package image

import (
	"os"
	"runtime"
)

// CollectFontCandidates 收集常见中文字体路径，允许用 DOUYU_FONT 指定自定义字体。
func CollectFontCandidates() []string {
	candidates := []string{}
	if custom := os.Getenv("DOUYU_FONT"); custom != "" {
		candidates = append(candidates, custom)
	}
	candidates = append(candidates,
		"Microsoft Yahei.ttf",
		"Microsoft YaHei.ttf",
		"NotoSansCJKsc-Regular.otf",
		"NotoSansCJK-Regular.ttc",
	)

	switch runtime.GOOS {
	case "darwin":
		candidates = append(candidates,
			"/System/Library/Fonts/PingFang.ttc",
			"/System/Library/Fonts/Supplemental/Arial Unicode.ttf",
			"/System/Library/Fonts/Supplemental/Songti.ttc",
		)
	case "windows":
		candidates = append(candidates,
			`C:\Windows\Fonts\msyh.ttc`,
			`C:\Windows\Fonts\simhei.ttf`,
			`C:\Windows\Fonts\simsun.ttc`,
		)
	default:
		candidates = append(candidates,
			"/usr/share/fonts/opentype/noto/NotoSansCJK-Regular.ttc",
			"/usr/share/fonts/opentype/noto/NotoSansCJK-Regular.otf",
			"/usr/share/fonts/truetype/noto/NotoSansCJK-Regular.ttc",
			"/usr/share/fonts/truetype/wqy/wqy-microhei.ttc",
			"/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
		)
	}
	return candidates
}