#!/bin/bash

# This script can be used like
# NOTMUCH_CONFIG=test/tmp.T580-thread-search/notmuch-config \
#    devel/draw-thread thread:0000000000000002 | dot -Tpdf > thread2.pdf

# In addition to notmuch, you will need the following tools installed
# - graphviz
# - formail (part of procmail)

threadid=$1

declare -a edges

declare -a dest
echo "digraph \"$threadid\" {"
for messageid in $(notmuch search --output=messages $threadid); do
    echo "subgraph \"cluster_$messageid\" {"
    printf "\"%s\" [shape=folder];\n" ${messageid#id:}
    for file in $(notmuch search --output=files $messageid); do
        node=$(basename $file)
        printf "\"%s\" [shape=note];\n" $node

        mapfile -t dest < <(formail -x references < $file | tr '<>,' '"" ')
        edge="\"$node\" -> { ${dest[*]} }"
        edges+=($edge)
    done
    echo "}"
done

for edge in "${edges[*]}"; do
    echo $edge
done

echo "}"