// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "chrome/browser/devtools/adb/android_usb_device.h"

#include <set>

#include "base/base64.h"
#include "base/lazy_instance.h"
#include "base/message_loop/message_loop.h"
#include "base/stl_util.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "chrome/browser/devtools/adb/android_rsa.h"
#include "chrome/browser/devtools/adb/android_usb_socket.h"
#include "chrome/browser/usb/usb_device.h"
#include "chrome/browser/usb/usb_interface.h"
#include "chrome/browser/usb/usb_service.h"
#include "content/public/browser/browser_thread.h"
#include "crypto/rsa_private_key.h"
#include "net/base/ip_endpoint.h"
#include "net/base/net_errors.h"
#include "net/socket/stream_socket.h"

namespace {

const size_t kHeaderSize = 24;

const int kAdbClass = 0xff;
const int kAdbSubclass = 0x42;
const int kAdbProtocol = 0x1;

const int kUsbTimeout = 0;

const uint32 kMaxPayload = 4096;
const uint32 kVersion = 0x01000000;

static const char kHostConnectMessage[] = "host::";

using content::BrowserThread;

typedef std::vector<scoped_refptr<UsbDevice> > UsbDevices;

base::LazyInstance<AndroidUsbDevices>::Leaky g_devices =
    LAZY_INSTANCE_INITIALIZER;

static scoped_refptr<AndroidUsbDevice> ClaimInterface(
    crypto::RSAPrivateKey* rsa_key,
    scoped_refptr<UsbDeviceHandle> usb_device,
    const UsbInterface* interface,
    int interface_id) {
  if (interface->GetNumAltSettings() == 0)
    return NULL;

  scoped_refptr<const UsbInterfaceDescriptor> idesc =
      interface->GetAltSetting(0).get();

  if (idesc->GetInterfaceClass() != kAdbClass ||
      idesc->GetInterfaceSubclass() != kAdbSubclass ||
      idesc->GetInterfaceProtocol() != kAdbProtocol ||
      idesc->GetNumEndpoints() != 2) {
    return NULL;
  }

  int inbound_address = 0;
  int outbound_address = 0;
  int zero_mask = 0;

  for (size_t i = 0; i < idesc->GetNumEndpoints(); ++i) {
    scoped_refptr<const UsbEndpointDescriptor> edesc =
        idesc->GetEndpoint(i).get();
    if (edesc->GetTransferType() != USB_TRANSFER_BULK)
      continue;
    if (edesc->GetDirection() == USB_DIRECTION_INBOUND)
      inbound_address = edesc->GetAddress();
    else
      outbound_address = edesc->GetAddress();
    zero_mask = edesc->GetMaximumPacketSize() - 1;
  }

  if (inbound_address == 0 || outbound_address == 0)
    return NULL;

  if (!usb_device->ClaimInterface(interface_id))
    return NULL;

  base::string16 serial;
  if (!usb_device->GetSerial(&serial) || serial.empty())
    return NULL;

  return new AndroidUsbDevice(rsa_key, usb_device, UTF16ToASCII(serial),
                              inbound_address, outbound_address, zero_mask);
}

static uint32 Checksum(const std::string& data) {
  unsigned char* x = (unsigned char*)data.data();
  int count = data.length();
  uint32 sum = 0;
  while (count-- > 0)
    sum += *x++;
  return sum;
}

static void DumpMessage(bool outgoing, const char* data, size_t length) {
#if 0
  std::string result = "";
  if (length == kHeaderSize) {
    for (size_t i = 0; i < 24; ++i) {
      result += base::StringPrintf("%02x",
          data[i] > 0 ? data[i] : (data[i] + 0x100) & 0xFF);
      if ((i + 1) % 4 == 0)
        result += " ";
    }
    for (size_t i = 0; i < 24; ++i) {
      if (data[i] >= 0x20 && data[i] <= 0x7E)
        result += data[i];
      else
        result += ".";
    }
  } else {
    result = base::StringPrintf("%d: ", (int)length);
    for (size_t i = 0; i < length; ++i) {
      if (data[i] >= 0x20 && data[i] <= 0x7E)
        result += data[i];
      else
        result += ".";
    }
  }
  LOG(ERROR) << (outgoing ? "[out] " : "[ in] ") << result;
#endif  // 0
}

