import vibe.core.core;
import vibe.db.mongo.mongo;
import vibe.http.router;
import vibe.http.server;
import vibe.web.web;

import mir.random : unpredictableSeedOf;
import mir.random.variable : UniformVariable;
import mir.random.engine.xorshift : Xorshift;

import std.conv : ConvException, to;
import std.array;
import std.exception : enforce;

enum worldSize = 10000;


void main()
{
	runWorkerTaskDist(&runServer);
	runApplication();
}

void runServer()
{
	auto router = new URLRouter;
	router.registerWebInterface(new WebInterface);
	router.rebuild();

	auto settings = new HTTPServerSettings;
	settings.options |= HTTPServerOption.reusePort;
	settings.port = 8080;
	listenHTTP(settings, router);
}

class WebInterface {
	private {
		MongoCollection _worldCollection;
		MongoCollection _fortuneCollection;
		UniformVariable!uint _uniformVariable;
		Xorshift _gen;
	}

	this()
	{
		import std.process : environment;
		auto db = connectMongoDB("tfb-database");
		_worldCollection = db.getCollection("hello_world.world");
		_fortuneCollection = db.getCollection("hello_world.fortune");

		_gen = Xorshift(unpredictableSeedOf!uint);
		_uniformVariable = UniformVariable!uint(1, worldSize);
	}

	// GET /
	void get()
	{
		render!"index.dt";
	}

	// GET /json
	void getJson(HTTPServerResponse res)
	{
		// NOTE: the status and content type parameters are optional, but we need
		// to specify them, because the default content type is "application/json; charset=UTF8"
		res.writeJsonBody(Message("Hello, World!"), HTTPStatus.ok, "application/json");
	}

	// GET /db
	void getDB(HTTPServerResponse res)
	{
		struct Q { int _id; }
		auto query = Q(_uniformVariable(_gen));
		auto world = _worldCollection.findOne!World(query);
		enforce(!world.isNull(), "expected world, found none.");
		auto w = WorldResponse(world.get);
		res.writeJsonBody(w, HTTPStatus.ok, "application/json");
	}

	// GET /queries?queries=...
	void getQueries(HTTPServerResponse res, string queries)
	{
		import std.algorithm : min, max;

		// Convert the "queries" parameter to int and ignore any conversion errors
		// Note that you'd usually declare queries as int instead. However, the
		// test required to gracefully handle errors here.
		int count = 1;
		try count = min(max(queries.to!int, 1), 500);
		catch (ConvException) {}

		// assemble the response array
		scope data = new WorldResponse[count];
		foreach (ref w; data) {
			static struct Q { int _id; }
			auto query = Q(_uniformVariable(_gen));
			auto world = _worldCollection.findOne!World(query);
			enforce(!world.isNull(), "expected world, found none.");
			w = WorldResponse(world.get);
		}

		// write response as JSON
		res.writeJsonBody(data, HTTPStatus.ok, "application/json");
	}

	// GET /fortunes
	void getFortunes()
	{
		import std.algorithm : map, sort;

		FortuneResponse[] data;
		data = _fortuneCollection.find!Fortune().map!(f => FortuneResponse(f)).array;
		data ~= FortuneResponse(Fortune(0, "Additional fortune added at request time."));
		data.sort!((a, b) => a.message < b.message);
		render!("fortunes.dt", data);
	}

	// GET /updates?queries=...
	void getUpdates(HTTPServerResponse res, string queries)
	{
		import std.algorithm : min, max;

		int count = 1;
		try count = min(max(queries.to!int, 1), 500);
		catch (ConvException e) {}

		scope data = new WorldResponse[count];
		foreach (ref w; data) {
			static struct Q { int _id; }
			auto query = Q(_uniformVariable(_gen));
			auto world = _worldCollection.findOne!World(query);
			enforce(!world.isNull(), "expected world, found none.");
			w = WorldResponse(world.get);

			// update random number
			w.randomNumber = _uniformVariable(_gen);

			// persist to DB
			static struct US {
				double randomNumber;
			}
			static struct U {
				@name("$set") US set;
			}
			_worldCollection.update(query, U(US(w.randomNumber)));
		}

		// write response as JSON
		res.writeJsonBody(data, HTTPStatus.ok, "application/json");
	}

	// GET /plaintext
	void getPlaintext(HTTPServerResponse res)
	{
		res.writeBody("Hello, World!", HTTPStatus.ok, "text/plain");
	}
}

struct Message {
	string message;
}

struct World {
	double _id;
	double randomNumber;
}

struct Fortune {
	double _id;
	string message;
}

struct WorldResponse {
	this(World w) { this.id = cast(int)w._id; this.randomNumber = cast(int)w.randomNumber; }
	int id;
	int randomNumber;
}

struct FortuneResponse {
	this(Fortune f) { this.id = cast(int)f._id; this.message = f.message; }
	int id;
	string message;
}