// Package gui provides the Fyne desktop app: a settings window and a system
// tray that start/stop the flinger engine.
//
// The engine itself lives in internal/flinger and is GUI-free, so the tray
// can control streaming without any UI dependency. This package wires the two
// together: config persistence, the settings form, the tray menu and the
// tray status icon.
package gui

import (
	"bytes"
	"image"
	"image/color"
	"image/png"
)

// traySize is the icon size in pixels. Tray hosts typically request 22px;
// we render larger and let the host scale down for crispness.
const traySize = 64

// newTrayResource renders a rounded square with a status dot into a
// fyne.Resource that SetSystemTrayIcon accepts.
func newTrayResource(bg, dot color.NRGBA) *staticResource {
	img := image.NewRGBA(image.Rect(0, 0, traySize, traySize))

	// Rounded-square background.
	radius := 14
	for y := 0; y < traySize; y++ {
		for x := 0; x < traySize; x++ {
			if inRoundedRect(x, y, radius) {
				img.Set(x, y, bg)
			}
		}
	}

	// Center status dot.
	cx, cy, r := traySize/2, traySize/2, 16
	for y := cy - r; y <= cy+r; y++ {
		for x := cx - r; x <= cx+r; x++ {
			if (x-cx)*(x-cx)+(y-cy)*(y-cy) <= r*r {
				img.Set(x, y, dot)
			}
		}
	}

	var buf bytes.Buffer
	_ = png.Encode(&buf, img)
	return &staticResource{name: "teleportfling-tray", data: buf.Bytes()}
}

// inRoundedRect reports whether (x,y) falls inside the rounded square.
func inRoundedRect(x, y, radius int) bool {
	const m = traySize - 1
	switch {
	case x >= radius && x <= m-radius:
		return true
	case y >= radius && y <= m-radius:
		return true
	}
	// Corner: within radius of the nearest corner centre.
	var cx, cy int
	if x < radius {
		cx = radius
	} else {
		cx = m - radius
	}
	if y < radius {
		cy = radius
	} else {
		cy = m - radius
	}
	dx, dy := x-cx, y-cy
	return dx*dx+dy*dy <= radius*radius
}

// staticResource is a simple in-memory fyne.Resource.
type staticResource struct {
	name string
	data []byte
}

func (r *staticResource) Name() string    { return r.name }
func (r *staticResource) Content() []byte { return r.data }