# Copyright (C) 2005, 2006 by Canonical Ltd

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA


"""Commit message editor support."""


import errno
import os
from subprocess import call
import sys

import bzrlib.config as config
from bzrlib.errors import BzrError


def _get_editor():
    """Return a sequence of possible editor binaries for the current platform"""
    try:
        yield os.environ["BZR_EDITOR"]
    except KeyError:
        pass

    e = config.GlobalConfig().get_editor()
    if e is not None:
        yield e
        
    try:
        yield os.environ["EDITOR"]
    except KeyError:
        pass

    if sys.platform == 'win32':
        for editor in 'wordpad.exe', 'notepad.exe':
            yield editor
    else:
        for editor in ['vi', 'pico', 'nano', 'joe']:
            yield editor


def _run_editor(filename):
    """Try to execute an editor to edit the commit message."""
    for e in _get_editor():
        edargs = e.split(' ')
        try:
            x = call(edargs + [filename])
        except OSError, e:
           # We're searching for an editor, so catch safe errors and continue
           if e.errno in (errno.ENOENT, ):
               continue
           raise
        if x == 0:
            return True
        elif x == 127:
            continue
        else:
            break
    raise BzrError("Could not start any editor.\nPlease specify one with:\n"
                   " - $BZR_EDITOR\n - editor=/some/path in %s\n - $EDITOR" % \
                    config.config_filename())


DEFAULT_IGNORE_LINE = "%(bar)s %(msg)s %(bar)s" % \
    { 'bar' : '-' * 14, 'msg' : 'This line and the following will be ignored' }


def edit_commit_message(infotext, ignoreline=DEFAULT_IGNORE_LINE):
    """Let the user edit a commit message in a temp file.

    This is run if they don't give a message or
    message-containing file on the command line.

    infotext:
        Text to be displayed at bottom of message for
        the user's reference; currently similar to
        'bzr status'.
    """
    import tempfile

    try:
        tmp_fileno, msgfilename = tempfile.mkstemp(prefix='bzr_log.', dir=u'.')
        msgfile = os.close(tmp_fileno)
        if infotext is not None and infotext != "":
            hasinfo = True
            msgfile = file(msgfilename, "w")
            msgfile.write("\n%s\n\n%s" % (ignoreline, infotext))
            msgfile.close()
        else:
            hasinfo = False

        if not _run_editor(msgfilename):
            return None
        
        started = False
        msg = []
        lastline, nlines = 0, 0
        for line in file(msgfilename, "r"):
            stripped_line = line.strip()
            # strip empty line before the log message starts
            if not started:
                if stripped_line != "":
                    started = True
                else:
                    continue
            # check for the ignore line only if there
            # is additional information at the end
            if hasinfo and stripped_line == ignoreline:
                break
            nlines += 1
            # keep track of the last line that had some content
            if stripped_line != "":
                lastline = nlines
            msg.append(line)
            
        if len(msg) == 0:
            return ""
        # delete empty lines at the end
        del msg[lastline:]
        # add a newline at the end, if needed
        if not msg[-1].endswith("\n"):
            return "%s%s" % ("".join(msg), "\n")
        else:
            return "".join(msg)
    finally:
        # delete the msg file in any case
        try: os.unlink(msgfilename)
        except IOError: pass


def make_commit_message_template(working_tree, specific_files):
    """Prepare a template file for a commit into a branch.

    Returns a unicode string containing the template.
    """
    # TODO: Should probably be given the WorkingTree not the branch
    #
    # TODO: make provision for this to be overridden or modified by a hook
    #
    # TODO: Rather than running the status command, should prepare a draft of
    # the revision to be committed, then pause and ask the user to
    # confirm/write a message.
    from StringIO import StringIO       # must be unicode-safe
    from bzrlib.status import show_tree_status
    status_tmp = StringIO()
    show_tree_status(working_tree, specific_files=specific_files, 
                     to_file=status_tmp)
    return status_tmp.getvalue()