import { createServer } from 'http'
import express from 'express'
import { WebSocketServer } from 'ws'
import { fileURLToPath, pathToFileURL } from 'url'
import { dirname, join } from 'path'
import { setupWebSocketHandler } from './src/websocket-handler.js'
import { printServerInfo } from './src/server-utils.js'
import { loadState, saveState } from './src/persist.js'

const __filename = fileURLToPath(import.meta.url)
const __dirname = dirname(__filename)

const DIST_DIR = join(__dirname, 'dist')

// Crea l'app Express (asset statici + route display/controller) senza avviare il
// listen né il WebSocket: così il routing è testabile in isolamento.
export function createApp(distDir = DIST_DIR) {
    const app = express()

    app.use(express.static(distDir, { index: false }))

    app.get(['/', '/display', '/display/*splat'], (_req, res) => {
        res.sendFile(join(distDir, 'index.html'))
    })

    app.get(['/controller', '/controller/*splat'], (_req, res) => {
        res.sendFile(join(distDir, 'controller.html'))
    })

    return app
}

// Avvia HTTP + WebSocket. Lo stato viene caricato da disco e ripersistito ad ogni azione.
export function startServer(port = process.env.PORT || 3000) {
    const app = createApp()
    const server = createServer(app)
    const wss = new WebSocketServer({ noServer: true })
    setupWebSocketHandler(wss, { initialState: loadState(), onStateChange: saveState })

    server.on('upgrade', (request, socket, head) => {
        const pathname = new URL(request.url, `http://${request.headers.host}`).pathname
        if (pathname === '/ws') {
            wss.handleUpgrade(request, socket, head, (ws) => {
                wss.emit('connection', ws, request)
            })
        } else {
            socket.destroy()
        }
    })

    server.listen(port, '0.0.0.0', () => {
        printServerInfo(port)
    })

    return server
}

// Avvia solo se eseguito direttamente (`node server.js`), non quando importato nei test.
if (process.argv[1] && import.meta.url === pathToFileURL(process.argv[1]).href) {
    startServer()
}