var _           = require('lodash'),
    passport    = require('passport'),
    url         = require('url'),
    os            = require('os'),
    errors      = require('../errors'),
    config      = require('../config'),
    labs        = require('../utils/labs'),
    i18n        = require('../i18n'),

    auth;

function isBearerAutorizationHeader(req) {
    var parts,
        scheme,
        credentials;

    if (req.headers && req.headers.authorization) {
        parts = req.headers.authorization.split(' ');
    } else if (req.query && req.query.access_token) {
        return true;
    } else {
        return false;
    }

    if (parts.length === 2) {
        scheme = parts[0];
        credentials = parts[1];
        if (/^Bearer$/i.test(scheme)) {
            return true;
        }
    }
    return false;
}

function getIPs() {
    var ifaces = os.networkInterfaces(),
        ips = [];

    Object.keys(ifaces).forEach(function (ifname) {
        ifaces[ifname].forEach(function (iface) {
            // only support IPv4
            if (iface.family !== 'IPv4') {
                return;
            }
            ips.push(iface.address);
        });
    });
    return ips;
}

function isValidOrigin(origin, client) {
    var configHostname = url.parse(config.url).hostname;

    if (origin && client && client.type === 'ua' && (
        _.indexOf(getIPs(), origin) >= 0
        || _.some(client.trustedDomains, {trusted_domain: origin})
        || origin === configHostname
        || configHostname === 'my-ghost-blog.com'
        || origin === url.parse(config.urlSSL ? config.urlSSL : '').hostname
        // @TODO do this in dev mode only, once we can auto-configure the url #2240
        || (origin === 'localhost')
    )) {
        return true;
    } else {
        return false;
    }
}

auth = {

    // ### Authenticate Client Middleware
    authenticateClient: function authenticateClient(req, res, next) {
        // skip client authentication if bearer token is present
        if (isBearerAutorizationHeader(req)) {
            return next();
        }

        if (req.query && req.query.client_id) {
            req.body.client_id = req.query.client_id;
        }

        if (req.query && req.query.client_secret) {
            req.body.client_secret = req.query.client_secret;
        }

        if (!req.body.client_id || !req.body.client_secret) {
            errors.logError(
                i18n.t('errors.middleware.auth.clientAuthenticaionFailed'),
                i18n.t('errors.middleware.auth.clientCredentialsNotProvided'),
                i18n.t('errors.middleware.auth.forInformationRead', {url: 'http://api.ghost.org/docs/client-authentication'})
            );
            return errors.handleAPIError(new errors.UnauthorizedError(i18n.t('errors.middleware.auth.accessDenied')), req, res, next);
        }

        return passport.authenticate(['oauth2-client-password'], {session: false, failWithError: false},
            function authenticate(err, client) {
                var origin = null,
                    error;
                if (err) {
                    return next(err); // will generate a 500 error
                }

                if (req.headers && req.headers.origin) {
                    origin = url.parse(req.headers.origin).hostname;
                }

                // req.body needs to be null for GET requests to build options correctly
                delete req.body.client_id;
                delete req.body.client_secret;

                if (!client || client.type !== 'ua') {
                    errors.logError(
                        i18n.t('errors.middleware.auth.clientAuthenticaionFailed'),
                        i18n.t('errors.middleware.auth.clientCredentialsNotValid'),
                        i18n.t('errors.middleware.auth.forInformationRead', {url: 'http://api.ghost.org/docs/client-authentication'})
                    );
                    return errors.handleAPIError(new errors.UnauthorizedError(i18n.t('errors.middleware.auth.accessDenied')), req, res, next);
                }

                if (!origin && client && client.type === 'ua') {
                    res.header('Access-Control-Allow-Origin', config.url);
                    req.client = client;
                    return next(null, client);
                }

                if (isValidOrigin(origin, client)) {
                    res.header('Access-Control-Allow-Origin', req.headers.origin);
                    req.client = client;
                    return next(null, client);
                } else {
                    error = new errors.UnauthorizedError(i18n.t('errors.middleware.auth.accessDeniedFromUrl', {origin: origin}));
                    errors.logError(error,
                        i18n.t('errors.middleware.auth.attemptedToAccessAdmin'),
                        i18n.t('errors.middleware.auth.forInformationRead', {url: 'http://support.ghost.org/config/#url'})
                    );
                    return errors.handleAPIError(error, req, res, next);
                }
            }
        )(req, res, next);
    },

    // ### Authenticate User Middleware
    authenticateUser: function authenticateUser(req, res, next) {
        return passport.authenticate('bearer', {session: false, failWithError: false},
            function authenticate(err, user, info) {
                if (err) {
                    return next(err); // will generate a 500 error
                }

                if (user) {
                    req.authInfo = info;
                    req.user = user;
                    return next(null, user, info);
                } else if (isBearerAutorizationHeader(req)) {
                    return errors.handleAPIError(new errors.UnauthorizedError(i18n.t('errors.middleware.auth.accessDenied')), req, res, next);
                } else if (req.client) {
                    return next();
                }

                return errors.handleAPIError(new errors.UnauthorizedError(i18n.t('errors.middleware.auth.accessDenied')), req, res, next);
            }
        )(req, res, next);
    },

    // Workaround for missing permissions
    // TODO: rework when https://github.com/TryGhost/Ghost/issues/3911 is  done
    requiresAuthorizedUser: function requiresAuthorizedUser(req, res, next) {
        if (req.user) {
            return next();
        } else {
            return errors.handleAPIError(new errors.NoPermissionError(i18n.t('errors.middleware.auth.pleaseSignIn')), req, res, next);
        }
    },

    // ### Require user depending on public API being activated.
    requiresAuthorizedUserPublicAPI: function requiresAuthorizedUserPublicAPI(req, res, next) {
        if (labs.isSet('publicAPI') === true) {
            return next();
        } else {
            if (req.user) {
                return next();
            } else {
                return errors.handleAPIError(new errors.NoPermissionError(i18n.t('errors.middleware.auth.pleaseSignIn')), req, res, next);
            }
        }
    }
};

module.exports = auth;