#!/bin/bash
# SSH Login Notifier - Installationsscript
# https://git.techniverse.net/scriptos/ssh-login-notifier

set -e

INSTALL_DIR="/opt/ssh-login-notifier"
PROFILE_HOOK="/etc/profile.d/ssh-login-notify.sh"
ZSH_HOOK_MARKER="# SSH Login Notifier"
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"

# --- Hilfsfunktionen ---

info()  { echo -e "\e[32m[INFO]\e[0m  $1"; }
warn()  { echo -e "\e[33m[WARN]\e[0m  $1"; }
error() { echo -e "\e[31m[ERROR]\e[0m $1"; exit 1; }

check_root() {
    if [[ $EUID -ne 0 ]]; then
        error "Dieses Script muss als root ausgefuehrt werden (sudo)."
    fi
}

check_os() {
    if [[ ! -f /etc/os-release ]]; then
        error "Betriebssystem nicht erkannt. Nur Debian/Ubuntu werden unterstuetzt."
    fi
    . /etc/os-release
    case "$ID" in
        debian|ubuntu) info "Erkanntes OS: ${PRETTY_NAME}" ;;
        *) warn "Ungetestetes OS: ${PRETTY_NAME} - Installation wird fortgesetzt." ;;
    esac
}

check_arch() {
    local arch
    arch="$(uname -m)"
    case "$arch" in
        x86_64)  info "Architektur: x64 (amd64)" ;;
        aarch64) info "Architektur: ARM64 (aarch64)" ;;
        armv7l)  info "Architektur: ARMv7 (armhf)" ;;
        *)       warn "Ungetestete Architektur: ${arch}" ;;
    esac
}

check_dependencies() {
    local missing=()

    if ! command -v curl &>/dev/null; then
        missing+=("curl")
    fi

    if ! command -v mail &>/dev/null && ! command -v sendmail &>/dev/null && ! command -v msmtp &>/dev/null; then
        warn "Kein Mail-Tool gefunden (mail, sendmail, msmtp)."
        warn "E-Mail-Benachrichtigungen funktionieren erst nach Installation eines Mail-Tools."
    fi

    if [[ ${#missing[@]} -gt 0 ]]; then
        info "Installiere fehlende Abhaengigkeiten: ${missing[*]}"
        apt-get update -qq
        apt-get install -y -qq "${missing[@]}"
    fi
}

# --- Installation ---

install_files() {
    info "Erstelle Installationsverzeichnis: ${INSTALL_DIR}"
    mkdir -p "$INSTALL_DIR"

    info "Kopiere Dateien..."
    cp "${SCRIPT_DIR}/ssh-login-notify.sh" "${INSTALL_DIR}/ssh-login-notify.sh"
    cp "${SCRIPT_DIR}/uninstall.sh" "${INSTALL_DIR}/uninstall.sh"

    if [[ -f "${INSTALL_DIR}/config.conf" ]]; then
        warn "Bestehende config.conf gefunden - wird nicht ueberschrieben."
        info "Neue Konfiguration als config.conf.new abgelegt."
        cp "${SCRIPT_DIR}/config.conf" "${INSTALL_DIR}/config.conf.new"
    else
        cp "${SCRIPT_DIR}/config.conf" "${INSTALL_DIR}/config.conf"
    fi

    chmod 755 "${INSTALL_DIR}/ssh-login-notify.sh"
    chmod 755 "${INSTALL_DIR}/uninstall.sh"
    chmod 644 "${INSTALL_DIR}/config.conf"
    chown root:root "${INSTALL_DIR}" -R

    info "Dateien installiert nach ${INSTALL_DIR}"
}

install_profile_hook() {
    if [[ -f "$PROFILE_HOOK" ]]; then
        info "Profile-Hook ist bereits vorhanden."
        return
    fi

    info "Erstelle Profile-Hook: ${PROFILE_HOOK}"
    cat > "$PROFILE_HOOK" << 'HOOKEOF'
# SSH Login Notifier - wird bei interaktivem Login ausgefuehrt
# Installiert von: https://git.techniverse.net/scriptos/ssh-login-notifier
[ -n "$SSH_CONNECTION" ] && [ -x /opt/ssh-login-notifier/ssh-login-notify.sh ] && /opt/ssh-login-notifier/ssh-login-notify.sh
HOOKEOF

    chmod 644 "$PROFILE_HOOK"
    info "Profile-Hook aktiviert (Bash, Sh)."
}

install_zsh_hook() {
    local zshrc="/etc/zsh/zshrc"

    if [[ ! -f "$zshrc" ]]; then
        info "Keine /etc/zsh/zshrc gefunden - Zsh-Hook wird uebersprungen."
        return
    fi

    if grep -qF "$ZSH_HOOK_MARKER" "$zshrc" 2>/dev/null; then
        info "Zsh-Hook ist bereits in ${zshrc} vorhanden."
        return
    fi

    info "Fuege Zsh-Hook in ${zshrc} ein..."
    cat >> "$zshrc" << 'HOOKEOF'

# SSH Login Notifier
# Installiert von: https://git.techniverse.net/scriptos/ssh-login-notifier
[ -n "$SSH_CONNECTION" ] && [ -x /opt/ssh-login-notifier/ssh-login-notify.sh ] && /opt/ssh-login-notifier/ssh-login-notify.sh
HOOKEOF

    info "Zsh-Hook aktiviert."
}

print_summary() {
    echo ""
    echo "=========================================="
    echo "  SSH Login Notifier - Installation"
    echo "=========================================="
    echo ""
    echo "  Status:     Installiert und aktiv"
    echo "  Version:    1.0.0"
    echo "  Pfad:       ${INSTALL_DIR}"
    echo "  Konfig:     ${INSTALL_DIR}/config.conf"
    echo "  Hook:       ${PROFILE_HOOK}"
    echo ""
    echo "  Naechste Schritte:"
    echo "  1. Konfiguration anpassen:"
    echo "     sudo nano ${INSTALL_DIR}/config.conf"
    echo ""
    echo "  2. Test durch SSH-Login auf diesen Server"
    echo ""
    echo "  Deinstallation:"
    echo "     sudo ${INSTALL_DIR}/uninstall.sh"
    echo ""
    echo "=========================================="
}

# --- Hauptprogramm ---

echo ""
echo "SSH Login Notifier - Installation"
echo "================================="
echo ""

check_root
check_os
check_arch
check_dependencies
install_files
install_profile_hook
install_zsh_hook
print_summary