#!/bin/bash
# Version: 20251218.GA02

# FileWave Booster (fwbooster) Upgrade Script (Debian 12/13)
#
# Safer recommended 1-liner (runs in screen):
#   sudo DEBIAN_FRONTEND=noninteractive bash -c 'apt-get update -y && apt-get install -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" screen && screen -S fw_upgrade bash -c "wget -qO- https://kb.filewave.com/attachments/412 | bash -s -- -v 16.3.0 -r 1 -p -y"'
#
# Options:
#   -v, --version    Target FileWave Booster version (e.g., 16.3.0)
#   -r, --revision   Legacy selector (accepted for compatibility; coerced to '1')
#   -d, --dev        Use Dev download server
#   -b, --beta       Use Beta download server
#   -p, --prod       Use Production download server (default)
#   -y, --yes        Auto-yes for routine prompts (install, OS patch upgrade, reboot)
#   -yy, --yesyes    Auto-yes for ALL prompts (includes screen warning + Debian 12->13 release upgrade);
#                   NOTE: if root has no password set, -yy will exit with an error (no prompting).
#
# Notes:
# - Supports Debian 12 and Debian 13 (enforced via version matrix below).
# - Debian 13 is required for FileWave versions >= 16.3.0.

set -u

# Ensure noninteractive package operations by default (we still prompt via /dev/tty where needed)
export DEBIAN_FRONTEND=${DEBIAN_FRONTEND:-noninteractive}
export DEBCONF_NONINTERACTIVE_SEEN=${DEBCONF_NONINTERACTIVE_SEEN:-true}
#################### DEFAULTS ####################
VERSION="16.3.0"
REVISION="1"
SERVER_TYPE="prod"
BASE_URL="https://fwdl.filewave.com"

auto_yes=false
auto_risky_yes=false
OS_UPGRADED=false

# Minimum FileWave version that requires Debian 13 (keep aligned with other FileWave upgrade scripts)
MIN_DEBIAN13_FW_VERSION="16.3.0"

#############################################
##### BEGIN SHARED PLATFORM BLOCK (KEEP IN SYNC) #####
# This block is intentionally identical across:
#   - FileWave IVS Upgrade Script
#   - FileWave Server (fwxserver) Upgrade Script
#   - FileWave Booster (fwbooster) Upgrade Script
# Any changes to Debian upgrade, screen safety, /boot safety,
# root-password enforcement, and download validation should be
# made in ALL THREE scripts.
#############################################

die() {
    echo "[ERROR] $1" >&2
    exit 1
}

require_amd64() {
    local arch
    arch=$(dpkg --print-architecture 2>/dev/null || echo \"unknown\")
    if [[ \"$arch\" != \"amd64\" ]]; then
        die \"[ARCH] Unsupported architecture: $arch. This script supports amd64 only.\"
    fi
}


is_running_under_multiplexer() {
    # Detect GNU screen via env or process ancestry (helps when sudo strips env).
    if [[ -n "${STY:-}" ]]; then
        return 0
    fi

    local pid=$$
    local depth=0
    while [[ "$pid" -gt 1 && $depth -lt 6 ]]; do
        local comm
        comm=$(ps -o comm= -p "$pid" 2>/dev/null | tr -d ' ')
        if [[ "$comm" == "screen" || "$comm" == "SCREEN" ]]; then
            return 0
        fi
        pid=$(ps -o ppid= -p "$pid" 2>/dev/null | tr -d ' ')
        [[ -z "$pid" ]] && break
        depth=$((depth + 1))
    done

    return 1
}

check_screen_session_safety() {
    # Enforce screen usage for long-running operations.
    # This is intentionally NOT based on SSH_* env vars because sudo can strip them.
    if ! command -v screen >/dev/null 2>&1; then
        echo "[SESSION] Installing 'screen' (recommended)..."
        DEBIAN_FRONTEND=noninteractive apt-get install -y -q screen || \
            die "[SESSION] Failed to install screen."
    fi

