package vision

import (
	"fmt"
	"image/color"
	"strconv"
	"strings"

	"apigo.cc/go/rand"
)

// ParseColor 将多种格式的十六进制颜色字符串转换为 color.Color
// 支持格式: #RRGGBB, #RRGGBBAA, #RGB, #RGBA
func ParseColor(hex string) color.Color {
	hex = strings.ToUpper(strings.TrimPrefix(hex, "#"))

	// 验证合法字符
	for _, ch := range hex {
		if !((ch >= '0' && ch <= '9') || (ch >= 'A' && ch <= 'F')) {
			return color.RGBA{}
		}
	}

	switch len(hex) {
	case 3:
		hex = fmt.Sprintf("%c%c%c%c%c%c", hex[0], hex[0], hex[1], hex[1], hex[2], hex[2])
	case 4:
		hex = fmt.Sprintf("%c%c%c%c%c%c%c%c", hex[0], hex[0], hex[1], hex[1], hex[2], hex[2], hex[3], hex[3])
	}

	switch len(hex) {
	case 6: // #RRGGBB
		return color.RGBA{R: parseHex(hex[0:2]), G: parseHex(hex[2:4]), B: parseHex(hex[4:6]), A: 255}
	case 8: // #RRGGBBAA
		return color.RGBA{R: parseHex(hex[0:2]), G: parseHex(hex[2:4]), B: parseHex(hex[4:6]), A: parseHex(hex[6:8])}
	}
	return color.RGBA{}
}

func parseHex(s string) uint8 {
	val, _ := strconv.ParseUint(s, 16, 8)
	return uint8(val)
}

// RandColor 生成随机颜色 hex 字符串
func RandColor() string {
	r := uint8(rand.Int(0, 255))
	g := uint8(rand.Int(0, 255))
	b := uint8(rand.Int(0, 255))
	a := uint8(rand.Int(105, 255)) // 105-255
	return fmt.Sprintf("#%02X%02X%02X%02X", r, g, b, a)
}