# Bugs Everywhere, a distributed bugtracker
# Copyright (C) 2008-2009 W. Trevor King <wking@drexel.edu>
#
# 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.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

"""
Define editor_string(), a function that invokes an editor to accept
user-produced text as a string.
"""

import codecs
import locale
import os
import sys
import tempfile
import doctest


default_encoding = sys.getfilesystemencoding() or locale.getpreferredencoding()

comment_marker = u"== Anything below this line will be ignored\n"

class CantFindEditor(Exception):
    def __init__(self):
        Exception.__init__(self, "Can't find editor to get string from")

def editor_string(comment=None, encoding=None):
    """Invokes the editor, and returns the user-produced text as a string

    >>> if "EDITOR" in os.environ:
    ...     del os.environ["EDITOR"]
    >>> if "VISUAL" in os.environ:
    ...     del os.environ["VISUAL"]
    >>> editor_string()
    Traceback (most recent call last):
    CantFindEditor: Can't find editor to get string from
    >>> os.environ["EDITOR"] = "echo bar > "
    >>> editor_string()
    u'bar\\n'
    >>> os.environ["VISUAL"] = "echo baz > "
    >>> editor_string()
    u'baz\\n'
    >>> del os.environ["EDITOR"]
    >>> del os.environ["VISUAL"]
    """
    if encoding == None:
        encoding = default_encoding
    for name in ('VISUAL', 'EDITOR'):
        try:
            editor = os.environ[name]
            break
        except KeyError:
            pass
    else:
        raise CantFindEditor()
    fhandle, fname = tempfile.mkstemp()
    try:
        if comment is not None:
            cstring = u'\n'+comment_string(comment)
            os.write(fhandle, cstring.encode(encoding))
        os.close(fhandle)
        oldmtime = os.path.getmtime(fname)
        os.system("%s %s" % (editor, fname))
        f = codecs.open(fname, "r", encoding)
        output = trimmed_string(f.read())
        f.close()
        if output.rstrip('\n') == "":
            output = None
    finally:
        os.unlink(fname)
    return output


def comment_string(comment):
    """
    >>> comment_string('hello') == comment_marker+"hello"
    True
    """
    return comment_marker + comment


def trimmed_string(instring):
    """
    >>> trimmed_string("hello\\n"+comment_marker)
    u'hello\\n'
    >>> trimmed_string("hi!\\n" + comment_string('Booga'))
    u'hi!\\n'
    """
    out = []
    for line in instring.splitlines(True):
        if line.startswith(comment_marker):
            break
        out.append(line)
    return ''.join(out)

suite = doctest.DocTestSuite()