var _ = require('lodash'),
    Hawk = require('hawk'),

    ASCII_SOURCE = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789',
    ASCII_SOURCE_LENGTH = ASCII_SOURCE.length,
    EMPTY = '';

/**
 * Generates a random string of given length (useful for nonce generation, etc).
 *
 * @param {Number} length
 */
function randomString (length) {
    length = length || 6;

    var result = [],
        i;

    for (i = 0; i < length; i++) {
        result[i] = ASCII_SOURCE[(Math.random() * ASCII_SOURCE_LENGTH) | 0];
    }
    return result.join(EMPTY);
}

module.exports = {
    /**
     * Initializes an item (extracts parameters from intermediate requests if any, etc)
     * before the actual authorization step.
     *
     * @param {AuthInterface} auth
     * @param {Response} response
     * @param done
     */
    init: function (auth, response, done) {
        done(null);
    },

    /**
     * Checks the item, and fetches any parameters that are not already provided.
     * Sanitizes the auth parameters if needed.
     *
     * @param {AuthInterface} auth
     * @param done
     */
    pre: function (auth, done) {
        !auth.get('nonce') && auth.set('nonce', randomString(6));
        !_.parseInt(auth.get('timestamp')) && auth.set('timestamp',
            // Hawk has this function in their Node distribution, but not in the browsers :/
            (_.isFunction(Hawk.utils.nowSecs) ? Hawk.utils.nowSecs() : Hawk.utils.now())
        );
        done(null, true);
    },

    /**
     * Verifies whether the request was successfully authorized after being sent.
     *
     * @param {AuthInterface} auth
     * @param {Response} response
     * @param done
     */
    post: function (auth, response, done) {
        done(null, true);
    },

    /**
     * Computes signature and Auth header for a request.
     *
     * @param {Object} params
     * @param {Object} params.credentials Contains hawk auth credentials, "id", "key" and "algorithm"
     * @param {String} params.nonce
     * @param {String} params.ext Extra data that may be associated with the request.
     * @param {String} params.app Application ID used in Oz authorization protocol
     * @param {String} params.dlg Delegation information (used in the Oz protocol)
     * @param {String} params.user User id
     * @param {String} params.url Complete request URL
     * @param {String} params.method Request method
     *
     * @returns {*}
     */
    computeHeader: function (params) {
        return Hawk.client.header(params.url, params.method, params);
    },

    /**
     * Signs a request.
     *
     * @param {AuthInterface} auth
     * @param {Request} request
     * @param done
     */
    sign: function (auth, request, done) {
        var result,
            params = auth.get([
                'authId',
                'authKey',
                'algorithm',
                'nonce',
                'timestamp',
                'extraData',
                'app',
                'delegation',
                'user'
            ]);
        if (!params.authId || !params.authKey) {
            return done(); // Nothing to do if no parameters are present.
        }

        request.removeHeader('Authorization', {ignoreCase: true});
        result = this.computeHeader({
            credentials: {
                id: params.authId,
                key: params.authKey,
                algorithm: params.algorithm
            },
            nonce: params.nonce,
            timestamp: params.timestamp,
            ext: params.extraData,
            app: params.app,
            dlg: params.delegation,
            user: params.user,
            url: request.url.toString(true), // force toString to add a protocol to the URL.
            method: request.method
        });
        request.addHeader({
            key: 'Authorization',
            value: result.field,
            system: true
        });
        return done();
    }
};

@@ -372,17 +372,17 @@
 ngth %7C%7C 
-6
+8
 ;%0A%0A    v
@@ -1197,17 +1197,17 @@
 mString(
-6
+8
 ));%0A    

increase nonce length to 8 for more entropy