var assert = require('assert');

var express = require('express');
var RedisPool = require('redis-mpool');
var cartodbRedis = require('cartodb-redis');
var _ = require('underscore');
var step = require('step');

var controller = require('./controllers');

var SurrogateKeysCache = require('./cache/surrogate_keys_cache');
var NamedMapsCacheEntry = require('./cache/model/named_maps_entry');
var VarnishHttpCacheBackend = require('./cache/backend/varnish_http');
var FastlyCacheBackend = require('./cache/backend/fastly');

var windshaft = require('windshaft');
var mapnik = windshaft.mapnik;

var TemplateMaps = require('./backends/template_maps.js');
var QueryTablesApi = require('./api/query_tables_api');
var UserLimitsApi = require('./api/user_limits_api');
var AuthApi = require('./api/auth_api');
var LayergroupAffectedTablesCache = require('./cache/layergroup_affected_tables');
var PgQueryRunner = require('./backends/pg_query_runner');
var PgConnection = require('./backends/pg_connection');

var CdbRequest = require('./models/cdb_request');
var cdbRequest = new CdbRequest();

var LZMA = require('lzma').LZMA;
// Whitelist query parameters and attach format
var REQUEST_QUERY_PARAMS_WHITELIST = [
    'config',
    'map_key',
    'api_key',
    'auth_token',
    'callback'
];

var lzmaWorker = new LZMA();

var timeoutErrorTilePath = __dirname + '/../../assets/render-timeout-fallback.png';
var timeoutErrorTile = require('fs').readFileSync(timeoutErrorTilePath, {encoding: null});


module.exports = function(serverOptions) {
    // Make stats client globally accessible
    global.statsClient = windshaft.stats.Client.getInstance(serverOptions.statsd);

    var redisPool = new RedisPool(_.defaults(global.environment.redis, {
        name: 'windshaft:server',
        unwatchOnRelease: false,
        noReadyCheck: true
    }));

    redisPool.on('status', function(status) {
        var keyPrefix = 'windshaft.redis-pool.' + status.name + '.db' + status.db + '.';
        global.statsClient.gauge(keyPrefix + 'count', status.count);
        global.statsClient.gauge(keyPrefix + 'unused', status.unused);
        global.statsClient.gauge(keyPrefix + 'waiting', status.waiting);
    });

    var metadataBackend = cartodbRedis({pool: redisPool});
    var pgConnection = new PgConnection(metadataBackend);
    var pgQueryRunner = new PgQueryRunner(pgConnection);
    var queryTablesApi = new QueryTablesApi(pgQueryRunner);
    var userLimitsApi = new UserLimitsApi(metadataBackend, {
        limits: {
            cacheOnTimeout: serverOptions.renderer.mapnik.limits.cacheOnTimeout || false,
            render: serverOptions.renderer.mapnik.limits.render || 0
        }
    });

    var templateMaps = new TemplateMaps(redisPool, {
        max_user_templates: global.environment.maxUserTemplates
    });

    var surrogateKeysCacheBackends = [];

    if (serverOptions.varnish_purge_enabled) {
        surrogateKeysCacheBackends.push(
            new VarnishHttpCacheBackend(serverOptions.varnish_host, serverOptions.varnish_http_port)
        );
    }

    if (serverOptions.fastly &&
        !!serverOptions.fastly.enabled && !!serverOptions.fastly.apiKey && !!serverOptions.fastly.serviceId) {
        surrogateKeysCacheBackends.push(
            new FastlyCacheBackend(serverOptions.fastly.apiKey, serverOptions.fastly.serviceId)
        );
    }

    var surrogateKeysCache = new SurrogateKeysCache(surrogateKeysCacheBackends);

    function invalidateNamedMap (owner, templateName) {
        var startTime = Date.now();
        surrogateKeysCache.invalidate(new NamedMapsCacheEntry(owner, templateName), function(err) {
            var logMessage = JSON.stringify({
                username: owner,
                type: 'named_map_invalidation',
                elapsed: Date.now() - startTime,
                error: !!err ? JSON.stringify(err.message) : undefined
            });
            if (err) {
                console.warn(logMessage);
            } else {
                console.info(logMessage);
            }
        });
    }
    ['update', 'delete'].forEach(function(eventType) {
        templateMaps.on(eventType, invalidateNamedMap);
    });

    serverOptions.grainstore.mapnik_version = mapnikVersion(serverOptions);

    validateOptions(serverOptions);

    bootstrapFonts(serverOptions);