    if is_running_under_multiplexer; then
        return 0
    fi

    echo "[SESSION] You are NOT running inside a 'screen' session."
    echo "[SESSION] This process can take a long time and an SSH disconnect can leave the system in a bad state."
    echo
    echo "[SESSION] Recommended:"
    echo "[SESSION]   screen -S fw_upgrade"
    echo "[SESSION]   <re-run the upgrade 1-liner inside screen>"
    echo
    echo "[SESSION] If you are already in screen, reconnect with:"
    echo "[SESSION]   screen -r fw_upgrade"
    echo

    if [[ "${auto_risky_yes:-false}" == "true" ]]; then
        echo "[SESSION] Risky auto-yes mode enabled; continuing despite not running inside 'screen'."
        return 0
    fi

    local resp
    read -p "Continue without screen? (yes/no): " resp < /dev/tty
    if [[ ! "$resp" =~ ^[Yy]([Ee][Ss])?$ ]]; then
        die "[SESSION] Aborting. Please start a 'screen' session and re-run."
    fi
}

check_root_password_state() {
    # passwd -S output format:
    #   root P ...  -> password set
    #   root L ...  -> locked
    #   root NP ... -> no password
    passwd -S root 2>/dev/null | awk '{print $2}'
}

ensure_root_password_set() {
    # Some package install steps invoke 'su' or call tools that enforce root auth policies.
    # For appliances where root is disabled by default, we require the operator to set it.
    while true; do
        local state
        state="$(check_root_password_state || true)"

        if [[ "$state" == "P" ]]; then
            echo "[ROOT] Root password is set."
            return 0
        fi

        # If running in fully non-interactive "yesyes" mode, do not try to prompt.
        if [[ "${auto_risky_yes:-false}" == "true" ]]; then
            echo
            echo "[ROOT] ERROR: Root password is NOT set (state: ${state:-unknown})."
            echo "[ROOT] This run is in -yy/--yesyes mode and cannot prompt for passwords."
            echo "[ROOT] Set a root password (and write it down), then re-run WITHOUT -yy:"
            echo "[ROOT]   sudo passwd root"
            echo
            exit 1
        fi

        echo
        echo "[ROOT] Root password is NOT set (state: ${state:-unknown})."
        echo
        echo "This upgrade requires a valid root password because parts of the installation"
        echo "process invoke 'su'. You MUST set a root password now and write it down."
        echo
        echo "Running: passwd root"
        echo

        if passwd root < /dev/tty > /dev/tty 2>&1; then
            echo
            echo "[ROOT] Password command completed. Re-checking root password state..."
        else
            echo
            echo "[ROOT] passwd returned an error. Please try again."
        fi
    done
}

boot_usage_percent() {
    df -P /boot 2>/dev/null | awk 'NR==2 {gsub("%","",$5); print $5}'
}

has_separate_boot() {
    mountpoint -q /boot 2>/dev/null
}

boot_fs_use_pct() {
    df -P /boot 2>/dev/null | awk 'NR==2 {print $5}' || echo "n/a"
}

root_fs_use_pct() {
    df -P / 2>/dev/null | awk 'NR==2 {print $5}' || echo "n/a"
}

boot_dir_size() {
    du -sh /boot 2>/dev/null | awk 'NR==1 {print $1}' || echo "n/a"
}


check_boot_space() {
    if mountpoint -q /boot; then
        local usep
        usep="$(boot_usage_percent)"
        if [[ -n "$usep" ]]; then
            echo "[BOOT] /boot usage: ${usep}%"
            if (( usep >= 95 )); then
                die "[BOOT] /boot is critically full (${usep}%). Run kernel cleanup before continuing."
            elif (( usep >= 80 )); then
                echo "[BOOT] Warning: /boot is getting full (${usep}%). Kernel cleanup is recommended."
            fi
        fi
    fi
}

kernel_cleanup_keep2() {
    # Purge old Debian kernel image packages, keeping:
    #  - currently running kernel
    #  - one newest additional kernel (fallback)
    if ! mountpoint -q /boot; then
        echo "[KERNEL-CLEANUP] /boot is not a separate mountpoint; skipping kernel cleanup."
        return 0
    fi

    echo "[KERNEL-CLEANUP] Checking for excess installed Debian kernels to prevent /boot filling..."

