package extract

import (
	"bufio"
	"io"
	"os"
	"path/filepath"

	"github.com/sirupsen/logrus"
)

const (
	EB_AUX         = "EB.AUX"
	PLAT_AUX       = "PLAT.AUX"
	PAN_RAW        = "PAN_RAW"
	MSS_RAW        = "MSS_RAW"
	PAN_HDR        = "PAN_HDR"
	MSS_HDR        = "MSS_HDR"
	MSS_ALL_IN_ONE = "MSS_ALL_IN_ONE"
)

type l0w struct {
	w    *bufio.Writer
	f    *os.File
	name string
}

type L0Writer struct {
	mssStoredType string
	ws            map[string]*l0w
}

func newL0Writer(outputDir, name string) *L0Writer {
	var err error
	suffix := []string{EB_AUX, PLAT_AUX, PAN_RAW, MSS_RAW, PAN_HDR, MSS_HDR}

	lw := &L0Writer{
		ws:            make(map[string]*l0w),
		mssStoredType: MSS_ALL_IN_ONE,
	}

	for _, s := range suffix {
		w := &l0w{}
		w.name = filepath.Join(outputDir, name+"_"+s)
		w.f, err = os.OpenFile(w.name, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0777)
		if err != nil {
			logrus.Panic("create file failed: ", w.name, err)
		}
		w.w = bufio.NewWriter(w.f)
		lw.ws[s] = w
	}

	return lw
}

func (lw *L0Writer) Close() {
	for _, w := range lw.ws {
		w.w.Flush()
		w.f.Close()
	}
}

// 写入 16 位像素值，小端序
func write16bPixelLittleEndian(w io.Writer, data []byte) (int, error) {
	for i := 0; i < len(data)-1; i += 2 {
		data[i], data[i+1] = data[i+1], data[i]
	}
	return w.Write(data)
}