package main

import (
	"flag"
	"image"
	"log"
	"os"
	"time"

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

type cvendState struct {
	ready 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(stateCh <-chan displayState) {
	fb, err := fb.Open()
	if err != nil {
		log.Fatalf("open fb: %v", err)
	}
	defer fb.Close()

	for state := range stateCh {
		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
	var cv ipp.Session
	var err error
	cv, err = cvend.OpenIPP(func(msgType byte, msgData []byte) {
		switch msgType {
		case 0x05: // StatusReply
			if !state.ready {
				state.ready = true
				out <- state
			}
		default:
			cvend.LogIPP(msgType, msgData)
		}
	})
	if err != nil {
		panic(err)
	}
	for {
		cv.SendIPP(0x04, nil) // Status
		time.Sleep(1 * time.Second)
	}
}