#!/bin/bash

# Usage: cat input.txt | grmfilter [-opts] <grammar file> name1,name2,... 
# With -r: select a random path
# With -s: find shortest path (default)
# name1, name2, ..., must all be defined in the grammar file.

: ${cleanup=1}

function usage {
    echo -e "Usage:\n\tcat input.txt | grmfilter [-opts] <grammar file> name1,name2,..." 
    echo "-r: select a random path"
    echo "-s: find shortest path (default)"
    echo "-h: print this help message (and exit)"
    echo -e "\nNote that fst1, fst2, ..., are all defined in machines.far"
    echo "At least one of -r or -s must NOT be set"
    exit
}

run_random=0
run_shortest=0

while getopts "rs" opt; do
    case $opt in
	r)
	    run_random=1
	    ;;
	s)
	    run_shortest=1
	    ;;
	*)
	    usage
	    ;;
    esac
done

if [[ $run_random -eq "1" ]] && [[ $run_shortest -eq "1" ]]; then
    echo "Cannot run with both random (-r) and shortest-path (-s) selected!"
    echo -e "\n"
    usage
fi

if [[ $run_random -eq "0" ]] && [[ $run_shortest -eq "0" ]]; then
    run_shortest=1
fi

shift $((OPTIND-1))

if [[ $# -lt 2 ]]; then
    usage
fi


#now extract provided .grm file and build far file from it
name=$1
if [[ $name =~ ^(.+)[\.]([^\.]*)$ ]]; then
    name=${BASH_REMATCH[1]};
fi

(thraxmakedep --save_symbols $name.grm && make) 1>&2 || exit

while read input_line; do
    #names for files
    current_fst=/tmp/$$.text.fst
    next_fst=/tmp/$$.postchannel.fst
    #create our current FST
    echo "$input_line" | fstcompilestring > $current_fst

    #work through the list of comma-separated rules
    IFS=',' read -ra RULES <<< "$2"
    for fstname in "${RULES[@]}"; do
	farextract --filename_prefix="/tmp/$$." --filename_suffix=".fst" --keys=$fstname $name.far
	FSTFILE=/tmp/$$.${fstname}.fst
	if [ ! -r $FSTFILE ]; then 
	    echo "Error: Failed to extract $fstname from $name.far (probably was not exported by $name.grm)"
	    exit 1
	fi
	#perform the composition
	fstcompose $current_fst $FSTFILE > $next_fst
	#and update the ``pointers''
	mv $next_fst $current_fst
    done

    #You can get results one of two ways: either randomly or shortest-path
    if [[ $run_random -eq 1 ]]; then
	fstrandgen --seed=$RANDOM --select=log_prob $current_fst | fstprintstring;
    else
	fstshortestpath $current_fst | fstprintstring;
    fi
done

if [[ "$cleanup" -eq "1" ]]; then
    rm /tmp/$$.*
fi