  = function() {
	this.cm.focus();
}

/*
Create a blank structure representing a text operation
*/
CodeMirrorEngine.prototype.createTextOperation = function() {
	var selections = this.cm.listSelections();
	if(selections.length > 0) {
		var anchorPos = this.cm.indexFromPos(selections[0].anchor),
			headPos = this.cm.indexFromPos(selections[0].head);
	}
	var operation = {
		text: this.cm.getValue(),
		selStart: Math.min(anchorPos,headPos),
		selEnd: Math.max(anchorPos,headPos),
		cutStart: null,
		cutEnd: null,
		replacement: null,
		newSelStart: null,
		newSelEnd: null
	};
	operation.selection = operation.text.substring(operation.selStart,operation.selEnd);
	return operation;
};

/*
Execute a text operation
*/
CodeMirrorEngine.prototype.executeTextOperation = function(operation) {
	// Perform the required changes to the text area and the underlying tiddler
	var newText = operation.text;
	if(operation.replacement !== null) {
		this.cm.replaceRange(operation.replacement,this.cm.posFromIndex(operation.cutStart),this.cm.posFromIndex(operation.cutEnd));
		this.cm.setSelection(this.cm.posFromIndex(operation.newSelStart),this.cm.posFromIndex(operation.newSelEnd));
		newText = operation.text.substring(0,operation.cutStart) + operation.replacement + operation.text.substring(operation.cutEnd);
	}
	this.cm.focus();
	return newText;
};

exports.CodeMirrorEngine = CodeMirrorEngine;

})();