/*

WikiTextParser.js

Parses a block of tiddlywiki-format wiki text into a parse tree object.

HTML elements are stored in the tree like this:

	{type: "div", attributes: {
			attr1: value,
			style: {
				name: value,
				name2: value2
			}
		}, children: [
			{child},
			{child},		
		]}

Text nodes are:

	{type: "text", value: "string of text node"}

*/

/*jslint node: true */
"use strict";

var wikiTextMacros = require("./WikiTextMacros.js"),
	wikiTextRules = require("./WikiTextRules.js").wikiTextRules,
	utils = require("./Utils.js"),
	util = require("util");

var WikiTextParser = function(text) {
	this.autoLinkWikiWords = true;
	this.source = text;
	this.nextMatch = 0;
	this.tree = [];
	this.output = null;
	this.subWikify(this.tree);
};

// Render the tiddler as HTML from its parse tree
//	type - MIME type of required output
//	store - store object providing context for inter-tiddler operations
//  title - render the tree as if it came from a tiddler of this title
WikiTextParser.prototype.render = function(type,store,title) {
	if(type === "text/html") {
		return this.renderAsHtml(store,title);
	} else if (type === "text/plain") {
		return this.renderAsText(store,title);
	} else {
		return null;
	}
};

WikiTextParser.prototype.renderAsHtml = function(store,title) {
	var output = [],
		renderSubTree;
	var renderElement = function(element, selfClosing) {
		var tagBits = [element.type];
		if(element.attributes) {
			for(var a in element.attributes) {
				var r = element.attributes[a];
				if(a === "style") {
					var s = [];
					for(var t in r) {
						s.push(t + ":" + r[t] + ";");
					}
					r = s.join("");
				}
				tagBits.push(a + "=\"" + utils.htmlEncode(r) + "\"");
			}
		}
		output.push("<" + tagBits.join(" ") + (selfClosing ? " /" : "") + ">");
		if(!selfClosing) {
			if(element.children) {
				renderSubTree(element.children);
			}
			output.push("</" + element.type + ">");
		}
	};
	renderSubTree = function(tree) {
		for(var t=0; t<tree.length; t++) {
			switch(tree[t].type) {
				case "text":
					output.push(utils.htmlEncode(tree[t].value));
					break;
				case "entity":
					output.push(tree[t].value);
					break;
				case "br":
				case "img":
					renderElement(tree[t],true); // Self closing elements
					break;
				case "macro":
					renderSubTree(tree[t].output);
					break;
				default:
					renderElement(tree[t]);
					break;
			}
		}
	};
	wikiTextMacros.executeMacros(this.tree,store,title);
	renderSubTree(this.tree);
	return output.join("");	
};

WikiTextParser.prototype.renderAsText = function(store,title) {
	var output = [];
	var renderSubTree = function(tree) {
		for(var t=0; t<tree.length; t++) {
			switch(tree[t].type) {
				case "text":
					output.push(tree[t].value);
					break;
				case "entity":
					var c = utils.entityDecode(tree[t].value);
					if(c) {
						output.push(c);
					} else {
						output.push(tree[t].value);
					}
					break;
				case "macro":
					renderSubTree(tree[t].output);
					break;
			}
			if(tree[t].children) {
				renderSubTree(tree[t].children);
			}
		}
	};
	wikiTextMacros.executeMacros(this.tree,store,title);
	renderSubTree(this.tree);
	return output.join("");	
};

WikiTextParser.prototype.outputText = function(place,startPos,endPos) {
	if(startPos < endPos) {
		place.push({type: "text", value: this.source.substring(startPos,endPos)});
	}
};

WikiTextParser.prototype.subWikify = function(output,terminator) {
	// Handle the terminated and unterminated cases separately, this speeds up wikifikation by about 30%
	if(terminator)
		this.subWikifyTerm(output,new RegExp("(" + terminator + ")","mg"));
	else
		this.subWikifyUnterm(output);
};

