package main

import (
	_ "image/jpeg"
	_ "image/png" //I'm needed
	"math"
	"os"
	"github.com/kenshaw/escpos"
)

const ESC = byte(27)

func pageWidth(widht int) []byte {
	return []byte{escpos.GS, 87, byte(widht), 0}
}
func pageMargin(margin int) []byte {
	return []byte{escpos.GS, 76, byte(margin), 0}
}
func pageMode() []byte {
	return []byte{ESC, 'L'}
}
func pageDirection(direction uint8) []byte {
	// https://www.epson-biz.com/modules/ref_escpos/index.php?content_id=55
	return []byte{ESC, 'T', direction}
}
func pagePrintArea(x, y, width, height int) []byte {
	return []byte{ESC, 'W',
		byte(x & 255), byte(x >> 8 & 255),
		byte(y & 255), byte(y >> 8 & 255),
		byte(width & 255), byte(width >> 8 & 255),
		byte(height & 255), byte(height >> 8 & 255)}
}
func offsetY(offset int) []byte {
	// A positive number specifies movement downward, and a negative number specifies movement upward.
	// The horizontal or vertical motion unit is used for the print direction set by ESC T.
	// When the starting position is set to the upper left or lower right of the print area using ESC T, the vertical motion unit is used.
	// When the starting position is set to the upper right or lower left of the print area using ESC T, the horizontal motion unit is used.
	return []byte{escpos.GS, '\\', byte(offset & 255), byte(offset >> 8 & 255)}
}
func offsetX(offset int) []byte {
	// A positive number specifies movement to the right, and a negative number specifies movement to the left.
	// When Standard mode is selected, the horizontal motion unit is used.
	// when Page mode is selected, the horizontal or vertical motion unit is used for the print direction set by ESC T.
	// When the starting position is set to the upper left or lower right of the print area using ESC T, the horizontal motion unit is used.
	// When the starting position is set to the upper right or lower left of the print area using ESC T, the vertical motion unit is used.
	return []byte{ESC, '\\', byte(offset & 255), byte(offset >> 8 & 255)}
}
func invert(n int) []byte {
	//When the LSB of n is 0, white/black reverse print mode is turned off.
	//n = 0 – 255
	return []byte{escpos.GS, byte('B'), byte(n)}
}
func disableSensors() []byte {
	return []byte{ESC, 'c', '3', 0}
}
func printSpeed(m int) []byte {
	// 	m = 0 – 9, 48 – 57 : slowest - fastest
	// [Default] 0 = Setting value of GS ( E   <Function 5> customize value (a = 6)
	// m = 0
	//Slower print speed seems to retain a bit more quality in dithered images. pure B/W images do not have a noticable difference
	return []byte{escpos.GS, '(', 'K', 2, 0, 50, byte(m & 255), byte(m >> 8 & 255)}
}

func main() {
	f, err := os.OpenFile("/dev/usb/lp0", os.O_WRONLY|os.O_CREATE, 0)
	if err != nil {
		panic(err)
	}
	defer f.Close()

	ep := escpos.New(f)

	ep.Init()
	ep.WriteRaw(pageMode())
	ep.WriteRaw(pageDirection(1))
	ep.WriteRaw(pagePrintArea(0, 0, int(math.Round((29.0/80.0)*512)), 850))
	ep.WriteRaw(offsetY(30))
	ep.SetFontSize(1,1)
	ep.Write("Technologia Incognita\n")
	ep.WriteRaw(offsetY(35))
	ep.SetFontSize(3,2)
	ep.SetEmphasize(1)
	ep.Write("Do Not Hack\n")
	ep.SetEmphasize(0)
	ep.WriteRaw(offsetY(15))
	ep.SetFontSize(1,1)
	ep.Write("Mattronix - 2023-10-14 \n")

	ep.WriteRaw([]byte{12}) // FF: in Page mode, prints all the data in the print buffer collectively and switches from Page mode to Standard mode.
	//ep.Formfeed()

	ep.Cut()
	ep.End()

}