var assert = require('assert');

var _ = require('underscore');
var step = require('step');

var LZMA = require('lzma').LZMA;
var lzmaWorker = new LZMA();

// Whitelist query parameters and attach format
var REQUEST_QUERY_PARAMS_WHITELIST = [
    'config',
    'map_key',
    'api_key',
    'auth_token',
    'callback'
];

function BaseController(authApi, pgConnection) {
    this.authApi = authApi;
    this.pgConnection = pgConnection;
}

module.exports = BaseController;

// jshint maxcomplexity:9
/**
 * Whitelist input and get database name & default geometry type from
 * subdomain/user metadata held in CartoDB Redis
 * @param req - standard express request obj. Should have host & table
 * @param callback
 */
BaseController.prototype.req2params = function(req, callback){
    var self = this;

    if ( req.query.lzma ) {

        // Decode (from base64)
        var lzma = new Buffer(req.query.lzma, 'base64')
            .toString('binary')
            .split('')
            .map(function(c) {
                return c.charCodeAt(0) - 128;
            });


        // Decompress
        lzmaWorker.decompress(
            lzma,
            function(result) {
                if (req.profiler) {
                    req.profiler.done('lzma');
                }
                try {
                    delete req.query.lzma;
                    _.extend(req.query, JSON.parse(result));
                    self.req2params(req, callback);
                } catch (err) {
                    req.profiler.done('req2params');
                    callback(new Error('Error parsing lzma as JSON: ' + err));
                }
            }
        );
        return;
    }

    req.query = _.pick(req.query, REQUEST_QUERY_PARAMS_WHITELIST);
    req.params = _.extend({}, req.params); // shuffle things as request is a strange array/object

    var user = req.context.user;

    if ( req.params.token ) {
        // Token might match the following patterns:
        // - {user}@{tpl_id}@{token}:{cache_buster}
        //console.log("Request parameters include token " + req.params.token);
        var tksplit = req.params.token.split(':');
        req.params.token = tksplit[0];
        if ( tksplit.length > 1 ) {
            req.params.cache_buster= tksplit[1];
        }
        tksplit = req.params.token.split('@');
        if ( tksplit.length > 1 ) {
            req.params.signer = tksplit.shift();
            if ( ! req.params.signer ) {
                req.params.signer = user;
            }
            else if ( req.params.signer !== user ) {
                var err = new Error(
                        'Cannot use map signature of user "' + req.params.signer + '" on db of user "' + user + '"'
                );
                err.http_status = 403;
                req.profiler.done('req2params');
                callback(err);
                return;
            }
            if ( tksplit.length > 1 ) {
                /*var template_hash = */tksplit.shift(); // unused
            }
            req.params.token = tksplit.shift();
            //console.log("Request for token " + req.params.token + " with signature from " + req.params.signer);
        }
    }

    // bring all query values onto req.params object
    _.extend(req.params, req.query);

    if (req.profiler) {
        req.profiler.done('req2params.setup');
    }

    step(
        function getPrivacy(){
            self.authApi.authorize(req, this);
        },
        function validateAuthorization(err, authorized) {
            if (req.profiler) {
                req.profiler.done('authorize');
            }
            assert.ifError(err);
            if(!authorized) {
                err = new Error("Sorry, you are unauthorized (permission denied)");
                err.http_status = 403;
                throw err;
            }
            return null;
        },
        function getDatabase(err){
            assert.ifError(err);
            self.pgConnection.setDBConn(user, req.params, this);
        },
        function finishSetup(err) {
            if ( err ) {
                req.profiler.done('req2params');
                return callback(err, req);
            }

            // Add default database connection parameters
            // if none given
            _.defaults(req.params, {
                dbuser: global.environment.postgres.user,
                dbpassword: global.environment.postgres.password,
                dbhost: global.environment.postgres.host,
                dbport: global.environment.postgres.port
            });

            req.profiler.done('req2params');
            callback(null, req);
        }
    );
};
// jshint maxcomplexity:6