#!/usr/bin/env bash
# SPDX-FileCopyrightText: 2022 Robin Vobruba <hoijui.quaero@gmail.com>
# SPDX-License-Identifier: AGPL-3.0-or-later
#
# See the output of "$0 -h" for details.

# Exit immediately on each error and unset variable;
# see: https://vaneyckt.io/posts/safer_bash_scripts_with_set_euxo_pipefail/
set -Eeuo pipefail
#set -Eeu

APP_NAME="Listing of files to tree view converter"
script_name="$(basename "$0")"
output=/dev/stdout
html=false
title=""

# parameters

function print_help() {

	echo -e ""
	echo -e "$APP_NAME - Given a file listing - as for example created by 'find',"
	echo -e "generates a tree view."
	echo -e "The input file-listing format has to follow these rules:"
	echo -e "* one file/dir per line"
	echo -e "* full paths, relative to the output-dir"
	echo -e "* each line indicating a dir needs to end with a '/'"
	echo -e "* empty lines and lines starting with '#' or ';', are ignored"
	echo -e "* any other line indicates a file"
	echo -e ""
	echo -e "Usage:"
	echo -e "\t$script_name [OPTION...]"
	echo -e "Options:"
	echo -e "\t-o, --output [FILE]"
	echo -e "\t\tSets the output file to write the tree to (default: '$output')"
	echo -e "\t--html"
	echo -e "\t\tWrite output as HTML (default: ASCII)"
	echo -e "\t--title [STRING]"
	echo -e "\t\tUse the given string as the title and H1 header, if HTML output"
	echo -e "\t-h, --help"
	echo -e "\t\tPrint this usage help and exit"
	echo -e "Examples:"
	echo -e "\tfind * | $script_name"
	echo -e ""
}

# Process command line arguments
while [[ $# -gt 0 ]]
do
	arg="$1"
	shift # $2 -> $1, $3 -> $2, ...

	case "$arg" in
		-h|--help)
			print_help
			exit 0
			;;
		-o|--output)
			output="$1"
			shift
			;;
		--html)
			html=true
			;;
		--title)
			title="$1"
			shift
			;;
		-*) # unknown switch
			>&2 echo "ERROR: Unknown switch '$arg'"
			exit 1
			;;
		*) # non-switch
			POSITIONAL+=("$arg") # save it in an array for later
			;;
	esac
done
set -- "${POSITIONAL[@]}" # restore positional parameters

lst_clean_tmp=$(mktemp "/tmp/$script_name-clean_listing-XXXXXX.txt")
while IFS= read -r line
do
	if [ -z "$line" ] || [[ $line =~ ^[#\;].* ]]
	then
		continue
	fi
	if [[ $line =~ (^\|/)\.\.(/\|$) ]]
	then
		>&2 echo "Invalid sequence '..' found in: '$line'"
		exit 1
	fi
	if [[ $line =~ ^/ ]]
	then
		>&2 echo "Please use relative listing paths; found: '$line'"
		exit 1
	fi
	echo "$line"
done > "$lst_clean_tmp"

tree_extra_args=()
if $html
then
	tree_extra_args+=("-H")
	tree_extra_args+=(".")
	tree_extra_args+=("--nolinks")
	if [ -n "$title" ]
	then
		tree_extra_args+=("-T")
		tree_extra_args+=("$title")
	fi
fi

tree \
	-a \
	-F \
	--noreport \
	-I ".git" \
	--dirsfirst \
	--fromfile \
	"${tree_extra_args[@]}" \
	-o "$output" \
	. \
	< "$lst_clean_tmp"

rm "$lst_clean_tmp"