}  // namespace

AdbMessage::AdbMessage(uint32 command,
                       uint32 arg0,
                       uint32 arg1,
                       const std::string& body)
    : command(command),
      arg0(arg0),
      arg1(arg1),
      body(body) {
}

AdbMessage::~AdbMessage() {
}

static void EnumerateOnFileThread(crypto::RSAPrivateKey* rsa_key,
                                  AndroidUsbDevices* result) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));

  UsbService* service = UsbService::GetInstance();
  AndroidUsbDevices& devices = g_devices.Get();

  UsbDevices usb_devices;
  service->GetDevices(&usb_devices);

  // GC Android devices with no actual usb device.
  AndroidUsbDevices::iterator it = devices.begin();
  std::set<UsbDevice*> claimed_devices;
  while (it != devices.end()) {
    bool found_device = false;
    for (UsbDevices::iterator it2 = usb_devices.begin();
         it2 != usb_devices.end() && !found_device; ++it2) {
      UsbDevice* usb_device = it2->get();
      AndroidUsbDevice* device = it->get();
      if (usb_device == device->usb_device()->device()) {
        found_device = true;
        claimed_devices.insert(usb_device);
      }
    }

    if (!found_device)
      it = devices.erase(it);
    else
      ++it;
  }

  // Add new devices.
  for (UsbDevices::iterator it = usb_devices.begin(); it != usb_devices.end();
       ++it) {
    if (ContainsKey(claimed_devices, it->get()))
      continue;

    scoped_refptr<UsbConfigDescriptor> config = new UsbConfigDescriptor();
    bool success = (*it)->ListInterfaces(config.get());
    if (!success)
      continue;

    scoped_refptr<UsbDeviceHandle> usb_device = (*it)->Open();
    if (!usb_device)
      continue;

    bool claimed = false;
    for (size_t j = 0; j < config->GetNumInterfaces(); ++j) {
      scoped_refptr<AndroidUsbDevice> device =
          ClaimInterface(rsa_key, usb_device, config->GetInterface(j), j);
      if (device.get()) {
        devices.push_back(device);
        claimed = true;
      }
    }
    if (!claimed)
      usb_device->Close();
  }

  *result = devices;
}

static void InitDevicesOnCallerThread(
    AndroidUsbDevices* devices,
    const AndroidUsbDevicesCallback& callback) {
  for (AndroidUsbDevices::iterator it = devices->begin(); it != devices->end();
       ++it) {
    (*it)->InitOnCallerThread();
  }
  callback.Run(*devices);
  delete devices;
}

// static
void AndroidUsbDevice::Enumerate(crypto::RSAPrivateKey* rsa_key,
                                 const AndroidUsbDevicesCallback& callback) {
  AndroidUsbDevices* devices = new AndroidUsbDevices();
  BrowserThread::PostTaskAndReply(
      BrowserThread::FILE, FROM_HERE,
      base::Bind(&EnumerateOnFileThread, rsa_key, devices),
      base::Bind(&InitDevicesOnCallerThread, devices, callback));
}

AndroidUsbDevice::AndroidUsbDevice(crypto::RSAPrivateKey* rsa_key,
                                   scoped_refptr<UsbDeviceHandle> usb_device,
                                   const std::string& serial,
                                   int inbound_address,
                                   int outbound_address,
                                   int zero_mask)
    : message_loop_(NULL),
      rsa_key_(rsa_key->Copy()),
      usb_device_(usb_device),
      serial_(serial),
      inbound_address_(inbound_address),
      outbound_address_(outbound_address),
      zero_mask_(zero_mask),
      is_connected_(false),
      signature_sent_(false),
      last_socket_id_(256),
      terminated_(false) {
}

void AndroidUsbDevice::InitOnCallerThread() {
  if (message_loop_)
    return;
  message_loop_ = base::MessageLoop::current();
  Queue(new AdbMessage(AdbMessage::kCommandCNXN, kVersion, kMaxPayload,
                       kHostConnectMessage));
  ReadHeader(true);
}

net::StreamSocket* AndroidUsbDevice::CreateSocket(const std::string& command) {
  uint32 socket_id = ++last_socket_id_;
  sockets_[socket_id] = new AndroidUsbSocket(this, socket_id, command,
      base::Bind(&AndroidUsbDevice::SocketDeleted, this));
  return sockets_[socket_id];
}

void AndroidUsbDevice::Send(uint32 command,
                            uint32 arg0,
                            uint32 arg1,
                            const std::string& body) {
  scoped_refptr<AdbMessage> m = new AdbMessage(command, arg0, arg1, body);
  // Delay open request if not yet connected.
  if (!is_connected_) {
    pending_messages_.push_back(m);
    return;
  }
  Queue(m);
}

