//go:build darwin

package dockicon

import (
	_ "embed"
	"log"
	"sync"
	"unsafe"

	"github.com/ebitengine/purego"
	"github.com/ebitengine/purego/objc"
)

//go:embed icon_idle.png
var iconIdlePNG []byte

//go:embed icon_connected.png
var iconConnectedPNG []byte

var (
	once     sync.Once
	ready    bool
	mu       sync.Mutex
	last     *bool
	selSet   objc.SEL
	selPerf  objc.SEL
	selShared objc.SEL
	selData  objc.SEL
	selAlloc objc.SEL
	selInit  objc.SEL
	selRetain objc.SEL
	clsApp   objc.Class
	clsData  objc.Class
	clsImage objc.Class
)

func initAppKit() {
	once.Do(func() {
		if _, err := purego.Dlopen("/System/Library/Frameworks/Foundation.framework/Foundation", purego.RTLD_GLOBAL|purego.RTLD_NOW); err != nil {
			log.Printf("dockicon: Foundation: %v", err)
			return
		}
		if _, err := purego.Dlopen("/System/Library/Frameworks/AppKit.framework/AppKit", purego.RTLD_GLOBAL|purego.RTLD_NOW); err != nil {
			log.Printf("dockicon: AppKit: %v", err)
			return
		}
		clsApp = objc.GetClass("NSApplication")
		clsData = objc.GetClass("NSData")
		clsImage = objc.GetClass("NSImage")
		if clsApp == 0 || clsData == 0 || clsImage == 0 {
			log.Printf("dockicon: missing AppKit classes")
			return
		}
		selShared = objc.RegisterName("sharedApplication")
		selSet = objc.RegisterName("setApplicationIconImage:")
		selPerf = objc.RegisterName("performSelectorOnMainThread:withObject:waitUntilDone:")
		selData = objc.RegisterName("dataWithBytes:length:")
		selAlloc = objc.RegisterName("alloc")
		selInit = objc.RegisterName("initWithData:")
		selRetain = objc.RegisterName("retain")
		ready = true
	})
}

// SetConnected swaps the Dock icon: sea-wave N when connected, original when idle.
func SetConnected(connected bool) {
	initAppKit()
	if !ready {
		return
	}
	mu.Lock()
	if last != nil && *last == connected {
		mu.Unlock()
		return
	}
	v := connected
	last = &v
	mu.Unlock()

	png := iconIdlePNG
	if connected {
		png = iconConnectedPNG
	}
	if len(png) == 0 {
		return
	}

	data := objc.ID(clsData).Send(selData, unsafe.Pointer(&png[0]), len(png))
	if data == 0 {
		return
	}
	img := objc.ID(clsImage).Send(selAlloc)
	img = img.Send(selInit, data)
	if img == 0 {
		return
	}
	img.Send(selRetain) // keep alive across async main-thread call

	app := objc.ID(clsApp).Send(selShared)
	if app == 0 {
		return
	}
	// AppKit must run on the main thread (glaze owns it).
	app.Send(selPerf, selSet, img, false)
}