# Copyright (c) 2014 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.

from autotest_lib.client.common_lib import error
import os

class FrameSender(object):
    """Context manager for sending management frames."""

    _sender_count = 0

    def __init__(self, router, frame_type, channel, ssid_prefix=None,
                 num_bss=None, frame_count=None, delay=None, dest_addr=None,
                 probe_resp_footer=None, instance=0):
        """
        @param router: LinuxRouter object router to send frames from.
        @param frame_type: int management frame type.
        @param channel: int targeted channel.
        @param ssid_prefix: string SSID prefix for BSSes in the frames.
        @param num_bss: int number of BSSes configured for sending frames.
        @param frame_count: int number of frames to send, frame_count of 0
                implies infinite number of frames.
        @param delay: int delay in between frames in milliseconds.
        @param dest_addr: MAC address of the destination address (DA).
        @param probe_resp_footer: footer bytes for probe responses.
        @param instance: int hostapd instance on router to send frames from.
        """
        if router.board == "panther":
            raise error.TestNAError('Panther router does not support manual '
                                    'beacon frame generation')
        self._router = router
        self._channel = channel
        self._frame_type = frame_type
        self._ssid_prefix = ssid_prefix
        self._num_bss = num_bss
        self._frame_count = frame_count
        self._delay = delay
        self._dest_addr = dest_addr
        self._probe_resp_footer = probe_resp_footer
        self._ap_interface = router.hostapd_instances[instance].interface
        self._injection_interface = None
        self._pid = None

        self._index = FrameSender._sender_count
        FrameSender._sender_count += 1


    def __enter__(self):
        self._injection_interface = self._router.get_configured_interface(
            'monitor', same_phy_as=self._ap_interface)
        self._pid = self._router.send_management_frame(
            self._injection_interface,
            self._frame_type, self._channel, ssid_prefix=self._ssid_prefix,
            num_bss=self._num_bss, frame_count=self._frame_count,
            delay=self._delay, dest_addr=self._dest_addr,
            probe_resp_footer=self._probe_resp_footer)
        return self


    def __exit__(self, exception, value, traceback):
        if self._injection_interface:
            self._router.release_interface(self._injection_interface)
        if self._pid:
            # Kill process and wait for termination.
            self._router.host.run(
                'kill {pid};'
                ' for i in $(seq 1 10); do'
                ' kill -0 {pid} || break; sleep 0.2;'
                ' done'.format(pid=self._pid), ignore_status=True)
            self._router.host.get_file(
                os.path.join(
                    self._router.logdir, self._router.MGMT_FRAME_SENDER_LOG_FILE),
                'debug/frame_sender_%d.log' % self._index)