/*
  mustache.js — Logic-less templates in JavaScript

  See http://mustache.github.com/ for more info.
*/

var Mustache = function() {
    var Renderer = function() {};

    Renderer.prototype = {
        otag: "{{",
        ctag: "}}",
        pragmas: {},
        buffer: [],
        pragmas_implemented: {
            "IMPLICIT-ITERATOR": true
        },
        context: {},

        render: function(template, context, partials, in_recursion) {
            // reset buffer & set context
            if (!in_recursion) {
                this.context = context;
                this.buffer = []; // TODO: make this non-lazy
            }

            // fail fast
            if (!this.includes("", template)) {
                if (in_recursion) {
                    return template;
                } else {
                    this.send(template);
                    return;
                }
            }

            template = this.render_pragmas(template);
            var html = this.render_section(template, context, partials);
            if (in_recursion) {
                return this.render_tags(html, context, partials, in_recursion);
            }

            this.render_tags(html, context, partials, in_recursion);
        },

        /*
      Sends parsed lines
    */
        send: function(line) {
            if (line != "") {
                this.buffer.push(line);
            }
        },

        /*
      Looks for %PRAGMAS
    */
        render_pragmas: function(template) {
            // no pragmas
            if (!this.includes("%", template)) {
                return template;
            }

            var that = this;
            var regex = new RegExp(this.otag + "%([\\w-]+) ?([\\w]+=[\\w]+)?" + this.ctag);
            return template.replace(regex, function(match, pragma, options) {
                if (!that.pragmas_implemented[pragma]) {
                    throw ({
                        message: "This implementation of mustache doesn't understand the '" + pragma + "' pragma"
                    });
                }
                that.pragmas[pragma] = {};
                if (options) {
                    var opts = options.split("=");
                    that.pragmas[pragma][opts[0]] = opts[1];
                }
                return "";
                // ignore unknown pragmas silently
            });
        },

        /*
          Tries to find a partial in the curent scope and render it
        */
        render_partial: function(name, context, partials) {
            name = this.trim(name);
            if (!partials || partials[name] === undefined) {
                throw ({
                    message: "unknown_partial '" + name + "'"
                });
            }
            if (typeof(context[name]) != "object") {
                return this.render(partials[name], context, partials, true);
            }
            return this.render(partials[name], context[name], partials, true);
        },

        /*
          Renders inverted (^) and normal (#) sections
        */
        render_section: function(template, context, partials) {
            if (!this.includes("#", template) && ! this.includes("^", template)) {
                return template;
            }

            var that = this;
            // CSW - Added "+?" so it finds the tighest bound, not the widest
            var regex = new RegExp(this.otag + "(\\^|\\#)\\s*(.+)\\s*" + this.ctag + "\n*([\\s\\S]+?)" + this.otag + "\\/\\s*\\2\\s*" + this.ctag + "\\s*", "mg");

            // for each {{#foo}}{{/foo}} section do...
            return template.replace(regex, function(match, type, name, content) {
                var value = that.find(name, context);
                if (type == "^") { // inverted section
                    if (!value || that.is_array(value) && value.length === 0) {
                        // false or empty list, render it
                        return that.render(content, context, partials, true);
                    } else {
                        return "";
                    }
                } else if (type == "#") { // normal section
                    if (that.is_array(value)) { // Enumerable, Let's loop!
                        return that.map(value, function(row) {
                            return that.render(content, that.create_context(row), partials, true);
                        }).join("");
                    } else if (that.is_object(value)) { // Object, Use it as subcontext!
                        return that.render(content, that.create_context(value), partials, true);
                    } else if (typeof value === "function") {
                        // higher order section
                        return value.call(context, content, function(text) {
                            return that.render(text, context, partials, true);
                        });
                    } else if (value) { // boolean section
                        return that.render(content, context, partials, true);
                    } else {
                        return "";
                    }
                }
            });
        },

