package main

import (
	"embed"
	"flag"
	"fmt"
	"io/fs"
	"log"
	"net/http"
	"time"

	"github.com/gorilla/websocket"
)

//go:embed webui/*
var webUI embed.FS

var wsUpgrader = websocket.Upgrader{
	CheckOrigin: func(r *http.Request) bool { return true },
}

func runServe(portName string, baud int, args []string) error {
	serveFlags := flag.NewFlagSet("serve", flag.ExitOnError)
	addr := serveFlags.String("addr", ":8080", "HTTP listen address")
	interval := serveFlags.Duration("interval", 2*time.Second, "UART poll interval")
	if err := serveFlags.Parse(args); err != nil {
		return err
	}
	if portName == "" {
		return fmt.Errorf("serve requires -port (master UART)")
	}

	link := newManagedSerial(portName, baud)
	link.quiet = true
	defer link.Close()

	hub := newWSHub()
	stop := make(chan struct{})
	defer close(stop)
	go runPoller(link, portName, hub, *interval, stop)

	mux := http.NewServeMux()
	mux.HandleFunc("/ws", func(w http.ResponseWriter, r *http.Request) {
		conn, err := wsUpgrader.Upgrade(w, r, nil)
		if err != nil {
			log.Printf("websocket upgrade: %v", err)
			return
		}
		hub.register(conn)
		defer hub.unregister(conn)
		defer conn.Close()

		for {
			if _, _, err := conn.ReadMessage(); err != nil {
				return
			}
		}
	})

	ui, err := fs.Sub(webUI, "webui")
	if err != nil {
		return err
	}
	mux.Handle("/", http.FileServer(http.FS(ui)))

	log.Printf("dashboard http://localhost%s  (UART %s @ %d baud, poll %s, auto-reconnect)",
		*addr, portName, baud, interval.String())
	return http.ListenAndServe(*addr, mux)
}