/*
 * Lenna Image Viewer - SDL3 Example
 *
 * Demonstrates loading an image from cell-image and rendering it with SDL3.
 * Use WASD to move the image around the window.
 *
 * Usage: cell run examples/lenna.ce
 */

var io = use('fd')
var video = use('video')
var render = use('render')
var surface = use('surface')
var events = use('events')
var keyboard = use('keyboard')
var png = use('gitea.pockle.world/john/cell-image/png')
var time = use('time')

// Create window
var win = new video.window({
  title: "Lenna - WASD to move",
  width: 640,
  height: 480
})

// Create renderer
var renderer = new render(win)

renderer.win = win

// Load lenna.png using cell-image
log.console("Loading lenna.png...")
var img_blob = io.slurp("lenna.png")
if (!img_blob) {
  log.console("Error: Could not load lenna.png")
  $_.stop()
}

var img = png.decode(img_blob)
if (!img) {
  log.console("Error: Could not decode lenna.png")
  $_.stop()
}

log.console("Image loaded: " + text(img.width) + "x" + text(img.height))

// Create SDL surface from image data
var surf = new surface({
  width: img.width,
  height: img.height,
  format: "rgba32",
  pixels: img.pixels,
  pitch: img.pitch
})

// Create texture from surface
var tex = renderer.load_texture(surf)
log.console("Texture created: " + text(tex.width) + "x" + text(tex.height))

// Image position (centered initially)
var img_x = (640 - img.width) / 2
var img_y = (480 - img.height) / 2
var speed = 200 // pixels per second

// Track key states
var keys = {
  w: false,
  a: false,
  s: false,
  d: false
}

var running = true
var last_time = time.number()

function frame() {
  if (!running) {
    log.console("Exiting...")
    $_.stop()
    return
  }

  // Calculate delta time
  var now = time.number()
  var dt = now - last_time
  last_time = now

  // Process events
  var ev
  while ((ev = events.poll()) != null) {
    if (ev.type == "quit" || ev.type == "window_close_requested") {
      running = false
      return
    }
    if (ev.type == "key_down" || ev.type == "key_up") {
      var key_name = keyboard.get_key_name(ev.key).toLowerCase()
      var pressed = ev.type == "key_down"
      if (key_name == "w") keys.w = pressed
      if (key_name == "a") keys.a = pressed
      if (key_name == "s") keys.s = pressed
      if (key_name == "d") keys.d = pressed
      if (key_name == "escape" && pressed) running = false
    }
  }

  // Update position based on keys
  if (keys.w) img_y -= speed * dt
  if (keys.s) img_y += speed * dt
  if (keys.a) img_x -= speed * dt
  if (keys.d) img_x += speed * dt

  // Clear screen (dark gray)
  renderer.draw_color([0.2, 0.2, 0.2, 1])
  renderer.clear()

  // Draw texture at current position
  renderer.texture(tex, { x: img_x, y: img_y, width: tex.width, height: tex.height }, null, null)

  // Present
  renderer.present()

  // Schedule next frame
  $_.delay(frame, 1/60)
}

log.console("Starting render loop... Press ESC to exit, WASD to move")
frame()