#!/bin/sh
opener=xdg-open

show_help() {
	printf 'usage: %s [OPTIONS] [FILE] ...\n' "${0##*/}"
	printf 'compiles each FILE to pdf. Supported input file types are:\n'
	printf '   - latex (extension .tex) including dependency recursion\n'
	printf '   - gnuplot (extension .gp)\n'
	printf '   - mandoc (extension .[0-9])\n'
	printf '   - groff/mom (extension .mom)\n'
	printf 'If no FILE is specified, compile all above in the present directory.\n'
	printf 'OPTIONS are one or more of the following:\n'
	printf '   -h    show this message\n'
	printf '   -c    continuously recompile upon file changes (requires entr(1))\n'
	printf '   -o    open output file after compiling (requires %s(1))\n' "$opener"
	printf '   --    do not consider any following args as options\n'
}

die() {
	printf '%s: error: %s\n' "${0##*/}" "$1" >&2
	exit 1
}

regeximatch() {
	printf '%s' "$1" | grep -iEq "$2"
}

extract_tex_includes() {
	if ! test -r "$1"
	then
		return
	fi
	awk '
		function firstval(s) {
			if(!match(s, /%.*\{/) && match(s, /\{.*\}/))
				return substr(s, RSTART+1, RLENGTH-2)
		}
		$0 ~ /\\input\{/ { print firstval($0) }
		$0 ~ /\\include\{/ { print firstval($0) }
		$0 ~ /\\includegraphics\[*.*\]*\{/ { print firstval($0) }
		$0 ~ /\\addbibresource\{/ { print firstval($0) }
		$0 ~ /\\bibliography\{/ && $0 !~ /%.*\{/ {
			m = firstval($0)
			if (m !~ /\.bib$/)
				printf("%s.bib", m)
			else
				print m
		}
	' "$1"
}

find_dependencies() {
	case "$1" in
		*.tex)
			printf '%s\n' "$1"
			extract_tex_includes "$1"
			;;
		*)
			die "cannot find dependencies in unknown file type $1";;
	esac
}

run_compile() {
	if test "$continuous" = 1
	then
		printf '%s\n' "$2" | entr -s "$1"
	else
		eval "$1"
	fi
}

handle_target() {
	base="$(basename "${1%.*}")"
	if test -e "$1"
	then
		case "$1" in
			*.tex)
				deps="$1"
				deps="$(find_dependencies "$1")"
				for d in $deps; do
					if [ "${d##*.}" = "tex" ]; then
						deps="$(printf '%s\n%s\n' "${deps}" "$(find_dependencies "$d")")"
					fi
				done
				deps="$(printf '%s\n' "$deps" | sort | uniq)"
				printf 'deps=%s\n' "$deps"
				if regeximatch "$deps" '\.bib'; then
					compile_string="pdflatex '$1'; bibtex '${1%.tex}'; pdflatex '$1'; pdflatex '$1'"
				else
					compile_string="pdflatex '$1' && pdflatex '$1'"
				fi
				run_compile "$compile_string" "$deps"
				if [ "$open" = 1 ]; then
					$opener "${1%.tex}.pdf"
				fi
				;;
			*.gp)
				run_compile "gnuplot '$1'" "$1";;
			*.[0-9])
				out="$(basename "${base}").pdf"
				if [ "$open" = 1 ]; then
					run_compile "refer -PS -e '$1' | groff -mandoc -T pdf > '$out' && $opener '$out'" "$1"
				else
					run_compile "refer -PS -e '$1' | groff -mandoc -T pdf > '$out'" "$1"
				fi;;
			*.mom)
				out="$(basename "${base}").pdf"
				if [ "$open" = 1 ]; then
					run_compile "pdfmom '$1' > '$out' && $opener '$out'" "$1"
				else
					run_compile "pdfmom '$1' > '$out'" "$1"
				fi;;
			*)
				die "File type ${1##*.} not supported";;
		esac
	else
		die "cannot read $1"
	fi
}

continuous=0
open=0
while :; do
	case "$1" in
		-h|-\?)
			show_help
			exit 0;;
		-c)
			continuous=1;;
		-o)
			open=1;;
		--) # end all options
			shift
			break;;
		-?*)
			die 'unknown option specified';;
		*)  # No more options
			break
	esac
	shift
done

if test $# -lt 1
then
	for f in *.tex *.gp *.[0-9] *.mom
	do
		handle_target "$f"
	done
else
	for f in "$@"
	do
		handle_target "$f"
	done
fi