        /*
          Replace {{foo}} and friends with values from our view
        */
        render_tags: function(template, context, partials, in_recursion) {
            // tit for tat
            var that = this;

            var new_regex = function() {
                return new RegExp(that.otag + "(=|!|>|\\{|%)?([^\\/#\\^]+?)\\1?" + that.ctag + "+", "g");
            };

            var regex = new_regex();
            var tag_replace_callback = function(match, operator, name) {
                switch (operator) {
                case "!":
                    // ignore comments
                    return "";
                case "=":
                    // set new delimiters, rebuild the replace regexp
                    that.set_delimiters(name);
                    regex = new_regex();
                    return "";
                case ">":
                    // render partial
                    return that.render_partial(name, context, partials);
                case "{":
                    // the triple mustache is unescaped
                    return that.find(name, context);
                default:
                    // escape the value
                    return that.escape(that.find(name, context));
                }
            };
            var lines = template.split("\n");
            for (var i = 0; i < lines.length; i++) {
                lines[i] = lines[i].replace(regex, tag_replace_callback, this);
                if (!in_recursion) {
                    this.send(lines[i]);
                }
            }

            if (in_recursion) {
                return lines.join("\n");
            }
        },

        set_delimiters: function(delimiters) {
            var dels = delimiters.split(" ");
            this.otag = this.escape_regex(dels[0]);
            this.ctag = this.escape_regex(dels[1]);
        },

        escape_regex: function(text) {
            // thank you Simon Willison
            if (!arguments.callee.sRE) {
                var specials = ['/', '.', '*', '+', '?', '|', '(', ')', '[', ']', '{', '}', '\\'];
                arguments.callee.sRE = new RegExp('(\\' + specials.join('|\\') + ')', 'g');
            }
            return text.replace(arguments.callee.sRE, '\\$1');
        },

        /*
          find `name` in current `context`. That is find me a value
          from the view object
        */
        find: function(name, context) {
            name = this.trim(name);

            // Checks whether a value is thruthy or false or 0
            function is_kinda_truthy(bool) {
                return bool === false || bool === 0 || bool;
            }

            var value;
            if (is_kinda_truthy(context[name])) {
                value = context[name];
            } else if (is_kinda_truthy(this.context[name])) {
                value = this.context[name];
            }

            if (typeof value === "function") {
                return value.apply(context);
            }
            if (value !== undefined) {
                return value;
            }
            // silently ignore unkown variables
            return "";
        },

        // Utility methods
        /* includes tag */
        includes: function(needle, haystack) {
            return haystack.indexOf(this.otag + needle) != - 1;
        },

        /*
      Does away with nasty characters
    */
        escape: function(s) {
            s = String(s === null ? "": s);
            return s.replace(/&(?!\w+;)|["'<>\\]/g, function(s) {
                switch (s) {
                case "&":
                    return "&amp;";
                case "\\":
                    return "\\\\";
                case '"':
                    return '&quot;';
                case "'":
                    return '&#39;';
                case "<":
                    return "&lt;";
                case ">":
                    return "&gt;";
                default:
                    return s;
                }
            });
        },

        // by @langalex, support for arrays of strings
        create_context: function(_context) {
            if (this.is_object(_context)) {
                return _context;
            } else {
                var iterator = ".";
                if (this.pragmas["IMPLICIT-ITERATOR"]) {
                    iterator = this.pragmas["IMPLICIT-ITERATOR"].iterator;
                }
                var ctx = {};
                ctx[iterator] = _context;
                return ctx;
            }
        },

        is_object: function(a) {
            return a && typeof a == "object";
        },

        is_array: function(a) {
            return Object.prototype.toString.call(a) === '[object Array]';
        },

        /*
      Gets rid of leading and trailing whitespace
    */
        trim: function(s) {
            return s.replace(/^\s*|\s*$/g, "");
        },

        /*
      Why, why, why? Because IE. Cry, cry cry.
    */
        map: function(array, fn) {
            if (typeof array.map == "function") {
                return array.map(fn);
            } else {
                var r = [];
                var l = array.length;
                for (var i = 0; i < l; i++) {
                    r.push(fn(array[i]));
                }
                return r;
            }
        }
    };

    return ({
        name: "mustache.js",
        version: "0.3.1-dev",

        /*
          Turns a template and view into HTML
        */
        to_html: function(template, view, partials, send_fun) {
            var renderer = new Renderer();
            if (send_fun) {
                renderer.send = send_fun;
            }
            renderer.render(template, view, partials);
            if (!send_fun) {
                return renderer.buffer.join("\n");
            }
        }
    });
} ();

