# Copyright (c) 2012 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.

import contextlib
import httplib
import logging
import os
import tempfile
import time

from pylib import android_commands
from pylib import constants
from pylib import ports
from pylib.chrome_test_server_spawner import SpawningServer
from pylib.flag_changer import FlagChanger
from pylib.forwarder import Forwarder
from pylib.valgrind_tools import CreateTool
# TODO(frankf): Move this to pylib/utils
import lighttpd_server


# A file on device to store ports of net test server. The format of the file is
# test-spawner-server-port:test-server-port
NET_TEST_SERVER_PORT_INFO_FILE = 'net-test-server-ports'


class BaseTestRunner(object):
  """Base class for running tests on a single device.

  A subclass should implement RunTests() with no parameter, so that calling
  the Run() method will set up tests, run them and tear them down.
  """

  def __init__(self, device, tool, build_type):
    """
      Args:
        device: Tests will run on the device of this ID.
        shard_index: Index number of the shard on which the test suite will run.
        build_type: 'Release' or 'Debug'.
    """
    self.device = device
    self.adb = android_commands.AndroidCommands(device=device)
    self.tool = CreateTool(tool, self.adb)
    self._http_server = None
    self._forwarder = None
    self._forwarder_device_port = 8000
    self.forwarder_base_url = ('http://localhost:%d' %
        self._forwarder_device_port)
    self.flags = FlagChanger(self.adb)
    self.flags.AddFlags(['--disable-fre'])
    self._spawning_server = None
    self._spawner_forwarder = None
    # We will allocate port for test server spawner when calling method
    # LaunchChromeTestServerSpawner and allocate port for test server when
    # starting it in TestServerThread.
    self.test_server_spawner_port = 0
    self.test_server_port = 0
    self.build_type = build_type

  def _PushTestServerPortInfoToDevice(self):
    """Pushes the latest port information to device."""
    self.adb.SetFileContents(self.adb.GetExternalStorage() + '/' +
                             NET_TEST_SERVER_PORT_INFO_FILE,
                             '%d:%d' % (self.test_server_spawner_port,
                                        self.test_server_port))

  def Run(self, test):
    """Calls subclass functions to set up test, run it and tear it down.

    Args:
      test: A Test to run.

    Returns:
      Test results returned from RunTest(test).
    """
    self.SetUp()
    try:
      return self.RunTest(test)
    finally:
      self.TearDown()

  def SetUp(self):
    """Called before tests run."""
    Forwarder.KillDevice(self.adb, self.tool)

  def RunTest(self, test):
    """Runs the tests. Needs to be overridden."""
    raise NotImplementedError

  def TearDown(self):
    """Called when tests finish running."""
    self.ShutdownHelperToolsForTestSuite()

  def CopyTestData(self, test_data_paths, dest_dir):
    """Copies |test_data_paths| list of files/directories to |dest_dir|.

    Args:
      test_data_paths: A list of files or directories relative to |dest_dir|
          which should be copied to the device. The paths must exist in
          |CHROME_DIR|.
      dest_dir: Absolute path to copy to on the device.
    """
    for p in test_data_paths:
      self.adb.PushIfNeeded(
          os.path.join(constants.CHROME_DIR, p),
          os.path.join(dest_dir, p))

  def LaunchTestHttpServer(self, document_root, port=None,
                           extra_config_contents=None):
    """Launches an HTTP server to serve HTTP tests.

    Args:
      document_root: Document root of the HTTP server.
      port: port on which we want to the http server bind.
      extra_config_contents: Extra config contents for the HTTP server.
    """
    self._http_server = lighttpd_server.LighttpdServer(
        document_root, port=port, extra_config_contents=extra_config_contents)
    if self._http_server.StartupHttpServer():
      logging.info('http server started: http://localhost:%s',
                   self._http_server.port)
    else:
      logging.critical('Failed to start http server')
    self.StartForwarderForHttpServer()
    return (self._forwarder_device_port, self._http_server.port)

  def _CreateAndRunForwarder(
      self, adb, port_pairs, tool, host_name, build_type):
    """Creates and run a forwarder."""
    forwarder = Forwarder(adb, build_type)
    forwarder.Run(port_pairs, tool, host_name)
    return forwarder

  def StartForwarder(self, port_pairs):
    """Starts TCP traffic forwarding for the given |port_pairs|.

    Args:
      host_port_pairs: A list of (device_port, local_port) tuples to forward.
    """
    if self._forwarder:
      self._forwarder.Close()
    self._forwarder = self._CreateAndRunForwarder(
        self.adb, port_pairs, self.tool, '127.0.0.1', self.build_type)

  def StartForwarderForHttpServer(self):
    """Starts a forwarder for the HTTP server.

    The forwarder forwards HTTP requests and responses between host and device.
    """
    self.StartForwarder([(self._forwarder_device_port, self._http_server.port)])

  def RestartHttpServerForwarderIfNecessary(self):
    """Restarts the forwarder if it's not open."""
    # Checks to see if the http server port is being used.  If not forwards the
    # request.
    # TODO(dtrainor): This is not always reliable because sometimes the port
    # will be left open even after the forwarder has been killed.
    if not ports.IsDevicePortUsed(self.adb,
        self._forwarder_device_port):
      self.StartForwarderForHttpServer()

  def ShutdownHelperToolsForTestSuite(self):
    """Shuts down the server and the forwarder."""
    # Forwarders should be killed before the actual servers they're forwarding
    # to as they are clients potentially with open connections and to allow for
    # proper hand-shake/shutdown.
    Forwarder.KillDevice(self.adb, self.tool)
    if self._http_server:
      self._http_server.ShutdownHttpServer()
    if self._spawning_server:
      self._spawning_server.Stop()
    self.flags.Restore()

  def LaunchChromeTestServerSpawner(self):
    """Launches test server spawner."""
    server_ready = False
    error_msgs = []
    # Try 3 times to launch test spawner server.
    for i in xrange(0, 3):
      # Do not allocate port for test server here. We will allocate
      # different port for individual test in TestServerThread.
      self.test_server_spawner_port = ports.AllocateTestServerPort()
      self._spawning_server = SpawningServer(self.test_server_spawner_port,
                                             self.adb,
                                             self.tool,
                                             self.build_type)
      self._spawning_server.Start()
      server_ready, error_msg = ports.IsHttpServerConnectable(
          '127.0.0.1', self.test_server_spawner_port, path='/ping',
          expected_read='ready')
      if server_ready:
        break
      else:
        error_msgs.append(error_msg)
      self._spawning_server.Stop()
      # Wait for 2 seconds then restart.
      time.sleep(2)
    if not server_ready:
      logging.error(';'.join(error_msgs))
      raise Exception('Can not start the test spawner server.')
    self._PushTestServerPortInfoToDevice()
    self._spawner_forwarder = self._CreateAndRunForwarder(
        self.adb,
        [(self.test_server_spawner_port, self.test_server_spawner_port)],
        self.tool, '127.0.0.1', self.build_type)
