package main

import (
	"encoding/binary"
	"log"
	flowdef "mxl-pattern-generator/internal/flow-def"
	"mxl-pattern-generator/internal/generator"
	"os"
	"os/signal"
	"syscall"

	"github.com/qvest-digital/go-mxl/mxl"
)

func main() {
	var width, height uint = 1920, 1080
	var fps_num, fps_den uint = 25, 1
	flowUUID := "5fbec3b1-1b0f-417d-9059-8b94a47197ed"
	log.Printf("Go Pattern Gen")
	log.Printf("Video: %dx%dp%d/%d", width, height, fps_num, fps_den)
	log.Printf("UUID: %s", flowUUID)
	domain := "/dev/shm/mxl"

	inst, err := mxl.NewInstance(domain, "")
	if err != nil {
		log.Fatalf("MXL Init Failed: %v", err)
	}
	defer inst.Close()

	flowDef, err := flowdef.NewFlowDefJSON(
		flowdef.TYPE_VIDEO,
		flowUUID,
		width,
		height,
		fps_num,
		fps_den,
	)
	if err != nil {
		log.Fatalf("Could not create Flow Definition: %v", err)
	}
	writer, isCreated, err := inst.NewWriter(flowDef)
	if err != nil {
		log.Fatalf("Failed to create MXL writer: %v", err)
	}
	if !isCreated {
		log.Printf("reusing existing flow: %s, domain: %s", flowUUID, domain)
	}
	defer writer.Close()

	var gen *generator.OpenCLGenerator
	gen, err = generator.NewOpenCLGenerator(width, height, "/home/itten/codeproj/go-mxl-pattern-gen/kernels/v210_pack.cl")
	gen, err = generator.NewOpenCLGenerator(width, height, "/home/itten/codeproj/go-mxl-pattern-gen/kernels/v210_pack.cl")
	if err != nil {
		log.Fatalf("OpenCL init failed: %v", err)
	}
	defer gen.Close()
	gen.SetText(generator.TextConfig{
		Str: "MXL PATTERN GEN",
		X:   0, Y: 0, Scale: 8,
		FG:    [3]uint32{940, 512, 512},
		BG:    [3]uint32{64, 512, 512},
		Boxed: true,
	})

	flowCfg := writer.Config()
	rate := flowCfg.Common.GrainRate
	idx := mxl.CurrentIndex(rate)
	log.Printf("writing flow grainRate=%d/%d starting at idx=%d", rate.Num, rate.Den, idx)

	stop := make(chan os.Signal, 1)
	signal.Notify(stop, os.Interrupt, syscall.SIGTERM)

	var written int64
	for {
		select {
		case <-stop:
			log.Printf("stopping after %d grains", written)
			return
		default:
		}

		gwa, err := writer.OpenGrain(idx)
		if err != nil {
			log.Fatalf("OpenGrain(%d): %v", idx, err)
		}
		// fillGrainRamp(gwa.Payload, idx)
		// smpteBars(gwa.Payload)
		gen.GenerateFrame(gwa.Payload, int(idx))
		// if err != nil {
		// 	log.Fatalf("Frame Generator: %v", err)
		// }
		if err := gwa.Commit(gwa.TotalSlices, 0); err != nil {
			log.Fatalf("Commit(%d): %v", idx, err)
		}

		written++
		idx++
		if written%100 == 0 {
			log.Printf("grains written=%d, index=%d", written, idx)
		}
		// Pace ourselves to roughly the grain rate
		mxl.SleepNs(mxl.NsUntilIndex(idx, rate))
	}
}

// fillGrainRamp writes byte((i+start)&0xFF) across buf. A matching reader
// uses the same pattern to verify grain continuit
func fillGrainRamp(buf []byte, start uint64) {
	for i := range buf {
		buf[i] = byte((uint64(i) + start) & 0xFF)
	}
}

func smpteBars(dest []byte) {
	const width = 1920

	// SMPTE 75% bars, Rec.709, 10-bit Y'CbCr: {Y, Cb, Cr}
	bars := [7][3]uint32{
		{721, 512, 512}, // 75% white
		{674, 176, 543}, // 75% yellow
		{581, 589, 176}, // 75% cyan
		{534, 253, 207}, // 75% green
		{251, 771, 817}, // 75% magenta
		{204, 435, 848}, // 75% red
		{111, 848, 481}, // 75% blue
	}

	barIdx := func(x int) int {
		idx := x * len(bars) / width
		if idx >= len(bars) {
			return len(bars) - 1
		}
		return idx
	}

	// v210: each 16-byte block carries 6 pixels (Y0..Y5, chroma co-sited at 0/2/4)
	for block := 0; block*16+16 <= len(dest); block++ {
		baseX := (block * 6) % width

		var y [6]uint32
		for i := range y {
			y[i] = bars[barIdx(baseX+i)][0]
		}
		cb0, cr0 := bars[barIdx(baseX)][1], bars[barIdx(baseX)][2]
		cb2, cr2 := bars[barIdx(baseX+2)][1], bars[barIdx(baseX+2)][2]
		cb4, cr4 := bars[barIdx(baseX+4)][1], bars[barIdx(baseX+4)][2]

		w0 := (cb0 & 0x3FF) | ((y[0] & 0x3FF) << 10) | ((cr0 & 0x3FF) << 20)
		w1 := (y[1] & 0x3FF) | ((cb2 & 0x3FF) << 10) | ((y[2] & 0x3FF) << 20)
		w2 := (cr2 & 0x3FF) | ((y[3] & 0x3FF) << 10) | ((cb4 & 0x3FF) << 20)
		w3 := (y[4] & 0x3FF) | ((cr4 & 0x3FF) << 10) | ((y[5] & 0x3FF) << 20)

		byteIdx := block * 16
		binary.LittleEndian.PutUint32(dest[byteIdx+0:], w0)
		binary.LittleEndian.PutUint32(dest[byteIdx+4:], w1)
		binary.LittleEndian.PutUint32(dest[byteIdx+8:], w2)
		binary.LittleEndian.PutUint32(dest[byteIdx+12:], w3)
	}
}