WikiTextParser.prototype.subWikifyUnterm = function(output) {
	// subWikify can be indirectly recursive, so we need to save the old output pointer
	var oldOutput = this.output;
	this.output = output;
	// Get the first match
	wikiTextRules.rulesRegExp.lastIndex = this.nextMatch;
	var ruleMatch = wikiTextRules.rulesRegExp.exec(this.source);
	while(ruleMatch) {
		// Output any text before the match
		if(ruleMatch.index > this.nextMatch)
			this.outputText(this.output,this.nextMatch,ruleMatch.index);
		// Set the match parameters for the handler
		this.matchStart = ruleMatch.index;
		this.matchLength = ruleMatch[0].length;
		this.matchText = ruleMatch[0];
		this.nextMatch = wikiTextRules.rulesRegExp.lastIndex;
		// Figure out which rule matched and call its handler
		var t;
		for(t=1; t<ruleMatch.length; t++) {
			if(ruleMatch[t]) {
				wikiTextRules.rules[t-1].handler(this);
				wikiTextRules.rulesRegExp.lastIndex = this.nextMatch;
				break;
			}
		}
		// Get the next match
		ruleMatch = wikiTextRules.rulesRegExp.exec(this.source);
	}
	// Output any text after the last match
	if(this.nextMatch < this.source.length) {
		this.outputText(this.output,this.nextMatch,this.source.length);
		this.nextMatch = this.source.length;
	}
	// Restore the output pointer
	this.output = oldOutput;
};

WikiTextParser.prototype.subWikifyTerm = function(output,terminatorRegExp) {
	// subWikify can be indirectly recursive, so we need to save the old output pointer
	var oldOutput = this.output;
	this.output = output;
	// Get the first matches for the rule and terminator RegExps
	terminatorRegExp.lastIndex = this.nextMatch;
	var terminatorMatch = terminatorRegExp.exec(this.source);
	wikiTextRules.rulesRegExp.lastIndex = this.nextMatch;
	var ruleMatch = wikiTextRules.rulesRegExp.exec(terminatorMatch ? this.source.substr(0,terminatorMatch.index) : this.source);
	while(terminatorMatch || ruleMatch) {
		// Check for a terminator match before the next rule match
		if(terminatorMatch && (!ruleMatch || terminatorMatch.index <= ruleMatch.index)) {
			// Output any text before the match
			if(terminatorMatch.index > this.nextMatch)
				this.outputText(this.output,this.nextMatch,terminatorMatch.index);
			// Set the match parameters
			this.matchText = terminatorMatch[1];
			this.matchLength = terminatorMatch[1].length;
			this.matchStart = terminatorMatch.index;
			this.nextMatch = this.matchStart + this.matchLength;
			// Restore the output pointer
			this.output = oldOutput;
			return;
		}
		// It must be a rule match; output any text before the match
		if(ruleMatch.index > this.nextMatch)
			this.outputText(this.output,this.nextMatch,ruleMatch.index);
		// Set the match parameters
		this.matchStart = ruleMatch.index;
		this.matchLength = ruleMatch[0].length;
		this.matchText = ruleMatch[0];
		this.nextMatch = wikiTextRules.rulesRegExp.lastIndex;
		// Figure out which rule matched and call its handler
		var t;
		for(t=1; t<ruleMatch.length; t++) {
			if(ruleMatch[t]) {
				wikiTextRules.rules[t-1].handler(this);
				wikiTextRules.rulesRegExp.lastIndex = this.nextMatch;
				break;
			}
		}
		// Get the next match
		terminatorRegExp.lastIndex = this.nextMatch;
		terminatorMatch = terminatorRegExp.exec(this.source);
		ruleMatch = wikiTextRules.rulesRegExp.exec(terminatorMatch ? this.source.substr(0,terminatorMatch.index) : this.source);
	}
	// Output any text after the last match
	if(this.nextMatch < this.source.length) {
		this.outputText(this.output,this.nextMatch,this.source.length);
		this.nextMatch = this.source.length;
	}
	// Restore the output pointer
	this.output = oldOutput;
};

exports.WikiTextParser = WikiTextParser;