#!/bin/bash
#
# script-name
# Author <email@example.com> 2020-02-02
# Last updated 2025-10-03
#
# Quick description of what the script does.
#
###############################################################################
#
# This script: (license)
#
# Copyright (C) 2025 whoever
#
# Details about this script's licensing
#
###############################################################################
#
# Original script template: MIT License
#
# Copyright (C) 2025 John Simpson
#
# 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.
#
###############################################################################

set -e

PATH="/usr/bin:/bin"

########################################
# Global variables
#   MYDIR   '/Users/jms1/bin'
#   MYNAME  'xyzzy'
#   MYSELF  '/Users/jms1/bin/xyzzy'

MYDIR="$( cd -- "$( dirname -- "$0" )" >/dev/null 2>&1 ; pwd -P )"
MYNAME="$( basename -- "$0" )"
MYSELF="$MYDIR/$MYNAME"

########################################
# Directories used by the script itself
# https://specifications.freedesktop.org/basedir-spec/latest/

CACHE_DIR="${XDG_CACHE_HOME:-$HOME/.cache}/${MYNAME}"
CONFIG_DIR="${XDG_CONFIG_HOME:-$HOME/.config}/${MYNAME}"
DATA_DIR="${XDG_DATA_HOME:-$HOME/.local/share}/${MYNAME}"
STATE_DIR="${XDG_STATE_HOME:-$HOME/.local/state}/${MYNAME}"

CONFIG_FILE="${CONFIG_DIR}/${MYNAME}.conf"

###############################################################################
#
# Coloured line functions

function redline {
    if [[ -t 1 ]]
    then
        printf "\e[0;1;37;41m%s\e[0K\e[0m\n" "$*"
    else
        echo "***** $* *****"
    fi
}

function yellowline {
    if [[ -t 1 ]]
    then
        printf "\e[0;30;43m%s\e[K\e[0m\n" "$*"
    else
        echo "===== $* ====="
    fi
}

function blueline {
    if [[ -t 1 ]]
    then
        printf "\e[0;1;37;44m%s\e[0K\e[0m\n" "$*"
    else
        echo "===== $* ====="
    fi
}

function greenline {
    if [[ -t 1 ]]
    then
        printf "\e[0;1;37;42m%s\e[0K\e[0m\n" "$*"
    else
        echo "----- $* -----"
    fi
}

function cyanline {
    if [[ -t 1 ]]
    then
        printf "\e[0;1;37;46m%s\e[0K\e[0m\n" "$*"
    else
        echo "===== $* ====="
    fi
}

function purpleline {
    if [[ -t 1 ]]
    then
        printf "\e[0;1;37;45m%s\e[0K\e[0m\n" "$*"
    else
        echo "===== $* ====="
    fi
}

function whiteline {
    if [[ -t 1 ]]
    then
        printf "\e[0;1;37;47m%s\e[0K\e[0m\n" "$*"
    else
        echo "===== $* ====="
    fi
}

function fail {
    redline "$@"
    exit 1
}

###############################################################################
#
# Maybe print a command before executing it

SET_X="${SET_X:-false}"

function set_x {
    local IFS=' '
    if [[ "${SET_X:-false}" == "true" ]]
    then
        cyanline "$PS4$*" 1>&2
    fi
    "$@"
}

########################################
# Show the same output that set_x would show,
# but don't actually run the command

function show_x {
    local IFS=' '
    if [[ "${SET_X:-false}" == "true" ]]
    then
        cyanline "$PS4$*" 1>&2
    fi
}

###############################################################################
#
# Debugging messages

DO_DEBUG="${DO_DEBUG:-false}"

function debug {
    if [[ "${DO_DEBUG:-false}" == "true" ]]
    then
        yellowline "$*"
    fi
}

###############################################################################
#
# Usage
# - https://docopt.org/ is the "standard" for how to describe options

function usage {
    local MSG="${*:-}"

    cat <<EOF
$0 [OPTIONS] [ARGS]

Detailed description of what the script does.

-b      Enable BVAR

-s ___  Specify SVAR

-x      Show the important commands before executing them.

-D      Show debugging messages.

-h      Show this help message.

Note: two arguments are required in order to do anything.

EOF

    if [[ -n "$MSG" ]]
    then
        fail "$MSG"
    fi

    exit 0
}

###############################################################################
###############################################################################
###############################################################################
#
# Process the command line

BVAR=false
SVAR="(default)"

while getopts ':hbs:xD' OPT
do
    case $OPT in
        h)  usage
            ;;
        b)  BVAR=true
            ;;
        s)  SVAR="$OPTARG"
            ;;
        x)  SET_X=true
            ;;
        D)  DO_DEBUG=true
            ;;
        *)  usage "ERROR: unknown option '-${OPTARG}'"
            ;;
    esac
done

shift $(( OPTIND - 1 ))

ARG1="${1:-}"
ARG2="${2:-}"

if [[ -z "$ARG1" ]]
then
    usage
fi

if [[ -z "$ARG2" ]]
then
    usage "ERROR: missing ARG2"
fi

###############################################################################
#
# Do the things

echo "MYDIR='${MYDIR}'"
echo "MYNAME='${MYNAME}'"
echo "MYSELF='${MYSELF}'"
echo "CONFIG_DIR='${CONFIG_DIR}'"
echo "CONFIG_FILE='${CONFIG_FILE}'"
echo "BVAR='${BVAR}'"
echo "SVAR='${SVAR}'"
echo "ARG1='${ARG1}'"
echo "ARG2='${ARG2}'"