/*
Pure Javascript implementation of Uniforum message translation.
Copyright (C) 2008 Joshua I. Miller <unrtst@cpan.org>, all rights reserved

This program is free software; you can redistribute it and/or modify it
under the terms of the GNU Library General Public License as published
by the Free Software Foundation; either version 2, or (at your option)
any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
USA.
*/

Gettext = function (args) {
    this.domain         = 'messages';
    // locale_data will be populated from <link...> if not specified in args
    this.locale_data    = undefined;

    // set options
    var options = [ "domain", "locale_data" ];
    if (this.isValidObject(args)) {
        for (var i in args) {
            for (var j=0; j<options.length; j++) {
                if (i == options[j]) {
                    // don't set it if it's null or undefined
                    if (this.isValidObject(args[i]))
                        this[i] = args[i];
                }
            }
        }
    }


    // try to load the lang file from somewhere
    this.try_load_lang();

    return this;
}

Gettext.context_glue = "\004";
Gettext._locale_data = {};

Gettext.prototype.try_load_lang = function() {
    // check to see if language is statically included
    if (typeof(this.locale_data) != 'undefined') {
        // we're going to reformat it, and overwrite the variable
        var locale_copy = this.locale_data;
        this.locale_data = undefined;
        this.parse_locale_data(locale_copy);

        if (typeof(Gettext._locale_data[this.domain]) == 'undefined') {
            throw new Error("Error: Gettext 'locale_data' does not contain the domain '"+this.domain+"'");
        }
    }


    // try loading from JSON
    // get lang links
    var lang_link = this.get_lang_refs();

    if (typeof(lang_link) == 'object' && lang_link.length > 0) {
        // NOTE: there will be a delay here, as this is async.
        // So, any i18n calls made right after page load may not
        // get translated.
        // XXX: we may want to see if we can "fix" this behavior
        for (var i=0; i<lang_link.length; i++) {
            var link = lang_link[i];
            if (link.type == 'application/json') {
                if (! this.try_load_lang_json(link.href) ) {
                    throw new Error("Error: Gettext 'try_load_lang_json' failed. Unable to exec xmlhttprequest for link ["+link.href+"]");
                }
            } else if (link.type == 'application/x-po') {
                if (! this.try_load_lang_po(link.href) ) {
                    throw new Error("Error: Gettext 'try_load_lang_po' failed. Unable to exec xmlhttprequest for link ["+link.href+"]");
                }
            } else {
                // TODO: implement the other types (.mo)
                throw new Error("TODO: link type ["+link.type+"] found, and support is planned, but not implemented at this time.");
            }
        }
    }
};

// This takes the bin/po2json'd data, and moves it into an internal form
// for use in our lib, and puts it in our object as:
//  Gettext._locale_data = {
//      domain : {
//          head : { headfield : headvalue },
//          msgs : {
//              msgid : [ msgid_plural, msgstr, msgstr_plural ],
//          },
Gettext.prototype.parse_locale_data = function(locale_data) {
    if (typeof(Gettext._locale_data) == 'undefined') {
        Gettext._locale_data = { };
    }

    // suck in every domain defined in the supplied data
    for (var domain in locale_data) {
        // skip empty specs (flexibly)
        if ((! locale_data.hasOwnProperty(domain)) || (! this.isValidObject(locale_data[domain])))
            continue;
        // skip if it has no msgid's
        var has_msgids = false;
        for (var msgid in locale_data[domain]) {
            has_msgids = true;
            break;
        }
        if (! has_msgids) continue;

        // grab shortcut to data
        var data = locale_data[domain];

        // if they specifcy a blank domain, default to "messages"
        if (domain == "") domain = "messages";
        // init the data structure
        if (! this.isValidObject(Gettext._locale_data[domain]) )
            Gettext._locale_data[domain] = { };
        if (! this.isValidObject(Gettext._locale_data[domain].head) )
            Gettext._locale_data[domain].head = { };
        if (! this.isValidObject(Gettext._locale_data[domain].msgs) )
            Gettext._locale_data[domain].msgs = { };

        for (var key in data) {
            if (key == "") {
                var header = data[key];
                for (var head in header) {
                    var h = head.toLowerCase();
                    Gettext._locale_data[domain].head[h] = header[head];
                }
            } else {
                Gettext._locale_data[domain].msgs[key] = data[key];
            }
        }
    }

