"""MH interface -- purely object-oriented (well, almost)

Executive summary:

import mhlib

mh = mhlib.MH()         # use default mailbox directory and profile

mh = mhlib.MH(mailbox)  # override mailbox location (default from profile)

mh = mhlib.MH(mailbox, profile) # override mailbox and profile

mh.error(format, ...)   # print error message -- can be overridden

s = mh.getprofile(key)  # profile entry (None if not set)

path = mh.getpath()     # mailbox pathname

name = mh.getcontext()  # name of current folder

mh.setcontext(name)     # set name of current folder

list = mh.listfolders() # names of top-level folders

list = mh.listallfolders() # names of all folders, including subfolders

list = mh.listsubfolders(name) # direct subfolders of given folder

list = mh.listallsubfolders(name) # all subfolders of given folder

mh.makefolder(name)     # create new folder

mh.deletefolder(name)   # delete folder -- must have no subfolders

f = mh.openfolder(name) # new open folder object

f.error(format, ...)    # same as mh.error(format, ...)

path = f.getfullname()  # folder's full pathname

path = f.getsequencesfilename() # full pathname of folder's sequences file

path = f.getmessagefilename(n)  # full pathname of message n in folder

list = f.listmessages() # list of messages in folder (as numbers)

n = f.getcurrent()      # get current message

f.setcurrent(n)         # set current message

list = f.parsesequence(seq)     # parse msgs syntax into list of messages

n = f.getlast()         # get last message (0 if no messagse)

f.setlast(n)            # set last message (internal use only)

dict = f.getsequences() # dictionary of sequences in folder {name: list}

f.putsequences(dict)    # write sequences back to folder

f.createmessage(n, fp)  # add message from file f as number n

f.removemessages(list)  # remove messages in list from folder

f.refilemessages(list, tofolder) # move messages in list to other folder

f.movemessage(n, tofolder, ton)  # move one message to a given destination

f.copymessage(n, tofolder, ton)  # copy one message to a given destination

m = f.openmessage(n)    # new open message object (costs a file descriptor)

m is a derived class of mimetools.Message(rfc822.Message), with:

s = m.getheadertext()   # text of message's headers

s = m.getheadertext(pred) # text of message's headers, filtered by pred

s = m.getbodytext()     # text of message's body, decoded

s = m.getbodytext(0)    # text of message's body, not decoded

"""

# XXX To do, functionality:

# - annotate messages

# - send messages

#

# XXX To do, organization:

# - move IntSet to separate file

# - move most Message functionality to module mimetools

# Customizable defaults

MH_PROFILE = '~/.mh_profile'

PATH = '~/Mail'

MH_SEQUENCES = '.mh_sequences'

FOLDER_PROTECT = 0700

# Imported modules

import os

import sys

import re

import mimetools

import multifile

import shutil

from bisect import bisect

__all__ = ["MH","Error","Folder","Message"]

# Exported constants

class Error(Exception):

    pass

class MH:

    """Class representing a particular collection of folders.

    Optional constructor arguments are the pathname for the directory

    containing the collection, and the MH profile to use.

    If either is omitted or empty a default is used; the default

    directory is taken from the MH profile if it is specified there."""

    def __init__(self, path = None, profile = None):

        """Constructor."""

        if profile is None: profile = MH_PROFILE

        self.profile = os.path.expanduser(profile)

        if path is None: path = self.getprofile('Path')

        if not path: path = PATH

        if not os.path.isabs(path) and path[0] != '~':

            path = os.path.join('~', path)

        path = os.path.expanduser(path)

        if not os.path.isdir(path): raise Error, 'MH() path not found'

        self.path = path

    def __repr__(self):

        """String representation."""

        return 'MH(%r, %r)' % (self.path, self.profile)

    def error(self, msg, *args):

        """Routine to print an error.  May be overridden by a derived class."""

        sys.stderr.write('MH error: %s\n' % (msg % args))

    def getprofile(self, key):

        """Return a profile entry, None if not found."""

