#!/usr/bin/python

# (C) 2005 Canonical Ltd.
# Author: Martin Pitt <martin.pitt@email-addr-hidden>
# License: GNU General Public License, version 2 or any later version
#
# Modified by: Thomas Hood
#
# Get and set configuration parameters in ~/.asoundrc.asoundconf.

import sys, re, os.path

our_conf_file = os.path.expanduser('~/.asoundrc.asoundconf')
asoundrc_file = os.path.expanduser('~/.asoundrc')

setting_re_template = '!?\s*%s\s*(?:=|\s)\s*([^;,]+)[;,]?$'

our_conf_header = '''# ALSA library configuration file managed by asoundconf(1).
#
# MANUAL CHANGES TO THIS FILE WILL BE OVERWRITTEN!
#
# Manual changes to the ALSA library configuration should be implemented
# by editing the ~/.asoundrc file, not by editing this file.
'''

asoundrc_header = '''# ALSA library configuration file
'''

inclusion_comment = '''# Include settings that are under the control of asoundconf(1).
# (To disable these settings, comment out this line.)'''

usage = '''Usage:
asoundconf is-active
asoundconf get|delete PARAMETER
asoundconf set PARAMETER VALUE
asoundconf list
'''


def help(): 
	print usage


def ensure_our_conf_exists():
    '''If it does not exist then generate a default configuration
    file with no settings.

    Return: True on success, False if the file could not be created.
    '''

    if os.path.exists(our_conf_file):
        return True

    try:
        open(our_conf_file, 'w').write(our_conf_header)
        return True
    except IOError:
        print >> sys.stderr, 'Error: could not create', our_conf_file
        return False


def ensure_asound_rc_exists():
    '''Generate a default user configuration file with only the
    inclusion line.

    Return: True on success, False if the file could not be created.
    '''

    if os.path.exists(asoundrc_file):
        return True

    try:
        open(asoundrc_file, 'w').write('%s\n%s\n<%s>\n\n' % (asoundrc_header, inclusion_comment, our_conf_file))
        return True
    except IOError:
        print >> sys.stderr, 'Error: could not create', asoundrc_file
        return False


def sds_transition():
    '''Replace the magic comments added to the user configuration file
    by the obsolete set-default-soundcard program with the standard
    inclusion statement for our configuration file.
    '''

    if not os.path.exists(asoundrc_file):
        return

    lines = open(asoundrc_file).readlines()

    start_marker_re = re.compile('### BEGIN set-default-soundcard')
    end_marker_re = re.compile('### END set-default-soundcard')

    userconf_lines = []
    our_conf_lines = []

    # read up to start comment
    lineno = 0
    found = 0
    for l in lines:
        lineno = lineno+1
        if start_marker_re.match(l):
            found = 1
            break
        userconf_lines.append(l)

    if found:
        # replace magic comment section with include
        userconf_lines.append('%s\n<%s>\n\n' % (inclusion_comment, our_conf_file))
    else:
        # no magic comment
        return

    # read magic comment section until end marker and add it to asoundconf
    found = 0
    for l in lines[lineno:]:
        lineno = lineno+1
        if end_marker_re.match(l):
            found = 1
            break
        if not l.startswith('#'):
            our_conf_lines.append(l)

    if not found:
        # no complete magic comment
        return

    # add the rest to user conf
    userconf_lines = userconf_lines + lines[lineno:]

    # write our configuration file
    if not ensure_our_conf_exists():
        return
    try:
        open(our_conf_file, 'a').writelines(our_conf_lines)
    except IOError:
        return # panic out

    # write user configuration file
    try:
        open(asoundrc_file, 'w').writelines(userconf_lines)
    except IOError:
        pass


def is_active():
    '''Check whether or not the user configuration file includes the
    asoundconf configuration file (so that the latter is "active").

    Also transition from the legacy set-default-soundcard program.