    // build the plural forms function
    for (var domain in Gettext._locale_data) {
        if (this.isValidObject(Gettext._locale_data[domain].head['plural-forms']) &&
            typeof(Gettext._locale_data[domain].head.plural_func) == 'undefined') {
            // untaint data
            var plural_forms = Gettext._locale_data[domain].head['plural-forms'];
            var pf_re = new RegExp('^(\\s*nplurals\\s*=\\s*[0-9]+\\s*;\\s*plural\\s*=\\s*(?:\\s|[-\\?\\|&=!<>+*/%:;a-zA-Z0-9_\(\)])+)', 'm');
            if (pf_re.test(plural_forms)) {
                //ex english: "Plural-Forms: nplurals=2; plural=(n != 1);\n"
                //pf = "nplurals=2; plural=(n != 1);";
                //ex russian: nplurals=3; plural=(n%10==1 && n%100!=11 ? 0 : n%10>=2 && n%10< =4 && (n%100<10 or n%100>=20) ? 1 : 2)
                //pf = "nplurals=3; plural=(n%10==1 && n%100!=11 ? 0 : n%10>=2 && n%10<=4 && (n%100<10 || n%100>=20) ? 1 : 2)";

                var pf = Gettext._locale_data[domain].head['plural-forms'];
                if (! /;\s*$/.test(pf)) pf = pf.concat(';');
                /* We used to use eval, but it seems IE has issues with it.
                 * We now use "new Function", though it carries a slightly
                 * bigger performance hit.
                var code = 'function (n) { var plural; var nplurals; '+pf+' return { "nplural" : nplurals, "plural" : (plural === true ? 1 : plural ? plural : 0) }; };';
                Gettext._locale_data[domain].head.plural_func = eval("("+code+")");
                */
                var code = 'var plural; var nplurals; '+pf+' return { "nplural" : nplurals, "plural" : (plural === true ? 1 : plural ? plural : 0) };';
                Gettext._locale_data[domain].head.plural_func = new Function("n", code);
            } else {
                throw new Error("Syntax error in language file. Plural-Forms header is invalid ["+plural_forms+"]");
            }   

        // default to english plural form
        } else if (typeof(Gettext._locale_data[domain].head.plural_func) == 'undefined') {
            Gettext._locale_data[domain].head.plural_func = function (n) {
                var p = (n != 1) ? 1 : 0;
                return { 'nplural' : 2, 'plural' : p };
                };
        } // else, plural_func already created
    }

    return;
};


// try_load_lang_po : do an ajaxy call to load in the .po lang defs
Gettext.prototype.try_load_lang_po = function(uri) {
    var data = this.sjax(uri);
    if (! data) return;

    var domain = this.uri_basename(uri);
    var parsed = this.parse_po(data);

    var rv = {};
    // munge domain into/outof header
    if (parsed) {
        if (! parsed[""]) parsed[""] = {};
        if (! parsed[""]["domain"]) parsed[""]["domain"] = domain;
        domain = parsed[""]["domain"];
        rv[domain] = parsed;

        this.parse_locale_data(rv);
    }

    return 1;
};

Gettext.prototype.uri_basename = function(uri) {
    var rv;
    if (rv = uri.match(/^(.*\/)?(.*)/)) {
        var ext_strip;
        if (ext_strip = rv[2].match(/^(.*)\..+$/))
            return ext_strip[1];
        else
            return rv[2];
    } else {
        return "";
    }
};