AndroidUsbDevice::~AndroidUsbDevice() {
  Terminate();
}

void AndroidUsbDevice::Queue(scoped_refptr<AdbMessage> message) {
  // Queue header.
  std::vector<uint32> header;
  header.push_back(message->command);
  header.push_back(message->arg0);
  header.push_back(message->arg1);
  bool append_zero = true;
  if (message->body.empty())
    append_zero = false;
  if (message->command == AdbMessage::kCommandAUTH &&
      message->arg0 == AdbMessage::kAuthSignature)
    append_zero = false;
  if (message->command == AdbMessage::kCommandWRTE)
    append_zero = false;

  size_t body_length = message->body.length() + (append_zero ? 1 : 0);
  header.push_back(body_length);
  header.push_back(Checksum(message->body));
  header.push_back(message->command ^ 0xffffffff);
  scoped_refptr<net::IOBuffer> header_buffer = new net::IOBuffer(kHeaderSize);
  memcpy(header_buffer.get()->data(), &header[0], kHeaderSize);
  outgoing_queue_.push(std::make_pair(header_buffer, kHeaderSize));

  // Queue body.
  if (!message->body.empty()) {
    scoped_refptr<net::IOBuffer> body_buffer = new net::IOBuffer(body_length);
    memcpy(body_buffer->data(), message->body.data(), message->body.length());
    if (append_zero)
      body_buffer->data()[body_length - 1] = 0;
    outgoing_queue_.push(std::make_pair(body_buffer, body_length));
    if (zero_mask_ && (body_length & zero_mask_) == 0) {
      // Send a zero length packet.
      outgoing_queue_.push(std::make_pair(body_buffer, 0));
    }
  }
  ProcessOutgoing();
}

void AndroidUsbDevice::ProcessOutgoing() {
  if (outgoing_queue_.empty() || terminated_)
    return;

  BulkMessage message = outgoing_queue_.front();
  outgoing_queue_.pop();
  DumpMessage(true, message.first->data(), message.second);
  usb_device_->BulkTransfer(USB_DIRECTION_OUTBOUND, outbound_address_,
      message.first, message.second, kUsbTimeout,
      base::Bind(&AndroidUsbDevice::OutgoingMessageSent, this));
}

void AndroidUsbDevice::OutgoingMessageSent(UsbTransferStatus status,
                                           scoped_refptr<net::IOBuffer> buffer,
                                           size_t result) {
  if (status != USB_TRANSFER_COMPLETED)
    return;
  message_loop_->PostTask(FROM_HERE,
                          base::Bind(&AndroidUsbDevice::ProcessOutgoing,
                                     this));
}

void AndroidUsbDevice::ReadHeader(bool initial) {
  if (terminated_)
    return;
  if (!initial && HasOneRef())
    return;  // Stop polling.
  scoped_refptr<net::IOBuffer> buffer = new net::IOBuffer(kHeaderSize);
  usb_device_->BulkTransfer(USB_DIRECTION_INBOUND, inbound_address_,
      buffer, kHeaderSize, kUsbTimeout,
      base::Bind(&AndroidUsbDevice::ParseHeader, this));
}

void AndroidUsbDevice::ParseHeader(UsbTransferStatus status,
                                   scoped_refptr<net::IOBuffer> buffer,
                                   size_t result) {
  if (status == USB_TRANSFER_TIMEOUT) {
    message_loop_->PostTask(FROM_HERE,
                            base::Bind(&AndroidUsbDevice::ReadHeader, this,
                                       false));
    return;
  }

  if (status != USB_TRANSFER_COMPLETED || result != kHeaderSize) {
    TransferError(status);
    return;
  }

