package fusion

import (
	"image"
	"os"
	"strings"

	"github.com/airbusgeo/godal"
	log "github.com/sirupsen/logrus"
	"gocv.io/x/gocv"
	"starwiz.cn/sjy01/image-proc/pkg/config"
	"starwiz.cn/sjy01/image-proc/pkg/utils"
)

type PansharpenMethod int

const (
	SimpleBrovey PansharpenMethod = iota
	Brovey
	SimpleMean
	ESRI
	GDALPansharpen
)

func Pansharpen(panTif, mssTif, fusTif string, method PansharpenMethod) error {
	log.Infof("Pansharpening %s and %s", panTif, mssTif)
	pan, err := utils.ReadTifftoMat(panTif)
	if err != nil {
		return err
	}
	defer pan.Close()

	log.Infof("PAN row %d, col %d", pan.Rows(), pan.Cols())

	mss, err := utils.ReadTifftoMat(mssTif)
	if err != nil {
		return err
	}
	defer mss.Close()

	log.Infof("MSS bands %d row %d, col %d", mss.Channels(), mss.Rows(), mss.Cols())

	mssResized := gocv.NewMat()
	defer mssResized.Close()
	gocv.Resize(*mss, &mssResized, image.Point{X: pan.Cols(), Y: pan.Rows()}, 0, 0, gocv.InterpolationCubic)

	BGRI := gocv.Split(mssResized)

	var fus gocv.Mat
	switch method {
	case ESRI:
		fus = PansharpenESRI(*pan, BGRI[0], BGRI[1], BGRI[2], BGRI[3])
	default:
		fus = PansharpenESRI(*pan, BGRI[0], BGRI[1], BGRI[2], BGRI[3])
	}

	defer fus.Close()

	var mt gocv.MatType
	switch fus.Channels() {
	case 1:
		mt = gocv.MatTypeCV16UC1
	case 3:
		mt = gocv.MatTypeCV16UC3
	case 4:
		mt = gocv.MatTypeCV16UC4
	}
	fus.ConvertTo(&fus, mt)

	var colorInterps []godal.ColorInterp
	if config.GCONFIG.CoRegistration.FUSBandOrder == "RGB" ||
		config.GCONFIG.CoRegistration.FUSBandOrder == "RGBI" {
		colorInterps = []godal.ColorInterp{godal.CIRed, godal.CIGreen, godal.CIBlue, godal.CIUndefined}
	} else {
		colorInterps = []godal.ColorInterp{godal.CIBlue, godal.CIGreen, godal.CIRed, godal.CIUndefined}
	}

	err = utils.SaveBGRToGDALGTiff(fus, fus.Channels(), 0, 0, 1.3, colorInterps, fusTif)

	for i := 0; i < len(BGRI); i++ {
		BGRI[i].Close()
	}

	// use rpc of PAN directly
	rpb := strings.Replace(panTif, ".tiff", ".rpb", -1)
	if _, err := os.Stat(rpb); err == nil {
		fusRPB := strings.Replace(fusTif, ".tiff", ".rpb", -1)
		if input, err := os.ReadFile(rpb); err == nil {
			os.WriteFile(fusRPB, input, 0644)
		}
	}

	return err
}

func PansharpenSimpleBrovey(pan, B, G, R, I gocv.Mat) error {
	return nil
}

func PansharpenBrovey(pan, B, G, R, I gocv.Mat) error { return nil }

func PansharpenSimpleMean(pan, B, G, R, I gocv.Mat) error { return nil }

func PansharpenESRI(pan, B, G, R, I gocv.Mat) gocv.Mat {
	bgrn_mean := gocv.NewMatWithSize(pan.Rows(), pan.Cols(), pan.Type())
	defer bgrn_mean.Close()
	ADJ := gocv.NewMat()
	defer ADJ.Close()

	bgrn_mean.MultiplyFloat(-1)
	gocv.Add(pan, bgrn_mean, &ADJ)
	gocv.Add(B, ADJ, &B)
	gocv.Add(G, ADJ, &G)
	gocv.Add(R, ADJ, &R)
	gocv.Add(I, ADJ, &I)

	mss := gocv.NewMat()
	switch config.GCONFIG.CoRegistration.FUSBandOrder {
	case "RGB":
		gocv.Merge([]gocv.Mat{R, G, B}, &mss)
	case "BGR":
		gocv.Merge([]gocv.Mat{B, G, R}, &mss)
	case "RGBI":
		gocv.Merge([]gocv.Mat{R, G, B, I}, &mss)
	case "BGRI":
		gocv.Merge([]gocv.Mat{B, G, R, I}, &mss)
	default:
		gocv.Merge([]gocv.Mat{R, G, B}, &mss)
	}

	return mss
}