prosperon/input/backends/sdl3.cm

// SDL3 Backend - Translates SDL events to canonical input format
var sdl_input = use('sdl3/input')

// SDL keycode to lowercase key name
// SDL3 keycodes are based on their name strings
function keycode_to_control(keycode) {
  var name = sdl_input.keyname(keycode)
  if (!name) return null
  return lower(name)
}

// Parse SDL mod bitmask to mods object
function parse_mods(mod) {
  return {
    ctrl: (mod & 0x00C0) != 0,   // KMOD_CTRL
    shift: (mod & 0x0003) != 0,  // KMOD_SHIFT
    alt: (mod & 0x0300) != 0,    // KMOD_ALT
    super: (mod & 0x0C00) != 0   // KMOD_GUI
  }
}

// Translate SDL event to canonical format
// Returns canonical event or null if not translatable
function translate(evt) {
  var control = null

  // Keyboard
  if (evt.type == 'key_down' || evt.type == 'key_up') {
    if (evt.repeat) return null  // Ignore key repeats

    control = keycode_to_control(evt.key)
    if (!control) return null

    return {
      kind: 'button',
      device_id: 'kbm',
      control: control,
      pressed: evt.down == true,
      released: evt.down != true,
      mods: parse_mods(evt.mod),
      which: evt.which,
      time: evt.timestamp
    }
  }
  
  // Mouse buttons
  if (evt.type == 'mouse_button_down' || evt.type == 'mouse_button_up') {
    return {
      kind: 'button',
      device_id: 'kbm',
      control: 'mouse_button_' + evt.button,
      pressed: evt.down == true,
      released: evt.down != true,
      pos: evt.pos,
      clicks: evt.clicks,
      which: evt.which,
      time: evt.timestamp
    }
  }
  
  // Mouse motion
  if (evt.type == 'mouse_motion') {
    return {
      kind: 'axis',
      device_id: 'kbm',
      control: 'mouse_pos',
      pos: evt.pos,
      delta: evt.d_pos,
      which: evt.which,
      time: evt.timestamp
    }
  }
  
  // Mouse wheel
  if (evt.type == 'mouse_wheel') {
    return {
      kind: 'axis',
      device_id: 'kbm',
      control: 'mouse_wheel',
      value: evt.scroll,
      pos: evt.pos,
      which: evt.which,
      time: evt.timestamp
    }
  }
  
  // Gamepad buttons
  if (evt.type == 'gamepad_button_down' || evt.type == 'gamepad_button_up') {
    return {
      kind: 'button',
      device_id: 'gp:' + evt.which,
      control: 'gamepad_' + evt.button,
      pressed: evt.down == true,
      released: evt.down != true,
      which: evt.which,
      time: evt.timestamp
    }
  }
  
  // Gamepad axes
  if (evt.type == 'gamepad_axis_motion') {
    return {
      kind: 'axis',
      device_id: 'gp:' + evt.which,
      control: 'gamepad_' + evt.axis,
      value: evt.value,
      which: evt.which,
      time: evt.timestamp
    }
  }
  
  // Gamepad touchpad
  if (evt.type == 'gamepad_touchpad_down') {
    return {
      kind: 'button',
      device_id: 'gp:' + evt.which,
      control: 'gamepad_touchpad',
      pressed: true,
      released: false,
      touchpad: evt.touchpad,
      finger: evt.finger,
      pos: evt.pos,
      pressure: evt.pressure,
      which: evt.which,
      time: evt.timestamp
    }
  }
  
  if (evt.type == 'gamepad_touchpad_up') {
    return {
      kind: 'button',
      device_id: 'gp:' + evt.which,
      control: 'gamepad_touchpad',
      pressed: false,
      released: true,
      touchpad: evt.touchpad,
      finger: evt.finger,
      pos: evt.pos,
      which: evt.which,
      time: evt.timestamp
    }
  }
  
  if (evt.type == 'gamepad_touchpad_motion') {
    return {
      kind: 'axis',
      device_id: 'gp:' + evt.which,
      control: 'gamepad_touchpad',
      touchpad: evt.touchpad,
      finger: evt.finger,
      pos: evt.pos,
      pressure: evt.pressure,
      which: evt.which,
      time: evt.timestamp
    }
  }
  
  // Touch events (screen touch, not gamepad)
  if (evt.type == 'finger_down') {
    return {
      kind: 'button',
      device_id: 'touch:' + evt.touch,
      control: 'touch',
      pressed: true,
      released: false,
      finger: evt.finger,
      pos: evt.pos,
      pressure: evt.pressure,
      which: evt.touch,
      time: evt.timestamp
    }
  }
  
  if (evt.type == 'finger_up') {
    return {
      kind: 'button',
      device_id: 'touch:' + evt.touch,
      control: 'touch',
      pressed: false,
      released: true,
      finger: evt.finger,
      pos: evt.pos,
      which: evt.touch,
      time: evt.timestamp
    }
  }
  
  if (evt.type == 'finger_motion') {
    return {
      kind: 'axis',
      device_id: 'touch:' + evt.touch,
      control: 'touch',
      finger: evt.finger,
      pos: evt.pos,
      delta: evt.d_pos,
      pressure: evt.pressure,
      which: evt.touch,
      time: evt.timestamp
    }
  }
  
  // Text input
  if (evt.type == 'text_input') {
    return {
      kind: 'text',
      device_id: 'kbm',
      control: 'text',
      text: evt.text,
      time: evt.timestamp
    }
  }
  
  // Window events
  if (starts_with(evt.type, 'window_')) {
    return {
      kind: 'window',
      device_id: 'system',
      control: evt.type,
      width: evt.width,
      height: evt.height,
      which: evt.which,
      time: evt.timestamp
    }
  }
  
  // Device connect/disconnect
  if (evt.type == 'gamepad_added') {
    return {
      kind: 'device',
      device_id: 'gp:' + evt.which,
      control: 'connected',
      which: evt.which,
      time: evt.timestamp
    }
  }
  
  if (evt.type == 'gamepad_removed') {
    return {
      kind: 'device',
      device_id: 'gp:' + evt.which,
      control: 'disconnected',
      which: evt.which,
      time: evt.timestamp
    }
  }
  
  // Not a translatable input event
  return null
}

return {
  translate: translate,
  keycode_to_control: keycode_to_control,
  parse_mods: parse_mods
}