const cors = require("cors");
const express = require("express");
const fs = require("fs");
const path = require("path");
const swaggerUi = require("swagger-ui-express");
const { config } = require("./config");
const { pingMongo } = require("./db/client");
const { router: apiRouter } = require("./routes/api");
const { openApiDocument } = require("./swagger/openapi");

const skillFilePaths = [
	path.join(__dirname, "SKILL.md"),
	path.join(__dirname, "..", ".idea", "SKILL.md"),
	path.join(__dirname, "..", ".ai", "SKILL.md"),
];

function getSkillFilePath() {
	return skillFilePaths.find((filePath) => fs.existsSync(filePath));
}

function createApp() {
	const app = express();

	app.set("trust proxy", true);
	app.use(cors());
	app.use(express.json({ limit: "2mb" }));
	app.use((request, response, next) => {
		const forwardedProto = request.get("x-forwarded-proto");
		const isSecure = request.secure || forwardedProto === "https";
		const isLocalhost = ["localhost", "127.0.0.1", "::1"].includes(
			request.hostname,
		);

		if (config.public.forceHttps && !isSecure && !isLocalhost) {
			const baseUrl =
				request.hostname === "ui.dune.api.coppnic.cc"
					? config.public.uiUrl
					: config.public.apiUrl;
			response.redirect(308, new URL(request.originalUrl, baseUrl).toString());
			return;
		}

		next();
	});

	app.get("/", (request, response) => {
		response.redirect(308, `${config.public.uiUrl}/docs`);
	});

	app.get("/health", async (request, response) => {
		try {
			await pingMongo();
			response.json({ ok: true, mongo: "connected" });
		} catch (error) {
			response
				.status(503)
				.json({ ok: false, mongo: "unavailable", error: error.message });
		}
	});

	app.get("/openapi.json", (request, response) => {
		response.json(openApiDocument);
	});

	app.get(["/SKILL.md", "/skill.md"], (request, response) => {
		const skillFilePath = getSkillFilePath();
		if (!skillFilePath) {
			response.status(404).json({ error: "SKILL.md not found" });
			return;
		}

		response.type("text/markdown");
		response.sendFile(skillFilePath);
	});

	app.use("/docs", swaggerUi.serve, swaggerUi.setup(openApiDocument));
	app.use("/api", apiRouter);

	app.use((request, response) => {
		response.status(404).json({ error: "Not found" });
	});

	app.use((error, request, response, next) => {
		const status = error.status || 500;
		response
			.status(status)
			.json({ error: error.message || "Internal server error" });
	});

	return app;
}

module.exports = { createApp };