#!/bin/bash
set -euo pipefail

# ==================================================
# Konfiguration
# ==================================================

BASE="/opt"
CURRENT="/opt/iventoy"

PERSIST="/srv/iventoy"
ISO_DIR="${PERSIST}/iso"
CONFIG_DIR="${PERSIST}/config"
CONFIG_FILE="${CONFIG_DIR}/config.dat"

SERVICE="iventoy"

TMP="/tmp/iventoy-update"
GITHUB_REPO="ventoy/PXE"

MAX_CONFIG_BACKUPS=10
KEEP_VERSIONS=3

# ==================================================
# Ausgabe
# ==================================================

echo "=========================================="
echo " iVentoy Update"
echo "=========================================="
echo

# ==================================================
# Root Check
# ==================================================

if [ "$(id -u)" -ne 0 ]; then
    echo "ERROR: Dieses Script muss als root laufen."
    exit 1
fi

# ==================================================
# Abhängigkeiten
# ==================================================

apt-get update -qq
apt-get install -y -qq curl tar iproute2 >/dev/null

# ==================================================
# Persistente Verzeichnisse
# ==================================================

mkdir -p "$ISO_DIR"
mkdir -p "$CONFIG_DIR"

# ==================================================
# Aktuelle Version online ermitteln
# ==================================================

echo "Ermittle aktuelle iVentoy-Version..."

LATEST_TAG=$(
    curl -fsSL \
        -o /dev/null \
        -w '%{url_effective}' \
        "https://github.com/${GITHUB_REPO}/releases/latest" \
    | awk -F/ '{print $NF}'
)

VERSION="${LATEST_TAG#v}"

if [ -z "$VERSION" ]; then
    echo "ERROR: Konnte aktuelle Version nicht ermitteln."
    exit 1
fi

TARGET="${BASE}/iventoy-${VERSION}"

echo "Neueste Version: $VERSION"

# ==================================================
# Bereits aktuell?
# ==================================================

if [ -L "$CURRENT" ]; then

    CURRENT_TARGET=$(readlink -f "$CURRENT" || true)

    if [ "$CURRENT_TARGET" = "$TARGET" ]; then

        echo
        echo "=========================================="
        echo " iVentoy ist bereits aktuell"
        echo "=========================================="
        echo
        echo "Aktive Version: $VERSION"
        echo "Installation:   $CURRENT -> $TARGET"
        echo

        exit 0
    fi
fi

# ==================================================
# Bestehende Config erstmalig übernehmen
# ==================================================

if [ ! -f "$CONFIG_FILE" ]; then

    if [ -f "${CURRENT}/data/config.dat" ]; then

        echo
        echo "Übernehme bestehende iVentoy Config..."

        cp -a "${CURRENT}/data/config.dat" "$CONFIG_FILE"

    else

        echo
        echo "WARNUNG: Keine bestehende config.dat gefunden."

    fi
fi

# ==================================================
# Config Backup
# ==================================================

if [ -f "$CONFIG_FILE" ]; then

    BACKUP="${CONFIG_FILE}.bak-$(date +%Y%m%d-%H%M%S)"

    echo
    echo "Sichere Config:"
    echo "  $BACKUP"

    cp -a "$CONFIG_FILE" "$BACKUP"

    # ----------------------------------------------
    # Backup Rotation
    # ----------------------------------------------

    echo "Behalte maximal ${MAX_CONFIG_BACKUPS} Config-Backups..."

    find "$CONFIG_DIR" \
        -maxdepth 1 \
        -type f \
        -name 'config.dat.bak-*' \
        -printf '%T@ %p\n' \
        | sort -nr \
        | tail -n +"$((MAX_CONFIG_BACKUPS + 1))" \
        | cut -d' ' -f2- \
        | xargs -r rm -f
fi

# ==================================================
# Download / Entpacken
# ==================================================

if [ -d "$TARGET" ]; then

    echo
    echo "Version $VERSION ist bereits vorhanden:"
    echo "  $TARGET"

else

    rm -rf "$TMP"
    mkdir -p "$TMP"

