#!/usr/bin/env zsh

function err(){ print -- $@ >&2; exit 1 }

# scriptdir is the directory of the current executable
if [[ ${0[0]} = '/' ]]; then
    scriptdir="${0:h}"
else
    scriptdir="$PWD/${0:h}"
fi

# the list of mp files without argument all file in the current tree
typeset -a fics
if (($#<1)); then
    err "Usage: ${0:t} FILES"
else
    fics=( $* );
fi

(( ${#fics} == 0 )) && err "No .mp files into $scriptdir"

# the tmp directory where compilation occurs with a lot of temporary files
tmpdir=/tmp/mp
[[ ! -d $tmpdir ]] && mkdir -p $tmpdir

for fic in $fics; do
    ficname=${fic:t}
    tmp=$tmpdir/${ficname:r}-tmp.mp
    eps=$tmpdir/${ficname:r}-tmp.1
    png=${fic:r}.png
    old=$tmpdir/${ficname:r}.old
    {
        echo -n >&2 "$png"
        cat $scriptdir/graph.mp
        echo 'beginfig(1)'
        echo '  drawoptions (withcolor base01);'
        cat $fic
        echo 'endfig;'
        echo 'bye;'
    } | sed 's/base00/baseZeroZero/g' \
      | sed 's/base01/baseZeroOne/g' \
      | sed 's/base02/baseZeroTwo/g' \
      | sed 's/base03/baseZeroThree/g' \
      | sed 's/base0/baseZero/g' \
      | sed 's/base1/baseOne/g' \
      | sed 's/base2/baseTwo/g' \
      | sed 's/base3/baseThree/g' \
      | sed 's/red/s_red/g' \
      | sed 's/blue/s_blue/g' \
      | sed 's/green/s_green/g' > $tmp
    [[ -e $old ]] && diff $tmp $old >/dev/null && { echo " unchanged (clean $tmpdir if you want to force rebuild)"; continue }

	dpi=$(grep '% DPI' $tmp | awk '{print $3}')
	[[ $dpi = "" ]] && dpi=600

    # addshadow="'(' +clone -background black -shadow 90x4+0+1 ')' +swap -background none -layers merge +repage"
    addshadow=""
    reducesize=" -colors 254 -quality 75"
    cmd="convert -colorspace rgb -density $((4*dpi)) $eps -resize 25% $addshadow $reducesize $png"

    cd $tmpdir && \
    mpost --tex=latex ${tmp:t} >/dev/null && \
        cd $OLDPWD && \
        eval $cmd && \
        \cp -f $tmp $old && \
        echo "updated" && \
done