#!/bin/sh

QUIET="${OK_QUIET:-false}"
NORUN="${OK_NORUN:-false}"
FORCE="${OK_FORCE:-false}"
NODIE="${OK_NODIE:-false}"

OKFILE="${OK_OKFILE:-./ok}"
FRFILE="${OK_FRFILE:-./.fr}"

DOARGS=true

usage() {
	cat >&2 <<EOF
Usage: ok [OPTION...] [TARGET...]
Options:
 -h	Show this help and exit
 -q	Run quietly
 -n	Only print what would happen
 -k	Keep going after failure
 -x	Run with trace
 -B	Run all targets as if they were "new"
 -f FILE
	Use FILE as the okfile (default: $OKFILE)
 -C DIRECTORY
	Change to DIRECTORY before doing anything
EOF
}

### API

ok() {
	$QUIET || echo >&2 "* $@"
	if ! $NORUN
	then
		"$@"; ec="$?"
		if ! test $ec -eq 0
		then
			echo >&2 "* not ok : $@"
			$NODIE || exit $((100 + $?))
		fi
	fi
}

fr() (
	exec > "$FRFILE"
	while read -r target job deps
	do printf '%s\tok %s\t%s\n' "$target" "$job" "$deps"
	done
)

dep() {
	if ! DOARGS=false go "$@"
	then
		echo >&2 dep not ok
		exit $((200 + $?))
	fi
}

all() {
	while read -r target job deps
	do
		if split "$line" | buildp "$target"
		then TARGET="$target" eval "$job" "$deps"
		fi
	done < "$FRFILE"
}

### Backend

buildp() {
	$FORCE && return 0
	target="$1"; shift
	test -e "$target" || return 0
	while read -r dep
	do
		if test "$dep" -nt "$target"
		then
			echo >&2 "$dep newer than $target"
			return 0
		fi
	done
	return 1
}

### Entry point

args() {
	$DOARGS || return 1
	while getopts hqnBkxf:C: OPT
	do
		case "$OPT" in
			(h) usage; exit ;;
			(q) QUIET=true ;;
			(n) NORUN=true ;;
			(B) FORCE=true ;;
			(k) NODIE=true ;;
			(x) set -x ;;
			(f)
				if test -f "$OPTARG"
				then OKFILE="$OPTARG"
				else
					echo >&2 No okfile given.
					exit 2
				fi
				;;
			(C) if ! cd "$OPTARG"
			    then
				    echo >&2 Directory does not exist.
				    exit 2
			    fi
			    ;;
			(*) usage; exit 1 ;;
		esac
	done
}

go() {
	args "$@" && shift $((OPTIND - 1))

	case "$OKFILE" in
		(*/*) ;;
		(*) OKFILE="./$OKFILE" ;;
	esac

	if ! test -f "$OKFILE"
	then
		echo >&2 Cannot find okfile "$OKFILE"
		exit 3
	fi

	DEFAULT="$(sed -n 's/\([a-z][a-z]*\)().*/\1/p' "$OKFILE"|sed q)"
	test -z "$DEFAULT" && DEFAULT=all

	if ! . "$OKFILE"
	then
		echo >&2 Cannot source okfile "$OKFILE"
		exit 3
	fi

	if test $# -eq 0
	then "$DEFAULT"
	else
		for tgt
		do
			if grep -q "$tgt" "$FRFILE"
			then
				if split "$(grep "$tgt" "$FRFILE"|cut -f3-)"| \
						buildp "$tgt"
				then TARGET="$tgt" eval \
					   "$(grep "$tgt" "$FRFILE"|cut -f2-)"
				fi
			else "$tgt"
			fi
		done
	fi
}

### Utilities

split() {
	eval set -- "$*"
	printf '%s\n' "$@"
}

### Do it

go "$@" && echo ok