    local running_ver running_pkg
    running_ver="$(uname -r)"
    running_pkg="linux-image-${running_ver}"

    mapfile -t images < <(dpkg-query -W -f='${Package}\n' 'linux-image-[0-9]*-amd64' 2>/dev/null | sort -V || true)

    if ((${#images[@]} <= 2)); then
        echo "[KERNEL-CLEANUP] ${#images[@]} kernel image package(s) installed; nothing to clean."
        df -h /boot || true
        return 0
    fi

    local keep=("$running_pkg")
    local i
    for (( i=${#images[@]}-1; i>=0; i-- )); do
        [[ "${images[$i]}" == "$running_pkg" ]] && continue
        keep+=("${images[$i]}")
        break
    done

    local remove=()
    local pkg k skip
    for pkg in "${images[@]}"; do
        skip=false
        for k in "${keep[@]}"; do
            [[ "$pkg" == "$k" ]] && skip=true && break
        done
        $skip || remove+=("$pkg")
    done

    echo "[KERNEL-CLEANUP] Running kernel : $running_ver"
    echo "[KERNEL-CLEANUP] Keeping        : ${keep[*]}"
    echo "[KERNEL-CLEANUP] Removing       : ${remove[*]:-(none)}"

    if ((${#remove[@]})); then
        DEBIAN_FRONTEND=noninteractive apt-get -y purge "${remove[@]}" || \
            echo "[KERNEL-CLEANUP] Warning: kernel purge encountered issues; check logs."
        DEBIAN_FRONTEND=noninteractive apt-get -y autoremove --purge || true
        update-grub >/dev/null 2>&1 || true
    fi

    df -h /boot || true
}
ensure_boot_space() {
    local phase="${1:-unspecified}"
    echo "[BOOT] Preflight check before: ${phase}"
    # Proactively free space in /boot by purging old kernels (keeping running + one fallback).
    # If /boot is still critically full after cleanup, abort before attempting any upgrades that
    # may generate new initramfs images (which writes to /boot and can brick the upgrade).
    if ! mountpoint -q /boot; then
        return 0
    fi

    local usep
    usep="$(boot_usage_percent)"

    # If /boot is getting full, attempt cleanup first.
    if [[ -n "$usep" ]] && (( usep >= 80 )); then
        echo "[BOOT] /boot usage is high (${usep}%). Attempting kernel cleanup..."
        kernel_cleanup_keep2
        usep="$(boot_usage_percent)"
    fi

    # Hard stop if still critical after cleanup.
    if [[ -n "$usep" ]] && (( usep >= 95 )); then
        die "[BOOT] /boot is critically full (${usep}%) even after kernel cleanup. Manual remediation required before continuing."
    fi

    # If still high (but not critical), warn and continue.
    if [[ -n "$usep" ]] && (( usep >= 80 )); then
        echo "[BOOT] Warning: /boot is still high after cleanup (${usep}%). Upgrade may fail if additional kernels/initramfs are generated."
    fi
}


validate_download_exists() {
    # Validate a URL is reachable before download (clearer error than wget retries).
    local url="$1"
    echo "[DOWNLOAD] Validating download exists: $url"

    if command -v wget >/dev/null 2>&1; then
        if wget -q --spider "$url"; then
            return 0
        fi
    elif command -v curl >/dev/null 2>&1; then
        if curl -fsSI "$url" >/dev/null; then
            return 0
        fi
    else
        # Fall back: no validation tool available; caller will attempt download.
        echo "[DOWNLOAD] Warning: neither wget nor curl is available for existence check; skipping validation."
        return 0
    fi

    return 1
}

upgrade_to_debian13() {
    # Debian 12 -> 13 in-place upgrade. Requires screen session safety checks.
    check_screen_session_safety

    echo "[DEBIAN-UPGRADE] Debian 12 detected but target FileWave version requires Debian 13 (trixie)."
    echo "[DEBIAN-UPGRADE] This is a long-running in-place OS upgrade."

