xteink-apps/apps/BLETest/main.lua

-- DESCRIPTION: Test BLE scanning and connections

local screen = "devices"
local lastScreen = nil
local devices = {}
local selected = 1
local message = "Press Scan to find nearby devices"
local connectedDevice = nil

local function refreshMode()
  local mode = screen == lastScreen and REFRESH_FAST or REFRESH_HALF
  lastScreen = screen
  return mode
end

local function deviceLabel(device)
  return device.address .. " (" .. (device.name ~= "" and device.name or "N/A") .. ")"
end

local function drawDevices()
  gui.clear()
  gui.drawCenteredText(FONT_UI_12, 28, "BLE Devices", COLOR_BLACK, STYLE_BOLD)

  local visible = math.max(1, math.floor((gui.height() - 130) / 38))
  local first = math.max(1, math.min(selected - math.floor(visible / 2), #devices - visible + 1))
  local last = math.min(#devices, first + visible - 1)
  local y = 72
  for index = first, last do
    local prefix = index == selected and "> " or "  "
    gui.drawText(
      FONT_UI_12,
      36,
      y,
      prefix .. deviceLabel(devices[index]),
      COLOR_BLACK,
      index == selected and STYLE_BOLD or STYLE_NORMAL
    )
    y = y + 38
  end

  if #devices == 0 then
    gui.drawCenteredText(FONT_UI_10, math.floor(gui.height() / 2), message)
  elseif message ~= "" then
    gui.drawCenteredText(FONT_UI_10, gui.height() - 82, message)
  end

  gui.drawButtonHints("Back", #devices > 0 and "Info" or "", "", #devices > 0 and "Refresh" or "Scan")
  gui.refresh(refreshMode())
end

local function drawStatus(text)
  gui.clear()
  gui.drawCenteredText(FONT_UI_12, math.floor(gui.height() / 2), text, COLOR_BLACK, STYLE_BOLD)
  gui.refresh(refreshMode())
end

local function drawInfo()
  local device = devices[selected]
  gui.clear()
  gui.drawCenteredText(FONT_UI_12, 28, "Device Info", COLOR_BLACK, STYLE_BOLD)
  gui.drawText(FONT_UI_12, 36, 88, "Address: " .. device.address)
  gui.drawText(FONT_UI_12, 36, 126, "Name: " .. (device.name ~= "" and device.name or "N/A"))
  gui.drawText(FONT_UI_12, 36, 164, "RSSI: " .. device.rssi .. " dBm")
  gui.drawText(FONT_UI_12, 36, 202, "Index: " .. selected .. "/" .. #devices)
  gui.drawButtonHints("Back", "Connect", "", "")
  gui.refresh(refreshMode())
end

local function drawConnected()
  gui.clear()
  gui.drawCenteredText(FONT_UI_12, 44, "Connected", COLOR_BLACK, STYLE_BOLD)
  gui.drawCenteredText(FONT_UI_12, 100, deviceLabel(connectedDevice))
  gui.drawButtonHints("Back", "Disconnect", "", "")
  gui.refresh(refreshMode())
end

local function render()
  if screen == "devices" then
    drawDevices()
  elseif screen == "info" then
    drawInfo()
  elseif screen == "connected" then
    drawConnected()
  end
end

local function scan()
  screen = "scanning"
  drawStatus "Scanning..."

  devices = {}
  collectgarbage "collect"
  local results, err = ble.scan(3000)
  devices = results or {}
  selected = 1
  message = results and (#devices .. " devices found") or (err or "Scan failed")
  screen = "devices"
  render()
end

local function connect()
  local device = devices[selected]
  if not device then
    return
  end

  screen = "connecting"
  drawStatus "Connecting..."
  if ble.connect(device.address) then
    connectedDevice = device
    screen = "connected"
  else
    message = "Could not connect to " .. device.address
    screen = "devices"
  end
  render()
end

local function disconnect()
  ble.disconnect()
  connectedDevice = nil
  message = "Disconnected"
  screen = "devices"
  render()
end

function init()
  if not ble.init "BLETest" then
    message = "BLE initialization failed"
  end
  render()
end

function on_button(name, event)
  if event ~= "down" then
    return
  end

  if screen == "devices" and #devices > 0 and (name == "page_back" or name == "page_forward") then
    local step = name == "page_back" and -1 or 1
    selected = (selected - 1 + step) % #devices + 1
    render()
  elseif name == "right" and screen == "devices" then
    scan()
  elseif name == "confirm" and screen == "devices" and #devices > 0 then
    screen = "info"
    render()
  elseif name == "confirm" and screen == "info" then
    connect()
  elseif name == "back" and screen == "info" then
    screen = "devices"
    render()
  elseif name == "confirm" and screen == "connected" then
    disconnect()
  elseif name == "back" and screen == "connected" then
    disconnect()
  elseif name == "back" then
    ble.deinit()
    sys.exit()
  end
end