(function () {

    var identityDecoder = function (src) {
        return src;
    };

    var identityEncoder = function (src) {
        return src;
    };

    var mapDecoder = function (src) {
        var map   = {};
        var lines = src.split(/\n/);

        $.each(lines, function () {
            var m = this.match(/^(\S+)\s+(\S+)$/);

            if (m) {
                map[ m[1] ] = m[2];
            }
        });

        return map;
    };

    var mapEncoder = function (map) {
        var lines = [];

        $.each(map, function (key) {
                   lines.push(key + " " + this);
               });

        return lines.join("\n");
    };

    var boolDecoder = function (src) {
        return src == "*";
    };

    var boolEncoder = function (bool) {
        return bool ? "*" : "";
    };

    var decoder_of = {
        siteName   : identityDecoder,
        baseURI    : identityDecoder,
        defaultPage: identityDecoder,
        styleSheet : identityDecoder,
        languages  : mapDecoder,
        globalLock : boolDecoder
    };

    var encoder_of = {
        siteName   : identityEncoder,
        baseURI    : identityEncoder,
        defaultPage: identityEncoder,
        styleSheet : identityEncoder,
        languages  : mapEncoder,
        globalLock : boolEncoder
    };

    var cachedConf = null;

    var isValidBaseURI = function (str) {
        parseUri.options.strictMode = true;
        var uri = parseUri(str);

        return (uri.protocol  != "" &&
                uri.authority != "" &&
                uri.path      != "" &&
                uri.path.match(/\/$/) &&
                uri.query     == "" &&
                uri.anchor    == "");
    };

     // FIXME: Don't let user to manipulate directly this structure.
     // FIXME: Values may include spaces.
    var isValidMap = function (src) {
        return src.match(/^(?:\S+\s+\S+(?:\n\S+\s+\S+)*\n?)?$/) != null;
    };

    Rakka.getUserList = function () {
        var users = [];

        $.ajax({
           type: "GET",
           url: Rakka.baseURI + "users",
           async: false,
           beforeSend: function (req) {
               Rakka.setAuthorization(req);
           },
           success: function (xml) {
               $(xml).find("user").each(function () {
                   users.push(this.getAttribute("id"));
               });
           },
           error: function (req) {
               throw new Error(req.status + " " + req.statusText);
           }
        });

        return users;
    };

    Rakka.getSystemConfig = function () {
        if (cachedConf != null) {
            return cachedConf;
        }

        var conf = {};
        cachedConf = conf;

        $.ajax({
            type   : "GET",
            url    : Rakka.baseURI + "systemConfig",
            async  : false,
            success: function (xml) {
                $(xml).find("value").each(function () {
                    var path    = this.getAttribute("path");
                    var decoder = decoder_of[path];

                    if (decoder == null) {
                        throw new Error("unknown config path: " + path);
                    }
                    else {
                        conf[path] = decoder($(this).text());
                    }
                });
            },
            error  : function (req) {
                throw new Error(req.status + " " + req.statusText);
            }
        });

        return conf;
    };

    var appendConfigPanel = function ($area) {
        $area.append($.H1({}, "Configuration"));

        var fldSiteName
            = $.INPUT({type: "text"});

        var fldBaseURI
            = $.INPUT({type: "text"});

        var fldDefaultPage
            = $.INPUT({type: "text"});

        var fldStyleSheet
            = $.INPUT({type: "text"});

        var fldLanguages
            = $.TEXTAREA({});

        var chkGlobalLock
            = $.INPUT({type: "checkbox"});

        var btnSave
            = $.INPUT({type: "button", value: "Save changes"});

        var btnRevert
            = $.INPUT({type: "button", value: "Revert changes"});

        var makeClean = function () {
            $(btnSave).attr({disabled: "disabled"});
            $(btnRevert).attr({disabled: "disabled"});
        };

        var updateConfig = function () {
            var conf  = Rakka.getSystemConfig();

            fldSiteName.value     = conf.siteName;
            fldBaseURI.value      = conf.baseURI;
            fldDefaultPage.value  = conf.defaultPage;
            fldStyleSheet.value   = conf.styleSheet;
            fldLanguages.value    = encoder_of.languages(conf.languages);
            chkGlobalLock.checked = conf.globalLock;

            makeClean();
        };
        updateConfig();

        var validate = function () {
            var isValid = (function () {
                               if (!isValidBaseURI(fldBaseURI.value)) {
                                   return false;
                               }

                               if (fldDefaultPage.value.match(Rakka.rePageName) == null) {
                                   return false;
                               }

                               if (fldStyleSheet.value.match(Rakka.rePageName) == null) {
                                   return false;
                               }

                               if (!isValidMap(fldLanguages.value)) {
                                   return false;
                               }

                               return true;
                           })();

            $(btnSave).attr({disabled: (isValid ? "" : "disabled")});
        };

        var makeDirty = function () {
            $(btnRevert).attr({disabled: ""});
            validate();
        };

        $(btnSave).click(function () {
            var NS  = "http://cielonegro.org/schema/Rakka/Config/1.0";
            var doc = document.implementation.createDocument(NS, "systemConfig", null);
            var sc  = doc.documentElement;

            var mkValue = function (path, value) {
                var elem = doc.createElementNS(NS, "value");
                elem.setAttribute("path", path);
                elem.appendChild(doc.createTextNode(value));
                return elem;
            };

            sc.appendChild(mkValue("siteName"   , fldSiteName.value));
            sc.appendChild(mkValue("baseURI"    , fldBaseURI.value));
            sc.appendChild(mkValue("defaultPage", fldDefaultPage.value));
            sc.appendChild(mkValue("styleSheet" , fldStyleSheet.value));
            sc.appendChild(mkValue("languages"  , fldLanguages.value));
            sc.appendChild(mkValue("globalLock" , encoder_of["globalLock"](chkGlobalLock.checked)));

