/**
 * Copyright JS Foundation and other contributors, http://js.foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 **/

var passport = require("passport");
var oauth2orize = require("oauth2orize");

var strategies = require("./strategies");
var Tokens = require("./tokens");
var Users = require("./users");
var permissions = require("./permissions");

var theme = require("../theme");

var settings = null;
var log = null


passport.use(strategies.bearerStrategy.BearerStrategy);
passport.use(strategies.clientPasswordStrategy.ClientPasswordStrategy);
passport.use(strategies.anonymousStrategy);

var server = oauth2orize.createServer();

server.exchange(oauth2orize.exchange.password(strategies.passwordTokenExchange));

function init(runtime) {
    settings = runtime.settings;
    log = runtime.log;
    if (settings.adminAuth) {
        Users.init(settings.adminAuth);
        Tokens.init(settings.adminAuth,runtime.storage);
        strategies.init(runtime);
    }
}

function needsPermission(permission) {
    return function(req,res,next) {
        if (settings && settings.adminAuth) {
            return passport.authenticate(['bearer','anon'],{ session: false })(req,res,function() {
                if (!req.user) {
                    return next();
                }
                if (permissions.hasPermission(req.authInfo.scope,permission)) {
                    return next();
                }
                log.audit({event: "permission.fail", permissions: permission},req);
                return res.status(401).end();
            });
        } else {
            next();
        }
    }
}

function ensureClientSecret(req,res,next) {
    if (!req.body.client_secret) {
        req.body.client_secret = 'not_available';
    }
    next();
}
function authenticateClient(req,res,next) {
    return passport.authenticate(['oauth2-client-password'], {session: false})(req,res,next);
}
function getToken(req,res,next) {
    return server.token()(req,res,next);
}

function login(req,res) {
    var response = {};
    if (settings.adminAuth) {
        if (settings.adminAuth.type === "credentials") {
            response = {
                "type":"credentials",
                "prompts":[{id:"username",type:"text",label:"Username"},{id:"password",type:"password",label:"Password"}]
            }
        } else if (settings.adminAuth.type === "oauth") {
            response = {
                "type":"oauth",
                "prompts":[{type:"button",label:settings.adminAuth.strategy.label, url:"/auth/oauth"}]
            }
            if (settings.adminAuth.strategy.icon) {
                response.prompts[0].icon = settings.adminAuth.strategy.icon;
            }
            if (settings.adminAuth.strategy.image) {
                response.prompts[0].image = theme.serveFile('/login/',settings.adminAuth.strategy.image);
            }
        }
        if (theme.context().login && theme.context().login.image) {
            response.image = theme.context().login.image;
        }
    }
    res.json(response);
}

function revoke(req,res) {
    var token = req.body.token;
    // TODO: audit log
    Tokens.revoke(token).then(function() {
        log.audit({event: "auth.login.revoke"},req);
        if (settings.editorTheme && settings.editorTheme.logout && settings.editorTheme.logout.redirect) {
            res.json({redirect:settings.editorTheme.logout.redirect});
        } else {
            res.status(200).end();
        }
    });
}

module.exports = {
    init: init,
    needsPermission: needsPermission,
    ensureClientSecret: ensureClientSecret,
    authenticateClient: authenticateClient,
    getToken: getToken,
    errorHandler: function(err,req,res,next) {
        //TODO: audit log statment
        //console.log(err.stack);
        //log.log({level:"audit",type:"auth",msg:err.toString()});
        return server.errorHandler()(err,req,res,next);
    },
    login: login,
    revoke: revoke,
    oauthStrategy: function(adminApp,strategy) {
        var session = require('express-session');
        adminApp.use(session({
            secret: 'keyboard cat', // TODO: pull this out
            resave: false,
            saveUninitialized:false
        }));
        //TODO: all passport references ought to be in ./auth
        adminApp.use(passport.initialize());
        adminApp.use(passport.session());

        var options = strategy.options;
        passport.use(new strategy.strategy(options,
            function(token, tokenSecret, profile, done) {
                Users.authenticate(profile).then(function(user) {
                    if (user) {
                        Tokens.create(user.username,"node-red-editor",user.permissions).then(function(tokens) {
                            log.audit({event: "auth.login",username:user.username,scope:user.permissions});
                            user.tokens = tokens;
                            done(null,user);
                        });
                    } else {
                        log.audit({event: "auth.login.fail.oauth",username:profile.id});
                        done(null,false);
                    }
                });
            }
        ));

        adminApp.get('/auth/oauth', passport.authenticate(strategy.name));
        adminApp.get('/auth/oauth/callback',
            passport.authenticate(strategy.name, {session:false, failureRedirect: '/' }),
            function(req, res) {
                var tokens = req.user.tokens;
                delete req.user.tokens;
                // Successful authentication, redirect home.
                res.redirect('/?access_token='+tokens.accessToken);
            }
        );

    }
}