    // initialize express server
    var app = bootstrap(serverOptions);
    // Extend windshaft with all the elements of the options object
    _.extend(app, serverOptions);

    var mapStore  = new windshaft.storage.MapStore({
        pool: redisPool,
        expire_time: serverOptions.grainstore.default_layergroup_ttl
    });

    var onTileErrorStrategy;
    if (global.environment.enabledFeatures.onTileErrorStrategy !== false) {
        onTileErrorStrategy = function onTileErrorStrategy$TimeoutTile(err, tile, headers, stats, format, callback) {
            if (err && err.message === 'Render timed out' && format === 'png') {
                return callback(null, timeoutErrorTile, { 'Content-Type': 'image/png' }, {});
            } else {
                return callback(err, tile, headers, stats);
            }
        };
    }

    var rendererFactory = new windshaft.renderer.Factory({
        onTileErrorStrategy: onTileErrorStrategy,
        mapnik: {
            redisPool: redisPool,
            grainstore: serverOptions.grainstore,
            mapnik: serverOptions.renderer.mapnik
        },
        http: serverOptions.renderer.http
    });

    // initialize render cache
    var rendererCacheOpts = _.defaults(serverOptions.renderCache || {}, {
        ttl: 60000, // 60 seconds TTL by default
        statsInterval: 60000 // reports stats every milliseconds defined here
    });
    var rendererCache = new windshaft.cache.RendererCache(rendererFactory, rendererCacheOpts);

    var attributesBackend = new windshaft.backend.Attributes(rendererCache, mapStore);
    var previewBackend = new windshaft.backend.Preview(rendererCache);
    var tileBackend = new windshaft.backend.Tile(rendererCache);
    var mapValidatorBackend = new windshaft.backend.MapValidator(tileBackend, attributesBackend);
    var mapBackend = new windshaft.backend.Map(rendererCache, mapStore, mapValidatorBackend);

    var layergroupAffectedTablesCache = new LayergroupAffectedTablesCache();
    app.layergroupAffectedTablesCache = layergroupAffectedTablesCache;

    var authApi = new AuthApi(pgConnection, metadataBackend, mapStore, templateMaps);

    app.findStatusCode = function(err) {
        var statusCode;
        if ( err.http_status ) {
            statusCode = err.http_status;
        } else {
            statusCode = statusFromErrorMessage('' + err);
        }
        return statusCode;
    };

    var TablesExtentApi = require('./api/tables_extent_api');
    var tablesExtentApi = new TablesExtentApi(pgQueryRunner);

    /*******************************************************************************************************************
     * Routing
     ******************************************************************************************************************/

    app.all('*', function(req, res, next) {
        req.context.user = cdbRequest.userByReq(req);
        next();
    });

    new controller.Layergroup(
        app,
        mapStore,
        tileBackend,
        previewBackend,
        attributesBackend,
        surrogateKeysCache,
        userLimitsApi,
        queryTablesApi,
        layergroupAffectedTablesCache
    ).register(app);

    new controller.Map(
        app,
        pgConnection,
        templateMaps,
        mapBackend,
        metadataBackend,
        queryTablesApi,
        surrogateKeysCache,
        userLimitsApi,
        layergroupAffectedTablesCache
    ).register(app);

    new controller.NamedMaps(
        app,
        pgConnection,
        templateMaps,
        tileBackend,
        previewBackend,
        surrogateKeysCache,
        tablesExtentApi,
        userLimitsApi
    ).register(app);

    new controller.NamedMapsAdmin(app, templateMaps, authApi).register(app);

    new controller.ServerInfo().register(app);

    /*******************************************************************************************************************
     * END Routing
     ******************************************************************************************************************/

        // temporary measure until we upgrade to newer version expressjs so we can check err.status
    app.use(function(err, req, res, next) {
        if (err) {
            if (err.name === 'SyntaxError') {
                app.sendError(res, { errors: [err.name + ': ' + err.message] }, 400, 'JSON', err);
            } else {
                next(err);
            }
        } else {
            next();
        }
    });

    app.sendResponse = function(res, args) {
        var req = res.req;

        if (global.environment && global.environment.api_hostname) {
            res.header('X-Served-By-Host', global.environment.api_hostname);
        }

        if (req && req.params && req.params.dbhost) {
            res.header('X-Served-By-DB-Host', req.params.dbhost);
        }

        if ( req && req.profiler ) {
            res.header('X-Tiler-Profiler', req.profiler.toJSONString());
        }

