var oauth2orize = require('oauth2orize'),
    passport = require('passport'),
    models = require('../models'),
    errors = require('../errors'),
    authUtils = require('./utils'),
    spamPrevention = require('../middleware/api/spam-prevention'),
    i18n = require('../i18n'),
    oauthServer,
    oauth;

function exchangeRefreshToken(client, refreshToken, scope, body, authInfo, done) {
    models.Refreshtoken.findOne({token: refreshToken})
        .then(function then(model) {
            if (!model) {
                return done(new errors.NoPermissionError({message: i18n.t('errors.middleware.oauth.invalidRefreshToken')}), false);
            } else {
                var token = model.toJSON();

                if (token.expires > Date.now()) {
                    spamPrevention.userLogin.reset(authInfo.ip, body.refresh_token + 'login');

                    authUtils.createTokens({
                        clientId: token.client_id,
                        userId: token.user_id,
                        oldAccessToken: authInfo.accessToken,
                        oldRefreshToken: refreshToken
                    }).then(function (response) {
                        return done(null, response.access_token, {expires_in: response.expires_in});
                    }).catch(function handleError(error) {
                        return done(error, false);
                    });
                } else {
                    done(new errors.UnauthorizedError({message: i18n.t('errors.middleware.oauth.refreshTokenExpired')}), false);
                }
            }
        });
}
// We are required to pass in authInfo in order to reset spam counter for user login
function exchangePassword(client, username, password, scope, body, authInfo, done) {
    models.Client.findOne({slug: client.slug})
        .then(function then(client) {
            if (!client) {
                return done(new errors.NoPermissionError({
                    message: i18n.t('errors.middleware.oauth.invalidClient')
                }), false);
            }

            // Validate the user
            return models.User.check({email: username, password: password})
                .then(function then(user) {
                    return authUtils.createTokens({
                        clientId: client.id,
                        userId: user.id
                    });
                })
                .then(function then(response) {
                    spamPrevention.userLogin.reset(authInfo.ip, username + 'login');
                    return done(null, response.access_token, response.refresh_token, {expires_in: response.expires_in});
                });
        })
        .catch(function handleError(error) {
            return done(error, false);
        });
}

function exchangeAuthorizationCode(req, res, next) {
    if (!req.body.authorizationCode) {
        return next(new errors.UnauthorizedError({
            message: i18n.t('errors.middleware.auth.accessDenied')
        }));
    }

    req.query.code = req.body.authorizationCode;

    passport.authenticate('ghost', {session: false, failWithError: false}, function authenticate(err, user) {
        if (err) {
            return next(new errors.UnauthorizedError({
                err: err
            }));
        }

        if (!user) {
            return next(new errors.UnauthorizedError({
                message: i18n.t('errors.middleware.auth.accessDenied')
            }));
        }

        spamPrevention.userLogin.reset(req.authInfo.ip, req.body.authorizationCode + 'login');

        authUtils.createTokens({
            clientId: req.client.id,
            userId: user.id
        }).then(function then(response) {
            res.json({
                access_token: response.access_token,
                refresh_token: response.refresh_token,
                expires_in: response.expires_in
            });
        }).catch(function (err) {
            next(err);
        });
    })(req, res, next);
}

oauth = {

    init: function init() {
        oauthServer = oauth2orize.createServer();
        // remove all expired accesstokens on startup
        models.Accesstoken.destroyAllExpired();

        // remove all expired refreshtokens on startup
        models.Refreshtoken.destroyAllExpired();

        // Exchange user id and password for access tokens.  The callback accepts the
        // `client`, which is exchanging the user's name and password from the
        // authorization request for verification. If these values are validated, the
        // application issues an access token on behalf of the user who authorized the code.
        oauthServer.exchange(oauth2orize.exchange.password({userProperty: 'client'},
            exchangePassword));

        // Exchange the refresh token to obtain an access token.  The callback accepts the
        // `client`, which is exchanging a `refreshToken` previously issued by the server
        // for verification. If these values are validated, the application issues an
        // access token on behalf of the user who authorized the code.
        oauthServer.exchange(oauth2orize.exchange.refreshToken({userProperty: 'client'},
            exchangeRefreshToken));

        /**
         * Exchange authorization_code for an access token.
         * We forward to authorization code to Ghost.org.
         *
         * oauth2orize offers a default implementation via exchange.authorizationCode, but this function
         * wraps the express request and response. So no chance to get access to it.
         * We use passport to communicate with Ghost.org. Passport's module design requires the express req/res.
         *
         * For now it's OK to not use exchange.authorizationCode. You can read through the implementation here:
         * https://github.com/jaredhanson/oauth2orize/blob/master/lib/exchange/authorizationCode.js
         * As you can see, it does some validation and set's some headers, not very very important,
         * but it's part of the oauth2 spec.
         *
         * @TODO: How to use exchange.authorizationCode in combination of passport?
         */
        oauthServer.exchange('authorization_code', exchangeAuthorizationCode);
    },

    // ### Generate access token Middleware
    // register the oauth2orize middleware for password and refresh token grants
    generateAccessToken: function generateAccessToken(req, res, next) {
        /**
         * TODO:
         * https://github.com/jaredhanson/oauth2orize/issues/182
         * oauth2orize only offers the option to forward request information via authInfo object
         *
         * Important: only used for resetting the brute count (access to req.ip)
         */
        req.authInfo = {
            ip: req.ip,
            accessToken: authUtils.getBearerAutorizationToken(req)
        };

        return oauthServer.token()(req, res, next);
    }
};

module.exports = oauth;