package gtp

import (
	"fmt"
	"git.noahlan.cn/noahlan/ntool/nmath"
	"strings"
)

const alpha = "abcdefghjklmnopqrstuvwxyz" // 无 'I' 的alpha
const alphaUpper = "ABCDEFGHJKLMNOPQRSTUVWXYZ"

func Point(x, y int) string {
	if x < 0 || x >= 25 || y < 0 || y >= 25 {
		return ""
	}
	return fmt.Sprintf("%s%d", byteToString(alphaUpper[x]), y+1)
}

func byteToString(b byte) string {
	return string([]byte{b})
}

func ParsePoint(pos string) (x, y int) {
	x = byteToIndex(alpha, pos[0])
	if x == -1 {
		x = byteToIndex(alphaUpper, pos[0])
	}
	y, _ = nmath.Int(pos[1:])
	y = y - 1
	return
}

func byteToIndex(str string, b byte) int {
	return strings.Index(str, string([]byte{b}))
}