    local deb13_confirm
    if [[ "${auto_risky_yes:-false}" == "true" ]]; then
        deb13_confirm="yes"
        echo "[DEBIAN-UPGRADE] Risky auto-yes mode enabled; proceeding without interactive confirmation."
    else
        read -p "Proceed with Debian 12 -> 13 OS upgrade now? (yes/no): " deb13_confirm < /dev/tty
    fi
    if [[ ! "$deb13_confirm" =~ ^[Yy]([Ee][Ss])?$ ]]; then
        die "[DEBIAN-UPGRADE] Aborting. Debian 13 is required for this target version."
    fi

    local REQUIRED_GIB=5
    local avail_gib
    avail_gib=$(df -BG / | awk 'NR==2 {gsub(/G/,"",$4); print $4}')
    [[ -z "$avail_gib" ]] && die "[DEBIAN-UPGRADE] Unable to determine free disk space on /."
    (( avail_gib < REQUIRED_GIB )) && die "[DEBIAN-UPGRADE] Not enough free disk space: ${avail_gib} GiB available, need ${REQUIRED_GIB} GiB."
    echo "[DEBIAN-UPGRADE] Disk space OK: ${avail_gib} GiB free."

    # Remove legacy FileWave APT lists to avoid stale suites
    rm -f /etc/apt/sources.list.d/filewave-beta.list >/dev/null 2>&1 || true
    rm -f /etc/apt/sources.list.d/filewave-dev.list >/dev/null 2>&1 || true
    rm -f /etc/apt/sources.list.d/filewave-release.list >/dev/null 2>&1 || true
    ensure_boot_space "Debian 12 pre-upgrade kernel space check"
    echo "[DEBIAN-UPGRADE] Updating Debian 12 (bookworm) fully before release upgrade..."
    apt-get update -y || die "[DEBIAN-UPGRADE] apt-get update failed on Debian 12."
    DEBIAN_FRONTEND=noninteractive apt-get dist-upgrade -y \
        -o Dpkg::Options::="--force-confdef" \
        -o Dpkg::Options::="--force-confold" \
        --autoremove || die "[DEBIAN-UPGRADE] dist-upgrade failed on Debian 12."

    echo "[DEBIAN-UPGRADE] Switching APT sources from bookworm -> trixie..."
    sed -i 's/bookworm/trixie/g' /etc/apt/sources.list || die "[DEBIAN-UPGRADE] Failed to update /etc/apt/sources.list."
    find /etc/apt/sources.list.d -maxdepth 1 -type f -exec sed -i 's/bookworm/trixie/g' {} \; 2>/dev/null || true

    # Preseed grub-pc device selection (noninteractive safety)
    if dpkg-query -W -f='${Status}' grub-pc 2>/dev/null | grep -q "install ok installed"; then
        local ROOT_OR_BOOT_DEV BOOT_DISK PARENT_DISK
        ROOT_OR_BOOT_DEV=$(findmnt -no SOURCE /boot 2>/dev/null || findmnt -no SOURCE / 2>/dev/null || echo "")
        BOOT_DISK=""
        if [[ -n "$ROOT_OR_BOOT_DEV" ]]; then
            PARENT_DISK=$(lsblk -no PKNAME "$ROOT_OR_BOOT_DEV" 2>/dev/null || echo "")
            if [[ -n "$PARENT_DISK" ]]; then
                BOOT_DISK="$PARENT_DISK"
            else
                BOOT_DISK=$(basename "$ROOT_OR_BOOT_DEV")
            fi
        fi
        if [[ -n "$BOOT_DISK" ]]; then
            echo "[DEBIAN-UPGRADE] Preseeding grub-pc install device as /dev/$BOOT_DISK..."
            echo "grub-pc grub-pc/install_devices multiselect /dev/$BOOT_DISK" | debconf-set-selections
            echo "grub-pc grub-pc/install_devices_empty boolean false" | debconf-set-selections
        else
            echo "[DEBIAN-UPGRADE] Warning: Could not determine boot disk for grub preseeding."
        fi
    fi
    ensure_boot_space "Debian sources switched pre-upgrade kernel space check"
    echo "[DEBIAN-UPGRADE] Running Debian 13 dist-upgrade (with retry)..."
    local max_attempts=2
    local attempt=1
    while (( attempt <= max_attempts )); do
        echo "[DEBIAN-UPGRADE] Attempt $attempt of $max_attempts..."
        apt-get clean
        rm -rf /var/lib/apt/lists/*
        apt-get update -y || die "[DEBIAN-UPGRADE] apt-get update failed after switching to trixie."

