var debug        = require('debug')('ff:tcrud:build:server:express');

var mod = (function () {
	
	var walkRouteTree = function(result,stack,parent_path) {
		if (parent_path == null) {
			parent_path = '';
		}
		stack.forEach(function(middleware) {
			if (middleware.route){
				var path = parent_path + middleware.route.path;
				for (var httpMethod in middleware.route.methods) {
					var data = {
						uriPath: path,
						httpMethod: httpMethod
					};
					result.push(data);
				}
			} else if (middleware.name === 'router') {
				var pp = parent_path + middleware.handle.path;
				walkRouteTree(result,middleware.handle.stack,pp);
			} else {
				//log.info('route err: '+JSON.stringify(middleware));
			}
		});
		return result;
	}
	
	var buildRouteLine = function(routes) {
		var result = [];
		for (var routeIdx in routes) {
			
		}
		return result;
	}
	
	var buildRouteDiff = function(obj,objOld) {
		var result = [];
		for (var objIdx in obj) {
			var objResult = obj[objIdx];
			var objAdd = true;
			for (var objOldIdx in objOld) {
				var objOldResult = objOld[objOldIdx];
				
				if (objResult.uriPath === objOldResult.uriPath && objResult.httpMethod === objOldResult.httpMethod) {
					objAdd = false;
					break;
				}
			}
			if (objAdd) {
				result.push(objResult);
			}
		}
		return result;
	}
	
	return function BuildServerExpress() {
		
		this.saveRoutes = function(server) {
			if (!server) {
				throw new Error('no server given');
			}
			var resultOld = server.get('ff_tcrud_route_list');
			var result = walkRouteTree([],server._router.stack);
			result.sort(function(a, b) {
				return a.uriPath.localeCompare(b.uriPath);
			});
			server.set('ff_tcrud_route_list',result);
			server.set('ff_tcrud_route_list_diff',buildRouteDiff(result,resultOld));
		};
		
		this.getRoutes = function(server) {
			return server.get('ff_tcrud_route_list');
		};
		
		this.getRoutesDiff = function(server) {
			return server.get('ff_tcrud_route_list_diff');
		};
		
		this.renderRedirect = function(location) {
			if (!location) {
				throw 'no location';
			}
			return function(req, res) {
				res.redirect(location);
			};
		};
		
		this.renderFunctionJSON = function(fn) {
			return function (req, res, next) {
				res.json({
					data: fn()
				});
			};
		};
	};
})();

module.exports = new mod();