var step = require('step');
var assert = require('assert');
var _ = require('underscore');
var NamedMapsCacheEntry = require('../cache/model/named_maps_entry');
var cors = require('../middleware/cors');

var TablesCacheEntry = require('../cache/model/database_tables_entry');

function NamedMapsController(app, namedMapProviderCache, tileBackend, previewBackend, surrogateKeysCache,
                             tablesExtentApi) {
    this.app = app;
    this.namedMapProviderCache = namedMapProviderCache;
    this.tileBackend = tileBackend;
    this.previewBackend = previewBackend;
    this.surrogateKeysCache = surrogateKeysCache;
    this.tablesExtentApi = tablesExtentApi;
}

module.exports = NamedMapsController;

NamedMapsController.prototype.register = function(app) {
    app.get(app.base_url_templated + '/:template_id/:layer/:z/:x/:y.(:format)', cors(), this.tile.bind(this));
    app.get(
        app.base_url_mapconfig + '/static/named/:template_id/:width/:height.:format', cors(), this.staticMap.bind(this)
    );
};

NamedMapsController.prototype.sendResponse = function(req, res, resource, headers, namedMapProvider) {
    this.surrogateKeysCache.tag(res, new NamedMapsCacheEntry(req.context.user, namedMapProvider.getTemplateName()));
    res.header('Content-Type', headers['Content-Type']);
    res.header('Cache-Control', 'public,max-age=7200,must-revalidate');

    var self = this;

    var dbName = req.params.dbname;
    step(
        function getAffectedTablesAndLastUpdatedTime() {
            namedMapProvider.getAffectedTablesAndLastUpdatedTime(this);
        },
        function sendResponse(err, result) {
            req.profiler.done('affectedTables');
            if (err) {
                console.log('ERROR generating cache channel: ' + err);
            }
            if (!result || !!result.affectedTables) {
                // we increase cache control as we can invalidate it
                res.header('Cache-Control', 'public,max-age=31536000');

                var lastModifiedDate;
                if (Number.isFinite(result.lastUpdatedTime)) {
                    lastModifiedDate = new Date(result.lastUpdatedTime);
                } else {
                    lastModifiedDate = new Date();
                }
                res.header('Last-Modified', lastModifiedDate.toUTCString());

                var tablesCacheEntry = new TablesCacheEntry(dbName, result.affectedTables);
                res.header('X-Cache-Channel', tablesCacheEntry.getCacheChannel());
                if (result.affectedTables.length > 0) {
                    self.surrogateKeysCache.tag(res, tablesCacheEntry);
                }
            }
            self.app.sendResponse(res, [resource, 200]);
        }
    );
};

NamedMapsController.prototype.tile = function(req, res) {
    var self = this;

    var cdbUser = req.context.user;

    var namedMapProvider;
    step(
        function reqParams() {
            self.app.req2params(req, this);
        },
        function getTile() {
            namedMapProvider = self.namedMapProviderCache.get(
                cdbUser,
                req.params.template_id,
                req.query.config,
                req.query.auth_token,
                req.params
            );
            self.tileBackend.getTile(namedMapProvider, req.params, this);
        },
        function handleImage(err, tile, headers, stats) {
            if (req.profiler) {
                req.profiler.add(stats);
            }
            if (err) {
                if (!err.error) {
                    err.error = err.message;
                }
                self.app.sendError(res, err, self.app.findStatusCode(err), 'NAMED_MAP_TILE', err);
            } else {
                self.sendResponse(req, res, tile, headers, namedMapProvider);
            }
        }
    );
};

NamedMapsController.prototype.staticMap = function(req, res) {
    var self = this;

    var cdbUser = req.context.user;

    var format = req.params.format === 'jpg' ? 'jpeg' : 'png';
    req.params.format = 'png';
    req.params.layer = 'all';

    var namedMapProvider;
    step(
        function reqParams() {
            self.app.req2params(req, this);
        },
        function getTemplate(err) {
            assert.ifError(err);
            namedMapProvider = self.namedMapProviderCache.get(
                cdbUser,
                req.params.template_id,
                req.query.config,
                req.query.auth_token,
                req.params
            );
            namedMapProvider.getTemplate(this);
        },
        function prepareStaticImageOptions(err, template) {
            assert.ifError(err);
            getStaticImageOptions(template, this);
        },
        function estimateBounds(err, imageOpts) {
            assert.ifError(err);
            if (imageOpts) {
                return imageOpts;
            }

            var defaultZoomCenter = {
                zoom: 1,
                center: {
                    lng: 0,
                    lat: 0
                }
            };

            var cacheChannel = '';

            var dbTables = cacheChannel.split(':');
            if (dbTables.length <= 1 || dbTables[1].length === 0) {
                return defaultZoomCenter;
            }

            var tableNames = dbTables[1].split(',');
            if (tableNames.length === 0) {
                return defaultZoomCenter;
            }

            var next = this;
            self.tablesExtentApi.getBounds(cdbUser, tableNames, function(err, result) {
                next(null, result || defaultZoomCenter);
            });
        },
        function getImage(err, imageOpts) {
            assert.ifError(err);

            var width = +req.params.width;
            var height = +req.params.height;

            if (!_.isUndefined(imageOpts.zoom) && imageOpts.center) {
                self.previewBackend.getImage(
                    namedMapProvider, format, width, height, imageOpts.zoom, imageOpts.center, this);
            } else {
                self.previewBackend.getImage(
                    namedMapProvider, format, width, height, imageOpts.bounds, this);
            }
        },
        function handleImage(err, image, headers, stats) {
            if (req.profiler) {
                req.profiler.done('render-' + format);
                req.profiler.add(stats || {});
            }

            if (err) {
                if (!err.error) {
                    err.error = err.message;
                }
                self.app.sendError(res, err, self.app.findStatusCode(err), 'STATIC_VIZ_MAP', err);
            } else {
                self.sendResponse(req, res, image, headers, namedMapProvider);
            }
        }
    );
};

function getStaticImageOptions(template, callback) {
    if (template.view) {
        var zoomCenter = templateZoomCenter(template.view);
        if (zoomCenter) {
            return callback(null, zoomCenter);
        }

        var bounds = templateBounds(template.view);
        if (bounds) {
            return callback(null, bounds);
        }
    }
    return callback(null, null);
}

function templateZoomCenter(view) {
    if (!_.isUndefined(view.zoom) && view.center) {
        return {
            zoom: view.zoom,
            center: view.center
        };
    }
    return false;
}

function templateBounds(view) {
    if (view.bounds) {
        var hasAllBounds = _.every(['west', 'south', 'east', 'north'], function(prop) {
            return !!view.bounds[prop];
        });
        if (hasAllBounds) {
            return {
                bounds: {
                    west: view.bounds.west,
                    south: view.bounds.south,
                    east: view.bounds.east,
                    north: view.bounds.north
                }
            };
        } else {
            return false;
        }
    }
    return false;
}