package qrsvg

import (
	"strconv"
	"strings"

	"github.com/boombuler/barcode/qr"
)

const QuietZone = 4

type Symbol struct {
	Size int
	Path string
}

func Encode(content string) (Symbol, error) {
	code, err := qr.Encode(content, qr.M, qr.Unicode)
	if err != nil {
		return Symbol{}, err
	}
	n := code.Bounds().Dx()
	dark := func(x, y int) bool {
		r, _, _, _ := code.At(x, y).RGBA()
		return r == 0
	}
	var b strings.Builder
	cx, cy := 0, 0
	for y := 0; y < n; y++ {
		for x := 0; x < n; {
			if !dark(x, y) {
				x++
				continue
			}
			start := x
			for x < n && dark(x, y) {
				x++
			}
			sx, sy := start+QuietZone, y+QuietZone
			if b.Len() == 0 {
				b.WriteString("M" + strconv.Itoa(sx) + " " + strconv.Itoa(sy) + ".5")
			} else {
				b.WriteString("m" + strconv.Itoa(sx-cx) + " " + strconv.Itoa(sy-cy))
			}
			b.WriteString("h" + strconv.Itoa(x-start))
			cx, cy = x+QuietZone, sy
		}
	}
	return Symbol{Size: n + 2*QuietZone, Path: b.String()}, nil
}