package main

import (
	"bufio"
	"fmt"
	"image"
	"math"
	"os"

	"github.com/chai2010/tiff"
	log "github.com/sirupsen/logrus"
	"gocv.io/x/gocv"
)

type Registrate interface{}

const (
	MssBands                   = 4
	PixelBytes                 = 2
	PanWidth                   = 9344 // 像素宽度
	MssWidth                   = 2336
	BlockNH                    = 5
	BlockNW                    = 10
	DownSampled ResampleMethod = "down_sample_pan"
	UpSampled   ResampleMethod = "up_sample_mss"
)

type ResampleMethod string

type Registrator struct {
	PanImage  gocv.Mat
	PanHeight int
	PanWidth  int

	MssImages [4]gocv.Mat
	MssHeight int
	MssWidth  int

	phaseShifts      [4][]*PhaseShiftM
	registeredImages [4]gocv.Mat
	rgbirImage       gocv.Mat

	resampleMethod ResampleMethod
}

func NewRegistrator() *Registrator {
	var r Registrator

	return &r
}

func (r *Registrator) LoadPanRaw(raw string) error {
	data, err := os.ReadFile(raw)
	if err != nil {
		log.Error("Error reading raw file: ", err)
		return err
	}

	height := len(data) / (PanWidth * PixelBytes)
	r.PanImage, err = gocv.NewMatFromBytes(height, PanWidth, gocv.MatTypeCV16U, data)
	if err != nil {
		log.Error("Error creating Mat from bytes: ", err)
		return err
	}

	r.PanHeight = height
	r.PanWidth = PanWidth

	return nil
}

func (r *Registrator) LoadMssRaw(raw string) error {
	data, err := os.ReadFile(raw)
	if err != nil {
		log.Error("Error reading raw file: ", err)
		return err
	}

	height := len(data) / (MssWidth * PixelBytes * MssBands)
	mssData := make([][]byte, MssBands)
	for h := 0; h < height; h++ {
		row := data[h*MssWidth*MssBands*PixelBytes : (h+1)*MssWidth*MssBands*PixelBytes]
		for i := 0; i < MssBands; i++ {
			mssData[i] = append(mssData[i], row[i*MssWidth*PixelBytes:(i+1)*MssWidth*PixelBytes]...)
		}
	}

	for i := 0; i < MssBands; i++ {
		r.MssImages[i], err = gocv.NewMatFromBytes(height, MssWidth, gocv.MatTypeCV16U, mssData[i])
		if err != nil {
			log.Error("Error creating Mat from bytes: ", err)
			return err
		}
	}

	r.MssHeight = height
	r.MssWidth = MssWidth

	return nil
}

// 将PAN降采样后计算相位相关的偏移量
func (r *Registrator) DoDownPhaseCorrelation() error {
	// 确保 MSS 高度是 PAN 高度的 1/4
	if r.MssHeight*4 != r.PanHeight {
		err := fmt.Errorf("MSS height is not 1/4 of PAN height, invalid raw file")
		log.Error(err)
		return err
	}

	// 将PAN将采样作为轮廓匹配基准图像
	downsampledPanImage := gocv.NewMat()
	gocv.Resize(r.PanImage, &downsampledPanImage,
		image.Point{X: r.MssWidth, Y: r.MssHeight}, 0, 0, gocv.InterpolationLinear)

	// 对每个 MSS 波段图像进行上采样
	// upsampledMSSImages := make([]gocv.Mat, MssBands)

	for i := 0; i < MssBands; i++ {
		// upsampledMSSImages[i] = gocv.NewMat()
		// gocv.Resize(r.MssImages[i], &upsampledMSSImages[i],
		// 	image.Point{X: r.PanWidth, Y: r.PanHeight}, 0, 0, gocv.InterpolationLinear)

		// r.msToRaw(upsampledMSSImages[i].ToBytes(), fmt.Sprintf("MSS%d.RAW", i+1))
	}

	fmt.Println("down sampled PAN images size:", downsampledPanImage.Size())

