//go:build gl

// 界面屏幕构建：中文标题与按钮（UI还原.md §2、§4 中文回退）。
package main

import (
	"image/color"
	"os"
	"path/filepath"

	"mc/internal/assets"
	"mc/internal/cjkfont"
	"mc/internal/ui"
)

// cjkPaths 系统 CJK 字体候选。
var cjkPaths = []string{
	filepath.Join(os.Getenv("WINDIR"), "Fonts", "msyh.ttc"),
	filepath.Join(os.Getenv("WINDIR"), "Fonts", "msyh.ttf"),
}

// buildScreens 构建主菜单与暂停菜单（按钮纹理 = 中文文本光栅化）。
func buildScreens(r *ui.Renderer, lang *assets.Lang) (*ui.TitleScreen, *ui.PauseScreen) {
	cjk := loadCJK()
	text := func(key, fallback string, size float64) (uint32, float32, float32) {
		label := fallback
		if lang != nil {
			label = lang.Get(key)
		}
		if cjk != nil {
			img := cjk.Draw(label, color.RGBA{255, 255, 255, 255})
			tex := r.UploadImage(img)
			return tex, float32(img.Bounds().Dx()), float32(img.Bounds().Dy())
		}
		return 0, 0, 0
	}

	titleTex, titleW, titleH := text("menu.title", "年糕历险记", 48)
	if titleW == 0 {
		titleW, titleH = 320, 48 // 无 CJK 字体时占位
	}

	// 主菜单按钮（居中列，UI还原.md §2）
	btn := func(key, fallback, action string, y float32, w, h int) ui.Button {
		tex, tw, th := text(key, fallback, 24)
		x := float32(w)/2 - tw/2
		return ui.Button{X: x, Y: y, W: tw, H: th, Tex: tex, Action: action}
	}
	title := &ui.TitleScreen{}
	title.TitleTex = titleTex
	title.TitleW = titleW
	title.TitleH = titleH
	title.Buttons = []ui.Button{
		btn("menu.singleplayer", "单人游戏", "play", 300, 1280, 720),
		btn("menu.multiplayer", "多人游戏", "multi", 350, 1280, 720),
		btn("menu.quit", "退出游戏", "quit", 400, 1280, 720),
	}
	_ = titleTex
	_ = titleH

	pause := &ui.PauseScreen{}
	pause.TitleTex, pause.TitleW, pause.TitleH = text("menu.game", "游戏菜单", 32)
	pause.Buttons = []ui.Button{
		btn("gui.resume", "继续游戏", "resume", 300, 1280, 720),
		btn("menu.quit", "保存并退出", "quit", 350, 1280, 720),
	}
	return title, pause
}

// loadCJK 加载系统 CJK 字体（失败返回 nil → 按钮退化不显示文本）。
func loadCJK() *cjkfont.Renderer {
	for _, p := range cjkPaths {
		if _, err := os.Stat(p); err == nil {
			if r, err := cjkfont.Load(p, 24); err == nil {
				return r
			}
		}
	}
	return nil
}