#!/bin/sh

wget_or_curl=$( (command -v wget > /dev/null 2>&1 && echo "wget -qO-") || \

(command -v curl > /dev/null 2>&1 && echo "curl -skL"))

sha256sum=$( (command -v shasum > /dev/null 2>&1 && echo "shasum -a 256") || \

(command -v sha256sum > /dev/null 2>&1 && echo "sha256sum"))

if [ -z "$sha256sum" ]; then

>&2 echo "sha256sum not found, NNUE files will be assumed valid."

fi

get_nnue_filename() {

grep "$1" evaluate.h | grep "#define" | sed "s/.*\(nn-[a-z0-9]\{12\}.nnue\).*/\1/"

}

validate_network() {

# If no sha256sum command is available, assume the file is always valid.

if [ -n "$sha256sum" ] && [ -f "$1" ]; then

if [ "$1" != "nn-$($sha256sum "$1" | cut -c 1-12).nnue" ]; then

rm -f "$1"

return 1

fi

fi

}

fetch_network() {

_filename="$(get_nnue_filename "$1")"

if [ -z "$_filename" ]; then

>&2 echo "NNUE file name not found for: $1"

return 1

fi

if [ -f "$_filename" ]; then

if validate_network "$_filename"; then

echo "Existing $_filename validated, skipping download"

return

else

echo "Removing invalid NNUE file: $_filename"

fi

fi

if [ -z "$wget_or_curl" ]; then

>&2 printf "%s\n" "Neither wget or curl is installed." \

"Install one of these tools to download NNUE files automatically."

exit 1

fi

for url in \

"https://tests.stockfishchess.org/api/nn/$_filename" \

"https://github.com/official-stockfish/networks/raw/master/$_filename"; do

echo "Downloading from $url ..."

if $wget_or_curl "$url" > "$_filename"; then

if validate_network "$_filename"; then

echo "Successfully validated $_filename"

else

echo "Downloaded $_filename is invalid"

continue

fi

else

echo "Failed to download from $url"

fi

if [ -f "$_filename" ]; then

return

fi

done

# Download was not successful in the loop, return false.

>&2 echo "Failed to download $_filename"

return 1

}

fetch_network EvalFileDefaultNameBig && \

fetch_network EvalFileDefaultNameSmall