            Rakka.displayWaitingMessage("Submitting... please wait.");

            var url = Rakka.baseURI + "systemConfig";
            $.ajax({ type       : "PUT",
                     url        : url,
                     contentType: "text/xml",
                     data       : doc,
                     processData: false,
                     beforeSend : function (req) {
                         Rakka.setAuthorization(req);
                     },
                     success    : function () {
                         cachedConf = null;
                         Rakka.hideWaitingMessage();
                         makeClean();
                     },
                     error      : function (req) {
                         Rakka.hideWaitingMessage();

                         // FIXME: better error handling
                         var $area = Rakka.switchScreen();
                         $area.text("Error: " + req.status + " " + req.statusText);
                     }
            });
        });

        $(btnRevert).click(function () {
            if (window.confirm("Do you really want to discard changes?")) {
                updateConfig();
            }
        });

        var configPanel
            = $.TABLE({className: "pageEditor"},
                      $.TBODY({},
                              $.TR({},
                                   $.TH({}, "Site name"),
                                   $.TD({}, fldSiteName)),
                              $.TR({},
                                   $.TH({}, "Base URI"),
                                   $.TD({}, fldBaseURI)),
                              $.TR({},
                                   $.TH({}, "Default page"),
                                   $.TD({}, fldDefaultPage)),
                              $.TR({},
                                   $.TH({}, "Style sheet"),
                                   $.TD({}, fldStyleSheet)),
                              $.TR({},
                                   $.TH({}, "Languages"),
                                   $.TD({}, fldLanguages)),
                              $.TR({},
                                   $.TH({}, "Global lock"),
                                   $.TD({},
                                        $.LABEL({},
                                                chkGlobalLock,
                                                "Disallow guest users to edit pages."))),
                              $.TR({},
                                   $.TH({}),
                                   $.TD({}, btnSave, btnRevert))));

         $(fldSiteName)
             .add(fldBaseURI)
             .add(fldDefaultPage)
             .add(fldStyleSheet)
             .add(fldLanguages)
             .keyup(makeDirty)
             .change(makeDirty);

         $area.append(configPanel);
     };

     var appendUsersPanel = function ($area) {
         $area.append($.H2({}, "Users"));
         $area.append($.H3({}, "Existing Users"));

         var tbody = $.TBODY();

         var usersPanel
             = $.TABLE({className: "pageEditor"},
                       $.THEAD({},
                               $.TR({},
                                    $.TH({}, "User ID"),
                                    $.TH({}, "Change Password"),
                                    $.TH({}, "Delete User"))),
                       tbody);

         var updateUserList = function () {
             var users = Rakka.getUserList();

             $(tbody).empty();

             for (var i = 0; i < users.length; i++) {
                 var pass1  = $.INPUT({type: "password"});
                 var pass2  = $.INPUT({type: "password"});
                 var change = $.INPUT({type: "button", value: "Change"});

                 var chpass = $.TABLE({className: "pageEditor"},
                                      $.TR({},
                                           $.TD({}, pass1),
                                           $.TD({rowSpan: 2}, change)),
                                      $.TR({},
                                           $.TD({}, pass2)));

                 var delUser = $.INPUT({type: "button", value: "Delete"});

                 var validatePassword = function () {
                     var isValid = (function () {
                                       if (pass1.value == "") {
                                           return false;
                                       }

                                       if (pass1.value != pass2.value) {
                                           return false;
                                       }

                                       return true;
                                    })();
                     $(change).attr({disabled: (isValid ? "" : "disabled")});
                 };
                 validatePassword();
                 $(pass1)
                     .add(pass2)
                     .change(validatePassword)
                     .keyup(validatePassword);

                 $.each(users, function () {
                     var id = users[i];
                     var tr = $.TR({},
                                   $.TD({}, id),
                                   $.TD({}, chpass),
                                   $.TD({}, delUser)
                                  );
                     tbody.appendChild(tr);
                 });
             }
         };
         updateUserList();

         $area.append(usersPanel);

         $area.append($.H3({}, "Add new user"));

         var userID  = $.INPUT({type: "text"});
         var pass1   = $.INPUT({type: "password"});
         var pass2   = $.INPUT({type: "password"});
         var addUser = $.INPUT({type: "button", value: "Add"});
         var addUserPanel = $.TABLE({className: "pageEditor"},
                                    $.TR({},
                                         $.TH({}, "User ID"),
                                         $.TD({}, userID)),
                                    $.TR({},
                                         $.TH({}, "Password"),
                                         $.TD({}, pass1)),
                                    $.TR({},
                                         $.TH({}, "Password (retype)"),
                                         $.TD({}, pass2)),
                                    $.TR({},
                                         $.TH({}),
                                         $.TD({}, addUser)));

         $area.append(addUserPanel);
     };

     Rakka.showConfigPanel = function () {
         var $area = Rakka.switchScreen();

         appendConfigPanel($area);
         appendUsersPanel($area);
     };

     $(document).ready(function () {
         $("input.configButton")
             .click(function () {
                        Rakka.showConfigPanel();
                    });
     });
})();