    ARCHIVE="iventoy-${VERSION}-linux-x86_64-free.tar.gz"
    URL="https://github.com/${GITHUB_REPO}/releases/download/v${VERSION}/${ARCHIVE}"

    echo
    echo "Lade herunter:"
    echo "  $URL"

    curl -fL "$URL" -o "${TMP}/${ARCHIVE}"

    echo
    echo "Entpacke iVentoy..."

    tar -xzf "${TMP}/${ARCHIVE}" -C "$TMP"

    EXTRACTED="${TMP}/iventoy-${VERSION}"

    if [ ! -d "$EXTRACTED" ]; then

        echo "ERROR: Erwartetes Verzeichnis wurde nicht gefunden:"
        echo "  $EXTRACTED"

        exit 1
    fi

    mv "$EXTRACTED" "$TARGET"
fi

# ==================================================
# ISO Symlink
# ==================================================

echo
echo "Setze ISO-Symlink..."

rm -rf "${TARGET}/iso"
ln -s "$ISO_DIR" "${TARGET}/iso"

# ==================================================
# Config Symlink
# ==================================================

if [ -f "$CONFIG_FILE" ]; then

    echo "Setze Config-Symlink..."

    rm -f "${TARGET}/data/config.dat"

    ln -s \
        "$CONFIG_FILE" \
        "${TARGET}/data/config.dat"
fi

# ==================================================
# iVentoy stoppen
# ==================================================

echo
echo "Stoppe iVentoy..."

systemctl stop "$SERVICE" 2>/dev/null || true

sleep 2

# ==================================================
# Alte direkte Installation migrieren
# ==================================================
#
# Falls /opt/iventoy beim ersten Lauf noch ein
# echtes Verzeichnis statt eines Symlinks ist.
#

if [ -e "$CURRENT" ] && [ ! -L "$CURRENT" ]; then

    OLD="${BASE}/iventoy-old-$(date +%Y%m%d-%H%M%S)"

    echo
    echo "Bestehende Installation wird verschoben:"
    echo "  $CURRENT -> $OLD"

    mv "$CURRENT" "$OLD"
fi

# ==================================================
# Current Symlink atomar umschalten
# ==================================================

echo
echo "Aktiviere iVentoy $VERSION..."

ln -sfn "$TARGET" "${CURRENT}.new"
mv -Tf "${CURRENT}.new" "$CURRENT"

# ==================================================
# Service starten
# ==================================================

echo
echo "Starte iVentoy..."

systemctl start "$SERVICE"

sleep 4

# ==================================================
# Healthcheck
# ==================================================

echo
echo "Führe Healthcheck aus..."

FAILED=0

# Service
if systemctl is-active --quiet "$SERVICE"; then
    echo "OK: iVentoy systemd service is active"
else
    echo "ERROR: iVentoy systemd service is NOT active"
    FAILED=1
fi

# TCP 26000
if ss -lntH | awk '{print $4}' | grep -Eq '[:.]26000$'; then
    echo "OK: TCP 26000 is listening"
else
    echo "ERROR: TCP 26000 is NOT listening"
    FAILED=1
fi

# TCP 16000
if ss -lntH | awk '{print $4}' | grep -Eq '[:.]16000$'; then
    echo "OK: TCP 16000 is listening"
else
    echo "ERROR: TCP 16000 is NOT listening"
    FAILED=1
fi

# UDP 69
if ss -lnuH | awk '{print $4}' | grep -Eq '[:.]69$'; then
    echo "OK: UDP 69 is listening"
else
    echo "ERROR: UDP 69 is NOT listening"
    FAILED=1
fi

# UDP 4011
if ss -lnuH | awk '{print $4}' | grep -Eq '[:.]4011$'; then
    echo "OK: UDP 4011 is listening"
else
    echo "ERROR: UDP 4011 is NOT listening"
    FAILED=1
fi

# UDP 67
if ss -lnuH | awk '{print $4}' | grep -Eq '[:.]67$'; then
    echo "OK: UDP 67 is listening"
else
    echo "ERROR: UDP 67 is NOT listening"
    FAILED=1
fi

