const express = require("express");
const traverse = require("traverse");

// Route building function:
// Expects an initial path used as the root of the route,
// as well as the path the the module within the routes folder
// Routes are build as
// domain.tld[path]/[moduleName]/[modulePath]
// where path is the passed in string, moduleName is one of the strings in the
// moduleNames array (moduleNames can be excluded from the route if includeNameInPath
// is false), and modulePath is the path generated by going up the keys of the route
// module which is described below.

// A routing module should return an object of the following structure:
/*
{
    get: {
        path: {
            to: {
                endpoint: function (req, res) {...}
            }
        },
        "alternate/path/to/endpoint": function (req, res) {...}
    },
    post: {...},
    delete: {...}
}
*/
// The root of the object, must be at least a get, post, or delete,
// this determines the endpoint type of the route. The path can be either
// built as a path from the keys of the object, or as a single key that
// is already the built path. You can also make a route object as so:
/*
{
    get: function (req, res) {},
    post: {...},
    delete: {...}
}
*/
// in which case there is no additional modulePath added to the route
// when it is built.

module.exports = function(path, moduleNames, includeNameInPath) {
    const router = express.Router();
    moduleNames.forEach(function(name) {
        let route = path;
        if (includeNameInPath) {
            route += name + "/";
        }
        console.log("Build routes for " + path + name);
        let routeData = require("./routes" + path + name);
        for (let endpointType in routeData) {
            console.log("Build " + endpointType + " endpoints...");
            let routes = routeData[endpointType];
            if (typeof routes === "object") {
                traverse(routes).forEach(function() {
                    if (this.isLeaf) {
                        let fullPath = route + this.path.join("/");
                        console.log(fullPath);
                        router[endpointType](fullPath, this.node);
                    }
                });
            } else {
                console.log(route);
                // There is only 1 path at root for the endpoint type
                // Rather than traversing the object
                router[endpointType](route, routes);
            }
            console.log("done\n");
        }
    });
    return router;
};