Gettext.prototype.parse_po = function(data) {
    var rv = {};
    var buffer = {};
    var lastbuffer = "";
    var errors = [];
    var lines = data.split("\n");
    for (var i=0; i<lines.length; i++) {
        // chomp
        lines[i] = lines[i].replace(/(\n|\r)+$/, '');

        var match;

        // Empty line / End of an entry.
        if (/^$/.test(lines[i])) {
            if (typeof(buffer['msgid']) != 'undefined') {
                var msg_ctxt_id = (typeof(buffer['msgctxt']) != 'undefined' &&
                                   buffer['msgctxt'].length) ?
                                  buffer['msgctxt']+Gettext.context_glue+buffer['msgid'] :
                                  buffer['msgid'];
                var msgid_plural = (typeof(buffer['msgid_plural']) != 'undefined' &&
                                    buffer['msgid_plural'].length) ?
                                   buffer['msgid_plural'] :
                                   null;

                // find msgstr_* translations and push them on
                var trans = [];
                for (var str in buffer) {
                    var match;
                    if (match = str.match(/^msgstr_(\d+)/))
                        trans[parseInt(match[1])] = buffer[str];
                }
                trans.unshift(msgid_plural);

                // only add it if we've got a translation
                // NOTE: this doesn't conform to msgfmt specs
                if (trans.length > 1) rv[msg_ctxt_id] = trans;

                buffer = {};
                lastbuffer = "";
            }

        // comments
        } else if (/^#/.test(lines[i])) {
            continue;

        // msgctxt
        } else if (match = lines[i].match(/^msgctxt\s+(.*)/)) {
            lastbuffer = 'msgctxt';
            buffer[lastbuffer] = this.parse_po_dequote(match[1]);

        // msgid
        } else if (match = lines[i].match(/^msgid\s+(.*)/)) {
            lastbuffer = 'msgid';
            buffer[lastbuffer] = this.parse_po_dequote(match[1]);

        // msgid_plural
        } else if (match = lines[i].match(/^msgid_plural\s+(.*)/)) {
            lastbuffer = 'msgid_plural';
            buffer[lastbuffer] = this.parse_po_dequote(match[1]);

        // msgstr
        } else if (match = lines[i].match(/^msgstr\s+(.*)/)) {
            lastbuffer = 'msgstr_0';
            buffer[lastbuffer] = this.parse_po_dequote(match[1]);

        // msgstr[0] (treak like msgstr)
        } else if (match = lines[i].match(/^msgstr\[0\]\s+(.*)/)) {
            lastbuffer = 'msgstr_0';
            buffer[lastbuffer] = this.parse_po_dequote(match[1]);

        // msgstr[n]
        } else if (match = lines[i].match(/^msgstr\[(\d+)\]\s+(.*)/)) {
            lastbuffer = 'msgstr_'+match[1];
            buffer[lastbuffer] = this.parse_po_dequote(match[2]);

        // continued string
        } else if (/^"/.test(lines[i])) {
            buffer[lastbuffer] += this.parse_po_dequote(lines[i]);

        // something strange
        } else {
            errors.push("Strange line ["+i+"] : "+lines[i]);
        }
    }


    // handle the final entry
    if (typeof(buffer['msgid']) != 'undefined') {
        var msg_ctxt_id = (typeof(buffer['msgctxt']) != 'undefined' &&
                           buffer['msgctxt'].length) ?
                          buffer['msgctxt']+Gettext.context_glue+buffer['msgid'] :
                          buffer['msgid'];
        var msgid_plural = (typeof(buffer['msgid_plural']) != 'undefined' &&
                            buffer['msgid_plural'].length) ?
                           buffer['msgid_plural'] :
                           null;

        // find msgstr_* translations and push them on
        var trans = [];
        for (var str in buffer) {
            var match;
            if (match = str.match(/^msgstr_(\d+)/))
                trans[parseInt(match[1])] = buffer[str];
        }
        trans.unshift(msgid_plural);

