#!/bin/bash
# FTB Pack Installation Script
#
# Server Files: /mnt/server
if [ ! -d /mnt/server ]; then
    mkdir -p /mnt/server
fi
cd /mnt/server || { echo "Failed to change into server directory"; exit 1; }


# Download needed software.
function install_required {
    apt update
    apt install -y curl jq
}

function get_modpack_id {
    urlencode() {
        local string="${1// /%20}"
        echo "$string"
    }
    
    # if no modpack id is set and modpack search term is set.
    if [ -z "${FTB_MODPACK_ID}" ] && [ -n "${FTB_SEARCH_TERM}" ]; then
        encoded_search_term=$(urlencode "$FTB_SEARCH_TERM")
        JSON_DATA=$(curl -sSL https://api.feed-the-beast.com/v1/modpacks/public/modpack/search/8?term="${encoded_search_term}")
    
        # grabs the first modpack in array.
        FTB_MODPACK_ID=$(echo -e "${JSON_DATA}" | jq -r ".packs[0]")
    fi
    
    if [ -z "${FTB_MODPACK_VERSION_ID}" ] && [ -n "${FTB_VERSION_STRING}" ]; then
        # grabs the correct version id matching the string.
        FTB_MODPACK_VERSION_ID=$(curl -sSL https://api.feed-the-beast.com/v1/modpacks/public/modpack/"${FTB_MODPACK_ID}" | jq -r --arg VSTRING "${FTB_VERSION_STRING}" '.versions[] | select(.name == $VSTRING) | .id')
    fi
}

function run_installer {
    # get architecture for installer
    INSTALLER_TYPE=$([ "$(uname -m)" == "x86_64" ] && echo "linux" || echo "arm/linux")
    echo "ModpackID: ${FTB_MODPACK_ID} VersionID: ${FTB_MODPACK_VERSION_ID:-latest} InstallerType: ${INSTALLER_TYPE}"

    # download installer
    curl -Ls https://api.feed-the-beast.com/v1/modpacks/public/modpack/0/0/server/${INSTALLER_TYPE} --output serversetup
    chmod +x ./serversetup
    
    # remove old forge files (to allow updating)
    rm -rf libraries/net/minecraftforge/forge
    rm -rf libraries/net/neoforged/forge
    rm -f unix_args.txt
    
    # run installer
    # shellcheck disable=SC2046
    ./serversetup -pack "${FTB_MODPACK_ID}" $([ -n "$FTB_MODPACK_VERSION_ID" ] && echo "-version $FTB_MODPACK_VERSION_ID") -no-colours -no-java -auto -force || { echo "Failed to run FTB Installer"; exit 1; }
}

# allows startup command to work
function move_startup_files {
    # create symlink for forge unix_args.txt if exists
    if compgen -G "libraries/net/minecraftforge/forge/*/unix_args.txt"; then
        ln -sf libraries/net/minecraftforge/forge/*/unix_args.txt unix_args.txt
    fi
    
    # create symlink for neoforge unix_args.txt if exists
    if compgen -G "libraries/net/neoforged/forge/*/unix_args.txt"; then
        ln -sf libraries/net/neoforged/forge/*/unix_args.txt unix_args.txt
    fi
    
    # move forge/neoforge/fabric jar file to start-server.jar if exists
    if compgen -G "forge-*.jar"; then
        mv -f forge-*.jar start-server.jar
    elif compgen -G "fabric-*.jar"; then
        mv -f fabric-*.jar start-server.jar
    fi
}

# installer cleanup
function installer_cleanup {
    rm serversetup
    rm -f run.bat
    rm -f run.sh
}

# run installation steps
install_required
get_modpack_id
run_installer
move_startup_files
installer_cleanup

echo "Finished installing FTB modpack"