import argparse
import os
import shlex
import subprocess
import sys
import tempfile

from voussoirkit import pipeable
from voussoirkit import subproctools
from voussoirkit import winwhich

class NoEditor(Exception):
    pass

class BadStatus(Exception):
    pass

def tempeditor(initial_text=None):
    editor = os.environ.get('EDITOR')
    if not editor:
        raise NoEditor('You do not have an EDITOR variable.')

    command = shlex.split(editor)
    command[0] = winwhich.which(command[0])

    file = tempfile.TemporaryFile('r+', encoding='utf-8', prefix='tempeditor-', delete=False)
    command.append(file.name)

    if initial_text:
        file.write(initial_text)

    # The text editor may not be allowed to write to the file while Python has
    # the file handle, so let's close it and re-open after the user is finished.
    file.close()

    status = subprocess.check_call(command)
    if status == 0:
        handle = open(file.name, 'r', encoding='utf-8')
        text = handle.read()
        handle.close()

    try:
        os.remove(file.name)
    except Exception:
        pass

    if status == 0:
        return text
    else:
        raise BadStatus(subproctools.format_command(command), status)

def tempeditor_argparse(args):
    initial_text = '\n'.join(pipeable.input(args.initial_text)) if args.initial_text else None
    try:
        text = tempeditor(initial_text=initial_text)
        pipeable.output(text)
        return 0
    except NoEditor as exc:
        pipeable.stderr(exc)
        return 1
    except BadStatus as exc:
        pipeable.stderr(f'Command {exc.args[0]} returned status {exc.args[1]}.')
        return 1

def main(argv):
    parser = argparse.ArgumentParser(description=__doc__)

    parser.add_argument('--text', dest='initial_text', default=None)
    parser.set_defaults(func=tempeditor_argparse)

    args = parser.parse_args(argv)
    return args.func(args)

if __name__ == '__main__':
    raise SystemExit(main(sys.argv[1:]))