        // only add it if we've got a translation
        // NOTE: this doesn't conform to msgfmt specs
        if (trans.length > 1) rv[msg_ctxt_id] = trans;

        buffer = {};
        lastbuffer = "";
    }


    // parse out the header
    if (rv[""] && rv[""][1]) {
        var cur = {};
        var hlines = rv[""][1].split(/\\n/);
        for (var i=0; i<hlines.length; i++) {
            if (! hlines.length) continue;

            var pos = hlines[i].indexOf(':', 0);
            if (pos != -1) {
                var key = hlines[i].substring(0, pos);
                var val = hlines[i].substring(pos +1);
                var keylow = key.toLowerCase();

                if (cur[keylow] && cur[keylow].length) {
                    errors.push("SKIPPING DUPLICATE HEADER LINE: "+hlines[i]);
                } else if (/#-#-#-#-#/.test(keylow)) {
                    errors.push("SKIPPING ERROR MARKER IN HEADER: "+hlines[i]);
                } else {
                    // remove begining spaces if any
                    val = val.replace(/^\s+/, '');
                    cur[keylow] = val;
                }

            } else {
                errors.push("PROBLEM LINE IN HEADER: "+hlines[i]);
                cur[hlines[i]] = '';
            }
        }

        // replace header string with assoc array
        rv[""] = cur;
    } else {
        rv[""] = {};
    }

    // TODO: XXX: if there are errors parsing, what do we want to do?
    // GNU Gettext silently ignores errors. So will we.
    // alert( "Errors parsing po file:\n" + errors.join("\n") );

    return rv;
};


Gettext.prototype.parse_po_dequote = function(str) {
    var match;
    if (match = str.match(/^"(.*)"/)) {
        str = match[1];
    }
    str = str.replace(/\\"/, "");
    return str;
};


// try_load_lang_json : do an ajaxy call to load in the lang defs
Gettext.prototype.try_load_lang_json = function(uri) {
    var data = this.sjax(uri);
    if (! data) return;

    var rv = this.JSON(data);
    this.parse_locale_data(rv);

    return 1;
};

// this finds all <link> tags, filters out ones that match our
// specs, and returns a list of hashes of those
Gettext.prototype.get_lang_refs = function() {
    var langs = new Array();
    var links = document.getElementsByTagName("link");
    // find all <link> tags in dom; filter ours
    for (var i=0; i<links.length; i++) {
        if (links[i].rel == 'gettext' && links[i].href) {
            if (typeof(links[i].type) == 'undefined' ||
                links[i].type == '') {
                if (/\.json$/i.test(links[i].href)) {
                    links[i].type = 'application/json';
                } else if (/\.js$/i.test(links[i].href)) {
                    links[i].type = 'application/json';
                } else if (/\.po$/i.test(links[i].href)) {
                    links[i].type = 'application/x-po';
                } else if (/\.mo$/i.test(links[i].href)) {
                    links[i].type = 'application/x-mo';
                } else {
                    throw new Error("LINK tag with rel=gettext found, but the type and extension are unrecognized.");
                }
            }

            links[i].type = links[i].type.toLowerCase();
            if (links[i].type == 'application/json') {
                links[i].type = 'application/json';
            } else if (links[i].type == 'text/javascript') {
                links[i].type = 'application/json';
            } else if (links[i].type == 'application/x-po') {
                links[i].type = 'application/x-po';
            } else if (links[i].type == 'application/x-mo') {
                links[i].type = 'application/x-mo';
            } else {
                throw new Error("LINK tag with rel=gettext found, but the type attribute ["+links[i].type+"] is unrecognized.");
            }

            langs.push(links[i]);
        }
    }
    return langs;
};



Gettext.prototype.textdomain = function (domain) {
    if (domain && domain.length) this.domain = domain;
    return this.domain;
}


// gettext
Gettext.prototype.gettext = function (msgid) {
    var msgctxt;
    var msgid_plural;
    var n;
    var category;
    return this.dcnpgettext(null, msgctxt, msgid, msgid_plural, n, category);
};