# Web GUI
if curl -fsS \
    --max-time 5 \
    http://127.0.0.1:26000/ \
    >/dev/null 2>&1; then

    echo "OK: Web GUI responds"

else

    echo "ERROR: Web GUI does NOT respond"
    FAILED=1

fi

# PXE HTTP Bind-IP bestimmen
PXE_BIND=$(ss -lntH | awk '$4 ~ /:16000$/ {print $4; exit}')

if [ -n "$PXE_BIND" ]; then

    PXE_IP="${PXE_BIND%:16000}"

    PXE_IP="${PXE_IP#[}"
    PXE_IP="${PXE_IP%]}"

    if [[ "$PXE_IP" == "*" || \
          "$PXE_IP" == "0.0.0.0" || \
          "$PXE_IP" == "::" ]]; then

        PXE_IP="127.0.0.1"

    fi

    if curl -sS \
        --max-time 5 \
        -o /dev/null \
        "http://${PXE_IP}:16000/" \
        >/dev/null 2>&1; then

        echo "OK: PXE HTTP service on ${PXE_IP}:16000 responds"

    else

        echo "ERROR: PXE HTTP service on ${PXE_IP}:16000 does NOT respond"
        FAILED=1

    fi

else

    echo "ERROR: Could not determine PXE HTTP bind address"
    FAILED=1

fi

# ==================================================
# Healthcheck fehlgeschlagen
# ==================================================

if [ "$FAILED" -ne 0 ]; then

    echo
    echo "=========================================="
    echo " UPDATE FEHLGESCHLAGEN"
    echo "=========================================="
    echo

    if [ -f "${CURRENT}/log/log.txt" ]; then

        echo "Letzte iVentoy Log-Einträge:"
        echo

        tail -n 50 "${CURRENT}/log/log.txt" || true

    fi

    echo
    echo "Alte iVentoy-Versionen wurden NICHT gelöscht."
    echo "Damit ist ein manueller Rollback weiterhin möglich."

    exit 1
fi

# ==================================================
# Alte Versionen aufräumen
# ==================================================

echo
echo "Räume alte iVentoy-Versionen auf..."
echo "Behalte maximal ${KEEP_VERSIONS} Versionen."

ACTIVE_TARGET=$(readlink -f "$CURRENT")

mapfile -t VERSION_DIRS < <(
    find "$BASE" \
        -maxdepth 1 \
        -mindepth 1 \
        -type d \
        -name 'iventoy-[0-9]*' \
        -printf '%T@ %p\n' \
        | sort -nr \
        | cut -d' ' -f2-
)

COUNT=0

for DIR in "${VERSION_DIRS[@]}"; do

    # Aktive Version niemals löschen
    if [ "$(readlink -f "$DIR")" = "$ACTIVE_TARGET" ]; then
        COUNT=$((COUNT + 1))
        continue
    fi

    COUNT=$((COUNT + 1))

    if [ "$COUNT" -gt "$KEEP_VERSIONS" ]; then

        echo "Lösche alte Version:"
        echo "  $DIR"

        rm -rf "$DIR"
    fi
done

# ==================================================
# Temp-Dateien aufräumen
# ==================================================

rm -rf "$TMP"

# ==================================================
# Abschluss
# ==================================================

echo
echo "=========================================="
echo " Update erfolgreich"
echo "=========================================="
echo
echo "Aktive Version:"
echo "  $VERSION"
echo
echo "Installation:"
echo "  $CURRENT -> $TARGET"
echo
echo "Config:"
echo "  ${CURRENT}/data/config.dat -> $CONFIG_FILE"
echo
echo "ISO:"
echo "  ${CURRENT}/iso -> $ISO_DIR"
echo
echo "Config-Backups:"
echo "  maximal $MAX_CONFIG_BACKUPS"
echo
echo "Installierte iVentoy-Versionen:"
echo "  maximal $KEEP_VERSIONS"
echo