#!/usr/bin/env bash

# Use python's argparse module in shell scripts

#

# The function `argparse` parses its arguments using

# argparse.ArgumentParser; the parser is defined in the function's

# stdin.

#

# Executing ``argparse.bash`` (as opposed to sourcing it) prints a

# script template.

#

# https://github.com/nhoffman/argparse-bash

# MIT License - Copyright (c) 2015 Noah Hoffman

#

# The MIT License (MIT)

#

# Copyright (c) 2015 Noah Hoffman

#

# Permission is hereby granted, free of charge, to any person obtaining a copy

# of this software and associated documentation files (the "Software"), to deal

# in the Software without restriction, including without limitation the rights

# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

# copies of the Software, and to permit persons to whom the Software is

# furnished to do so, subject to the following conditions:

#

# The above copyright notice and this permission notice shall be included in

# all copies or substantial portions of the Software.

#

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

# THE SOFTWARE.

argparse(){

    argparser=$(mktemp 2>/dev/null || mktemp -t argparser)

    cat > "$argparser" <<EOF

from __future__ import print_function

import argparse

import os

import sys

class MyArgumentParser(argparse.ArgumentParser):

    def print_help(self, file=None):

        """Print help and exit with error"""

        super(MyArgumentParser, self).print_help(file=file)

        sys.exit(1)

parser = MyArgumentParser(prog=os.path.basename("$0"),

            description="""$ARGPARSE_DESCRIPTION""")

EOF

    # stdin to this function should contain the parser definition

    cat >> "$argparser"

    cat >> "$argparser" <<EOF

args = parser.parse_args()

for arg in [a for a in dir(args) if not a.startswith('_')]:

    key = arg.upper()

    value = getattr(args, arg, None)

    if isinstance(value, bool) or value is None:

        print('{0}="{1}";'.format(key, 'yes' if value else ''))

    elif isinstance(value, list):

        print('{0}=({1});'.format(key, ' '.join('"{0}"'.format(s) for s in value)))

    else:

        print('{0}="{1}";'.format(key, value))

EOF

    # Define variables corresponding to the options if the args can be

    # parsed without errors; otherwise, print the text of the error

    # message.

    if python "$argparser" "$@" &> /dev/null; then

        eval $(python "$argparser" "$@")

        retval=0

    else

        python "$argparser" "$@"

        retval=1

    fi

    rm "$argparser"

    return $retval

}

# print a script template when this script is executed

if [[ $0 == *argparse.bash ]]; then

    cat <<FOO

#!/usr/bin/env bash

source \$(dirname \$0)/argparse.bash || exit 1

argparse "\$@" <<EOF || exit 1

parser.add_argument('infile')

parser.add_argument('-o', '--outfile')

EOF

echo "INFILE: \${INFILE}"

echo "OUTFILE: \${OUTFILE}"

FOO

fi