Gettext.prototype.dgettext = function (domain, msgid) {
    var msgctxt;
    var msgid_plural;
    var n;
    var category;
    return this.dcnpgettext(domain, msgctxt, msgid, msgid_plural, n, category);
};

Gettext.prototype.dcgettext = function (domain, msgid, category) {
    var msgctxt;
    var msgid_plural;
    var n;
    return this.dcnpgettext(domain, msgctxt, msgid, msgid_plural, n, category);
};

// ngettext
Gettext.prototype.ngettext = function (msgid, msgid_plural, n) {
    var msgctxt;
    var category;
    return this.dcnpgettext(null, msgctxt, msgid, msgid_plural, n, category);
};

Gettext.prototype.dngettext = function (domain, msgid, msgid_plural, n) {
    var msgctxt;
    var category;
    return this.dcnpgettext(domain, msgctxt, msgid, msgid_plural, n, category);
};

Gettext.prototype.dcngettext = function (domain, msgid, msgid_plural, n, category) {
    var msgctxt;
    return this.dcnpgettext(domain, msgctxt, msgid, msgid_plural, n, category, category);
};

// pgettext
Gettext.prototype.pgettext = function (msgctxt, msgid) {
    var msgid_plural;
    var n;
    var category;
    return this.dcnpgettext(null, msgctxt, msgid, msgid_plural, n, category);
};

Gettext.prototype.dpgettext = function (domain, msgctxt, msgid) {
    var msgid_plural;
    var n;
    var category;
    return this.dcnpgettext(domain, msgctxt, msgid, msgid_plural, n, category);
};

Gettext.prototype.dcpgettext = function (domain, msgctxt, msgid, category) {
    var msgid_plural;
    var n;
    return this.dcnpgettext(domain, msgctxt, msgid, msgid_plural, n, category);
};

// npgettext
Gettext.prototype.npgettext = function (msgctxt, msgid, msgid_plural, n) {
    var category;
    return this.dcnpgettext(null, msgctxt, msgid, msgid_plural, n, category);
};

Gettext.prototype.dnpgettext = function (domain, msgctxt, msgid, msgid_plural, n) {
    var category;
    return this.dcnpgettext(domain, msgctxt, msgid, msgid_plural, n, category);
};

// this has all the options, so we use it for all of them.
Gettext.prototype.dcnpgettext = function (domain, msgctxt, msgid, msgid_plural, n, category) {
    if (! this.isValidObject(msgid)) return '';

    var plural = this.isValidObject(msgid_plural);
    var msg_ctxt_id = this.isValidObject(msgctxt) ? msgctxt+Gettext.context_glue+msgid : msgid;

    var domainname = this.isValidObject(domain)      ? domain :
                     this.isValidObject(this.domain) ? this.domain :
                                                       'messages';

    // category is always LC_MESSAGES. We ignore all else
    var category_name = 'LC_MESSAGES';
    var category = 5;

    var locale_data = new Array();
    if (typeof(Gettext._locale_data) != 'undefined' &&
        this.isValidObject(Gettext._locale_data[domainname])) {
        locale_data.push( Gettext._locale_data[domainname] );

    } else if (typeof(Gettext._locale_data) != 'undefined') {
        // didn't find domain we're looking for. Search all of them.
        for (var dom in Gettext._locale_data) {
            locale_data.push( Gettext._locale_data[dom] );
        }
    }

    var trans = [];
    var found = false;
    var domain_used; // so we can find plural-forms if needed
    if (locale_data.length) {
        for (var i=0; i<locale_data.length; i++) {
            var locale = locale_data[i];
            if (this.isValidObject(locale.msgs[msg_ctxt_id])) {
                // make copy of that array (cause we'll be destructive)
                for (var j=0; j<locale.msgs[msg_ctxt_id].length; j++) {
                    trans[j] = locale.msgs[msg_ctxt_id][j];
                }
                trans.shift(); // throw away the msgid_plural
                domain_used = locale;
                found = true;
                // only break if found translation actually has a translation.
                if ( trans.length > 0 && trans[0].length != 0 )
                    break;
            }
        }
    }

