"""Various tools used by MIME-reading or MIME-writing programs."""


import os
import sys
import tempfile
from warnings import filterwarnings, catch_warnings
with catch_warnings():
    if sys.py3kwarning:
        filterwarnings("ignore", ".*rfc822 has been removed", DeprecationWarning)
    import rfc822

from warnings import warnpy3k
warnpy3k("in 3.x, mimetools has been removed in favor of the email package",
         stacklevel=2)

__all__ = ["Message","choose_boundary","encode","decode","copyliteral",
           "copybinary"]

class Message(rfc822.Message):
    """A derived class of rfc822.Message that knows about MIME headers and
    contains some hooks for decoding encoded and multipart messages."""

    def __init__(self, fp, seekable = 1):
        rfc822.Message.__init__(self, fp, seekable)
        self.encodingheader = \
                self.getheader('content-transfer-encoding')
        self.typeheader = \
                self.getheader('content-type')
        self.parsetype()
        self.parseplist()

    def parsetype(self):
        str = self.typeheader
        if str is None:
            str = 'text/plain'
        if ';' in str:
            i = str.index(';')
            self.plisttext = str[i:]
            str = str[:i]
        else:
            self.plisttext = ''
        fields = str.split('/')
        for i in range(len(fields)):
            fields[i] = fields[i].strip().lower()
        self.type = '/'.join(fields)
        self.maintype = fields[0]
        self.subtype = '/'.join(fields[1:])

    def parseplist(self):
        str = self.plisttext
        self.plist = []
        while str[:1] == ';':
            str = str[1:]
            if ';' in str:
                # XXX Should parse quotes!
                end = str.index(';')
            else:
                end = len(str)
            f = str[:end]
            if '=' in f:
                i = f.index('=')
                f = f[:i].strip().lower() + \
                        '=' + f[i+1:].strip()
            self.plist.append(f.strip())
            str = str[end:]

    def getplist(self):
        return self.plist

    def getparam(self, name):
        name = name.lower() + '='
        n = len(name)
        for p in self.plist:
            if p[:n] == name:
                return rfc822.unquote(p[n:])
        return None

    def getparamnames(self):
        result = []
        for p in self.plist:
            i = p.find('=')
            if i >= 0:
                result.append(p[:i].lower())
        return result

    def getencoding(self):
        if self.encodingheader is None:
            return '7bit'
        return self.encodingheader.lower()

    def gettype(self):
        return self.type

    def getmaintype(self):
        return self.maintype

    def getsubtype(self):
        return self.subtype




# Utility functions
# -----------------

#try:
import thread
#except ImportError:
#    import dummy_thread as thread
_counter_lock = thread.allocate_lock()
del thread

_counter = 0
def _get_next_counter():
    global _counter
    _counter_lock.acquire()
    _counter += 1
    result = _counter
    _counter_lock.release()
    return result

_prefix = None

#def choose_boundary():
#    """Return a string usable as a multipart boundary.
#
#    The string chosen is unique within a single program run, and
#    incorporates the user id (if available), process id (if available),
#    and current time.  So it's very unlikely the returned string appears
#    in message text, but there's no guarantee.
#
#    The boundary contains dots so you have to quote it in the header."""
#
#    global _prefix
#    import time
#    if _prefix is None:
#        import socket
#        try:
#            hostid = socket.gethostbyname(socket.gethostname())
#        except socket.gaierror:
#            hostid = '127.0.0.1'
#        try:
#            uid = repr(os.getuid())
#        except AttributeError:
#            uid = '1'
#        try:
#            pid = repr(os.getpid())
#        except AttributeError:
#            pid = '1'
#        _prefix = hostid + '.' + uid + '.' + pid
#    return "%s.%.3f.%d" % (_prefix, time.time(), _get_next_counter())


# Subroutines for decoding some common content-transfer-types

def decode(input, output, encoding):
    """Decode common content-transfer-encodings (base64, quopri, uuencode)."""
    if encoding == 'base64':
        import base64
        return base64.decode(input, output)
    if encoding == 'quoted-printable':
        import quopri
        return quopri.decode(input, output)
    if encoding in ('uuencode', 'x-uuencode', 'uue', 'x-uue'):
        import uu
        return uu.decode(input, output)
    if encoding in ('7bit', '8bit'):
        return output.write(input.read())
    if encoding in decodetab:
        pipethrough(input, decodetab[encoding], output)
    else:
        raise ValueError, \
              'unknown Content-Transfer-Encoding: %s' % encoding

def encode(input, output, encoding):
    """Encode common content-transfer-encodings (base64, quopri, uuencode)."""
    if encoding == 'base64':
        import base64
        return base64.encode(input, output)
    if encoding == 'quoted-printable':
        import quopri
        return quopri.encode(input, output, 0)
    if encoding in ('uuencode', 'x-uuencode', 'uue', 'x-uue'):
        import uu
        return uu.encode(input, output)
    if encoding in ('7bit', '8bit'):
        return output.write(input.read())
    if encoding in encodetab:
        pipethrough(input, encodetab[encoding], output)
    else:
        raise ValueError, \
              'unknown Content-Transfer-Encoding: %s' % encoding

# The following is no longer used for standard encodings

# XXX This requires that uudecode and mmencode are in $PATH

uudecode_pipe = '''(
TEMP=/tmp/@uu.$$
sed "s%^begin [0-7][0-7]* .*%begin 600 $TEMP%" | uudecode
cat $TEMP
rm $TEMP
)'''

decodetab = {
        'uuencode':             uudecode_pipe,
        'x-uuencode':           uudecode_pipe,
        'uue':                  uudecode_pipe,
        'x-uue':                uudecode_pipe,
        'quoted-printable':     'mmencode -u -q',
        'base64':               'mmencode -u -b',
}

encodetab = {
        'x-uuencode':           'uuencode tempfile',
        'uuencode':             'uuencode tempfile',
        'x-uue':                'uuencode tempfile',
        'uue':                  'uuencode tempfile',
        'quoted-printable':     'mmencode -q',
        'base64':               'mmencode -b',
}

def pipeto(input, command):
    pipe = os.popen(command, 'w')
    copyliteral(input, pipe)
    pipe.close()

def pipethrough(input, command, output):
    (fd, tempname) = tempfile.mkstemp()
    temp = os.fdopen(fd, 'w')
    copyliteral(input, temp)
    temp.close()
    pipe = os.popen(command + ' <' + tempname, 'r')
    copybinary(pipe, output)
    pipe.close()
    os.unlink(tempname)

def copyliteral(input, output):
    while 1:
        line = input.readline()
        if not line: break
        output.write(line)

def copybinary(input, output):
    BUFSIZE = 8192
    while 1:
        line = input.read(BUFSIZE)
        if not line: break
        output.write(line)
