#!/usr/bin/python
#
# USAGE: $0 frequency minutes outputfile
#
# $Id: fmcapture,v 1.2 2005/08/25 06:07:52 jake Exp jake $
# this script is for Linux
# FreeBSD counterpart available at http://angerman.net

__author__ = "Gary Burd"
__copyright__ = "Copyright 2003, Gary Burd"
__license__ = "GPL"
__version__ = "0.2"

import struct
import os
import fcntl
import sys
import time
import signal
from signal import SIGINT

# where line-in resides
DEV_AUDIO = '/dev/audio1'

# need full path to sox for execv() later
CAPTURE_CMD = '/usr/bin/sox -c2 -w -r32000 -tossdsp %s -t wav -r 44100 -w -c 2 -' % DEV_AUDIO
#CAPTURE_CMD = '/usr/bin/sox -t ossdsp /dev/dsp -t .wav -r 44100 -c 2 -'
#ENCODE_CMD = '/usr/local/bin/lame -S --quiet --silent --lowpass 15000 - -'

#
# Get arguments.
#

try:
    frequency = float(sys.argv[1])
    minutes = int(sys.argv[2]) * 60
    path = sys.argv[3]
except:
    print '''Usage: %s frequency minutes output-path''' % sys.argv[0]
    sys.exit(1)

# Path can contain time.strftime inserts. 
# Example: /mp3s/cartalk/%Y-%m-%d

path = time.strftime(path)

# 
# Tune the radio
#

# constants from linux/videodev.h
VIDIOCGTUNER = 0xc0347604
VIDIOCGAUDIO = 0x80287610
VIDIOCSAUDIO = 0x40287611
VIDIOCSFREQ =  0x4004760f
VIDEO_AUDIO_MUTE = 1
VIDEO_TUNER_LOW =  8

# open the radio device
radio_fd = os.open('/dev/radio', os.O_RDONLY)

# detect kilohertz or megahertz
# MENTAL VIOLENCE: negate ioctl to workaround overflow bug in Python 2.4
video_tuner = fcntl.ioctl(radio_fd, ~int(~VIDIOCGTUNER & 0xFFFFFFFF), struct.pack("52x"))
tuner, name, rangelow, rangehigh, vtflags, mode, signal = struct.unpack("i 32s I I I H H", video_tuner)
if vtflags & VIDEO_TUNER_LOW:
    multiplier = 16000
else:
    multiplier = 16

# tune frequency
fcntl.ioctl(radio_fd, VIDIOCSFREQ, struct.pack("I", int(frequency * multiplier)))

# unmute
# MENTAL VIOLENCE: negate ioctl to workaround overflow bug in Python 2.4
video_audio = fcntl.ioctl(radio_fd, ~int(~VIDIOCGAUDIO & 0xFFFFFFFF), struct.pack("40x"))
audio, volume, bass, treble, vaflags, vaname, vamode, balance, step = struct.unpack("i H H H 2x I 16s H H H 2x", video_audio)
vaflags = vaflags & ~VIDEO_AUDIO_MUTE
video_audio = struct.pack("i H H H 2x I 16x H H H 2x", 0, volume, bass, treble, vaflags, vamode, balance, step)
fcntl.ioctl(radio_fd, VIDIOCSAUDIO, video_audio)

#
# Capture the uncompressed sound
#

uncompressed_file = open(path, 'wb');

try:
    pid = os.fork()
    if pid == 0:
        os.dup2(uncompressed_file.fileno(), 1)
        uncompressed_file.close()
        args = CAPTURE_CMD.split()
        os.execv(args[0], args)

    time.sleep(minutes)

finally:
    os.kill(pid, SIGINT)
    os.wait()

    # mute
    vaflags = vaflags | VIDEO_AUDIO_MUTE
    video_audio = struct.pack("i H H H 2x I 16x H H H 2x", 0, volume, bass, treble, vaflags, vamode, balance, step)
    fcntl.ioctl(radio_fd, VIDIOCSAUDIO, video_audio)

    # close
    os.close(radio_fd)  

#
# Compress the temporay file.
#
#
#uncompressed_file.seek(0)
#compressed_file = open(path, 'wb')
#
#os.dup2(uncompressed_file.fileno(), 0)
#os.dup2(compressed_file.fileno(), 1)
#
#uncompressed_file.close()
#compressed_file.close()
#
#os.nice(10)
#
# Set TERM environment variable to keep lame quiet.
#
#args = ENCODE_CMD.split()
#os.execve(args[0], args, { 'TERM': 'dumb' })