    // default to english if we lack a match, or match has zero length
    if ( trans.length == 0 || trans[0].length == 0 ) {
        trans = [ msgid, msgid_plural ];
    }

    var translation = trans[0];
    if (plural) {
        var p;
        if (found && this.isValidObject(domain_used.head.plural_func) ) {
            var rv = domain_used.head.plural_func(n);
            if (! rv.plural) rv.plural = 0;
            if (! rv.nplural) rv.nplural = 0;
            // if plurals returned is out of bound for total plural forms
            if (rv.nplural <= rv.plural) rv.plural = 0;
            p = rv.plural;
        } else {
            p = (n != 1) ? 1 : 0;
        }
        if (this.isValidObject(trans[p]))
            translation = trans[p];
    }

    return translation;
};



/* utility method, since javascript lacks a printf */
Gettext.strargs = function (str, args) {
    // make sure args is an array
    if ( null == args ||
         'undefined' == typeof(args) ) {
        args = [];
    } else if (args.constructor != Array) {
        args = [args];
    }

    // NOTE: javascript lacks support for zero length negative look-behind
    // in regex, so we must step through w/ index.
    // The perl equiv would simply be:
    //    $string =~ s/(?<!\%)\%([0-9]+)/$args[$1]/g;
    //    $string =~ s/\%\%/\%/g; # restore escaped percent signs

    var newstr = "";
    while (true) {
        var i = str.indexOf('%');
        var match_n;

        // no more found. Append whatever remains
        if (i == -1) {
            newstr += str;
            break;
        }

        // we found it, append everything up to that
        newstr += str.substr(0, i);

        // check for escpaed %%
        if (str.substr(i, 2) == '%%') {
            newstr += '%';
            str = str.substr((i+2));

        // % followed by number
        } else if ( match_n = str.substr(i).match(/^%(\d+)/) ) {
            var arg_n = parseInt(match_n[1]);
            var length_n = match_n[1].length;
            if ( arg_n > 0 && args[arg_n -1] != null && typeof(args[arg_n -1]) != 'undefined' )
                newstr += args[arg_n -1];
            str = str.substr( (i + 1 + length_n) );

        // % followed by some other garbage - just remove the %
        } else {
            newstr += '%';
            str = str.substr((i+1));
        }
    }

    return newstr;
}

/* instance method wrapper of strargs */
Gettext.prototype.strargs = function (str, args) {
    return Gettext.strargs(str, args);
}

/* verify that something is an array */
Gettext.prototype.isArray = function (thisObject) {
    return this.isValidObject(thisObject) && thisObject.constructor == Array;
};

/* verify that an object exists and is valid */
Gettext.prototype.isValidObject = function (thisObject) {
    if (null == thisObject) {
        return false;
    } else if ('undefined' == typeof(thisObject) ) {
        return false;
    } else {
        return true;
    }
};

Gettext.prototype.sjax = function (uri) {
    var xmlhttp;
    if (window.XMLHttpRequest) {
        xmlhttp = new XMLHttpRequest();
    } else if (navigator.userAgent.toLowerCase().indexOf('msie 5') != -1) {
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
    } else {
        xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
    }

    if (! xmlhttp)
        throw new Error("Your browser doesn't do Ajax. Unable to support external language files.");

    xmlhttp.open('GET', uri, false);
    try { xmlhttp.send(null); }
    catch (e) { return; }

    // we consider status 200 and 0 as ok.
    // 0 happens when we request local file, allowing this to run on local files
    var sjax_status = xmlhttp.status;
    if (sjax_status == 200 || sjax_status == 0) {
        return xmlhttp.responseText;
    } else {
        var error = xmlhttp.statusText + " (Error " + xmlhttp.status + ")";
        if (xmlhttp.responseText.length) {
            error += "\n" + xmlhttp.responseText;
        }
        alert(error);
        return;
    }
}

Gettext.prototype.JSON = function (data) {
    return eval('(' + data + ')');
}