platform.go

package wui

// Platform identifies which renderer is running.
type Platform int

const (
	// PlatformTUI is a terminal build (bubbletea + lipgloss).
	PlatformTUI Platform = iota
	// PlatformWeb is a WASM build rendering to the DOM.
	PlatformWeb
)

func (p Platform) String() string {
	if p == PlatformWeb {
		return "web"
	}
	return "tui"
}

// Current reports which renderer this binary was built for. It is a
// build-time constant per binary, so branches on it cost nothing at
// runtime and the unused branch's data is still compiled in (both sides
// must type-check).
func Current() Platform { return currentPlatform }

// IsTUI reports whether this is a terminal build.
func IsTUI() bool { return currentPlatform == PlatformTUI }

// IsWeb reports whether this is a WASM build.
func IsWeb() bool { return currentPlatform == PlatformWeb }

// PlatformText returns tui in terminal builds and web in browser
// builds — the string form of the common case, where only the wording
// differs between platforms:
//
//	wui.Text(wui.PlatformText("press q to quit", "close this tab to quit"))
func PlatformText(tui, web string) string {
	if currentPlatform == PlatformWeb {
		return web
	}
	return tui
}

// PlatformValue returns tui in terminal builds and web in browser
// builds. It is the generic form of PlatformText, for any value type.
func PlatformValue[T any](tui, web T) T {
	if currentPlatform == PlatformWeb {
		return web
	}
	return tui
}

// OnPlatform renders tui in terminal builds and web in browser builds.
// Either may be nil to render nothing on that platform:
//
//	wui.OnPlatform(
//	    wui.Text("Tab/Shift+Tab to move, Enter to activate"),
//	    wui.Text("Click anything, or Tab through the page"),
//	)
func OnPlatform(tui, web Element) Element {
	if currentPlatform == PlatformWeb {
		return orEmpty(web)
	}
	return orEmpty(tui)
}

// TUIOnly renders its children only in terminal builds; browser builds
// render nothing.
func TUIOnly(children ...Element) Element {
	if currentPlatform != PlatformTUI {
		return Empty()
	}
	return groupOf(children)
}

// WebOnly renders its children only in WASM builds; terminal builds
// render nothing.
func WebOnly(children ...Element) Element {
	if currentPlatform != PlatformWeb {
		return Empty()
	}
	return groupOf(children)
}

func groupOf(children []Element) Element {
	if len(children) == 1 {
		return orEmpty(children[0])
	}
	return Box(Column, children...)
}

func orEmpty(el Element) Element {
	if el == nil {
		return Empty()
	}
	return el
}