	// 分块高度
	blockHeight := r.MssHeight / BlockNH

	alignedMssData := make([][]byte, MssBands)

	for band := 0; band < MssBands; band++ {
		alignedMSSImage := gocv.NewMatWithSize(r.MssHeight, r.MssWidth, gocv.MatTypeCV16U)
		for bh := 0; bh < BlockNH; bh++ {
			// 读取 PAN 和 MSS 分块数据
			y1 := (bh + 1) * blockHeight
			if bh == BlockNH-1 {
				y1 = r.MssHeight
			}

			var shiftM PhaseShiftM
			shiftM.Block.width = r.MssWidth           // 块宽度
			shiftM.Block.height = y1 - bh*blockHeight // 块高度
			shiftM.Block.coord.X = 0                  // 块左上角x坐标
			shiftM.Block.coord.Y = bh * blockHeight   // 块左上角y坐标

			rect := image.Rect(
				shiftM.Block.coord.X, shiftM.Block.coord.Y,
				shiftM.Block.coord.X+shiftM.Block.width, shiftM.Block.coord.Y+shiftM.Block.height,
			)
			log.Println("Band", band+1, ", processing block", bh, rect)

			panBlock := downsampledPanImage.Region(rect)
			mssBlock := r.MssImages[band].Region(rect)

			// 处理每个分块
			alignedBlock, phaseShift := r.processBlock(panBlock, mssBlock)
			shiftM.dx = phaseShift.X
			shiftM.dy = phaseShift.Y

			r.phaseShifts[band] = append(r.phaseShifts[band], &shiftM)

			// alignedBlockData := alignedBlock.ToBytes()
			// alignedMssData[band] = append(alignedMssData[band], alignedBlockData...)

			// if alignedMSSImage.Empty() {
			// 	alignedMSSImage = alignedBlock.Clone()
			// } else {
			// 	gocv.Vconcat(alignedMSSImage, alignedBlock, &alignedMSSImage)
			// 	alignedBlock.Close()
			// }

			panBlock.Close()
			mssBlock.Close()
			alignedBlock.Close()
		}

		r.registeredImages[band] = alignedMSSImage
	}

	// 使用平均偏移量来做平移变换
	for band := 0; band < MssBands; band++ {
		var efficientShiftM int
		var xTotal, yTotal float32
		for _, shift := range r.phaseShifts[band] {
			if math.IsNaN(float64(shift.dx)) || math.IsNaN(float64(shift.dy)) {
				continue
			}
			efficientShiftM += 1
			xTotal += shift.dx
			yTotal += shift.dy
		}
		dx := xTotal / float32(efficientShiftM)
		dy := yTotal / float32(efficientShiftM)
		log.Println("Band", band+1, "average shift:", dx, dy, "efficientShiftM:", efficientShiftM)

		translationMat := gocv.NewMatWithSize(2, 3, gocv.MatTypeCV32F)
		translationMat.SetFloatAt(0, 0, 1)
		translationMat.SetFloatAt(0, 1, 0)
		translationMat.SetFloatAt(0, 2, dx)
		translationMat.SetFloatAt(1, 0, 0)
		translationMat.SetFloatAt(1, 1, 1)
		translationMat.SetFloatAt(1, 2, dy)

		alignedMss := gocv.NewMatWithSize(r.MssHeight, r.MssWidth, gocv.MatTypeCV32FC1)
		cvtMss := gocv.NewMat()
		r.MssImages[band].ConvertTo(&cvtMss, gocv.MatTypeCV32FC1)
		// 手动平移像素
		outY := math.MaxInt
		for y := 0; y < r.MssHeight; y++ {
			for x := 0; x < r.MssWidth; x++ {
				// 计算新的坐标
				newX := x + int(dx)
				newY := y + int(dy)