        return pickline(self.profile, key)

    def getpath(self):

        """Return the path (the name of the collection's directory)."""

        return self.path

    def getcontext(self):

        """Return the name of the current folder."""

        context = pickline(os.path.join(self.getpath(), 'context'),

                  'Current-Folder')

        if not context: context = 'inbox'

        return context

    def setcontext(self, context):

        """Set the name of the current folder."""

        fn = os.path.join(self.getpath(), 'context')

        f = open(fn, "w")

        f.write("Current-Folder: %s\n" % context)

        f.close()

    def listfolders(self):

        """Return the names of the top-level folders."""

        folders = []

        path = self.getpath()

        for name in os.listdir(path):

            fullname = os.path.join(path, name)

            if os.path.isdir(fullname):

                folders.append(name)

        folders.sort()

        return folders

    def listsubfolders(self, name):

        """Return the names of the subfolders in a given folder

        (prefixed with the given folder name)."""

        fullname = os.path.join(self.path, name)

        # Get the link count so we can avoid listing folders

        # that have no subfolders.

        nlinks = os.stat(fullname).st_nlink

        if nlinks <= 2:

            return []

        subfolders = []

        subnames = os.listdir(fullname)

        for subname in subnames:

            fullsubname = os.path.join(fullname, subname)

            if os.path.isdir(fullsubname):

                name_subname = os.path.join(name, subname)

                subfolders.append(name_subname)

                # Stop looking for subfolders when

                # we've seen them all

                nlinks = nlinks - 1

                if nlinks <= 2:

                    break

        subfolders.sort()

        return subfolders

    def listallfolders(self):

        """Return the names of all folders and subfolders, recursively."""

        return self.listallsubfolders('')

    def listallsubfolders(self, name):

        """Return the names of subfolders in a given folder, recursively."""

        fullname = os.path.join(self.path, name)

        # Get the link count so we can avoid listing folders

        # that have no subfolders.

        nlinks = os.stat(fullname).st_nlink

        if nlinks <= 2:

            return []

        subfolders = []

        subnames = os.listdir(fullname)

        for subname in subnames:

            if subname[0] == ',' or isnumeric(subname): continue

            fullsubname = os.path.join(fullname, subname)

            if os.path.isdir(fullsubname):

                name_subname = os.path.join(name, subname)

                subfolders.append(name_subname)

                if not os.path.islink(fullsubname):

                    subsubfolders = self.listallsubfolders(

                              name_subname)

                    subfolders = subfolders + subsubfolders

                # Stop looking for subfolders when

                # we've seen them all

                nlinks = nlinks - 1

                if nlinks <= 2:

                    break

        subfolders.sort()

        return subfolders

    def openfolder(self, name):

        """Return a new Folder object for the named folder."""

        return Folder(self, name)

    def makefolder(self, name):

        """Create a new folder (or raise os.error if it cannot be created)."""

        protect = pickline(self.profile, 'Folder-Protect')

        if protect and isnumeric(protect):

            mode = int(protect, 8)

        else:

            mode = FOLDER_PROTECT

        os.mkdir(os.path.join(self.getpath(), name), mode)

    def deletefolder(self, name):

        """Delete a folder.  This removes files in the folder but not

        subdirectories.  Raise os.error if deleting the folder itself fails."""

        fullname = os.path.join(self.getpath(), name)

        for subname in os.listdir(fullname):

            fullsubname = os.path.join(fullname, subname)

            try:

                os.unlink(fullsubname)

            except os.error:

                self.error('%s not deleted, continuing...' %

                          fullsubname)

        os.rmdir(fullname)

numericprog = re.compile('^[1-9][0-9]*$')

def isnumeric(str):

    return numericprog.match(str) is not None

class Folder:

    """Class representing a particular folder."""

    def __init__(self, mh, name):

        """Constructor."""

        self.mh = mh

        self.name = name

        if not os.path.isdir(self.getfullname()):

            raise Error, 'no folder %s' % name

    def __repr__(self):

        """String representation."""

