crazyradio.js

var Crazyradio = (function() {
  "use strict";
  var state = "closed";
  
  var noop = function(state, data) {
    return;
  };
  
  // Generic helper function to implement the radio control transfer
  function controlTransfer(request, value, data, callback) {
    var transfer = {
      direction: "out",
      recipient: "device",
      requestType: "vendor",
      request: request,
      index: 0,
      value: value,
      data: data
    };
    
    chrome.usb.controlTransfer(my.handle, transfer, function(info) {
      if (!info || info.resultCode !== 0) {
        console.error("Error executing control channel");
        callback(false);
      } else {
        callback(true);
      }
    });
  }
  
  // Public methods and states
  var my = {handle: undefined};
  
  my.open = function(openedCb) {
    if (typeof(openedCb) !== "function") {
      openedCb = noop;
    }
    
    if (state !== "closed") {
      console.warn("Trying to re-open already openned radio, ignoring");
      openedCb(false);
      return;
    }
    
    chrome.usb.getDevices(        {
          "vendorId": 6421,
          "productId": 30583
        }, function(found_devices) {
      if (chrome.runtime.lastError !== undefined) {
        console.warn('chrome.usb.getDevices error: ' +
                     chrome.runtime.lastError.message);
        openedCb(false);
        return;
      }
      
      if (found_devices.length > 0) {
        var device = found_devices[0];
        console.log("Oppening Crazyradio dongle");
        chrome.usb.openDevice(device, function(handle) {
          console.log(handle);
          
          chrome.usb.claimInterface(handle, 0, function () {
            
            if (chrome.runtime.lastError !== undefined) {
              console.warn('chrome.usb.claimInterface error: ' +
                           chrome.runtime.lastError.message);
              openedCb(false);
              return;
            }
            
            my.handle = handle;
            state = "opened";
            openedCb(true);
          });
        });
      } else {
        console.error("Cannot find Crazyradio dongle!");
        openedCb(false);
      }
    });
  };
  
  my.sendPacket = function(buffer, packetSendCb) {
    var to = {
      'direction': 'out',
      'endpoint': 1,
      'data' : buffer
    };
    
    chrome.usb.bulkTransfer(my.handle, to, function(info) {
      //console.log(info);
      
      if (info.resultCode !== 0) {
        console.error("Cannot send data to the dongle");
      } else {
        var ti = {
          'direction': 'in',
          'endpoint': 1,
          'length': 64,
        };
          
          chrome.usb.bulkTransfer(my.handle, ti, function(info) {
            if (info.resultCode !== 0) {
              console.error("Cannot receive data from the dongle");
            } else {
              var ack = new Uint8Array(info.data);
              
              packetSendCb(ack[0]!==0, ack.subarray(1).buffer);
            }
          });
      }
    });
  };
  
  my.setChannel = function(channel, callback) {
    channel = Number(channel);
    
    if ((channel<0) || (channel>125)) {
      callback(false);
      my.error = "Error: cannot set a channel outside of [0 125]";
    }
    
    controlTransfer(0x01, channel, new ArrayBuffer(0), callback);
  };
  
  my.setDatarate = function(datarate_str, callback) {
    var datarate;
    if (datarate_str === "250Kbps") datarate = 0;
    else if (datarate_str === "1Mbps") datarate = 1;
    else if (datarate_str === "2Mbps") datarate = 2;
    else {
      my.error = "Error: Wrong value, not a datarate: " + datarate_str;
      callback(false);
      console.error(my.error);
      return;
    }
    
    controlTransfer(0x03, datarate, new ArrayBuffer(0), callback);
  };
  
  my.close = function() {
    if (state !== "opened") {
      return;
    }
    
    state = "closing";
    
    chrome.usb.releaseInterface(my.handle, 0, function() {
      chrome.usb.closeDevice(my.handle, noop);
      state = "closed";
    });
  };
  
  my.packetSent = noop;
  
  return my;
}());