package main

import (
	"errors"
	"flag"
	"image"
	"image/color"
	"log"

	"github.com/llgcode/draw2d/draw2dkit"

	"github.com/llgcode/draw2d/draw2dimg"
)

func main() {
	err := run()
	if err != nil {
		log.Fatal(err)
	}
}

func run() error {
	var dpi int
	flag.IntVar(&dpi, "dpi", 300, "dpi")
	flag.Parse()
	path := flag.Arg(0)
	if path == "" {
		return errors.New("no output path specified")
	}

	bounds := image.Rect(0, 0, dpi*827/100, dpi*1169/100)
	scale := float64(dpi) / 100
	margin := 5. * scale
	tileWidth, tileHeight := 140.*scale, 200.*scale
	tileOffsetWidth, tileOffsetHeight := tileWidth+4.*margin, tileHeight+4.*margin
	im := image.NewRGBA(bounds)
	gc := draw2dimg.NewGraphicContext(im)
	marginColor := color.Gray{Y: 63}
	tileColor := color.Gray{Y: 127}
	gc.SetLineWidth(1)
	for y := 0.; y < float64(bounds.Max.Y)-tileOffsetHeight; y += tileOffsetHeight {
		for x := 0.; x < float64(bounds.Max.X)-tileOffsetWidth; x += tileOffsetWidth {
			draw2dkit.Rectangle(gc, x+margin-1, y+margin-1, x+tileOffsetWidth-margin, y+tileOffsetHeight-margin)
			gc.SetStrokeColor(marginColor)
			gc.Stroke()

			tileX, tileY := x+2*margin-.5, y+2*margin-.5
			gc.MoveTo(tileX, tileY+.25*tileHeight)
			gc.LineTo(tileX, tileY+.75*tileHeight)
			gc.LineTo(tileX+.5*tileWidth, tileY+tileHeight)
			gc.LineTo(tileX+tileWidth, tileY+.75*tileHeight)
			gc.LineTo(tileX+tileWidth, tileY+.25*tileHeight)
			gc.LineTo(tileX+.5*tileWidth, tileY+.5*tileHeight)
			gc.LineTo(tileX, tileY+.25*tileHeight)
			gc.LineTo(tileX+.5*tileWidth, tileY)
			gc.LineTo(tileX+tileWidth, tileY+.25*tileHeight)
			gc.MoveTo(tileX+.5*tileWidth, tileY+.5*tileHeight)
			gc.LineTo(tileX+.5*tileWidth, tileY+tileHeight)
			gc.SetStrokeColor(tileColor)
			gc.Stroke()
		}
	}
	return draw2dimg.SaveToPngFile(path, im)
}