        return 'Folder(%r, %r)' % (self.mh, self.name)

    def error(self, *args):

        """Error message handler."""

        self.mh.error(*args)

    def getfullname(self):

        """Return the full pathname of the folder."""

        return os.path.join(self.mh.path, self.name)

    def getsequencesfilename(self):

        """Return the full pathname of the folder's sequences file."""

        return os.path.join(self.getfullname(), MH_SEQUENCES)

    def getmessagefilename(self, n):

        """Return the full pathname of a message in the folder."""

        return os.path.join(self.getfullname(), str(n))

    def listsubfolders(self):

        """Return list of direct subfolders."""

        return self.mh.listsubfolders(self.name)

    def listallsubfolders(self):

        """Return list of all subfolders."""

        return self.mh.listallsubfolders(self.name)

    def listmessages(self):

        """Return the list of messages currently present in the folder.

        As a side effect, set self.last to the last message (or 0)."""

        messages = []

        match = numericprog.match

        append = messages.append

        for name in os.listdir(self.getfullname()):

            if match(name):

                append(name)

        messages = map(int, messages)

        messages.sort()

        if messages:

            self.last = messages[-1]

        else:

            self.last = 0

        return messages

    def getsequences(self):

        """Return the set of sequences for the folder."""

        sequences = {}

        fullname = self.getsequencesfilename()

        try:

            f = open(fullname, 'r')

        except IOError:

            return sequences

        while 1:

            line = f.readline()

            if not line: break

            fields = line.split(':')

            if len(fields) != 2:

                self.error('bad sequence in %s: %s' %

                          (fullname, line.strip()))

            key = fields[0].strip()

            value = IntSet(fields[1].strip(), ' ').tolist()

            sequences[key] = value

        return sequences

    def putsequences(self, sequences):

        """Write the set of sequences back to the folder."""

        fullname = self.getsequencesfilename()

        f = None

        for key, seq in sequences.iteritems():

            s = IntSet('', ' ')

            s.fromlist(seq)

            if not f: f = open(fullname, 'w')

            f.write('%s: %s\n' % (key, s.tostring()))

        if not f:

            try:

                os.unlink(fullname)

            except os.error:

                pass

        else:

            f.close()

    def getcurrent(self):

        """Return the current message.  Raise Error when there is none."""

        seqs = self.getsequences()

        try:

            return max(seqs['cur'])

        except (ValueError, KeyError):

            raise Error, "no cur message"

    def setcurrent(self, n):

        """Set the current message."""

        updateline(self.getsequencesfilename(), 'cur', str(n), 0)

    def parsesequence(self, seq):

        """Parse an MH sequence specification into a message list.

        Attempt to mimic mh-sequence(5) as close as possible.

        Also attempt to mimic observed behavior regarding which

        conditions cause which error messages."""

        # XXX Still not complete (see mh-format(5)).

        # Missing are:

        # - 'prev', 'next' as count

        # - Sequence-Negation option

        all = self.listmessages()

        # Observed behavior: test for empty folder is done first

        if not all:

            raise Error, "no messages in %s" % self.name

        # Common case first: all is frequently the default

        if seq == 'all':

            return all

        # Test for X:Y before X-Y because 'seq:-n' matches both

        i = seq.find(':')

        if i >= 0:

            head, dir, tail = seq[:i], '', seq[i+1:]

            if tail[:1] in '-+':

                dir, tail = tail[:1], tail[1:]

            if not isnumeric(tail):

                raise Error, "bad message list %s" % seq

            try:

                count = int(tail)

            except (ValueError, OverflowError):

                # Can't use sys.maxint because of i+count below

                count = len(all)

            try:

                anchor = self._parseindex(head, all)

            except Error, msg:

                seqs = self.getsequences()

                if not head in seqs:

                    if not msg:

                        msg = "bad message list %s" % seq

                    raise Error, msg, sys.exc_info()[2]

                msgs = seqs[head]

                if not msgs:

                    raise Error, "sequence %s empty" % head

                if dir == '-':

                    return msgs[-count:]

                else:

                    return msgs[:count]

            else:

                if not dir:

                    if head in ('prev', 'last'):

