#!/bin/sh

set -e

LATEST_RELEASE_URL="https://github.com/nullpo-head/wsl-distrod/releases/latest/download/opt_distrod.tar.gz"

HELP_STR="Usage: $0 <command>

command:
    - install
    - update
    - uninstall"

help () {
    echo "$HELP_STR"
}

error_help () {
    error "$HELP_STR"
}

install () {
    mkdir /opt/distrod || error "Failed to create /opt/distrod."
    cd /opt/distrod || error "Could not change directory to /opt/distrod"
    get_release_file
    tar xvf opt_distrod.tar.gz
    rm opt_distrod.tar.gz
    echo "Installation is complete!"
}

uninstall () {
    if grep -o systemd /proc/1/status > /dev/null; then
        error "This uninstall command cannot run inside a running Distrod distro."
        error "To uninstall it, do the following first."
        error "1. /opt/distrod/bin/distrod disable  # Stop systemd from starting as init"
        error "2. wsl.exe --shutdown  # Terminate WSL2"
        error "After that, Systemd will not run as the init and you can run uninstall."
        exit 1
    fi
    rm -rf /opt/distrod
    echo "Distrod has been uninstalled!"
}

update () {
    cd /opt/distrod || error "Could not change directory to /opt/distrod"
    get_release_file
    EXCLUDE=""
    for FILE in /opt/distrod/conf/*; do
        FILE=${FILE#/opt/distrod/}
        if printf "%s" "$FILE" | grep -E ' '; then
            error "Found a file with a name containing spaces. Please remove it. Aborting update command."
            exit 1
        fi
        EXCLUDE="$EXCLUDE --exclude $FILE"
    done
    # shellcheck disable=SC2086
    tar xvf opt_distrod.tar.gz $EXCLUDE
    echo "Ruuning post-update actions..."
    POST_UPDATE="/opt/distrod/misc/distrod-post-update"
    if [ -e "${POST_UPDATE}" ]; then
        "${POST_UPDATE}"
    fi
    echo "Distrod has been updated!"
}

get_release_file() {
    if [ -n "$RELEASE_FILE" ]; then
        if [ "$(realpath "$RELEASE_FILE")" != "$(realpath opt_distrod.tar.gz)" ]; then
            cp "$RELEASE_FILE" opt_distrod.tar.gz
        fi
    else
        curl -L -O "${LATEST_RELEASE_URL}"
    fi
}

error () {
    echo "$@" >&2
}


if [ -z "$1" ]; then
    error_help
    exit 1
fi

if [ "$(whoami)" != "root" ]; then
    error "You must be root to run this script, please use sudo ./install.sh"
    exit 1
fi

COMMAND=
while [ -n "$1" ]; do
    case "$1" in
    -h|--help)
        echo "$HELP_STR"
        exit 0
        ;;
    install)
        COMMAND=install
        shift
        ;;
    uninstall)
        COMMAND=uninstall
        shift
        ;;
    update)
        COMMAND=update
        shift
        ;;
    -r|--release-file)
        RELEASE_FILE="$(realpath "$2")"
        shift 2
        ;;
    -*)
        error "Error: Unknown flag $1"
        exit 1
        ;;
    *) # preserve positional arguments
        error "Error: Unknown command $1"
        exit 1
        ;;
    esac
done

"$COMMAND"