# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""
Chop up shoutcast stream into MP3s and metadata, if available.
"""

from twisted.web import http
from twisted import copyright


class ShoutcastClient(http.HTTPClient):
"""
Shoutcast HTTP stream.

Modes can be 'length', 'meta' and 'mp3'.

See U{http://www.smackfu.com/stuff/programming/shoutcast.html}
for details on the protocol.
"""

userAgent = "Twisted Shoutcast client " + copyright.version

def __init__(self, path="/"):
self.path = path
self.got_metadata = False
self.metaint = None
self.metamode = "mp3"
self.databuffer = ""

def connectionMade(self):
self.sendCommand("GET", self.path)
self.sendHeader("User-Agent", self.userAgent)
self.sendHeader("Icy-MetaData", "1")
self.endHeaders()

def lineReceived(self, line):
# fix shoutcast crappiness
if not self.firstLine and line:
if len(line.split(": ", 1)) == 1:
line = line.replace(":", ": ", 1)
http.HTTPClient.lineReceived(self, line)

def handleHeader(self, key, value):
if key.lower() == 'icy-metaint':
self.metaint = int(value)
self.got_metadata = True

def handleEndHeaders(self):
# Lets check if we got metadata, and set the
# appropriate handleResponsePart method.
if self.got_metadata:
# if we have metadata, then it has to be parsed out of the data stream
self.handleResponsePart = self.handleResponsePart_with_metadata
else:
# otherwise, all the data is MP3 data
self.handleResponsePart = self.gotMP3Data

def handleResponsePart_with_metadata(self, data):
self.databuffer += data
while self.databuffer:
stop = getattr(self, "handle_%s" % self.metamode)()
if stop:
return

def handle_length(self):
self.remaining = ord(self.databuffer[0]) * 16
self.databuffer = self.databuffer[1:]
self.metamode = "meta"

def handle_mp3(self):
if len(self.databuffer) > self.metaint:
self.gotMP3Data(self.databuffer[:self.metaint])
self.databuffer = self.databuffer[self.metaint:]
self.metamode = "length"
else:
return 1

def handle_meta(self):
if len(self.databuffer) >= self.remaining:
if self.remaining:
data = self.databuffer[:self.remaining]
self.gotMetaData(self.parseMetadata(data))
self.databuffer = self.databuffer[self.remaining:]
self.metamode = "mp3"
else:
return 1

def parseMetadata(self, data):
meta = []
for chunk in data.split(';'):
chunk = chunk.strip().replace("\x00", "")
if not chunk:
continue
key, value = chunk.split('=', 1)
if value.startswith("'") and value.endswith("'"):
value = value[1:-1]
meta.append((key, value))
return meta

def gotMetaData(self, metadata):
"""Called with a list of (key, value) pairs of metadata,
if metadata is available on the server.

Will only be called on non-empty metadata.
"""
raise NotImplementedError, "implement in subclass"

def gotMP3Data(self, data):
"""Called with chunk of MP3 data."""
raise NotImplementedError, "implement in subclass"