                        dir = '-'

                if dir == '-':

                    i = bisect(all, anchor)

                    return all[max(0, i-count):i]

                else:

                    i = bisect(all, anchor-1)

                    return all[i:i+count]

        # Test for X-Y next

        i = seq.find('-')

        if i >= 0:

            begin = self._parseindex(seq[:i], all)

            end = self._parseindex(seq[i+1:], all)

            i = bisect(all, begin-1)

            j = bisect(all, end)

            r = all[i:j]

            if not r:

                raise Error, "bad message list %s" % seq

            return r

        # Neither X:Y nor X-Y; must be a number or a (pseudo-)sequence

        try:

            n = self._parseindex(seq, all)

        except Error, msg:

            seqs = self.getsequences()

            if not seq in seqs:

                if not msg:

                    msg = "bad message list %s" % seq

                raise Error, msg

            return seqs[seq]

        else:

            if n not in all:

                if isnumeric(seq):

                    raise Error, "message %d doesn't exist" % n

                else:

                    raise Error, "no %s message" % seq

            else:

                return [n]

    def _parseindex(self, seq, all):

        """Internal: parse a message number (or cur, first, etc.)."""

        if isnumeric(seq):

            try:

                return int(seq)

            except (OverflowError, ValueError):

                return sys.maxint

        if seq in ('cur', '.'):

            return self.getcurrent()

        if seq == 'first':

            return all[0]

        if seq == 'last':

            return all[-1]

        if seq == 'next':

            n = self.getcurrent()

            i = bisect(all, n)

            try:

                return all[i]

            except IndexError:

                raise Error, "no next message"

        if seq == 'prev':

            n = self.getcurrent()

            i = bisect(all, n-1)

            if i == 0:

                raise Error, "no prev message"

            try:

                return all[i-1]

            except IndexError:

                raise Error, "no prev message"

        raise Error, None

    def openmessage(self, n):

        """Open a message -- returns a Message object."""

        return Message(self, n)

    def removemessages(self, list):

        """Remove one or more messages -- may raise os.error."""

        errors = []

        deleted = []

        for n in list:

            path = self.getmessagefilename(n)

            commapath = self.getmessagefilename(',' + str(n))

            try:

                os.unlink(commapath)

            except os.error:

                pass

            try:

                os.rename(path, commapath)

            except os.error, msg:

                errors.append(msg)

            else:

                deleted.append(n)

        if deleted:

            self.removefromallsequences(deleted)

        if errors:

            if len(errors) == 1:

                raise os.error, errors[0]

            else:

                raise os.error, ('multiple errors:', errors)

    def refilemessages(self, list, tofolder, keepsequences=0):

        """Refile one or more messages -- may raise os.error.

        'tofolder' is an open folder object."""

        errors = []

        refiled = {}

        for n in list:

            ton = tofolder.getlast() + 1

            path = self.getmessagefilename(n)

            topath = tofolder.getmessagefilename(ton)

            try:

                os.rename(path, topath)

            except os.error:

                # Try copying

                try:

                    shutil.copy2(path, topath)

                    os.unlink(path)

                except (IOError, os.error), msg:

                    errors.append(msg)

                    try:

                        os.unlink(topath)

                    except os.error:

                        pass

                    continue

            tofolder.setlast(ton)

            refiled[n] = ton

        if refiled:

            if keepsequences:

                tofolder._copysequences(self, refiled.items())

            self.removefromallsequences(refiled.keys())

        if errors:

            if len(errors) == 1:

                raise os.error, errors[0]

            else:

                raise os.error, ('multiple errors:', errors)

    def _copysequences(self, fromfolder, refileditems):

        """Helper for refilemessages() to copy sequences."""

        fromsequences = fromfolder.getsequences()

        tosequences = self.getsequences()

        changed = 0

        for name, seq in fromsequences.items():

            try:

                toseq = tosequences[name]