#!/bin/sh

finish() {
    echo "Status: $1"
    echo "Content-type: $2"
    echo
    cat -
    exit
}

echo "$REQUEST_URI" \
    | sed -nE "s#$DRASL_HEADS_ROOT/([[:xdigit:]]{32})/([[:digit:]]+)#\1 \2#p" \
    | {
        IFS=' '
        if ! read -r uuid size; then
            echo "Bad Request" | finish "400 Bad Request" "text/plain"
        fi

        if test "$size" -gt 64; then
            echo "Size Limit Exceeded" | finish "403 Forbidden" "text/plain"
        fi

        image="$(mktemp)"
        trap 'rm $image' EXIT

        if ./cache.sh ./head.sh "$uuid" "$size" 2>/dev/null > "$image"; then
            finish "200 OK" "image/png" < "$image"
        else
            echo "Not Found" | finish "404 Not Found" "text/plain" 
        fi
    }