        if DEBIAN_FRONTEND=noninteractive apt-get dist-upgrade -y \
            -o Dpkg::Options::="--force-confdef" \
            -o Dpkg::Options::="--force-confold" \
            --autoremove; then
            echo "[DEBIAN-UPGRADE] Release upgrade succeeded."
            break
        fi

        if (( attempt == max_attempts )); then
            die "[DEBIAN-UPGRADE] Release upgrade failed after retries. See log for remediation steps."
        fi

        echo "[DEBIAN-UPGRADE] dist-upgrade failed; retrying after cache cleanup..."
        attempt=$((attempt + 1))
        sleep 5
    done

    # Optional: modernize sources on Debian 13
    if command -v apt >/dev/null 2>&1; then
        if apt modernize-sources --help >/dev/null 2>&1; then
            echo "[DEBIAN-UPGRADE] Modernizing APT sources to deb822..."
            apt modernize-sources --assume-yes || echo "[DEBIAN-UPGRADE] Warning: apt modernize-sources failed."
        fi
    fi

    # Refresh version info and confirm Debian 13
    DEBIAN_VERSION=$(grep -E '^VERSION_ID=' /etc/os-release | cut -d= -f2 | tr -d '"')
    DEBIAN_MAJOR=${DEBIAN_VERSION%%.*}
    (( DEBIAN_MAJOR != 13 )) && die "[DEBIAN-UPGRADE] Debian upgrade appears incomplete (VERSION_ID=$DEBIAN_VERSION)."

    echo "[DEBIAN-UPGRADE] Debian 13 confirmed. Continuing..."
    OS_UPGRADED=true
}

#############################################
# SHARED PLATFORM BLOCK END
#############################################



#################### ROOT + OS CHECKS ####################
##### END SHARED PLATFORM BLOCK #####

if [[ "${EUID}" -ne 0 ]]; then
    die "This script must be run with sudo or as root."
fi



if ! grep -iq "^ID=debian" /etc/os-release; then
    die "Unsupported OS. This script must be run on Debian 12 or Debian 13."
fi

DEBIAN_VERSION=$(grep -E '^VERSION_ID=' /etc/os-release | cut -d= -f2 | tr -d '"')
DEBIAN_MAJOR=${DEBIAN_VERSION%%.*}
if ! [[ "$DEBIAN_MAJOR" =~ ^[0-9]+$ ]]; then
    die "Unable to determine Debian major version."
fi
if (( DEBIAN_MAJOR < 12 || DEBIAN_MAJOR > 13 )); then
    die "Unsupported Debian version ($DEBIAN_VERSION). Only Debian 12 and Debian 13 are supported."
fi

require_amd64

#################### LOGGING + PREFLIGHT ####################

echo "[DEBUG] Effective user: $(id -un) (uid=$(id -u))"


LOG_FILE="/var/log/filewave_booster_update.log"
touch "$LOG_FILE" || die "Failed to create log file $LOG_FILE. Check permissions."
chmod 644 "$LOG_FILE" || die "Failed to chmod log file $LOG_FILE."
[[ -w "$LOG_FILE" ]] || die "Cannot write to log file $LOG_FILE."

exec > >(stdbuf -oL tee -a "$LOG_FILE") 2>&1

#################### FAILURE HANDLING (screen-friendly) ####################
# When this script runs inside a short-lived `screen` session started by the 1-liner,
# a hard failure can close the screen window immediately and make the last error hard to read.
# To improve operator UX:
#  - In normal interactive runs (including -y), pause on failure and prompt "Press Enter to exit".
#  - In unattended/risky mode (-yy/--yesyes), do NOT pause; exit immediately.
pause_on_failure() {
    local rc="${1:-1}"

    # In risky auto-yes mode, never pause (assume unattended).
    if [[ "${auto_risky_yes:-false}" == "true" ]]; then
        return 0
    fi

    # Best-effort: only pause when we appear to have a TTY.
    if [[ -e /dev/tty ]]; then
        echo
        echo "================================================================================"
        echo "[FAILURE] Upgrade failed with exit code: ${rc}"
        echo "[FAILURE] Log File: ${LOG_FILE:-/var/log/filewave_update.log}"
        echo "[FAILURE] The screen session will close when this script exits."
        echo "[FAILURE] Press Enter to exit (or Ctrl+C)."
        echo "================================================================================"
        # Read directly from the controlling terminal so piping doesn't break the prompt.
        read -r </dev/tty || true
    fi
}

