package main

import (
	"encoding/hex"
	"flag"
	"image"
	"log"
	"os"
	"time"

	"pm3.dev/cvend"
	"pm3.dev/fb"
)

type cvendState struct {
	ready   bool
	hasCard bool
}

type displayState struct {
	now   time.Time
	cvend cvendState
}

func main() {
	flag.Parse()
	log.SetFlags(log.Lshortfile | log.Ldate | log.Ltime | log.Lmicroseconds)
	log.Println(os.Args[0], "start")

	displayStateCh := make(chan displayState)
	go displayTask(displayStateCh)

	displayState := displayState{
		now: time.Now(),
	}
	displayStateCh <- displayState

	cvendStateCh := make(chan cvendState)
	go cvendTask(cvendStateCh)

	tickerCh := wallTicker(time.Minute).C

	for {
		select {
		case now := <-tickerCh:
			displayState.now = now
		case cvendState := <-cvendStateCh:
			displayState.cvend = cvendState
		}
		displayStateCh <- displayState
	}
}

// wallTicker returns a ticker that fires whenever time.Now().Truncate(d) changes
func wallTicker(d time.Duration) *time.Ticker {
	first := time.Until(time.Now().Add(d).Truncate(d))
	ticker := time.NewTicker(first)
	go func() {
		time.Sleep(first)
		ticker.Reset(d)
	}()
	return ticker
}

func displayTask(in <-chan displayState) {
	fb, err := fb.Open()
	if err != nil {
		log.Fatalf("open fb: %v", err)
	}
	defer fb.Close()

	for state := range in {
		start := time.Now()
		img := image.NewRGBA(fb.Bounds())
		drawDisplay(img, state)
		fb.WriteRGBA(img)
		dur := time.Now().Sub(start)
		log.Printf("display update %s %+v", dur, state)
	}

}

func cvendTask(out chan<- cvendState) {
	var state cvendState
	cv, err := cvend.Open()
	if err != nil {
		log.Fatalf("cvend Open: %s", err)
	}
	status, err := cv.AwaitStatus()
	if err != nil {
		log.Fatalf("cvend AwaitStatus: %s", err)
	}
	log.Printf("cvend status: %q", string(status))
	reply, err := cv.ProxCardFunction(7, true)
	if err != nil {
		log.Fatalf("cvend ProxCardFunction: %s", err)
	}
	log.Printf("enabled DESFire %s", hex.EncodeToString(reply))
	state.ready = true
	out <- state
	go func() { // send periodic status requests to keep cvend from going to sleep
		for {
			time.Sleep(30 * time.Second)
			if err := cv.SendIPP(0x04, nil); err != nil {
				log.Printf("failed to send Status: %s", err)
			}
		}
	}()

	for {
		cardRaw, err := cv.AwaitCard()
		if err != nil {
			log.Println("error awaiting card: %s", err)
			continue
		}
		card := cardRaw.(*cvend.DESFireCard) // todo other types
		log.Println("got card %+v", card)
		state.hasCard = true
		out <- state
		card.AwaitRemoved()
		log.Println("card removed")
		state.hasCard = false
		out <- state
	}
}