package main

import (
	"embed"
	"errors"
	"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", "dashboard HTTP listen address")
	apiAddr := serveFlags.String("api-addr", ":8081", "external API HTTP listen address (empty to disable)")
	accelInterval := serveFlags.Duration("accel-interval", defaultAccelStreamInterval, "accel WebSocket sample period on API server")
	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

	hub := newWSHub()
	streamCtl := newAccelStreamCtl()
	tapCtl := newTapNotifyCtl()
	stop := make(chan struct{})

	var dashSrv *http.Server
	var apiSrv *http.Server
	registerShutdown(func() {
		close(stop)
		shutdownHTTPServer(dashSrv)
		shutdownAPIServer(apiSrv)
		if err := link.Close(); err != nil {
			log.Printf("UART close: %v", err)
		}
	})

	go runPoller(link, portName, hub, streamCtl, tapCtl, *interval, stop)
	go runBatteryPoller(link, hub, 5*time.Second, stop)
	go runCacheStatusDashboardPoller(link, hub, *accelInterval, stop)

	if *apiAddr != "" {
		apiSrv = runAPIServer(portName, link, *apiAddr, *accelInterval, hub, streamCtl, tapCtl, stop)
	}

	mux := http.NewServeMux()
	mountServeAPI(mux, link, hub, streamCtl, tapCtl)
	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, live-stream %s, auto-reconnect)",
		*addr, portName, baud, interval.String(), accelInterval.String())
	if *apiAddr == "" {
		log.Printf("external API disabled (-api-addr \"\")")
	}

	dashSrv = &http.Server{Addr: *addr, Handler: mux}
	go func() {
		if err := dashSrv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
			log.Printf("dashboard server: %v", err)
		}
	}()

	waitForShutdown()
	return nil
}