#!/bin/bash

# User input error handling
if [[ $# -eq 0 ]]; then
    echo "$0: A mod url is required."
    exit 4
fi

# Do everything relative to this files path
parent_path=$( cd "$(dirname "${BASH_SOURCE[0]}")" ; pwd -P )
cd "$parent_path"

# Paths
mods_dir="/tmp/"

# Options parsing
mod_url="$1"
out_file="${2:-$parent_path/modrinth.index.json}"

if [ -n "$v" ]; then
    echo "Verbose: $v, Mod url: $mod_url, Output: $out_file"
fi

# https://stackoverflow.com/questions/6250698/how-to-decode-url-encoded-string-in-shell#37840948
function urldecode() {
	: "${*//+/ }"
	echo -e "${_//%/\\x}"
}

# Get file name from url trimmed by slash and url decoded
mod_file="$(urldecode ${mod_url##*/})"
trap "rm ${mods_dir}/${mod_file}" HUP INT TERM EXIT
echo "Downloading file..."
wget -N --no-verbose --directory-prefix "$mods_dir" "$mod_url"

# Collect data required by modrinth.index.json
echo "Processing file info"
mod_path="${mods_dir}/${mod_file}"

modrinth_size="$(du --bytes "$mod_path" | cut -f -1)"
modrinth_sha1="$(sha1sum "$mod_path" | cut -d " " -f 1)"
modrinth_sha512="$(sha512sum "$mod_path" | cut -d " " -f -1)"

# Writing to file
echo "Writing to file"
jq ".files += [{ \
  \"downloads\": [
    \"${mod_url}\"
  ],
  \"env\": {
    \"client\": \"required\",
    \"server\": \"required\"
  },
  \"fileSize\": ${modrinth_size},
  \"hashes\": {
    \"sha1\": \"${modrinth_sha1}\",
    \"sha512\": \"${modrinth_sha512}\"
  },
  \"path\": \"mods/${mod_file}\"
}]" "$out_file" > "$out_file.tmp"

mv "$out_file.tmp" "$out_file"

[ $? -eq 0 ] && echo "Successfully appended mod to ${out_file}"