import { NextFunction, Request, Response } from "express"
import { Client } from "@elastic/elasticsearch"
import permission from "../interfaces/permission"

if (!process.env.ELASTICSEARCH_INDEX) {
	throw new Error("Require ELASTICSEARCH_INDEX to store log.")
}

const ELASTICSEARCH_INDEX = process.env.ELASTICSEARCH_INDEX

const LOG_LEVEL_MAP: Record<string, number> = {
	debug: 4,
	info: 3,
	warning: 2,
	error: 1,
	none: 0,
}

const elasticsearch = new Client({
	node: `${process.env.ELASTICSEARCH_PROTOCOL}://${process.env.ELASTICSEARCH_HOST}:${process.env.ELASTICSEARCH_PORT}`,
})
async function logMiddleware(req: Request, res: Response, next: NextFunction) {
	if (!req.url.startsWith("/api/")) return next()

	let data: any
	const originalJson = res.json

	res.json = function (v: any) {
		data = v
		return originalJson.call(this, v)
	}

	const timestamp = new Date().toISOString()
	const start = performance.now()

	req.app.locals.logData = {}

	res.on("finish", async () => {
		try {
			if (!req.url.startsWith("/api/")) return

			const level = LOG_LEVEL_MAP[process.env.LOG_LEVEL ?? "debug"] || 4

			if (level === 1 && res.statusCode < 500) return
			if (level === 2 && res.statusCode < 400) return
			if (level === 3 && res.statusCode < 200) return

			const token = req.headers["authorization"]
			let rootId = null

			try {
				rootId = token ? await new permission().checkRootDna(token, req.app.locals.logData.userId) : null
			} catch (err) {
				console.warn("Error fetching rootId:", err)
			}

			const obj = {
				logType: res.statusCode >= 500 ? "error" : res.statusCode >= 400 ? "warning" : "info",
				ip: req.ip,
				rootId: rootId?.rootDnaId ?? null,
				systemName: "probation",
				startTimeStamp: timestamp,
				endTimeStamp: new Date().toISOString(),
				processTime: performance.now() - start,
				host: req.hostname,
				method: req.method,
				endpoint: req.url,
				responseCode: String(res.statusCode === 304 ? 200 : res.statusCode),
				responseDescription: data?.message,
				input: level === 4 ? JSON.stringify(req.body, null, 2) : undefined,
				output: level === 4 ? JSON.stringify(data, null, 2) : undefined,
				...req.app.locals.logData,
			}

			// Send log to Elasticsearch
			await elasticsearch.index({
				index: ELASTICSEARCH_INDEX,
				document: obj,
			})
		} catch (err) {
			console.error("Error in logMiddleware:", err)
		}
	})

	return next()
}

export default logMiddleware