#!/bin/bash
# The assert function for Bash
function assert {
    local rc
    local message="$1"
    shift
    "$@" 2>&1 > /dev/null
    rc=$?
    [ $rc -eq 0 ] && return 0
    set $(caller)
    date=$(date "+%Y-%m-%d %T%z")
    echo "$date $2 [$$]: $message (line=$1, rc=$rc)" >&2
    exit $rc
}

# Retrieves the input and output filenames
infile="$1"
outfile="$2"

# Checks the system
assert "Inkscape not found" which inkscape
assert "Pstoedit not found" which pstoedit
assert "svg2dxf takes 2 arguments (infile, outfile)" test $# -eq 2
assert "Input file not found" test -f "$infile"

# Converts the SVG to DXF
printf "Converting %s to %s..." "$infile" "$outfile" >&2
inkscape --file="$infile" --export-eps=/dev/stderr 2>&1 >/dev/null \
    | pstoedit -dt -f 'dxf:-polyaslines -mm' /dev/stdin /dev/stdout \
    > "$outfile" 2> /dev/null
printf " OK\n" >&2