  DumpMessage(false, buffer->data(), result);
  std::vector<uint32> header(6);
  memcpy(&header[0], buffer->data(), result);
  scoped_refptr<AdbMessage> message =
      new AdbMessage(header[0], header[1], header[2], "");
  uint32 data_length = header[3];
  uint32 data_check = header[4];
  uint32 magic = header[5];
  if ((message->command ^ 0xffffffff) != magic) {
    TransferError(USB_TRANSFER_ERROR);
    return;
  }

  if (data_length == 0) {
    message_loop_->PostTask(FROM_HERE,
                            base::Bind(&AndroidUsbDevice::HandleIncoming, this,
                                       message));
    return;
  }

  message_loop_->PostTask(FROM_HERE,
                          base::Bind(&AndroidUsbDevice::ReadBody, this,
                                     message, data_length, data_check));
}

void AndroidUsbDevice::ReadBody(scoped_refptr<AdbMessage> message,
                                uint32 data_length,
                                uint32 data_check) {
  scoped_refptr<net::IOBuffer> buffer = new net::IOBuffer(data_length);
  usb_device_->BulkTransfer(USB_DIRECTION_INBOUND, inbound_address_,
      buffer, data_length, kUsbTimeout,
      base::Bind(&AndroidUsbDevice::ParseBody, this, message, data_length,
                 data_check));
}

void AndroidUsbDevice::ParseBody(scoped_refptr<AdbMessage> message,
                                 uint32 data_length,
                                 uint32 data_check,
                                 UsbTransferStatus status,
                                 scoped_refptr<net::IOBuffer> buffer,
                                 size_t result) {
  if (status == USB_TRANSFER_TIMEOUT) {
    message_loop_->PostTask(FROM_HERE,
                            base::Bind(&AndroidUsbDevice::ReadBody, this,
                            message, data_length, data_check));
    return;
  }

  if (status != USB_TRANSFER_COMPLETED ||
      static_cast<uint32>(result) != data_length) {
    TransferError(status);
    return;
  }

  DumpMessage(false, buffer->data(), data_length);
  message->body = std::string(buffer->data(), result);
  if (Checksum(message->body) != data_check) {
    TransferError(USB_TRANSFER_ERROR);
    return;
  }

  message_loop_->PostTask(FROM_HERE,
                          base::Bind(&AndroidUsbDevice::HandleIncoming, this,
                                     message));
}

void AndroidUsbDevice::HandleIncoming(scoped_refptr<AdbMessage> message) {
  switch (message->command) {
    case AdbMessage::kCommandAUTH:
      {
        DCHECK_EQ(message->arg0, static_cast<uint32>(AdbMessage::kAuthToken));
        if (signature_sent_) {
          Queue(new AdbMessage(AdbMessage::kCommandAUTH,
                               AdbMessage::kAuthRSAPublicKey, 0,
                               AndroidRSAPublicKey(rsa_key_.get())));
        } else {
          signature_sent_ = true;
          std::string signature = AndroidRSASign(rsa_key_.get(), message->body);
          if (!signature.empty()) {
            Queue(new AdbMessage(AdbMessage::kCommandAUTH,
                                 AdbMessage::kAuthSignature, 0,
                                 signature));
          } else {
            Queue(new AdbMessage(AdbMessage::kCommandAUTH,
                                 AdbMessage::kAuthRSAPublicKey, 0,
                                 AndroidRSAPublicKey(rsa_key_.get())));
          }
        }
      }
      break;
    case AdbMessage::kCommandCNXN:
      {
        is_connected_ = true;
        PendingMessages pending;
        pending.swap(pending_messages_);
        for (PendingMessages::iterator it = pending.begin();
             it != pending.end(); ++it) {
          Queue(*it);
        }
      }
      break;
    case AdbMessage::kCommandOKAY:
    case AdbMessage::kCommandWRTE:
    case AdbMessage::kCommandCLSE:
      {
        AndroidUsbSockets::iterator it = sockets_.find(message->arg1);
        if (it != sockets_.end())
          it->second->HandleIncoming(message);
      }
      break;
    default:
      break;
  }
  ReadHeader(false);
}

void AndroidUsbDevice::TransferError(UsbTransferStatus status) {
  message_loop_->PostTask(FROM_HERE,
                          base::Bind(&AndroidUsbDevice::Terminate,
                                     this));
}

void AndroidUsbDevice::Terminate() {
  if (terminated_)
    return;

  terminated_ = true;

  // Iterate over copy.
  AndroidUsbSockets sockets(sockets_);
  for (AndroidUsbSockets::iterator it = sockets.begin();
       it != sockets.end(); ++it) {
    it->second->Terminated();
  }

  usb_device_->ReleaseInterface(1);
  usb_device_->Close();
}

void AndroidUsbDevice::SocketDeleted(uint32 socket_id) {
  sockets_.erase(socket_id);
}