    Return True if active, False if not.
    '''

    if not os.path.exists(asoundrc_file):
	return True

    sds_transition()

    # check whether or not the file has the inclusion line
    include_re = re.compile('\s*<\s*%s\s*>' % our_conf_file)
    for l in open(asoundrc_file):
        if include_re.match(l):
            return True

    return False

def get(prmtr):
    '''Print the value of the given parameter on stdout

    Also transition from the legacy set-default-soundcard program.

    Return True on success, and False if the value is not set.
    '''

    sds_transition()

    if not os.path.exists(our_conf_file):
        return False

    setting_re = re.compile(setting_re_template % prmtr)

    try:
        for line in open(our_conf_file):
            m = setting_re.match(line)
            if m:
                print m.group(1).strip()
                return True
        return False
    except IOError:
        return False

def list():
	'''Get card names from /proc/asound/cards'''

	cardspath = '/proc/asound/cards'
	if not os.path.exists(cardspath):
		return False
	procfile = open(cardspath, 'rb')
	cardline = re.compile('^\d+\s*\[')
	card_lines = []
	lines = procfile.readlines()
	for l in lines:
		if cardline.match(l):
			card_lines.append(re.sub(r'^\d+\s*\[(\w+)\s*\].+','\\1',l))
	print "Names of available sound cards:"
	for cardname in card_lines:
		print cardname.strip()
	return True

def delete(prmtr):
    '''Delete the given parameter.

    Also transition from the legacy set-default-soundcard program.

    Return True on success, and False on an error.
    '''

    sds_transition()

    if not os.path.exists(our_conf_file):
        return False

    setting_re = re.compile(setting_re_template % prmtr)
    lines = []
    try:
        lines = open(our_conf_file).readlines()
    except IOError:
        return False

    found = 0
    for i in xrange(len(lines)):
        if setting_re.match(lines[i]):
            del lines[i]
            found = 1
            break

    if found:
        # write back file
        try:
            f = open(our_conf_file, 'w')
        except IOError:
            return False
        f.writelines(lines)

    return True


def set(prmtr, value):
    '''Set the given parameter to the given value

    Also transition from the legacy set-default-soundcard program.

    Return True on success, and False on an error.
    '''

    sds_transition()

    setting_re = re.compile(setting_re_template % prmtr)
    lines = []

    ensure_asound_rc_exists()
    # N.B. We continue even if asoundrc could not be created
    # and we do NOT ensure that our configuration is "active"

    if not ensure_our_conf_exists():
        return False

    try:
        lines = open(our_conf_file).readlines()
    except IOError:
        return False

    if value.isdigit():
        newsetting = '%s %s\n' % (prmtr, value)
    else:
        newsetting = '!%s %s\n' % (prmtr, value)

    # if setting is already present, change it
    found = 0
    for i in xrange(len(lines)):
        if setting_re.match(lines[i]):
            lines[i] = newsetting
            found = 1
            break

    if not found:
        lines.append(newsetting)

    # write back file
    try:
        f = open(our_conf_file, 'w')
    except IOError:
        return False
    f.writelines(lines)
    return True


def exit_code(result):
    '''Exit program with code 0 if result is True, otherwise exit with code
    1.
    '''

    if result:
        sys.exit(0)
    else:
        sys.exit(1)


##
## main
##

if len(sys.argv) < 2 or sys.argv[1] == '--help' or sys.argv[1] == '-h':
        help()
        sys.exit(0)

if sys.argv[1] == 'is-active':
    exit_code(is_active())

if sys.argv[1] == 'get':
    if len(sys.argv) != 3:
        help()
        sys.exit(1)
    exit_code(get(sys.argv[2]))

if sys.argv[1] == 'delete':
    if len(sys.argv) != 3:
        help()
        sys.exit(1)
    exit_code(delete(sys.argv[2]))

if sys.argv[1] == 'set':
    if len(sys.argv) != 4:
        help()
        sys.exit(1)
    exit_code(set(sys.argv[2], sys.argv[3]))

if sys.argv[1] == 'list':
	exit_code(list())

help()
sys.exit(1)