//        res.send(body|status[, headers|status[, status]])
        res.send.apply(res, args);

        if ( req && req.profiler ) {
            try {
                // May throw due to dns, see
                // See http://github.com/CartoDB/Windshaft/issues/166
                req.profiler.sendStats();
            } catch (err) {
                console.error("error sending profiling stats: " + err);
            }
        }
    };

    app.sendError = function(res, err, statusCode, label, tolog) {
        res._windshaftStatusCode = statusCode;

        var olabel = '[';
        if ( label ) {
            olabel += label + ' ';
        }
        olabel += 'ERROR]';
        if ( ! tolog ) {
            tolog = err;
        }
        var log_msg = olabel + " -- " + statusCode + ": " + tolog;
        //if ( tolog.stack ) log_msg += "\n" + tolog.stack;
        console.error(log_msg); // use console.log for statusCode != 500 ?
        // If a callback was requested, force status to 200
        if ( res.req ) {
            // NOTE: res.req can be undefined when we fake a call to
            //       ourself from POST to /layergroup
            if ( res.req.query.callback ) {
                statusCode = 200;
            }
        }
        // Strip connection info, if any
        // See https://github.com/CartoDB/Windshaft/issues/173
        err = JSON.stringify(err);
        err = err.replace(/Connection string: '[^']*'\\n/, '');
        // See https://travis-ci.org/CartoDB/Windshaft/jobs/20703062#L1644
        err = err.replace(/is the server.*encountered/im, 'encountered');
        err = JSON.parse(err);

        app.sendResponse(res, [err, statusCode]);
    };

    // jshint maxcomplexity:10
    /**
     * 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
     */
    app.req2params = function(req, callback){

        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));
                        app.req2params(req, callback);
                    } catch (err) {
                        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;
                    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(){
                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);
                pgConnection.setDBConn(user, req.params, this);
            },
            function finishSetup(err) {
                if ( err ) {
                    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
                });

                callback(null, req);
            }
        );
    };

    return app;
};

function validateOptions(opts) {
    if (!_.isString(opts.base_url) || !_.isString(opts.base_url_mapconfig) || !_.isString(opts.base_url_templated)) {
        throw new Error("Must initialise server with: 'base_url'/'base_url_mapconfig'/'base_url_templated' URLs");
    }

    // Be nice and warn if configured mapnik version is != instaled mapnik version
    if (mapnik.versions.mapnik !== opts.grainstore.mapnik_version) {
        console.warn('WARNING: detected mapnik version (' + mapnik.versions.mapnik + ')' +
            ' != configured mapnik version (' + opts.grainstore.mapnik_version + ')');
    }
}

function bootstrapFonts(opts) {
    // Set carto renderer configuration for MMLStore
    opts.grainstore.carto_env = opts.grainstore.carto_env || {};
    var cenv = opts.grainstore.carto_env;
    cenv.validation_data = cenv.validation_data || {};
    if ( ! cenv.validation_data.fonts ) {
        mapnik.register_system_fonts();
        mapnik.register_default_fonts();
        cenv.validation_data.fonts = _.keys(mapnik.fontFiles());
    }
}

function bootstrap(opts) {
    var app;
    if (_.isObject(opts.https)) {
        // use https if possible
        app = express.createServer(opts.https);
    } else {
        // fall back to http by default
        app = express.createServer();
    }
    app.enable('jsonp callback');
    app.use(express.bodyParser());

    app.use(function bootstrap$prepareRequestResponse(req, res, next) {
        req.context = req.context || {};
        req.profiler = new windshaft.stats.Profiler({
            statsd_client: global.statsClient,
            profile: opts.useProfiler
        });
        res.removeHeader('x-powered-by');
        next();
    });

    setupLogger(app, opts);

    return app;
}

function setupLogger(app, opts) {
    if (opts.log_format) {
        var loggerOpts = {
            // Allowing for unbuffered logging is mainly
            // used to avoid hanging during unit testing.
            // TODO: provide an explicit teardown function instead,
            //       releasing any event handler or timer set by
            //       this component.
            buffer: !opts.unbuffered_logging,
            // optional log format
            format: opts.log_format
        };
        if (global.log4js) {
            app.use(global.log4js.connectLogger(global.log4js.getLogger(), _.defaults(loggerOpts, {level: 'info'})));
        } else {
            app.use(express.logger(loggerOpts));
        }
    }
}

function statusFromErrorMessage(errMsg) {
    // Find an appropriate statusCode based on message
    var statusCode = 400;
    if ( -1 !== errMsg.indexOf('permission denied') ) {
        statusCode = 403;
    }
    else if ( -1 !== errMsg.indexOf('authentication failed') ) {
        statusCode = 403;
    }
    else if (errMsg.match(/Postgis Plugin.*[\s|\n].*column.*does not exist/)) {
        statusCode = 400;
    }
    else if ( -1 !== errMsg.indexOf('does not exist') ) {
        if ( -1 !== errMsg.indexOf(' role ') ) {
            statusCode = 403; // role 'xxx' does not exist
        } else {
            statusCode = 404;
        }
    }
    return statusCode;
}

function mapnikVersion(opts) {
    return opts.grainstore.mapnik_version || mapnik.versions.mapnik;
}