#!/bin/bash

# Usage

if [[ -z "${1}" || "${1}" =~ ^(--help|-h)$ ]]; then tee <<done

    The MSYS2 Shell Manager 2016.6.22
    Copyright (C) 2016 Renato Silva
    Licensed under public domain

Usage: source $(basename "${0}") mingw32|mingw64|msys

    Switch between shells without restarting MSYS2. This is done by setting the
    MSYSTEM variable and sourcing /etc/profile. For interactive shells,
    ~/.bashrc is also sourced.

Usage: $(basename "${0}") COMMAND [ARGUMENTS]...

    Execute native Windows programs with better MSYS2 integration. This is done
    by using winpty to execute the Windows command prompt and commands from
    /mingw32, /mingw64 and the Windows system32 directory, enabling them to work
    better under MinTTY and similar terminals.

Usage: $(basename "${0}") DIRECTORY_OR_FILE...

    Open each specified directory or file using Windows Explorer. This is done
    by running one separate instance per argument, with paths converted to the
    expected backslash format.

done
    if [[ "${BASH_SOURCE}" = "${0}" ]]
        then exit 1
        else return 1
    fi
fi

# Argument validation

if [[ "${BASH_SOURCE}" != "${0}" && ! "${1}" =~ ^(mingw32|mingw64|msys)$ ]]; then
    echo "Unrecognized shell type ${1}"
    return 1
fi

if [[ "${BASH_SOURCE}" = "${0}" && "${1}" =~ ^(mingw32|mingw64|msys)$ ]]; then
    echo "Cannot switch to ${1} shell without sourcing"
    exit 1
fi

if [[ "${BASH_SOURCE}" = "${0}" && -z "$(type -t "${1}")" && ! -e "${1}" ]]; then
    echo "Could not find command ${1}"
    exit 1
fi

# Main section

if [[ "${BASH_SOURCE}" != "${0}" ]]; then
    _current_directory="$(pwd)"
    export MSYSTEM="${1^^}"
    source /etc/profile
    [[ "${-}" = *i* && -f ~/.bashrc ]] && source ~/.bashrc
    cd "${_current_directory}"
    unset _current_directory
    return 0
elif [[ (-f "${1}" && ! -x "${1}") || -d "${1}" ]]; then
    explorer="$(cygpath --windir)/explorer.exe"
    for path in "${@}"; do
        path="$(cygpath --windows "${path}")"
        test -e "${path}" && "${explorer}" "${path}"
    done
    exit 0
else
    command="$(type -P "${1}")"
    command="${command,,}"
    command="${command%.exe}"
    system32="$(cygpath --windir)/system32"
    system32="${system32,,}"
    case "${command}" in
        "${system32}"/*) winpty "${@}" || exit ;;
        /usr/bin/cmd)    winpty "${@}" || exit ;;
        /mingw32/*)      winpty "${@}" || exit ;;
        /mingw64/*)      winpty "${@}" || exit ;;
        *)                      "${@}" || exit ;;
    esac
    exit 0
fi