				// 如果新坐标在图像范围内，进行像素值赋值
				if newX >= 0 && newX < r.MssWidth && newY >= 0 && newY < r.MssHeight {
					alignedMss.SetFloatAt(y, x, cvtMss.GetFloatAt(newY, newX))
				} else {
					// 如果新坐标不在图像范围内，设置为黑色
					alignedMss.SetFloatAt(y, x, 0)
					if outY > y {
						outY = y
						log.Println("Warning: pixel out of range", x, y)
					}
				}
			}
		}

		// gocv.WarpAffine(cvtMss, &alignedMss, translationMat, image.Pt(cvtMss.Size()[1], cvtMss.Size()[0]))
		alignedMss.ConvertTo(&alignedMss, gocv.MatTypeCV16U)
		alignedMssData[band] = append(alignedMssData[band], alignedMss.ToBytes()...)

		translationMat.Close()
		cvtMss.Close()
		alignedMss.Close()
	}

	r.mssToRaw(alignedMssData)

	return nil
}

func (r *Registrator) panToTiff(panImage gocv.Mat, filePath string) error {
	return nil
}

func (r *Registrator) mssToTiff(registeredImages [4]gocv.Mat, filePath string) error {
	// 创建合并后的图像（RGBIR）
	rgbirImage := gocv.NewMatWithSize(r.PanHeight, r.PanWidth, gocv.MatTypeCV16UC4) // 4通道，16位

	for y := 0; y < r.PanHeight; y++ {
		for x := 0; x < r.PanWidth; x++ {
			r := registeredImages[0].GetShortAt(y, x)
			g := registeredImages[1].GetShortAt(y, x)
			b := registeredImages[2].GetShortAt(y, x)
			ir := registeredImages[3].GetShortAt(y, x)
			rgbirImage.SetShortAt(y, x*4+0, r)
			rgbirImage.SetShortAt(y, x*4+1, g)
			rgbirImage.SetShortAt(y, x*4+2, b)
			rgbirImage.SetShortAt(y, x*4+3, ir)
		}
	}

	// 将合并后的图像保存为TIFF文件
	fileName := "data/registered_rgbir.tiff"
	tiffFile, err := os.Create(fileName)
	if err != nil {
		fmt.Println("Error creating TIFF file:", err)
		return err
	}
	defer tiffFile.Close()

	// 使用tiff库保存图像
	img, err := rgbirImage.ToImage()
	if err != nil {
		fmt.Println("Error converting Mat to image:", err)
		return err
	}
	if err := tiff.Encode(tiffFile, img, nil); err != nil {
		fmt.Println("Error encoding TIFF file:", err)
		return err
	}

	fmt.Println("Saved", fileName)
	return nil
}

func (r *Registrator) mssToRaw(mssData [][]byte) error {
	f, err := os.OpenFile("data/downsampled_registered_mss.RAW", os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0777)
	if err != nil {
		return err
	}

	log.Println("Writing downsampled registered MSS to RAW file...", len(mssData[0])*4)
	log.Println("width:", r.MssWidth*PixelBytes*4)
	log.Println("height:", r.MssHeight)
	w := bufio.NewWriter(f)
	for row := 0; row < r.MssHeight; row++ {
		w.Write(mssData[0][row*r.MssWidth*PixelBytes : (row+1)*r.MssWidth*PixelBytes])
		w.Write(mssData[1][row*r.MssWidth*PixelBytes : (row+1)*r.MssWidth*PixelBytes])
		w.Write(mssData[2][row*r.MssWidth*PixelBytes : (row+1)*r.MssWidth*PixelBytes])
		w.Write(mssData[3][row*r.MssWidth*PixelBytes : (row+1)*r.MssWidth*PixelBytes])
	}

	return nil
}

func (r *Registrator) bytesToRaw(mssData []byte, filePath string) error {
	f, err := os.OpenFile(filePath, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0777)
	if err != nil {
		return err
	}
	w := bufio.NewWriter(f)
	w.Write(mssData)

	return nil
}