proj/proj

#! /bin/bash
#
# proj
# A program for creating and managing individual projects and related files
# Copyright (C) 2021 Vintage Salt <rehashedsalt@cock.li>
#
# Distributed under terms of the MIT license.
#
set -e

# Read-only set-once variables
declare -r _name="$(basename -- "$0")"
# Options
declare -a _config=(
	[hook_pre_create]=""
	[hook_post_create]=""
	[hook_pre_spawn]=""
	[hook_env]=".projenv"
	[project_dir]="$HOME/Projects"
)
declare _optconfigfile="${XDG_CONFIG_HOME:-$HOME/.config}/${_name}.conf"
declare -i _opthelp
declare -i _optverbose
# Working variables
declare -a _args
declare _return

# Helper functions
log() {
	# Print a line to the terminal if _optverbose is greater than $2
	# $2 defaults to 0
	# loglevel 0: Daily-use messages
	# loglevel 1: Detailed but not quite debugging
	# loglevel 2: Definitely debugging
	[ -z "$1" ] && return 1
	if (( _optverbose >= ${2:-0} )); then
		printf "%s\\n" "$1"
	fi
}
warn() {
	# Print a yellow line to the terminal, respecting _optverbose
	[ -z "$1" ] && return 1
	if (( _optverbose >= ${2:-0} )); then
		if [ -t 1 ]; then
			printf "\\e[33m%s\\e[0m\\n" "$1"
		else
			printf "WARN: %s\\n" "$1"
		fi
	fi
}
error() {
	# Print a red line to the terminal, exit if $2 is specified
	[ -z "$1" ] && return 1
	if [ -t 2 ]; then
		printf "\\e[31m%s\\e[0m\\n" "$1" 1>&2
	else
		printf "ERROR: %s\\n" "$1" 1>&2
	fi
	[ -z "$2" ] && return
	exit "${2:-1}"
}
has() {
	# Parse out all arguments and try to find them in path
	# If an argument cannot be found, set _return and fail
	for prog in "$@"; do
		if ! command -v "$prog" > /dev/null 2>&1; then
			_return="$prog"
			return 1
		fi
	done
	return 0
}
validateline() {
	# Takes a line and errors if it's just whitespace or a comment
	local linenows=${1//[[:space:]]}
	if ! [ "${1#\#}" = "$1" ] || [ -z "$linenows" ]; then
		return 1
	fi
	return 0
}


# Core program functions
printhelp() {
	cat << EOF
Usage: $_name [OPTION]...

  -c [FILE]		Load the given file in place of the usual config file
  -h			Print this help text
  -v			Print more status messages. Stacks

Copyright (c) 2021 rehashedsalt@cock.li
Licensed under the MIT license
EOF
}
hook() {
	# Execute a hook, if it exists
	# If it fails for whatever reason, continue anyway silently
	# $1 path to executable
	# $2 name of hook
	[ -z "$1" ] && return 1
	[ -z "$2" ] && return 2
	log "Attempting to execute hook \"$2\": $1"
	if ! [ -e "$1" ]; then
		warn "Hook \"$2\" does not exist: $1"
		return
	fi
	if ! [ -x "$1" ]; then
		warn "Hook \"$2\" cannot be executed: $1"
		return
	fi
	if [ -d "$1" ]; then
		warn "Hook \"$2\" is a directory: $1"
		return
	fi
	"$1" || warn "Hook \"$2\" failed: $?"
}
proj() {
	# Create/find a project directory and get in there
	[ -z "$1" ] && return 1
	# Get to project_dir
	local projdir="${_config[project_dir]}"
	log "Using project_dir: $projdir" 2
	if ! [ -d "$projdir" ]; then
		if [ -e "$projdir" ]; then
			error "Project directory exists as another file type: $projdir" 61
		fi
		mkdir -p "$projdir"
		log "Created project directory: $projdir" 1
	fi

	log "Entering directory: $projdir" 2
	cd "$projdir"

	# Get to THE project directory
	local dir="$1"
	local dirnew
	if ! [ -d "$1" ]; then
		if [ -e "$1" ]; then
			error "File is in the way of creating a directory: $dir" 62
		fi
		# Execute the pre-create hook
		[ -n "${_config[hook_pre_create]}" ] && hook "${_config[hook_pre_create]}" "pre-create"
		mkdir -p "$dir"
		dirnew=1
	fi

	log "Entering directory: $dir" 2
	cd "$dir"

	# Execute a post-create hook if necessary
	if [ -n "$dirnew" ]; then
		[ -n "${_config[hook_post_create]}" ] && hook "${_config[hook_post_create]}" "post-create"
	fi

	# Execute the pre-spawn hook if necesary
	[ -n "${_config[hook_pre_spawn]}" ] && hook "${_config[hook_pre_spawn]}" "pre-spawn"

	# Get in there
	(
	:
	) || :
	unset dirnew precreatehook postcreatehook
}

# Main
main() {
	# Parse out arguments
	while [ -n "$1" ]; do
		# Parse out flags
		while getopts ":c:hv" opt; do
			case $opt in
				c)
					_optconfigfile="$OPTARG"
					;;
				h)
					_opthelp=1
					;;
				v)
					_optverbose+=1
					;;
				:)
					error "Option requires argument: -$OPTARG" 2
					;;
				*)
					error "Invalid option: -$OPTARG" 2
					;;
			esac
		done
		# Store arguments
		shift $((OPTIND - 1))
		if [ -n "$1" ]; then
			_args+=("$1")
			shift
		fi
		unset OPTIND
	done
	# Early hook for help
	[ -n "$_opthelp" ] && printhelp && exit 0
	# Parse out a config file if it exists
	if [ -f "$_optconfigfile" ]; then
		log "Loading config file: $_optconfigfile" 2
		while read line; do
			# If the line has an equals sign and isn't a comment
			if [ "$line" != "${line#*=}" ] && validateline "$line"; then
				local key="${line%=*}"
				local value="${line#*=}"
				_config[$key]="$value"
				log "Setting $key to $value" 2
			fi
		done < "$_optconfigfile"
	else
		warn "Could not find configuration file" 2
	fi
	# Validate critical options
	# TODO: That
	# Validate arguments
	if [ "${#_args[@]}" -ne "1" ]; then
		error "Required exactly 1 argument, got ${#_args[@]}" 50
	fi
	# Validate core program dependencies
	log "Validating dependencies" 2
	if ! has basename; then
		error "Failed to find program: $_return" 1
	fi

	# Do the do
	proj "${_args[0]}"
	exit 0
}

main "$@"