# Trap EXIT so we can pause on failures (rc != 0).
trap 'rc=$?; if (( rc != 0 )); then pause_on_failure "$rc"; fi' EXIT
echo "Logging to $LOG_FILE"

HYPERVISOR=$(systemd-detect-virt 2>/dev/null || echo "unknown")
CPU_MODEL=$(grep -m1 "model name" /proc/cpuinfo 2>/dev/null | cut -d: -f2- | xargs || echo "unknown")
TOTAL_MEM=$(awk '/MemTotal/ {printf "%.1f GB", $2/1024/1024}' /proc/meminfo 2>/dev/null || echo "unknown")
ROOT_FS_AVAIL=$(df -h / 2>/dev/null | awk 'NR==2 {print $4}')
if has_separate_boot; then
    BOOT_FS_USE="$(boot_fs_use_pct)"
    echo "[PRE-FLIGHT] /boot Usage: ${BOOT_FS_USE:-unknown}"
else
    echo "[PRE-FLIGHT] /boot Usage: N/A (no separate /boot filesystem; /boot is on /)"
    echo "[PRE-FLIGHT] Root FS Usage: $(root_fs_use_pct)"
    echo "[PRE-FLIGHT] /boot Directory Size: $(boot_dir_size)"
fi

echo "[PRE-FLIGHT] /boot Usage: ${BOOT_FS_USE:-unknown}"
echo "[PRE-FLIGHT] Hypervisor: $HYPERVISOR"
echo "[PRE-FLIGHT] CPU Model: ${CPU_MODEL:-unknown}"
echo "[PRE-FLIGHT] Memory: ${TOTAL_MEM:-unknown}"
echo "[PRE-FLIGHT] Root FS Free Space: ${ROOT_FS_AVAIL:-unknown}"
echo "[PRE-FLIGHT] Running Kernel: $(uname -r)"

#################### ARGUMENTS ####################
if [[ "$#" -eq 0 ]]; then
    echo "Usage: wget -qO- <url> | sudo bash -s -- -v <version> -r <revision> [-d|--dev | -b|--beta | -p|--prod] [-y|--yes] [-yy|--yesyes]"
    echo
    echo "Options:"
    echo "  -v, --version    Target FileWave Booster version (e.g., 16.3.0)"
    echo "  -r, --revision   Legacy selector (accepted for compatibility; coerced to '1')"
    echo "  -d, --dev        Use Dev download server"
    echo "  -b, --beta       Use Beta download server"
    echo "  -p, --prod       Use Production download server (default)"
    echo "  -y, --yes        Auto-yes for routine prompts (install, OS patch upgrade, reboot)"
    echo "  -yy, --yesyes    Auto-yes for ALL prompts (includes screen warning + Debian 12->13 release upgrade)"
    exit 1
fi

while [[ "$#" -gt 0 ]]; do
    case $1 in
        -v|--version)   VERSION="$2"; shift 2 ;;
        -r|--revision)  REVISION="$2"; shift 2 ;;
        -d|--dev)       SERVER_TYPE="dev"; shift ;;
        -b|--beta)      SERVER_TYPE="beta"; shift ;;
        -p|--prod)      SERVER_TYPE="prod"; shift ;;
        -y|--yes)       auto_yes=true; shift ;;
        -yy|--yesyes)   auto_yes=true; auto_risky_yes=true; shift ;;
        *)              die "Unknown option: $1" ;;
    esac
done

# Normalize revision for legacy compatibility
if [[ "$REVISION" != "1" ]]; then
    echo "[INFO] Ignoring requested revision '$REVISION' and using revision '1'. (fwbooster packages are not revisioned.)"
    REVISION="1"
fi

# Root password must be set for maintainer scripts that may invoke su.
ensure_root_password_set

#################### SUMMARY BLOCK ####################
INSTALLED_FWBOOSTER_VERSION=$(dpkg-query -W -f='${Version}' fwbooster 2>/dev/null || echo "not installed")
FWXSERVER_PRESENT="NO"
if [[ "$INSTALLED_FWBOOSTER_VERSION" != "not installed" && -n "$INSTALLED_FWBOOSTER_VERSION" ]]; then
    FWXSERVER_PRESENT="YES"
fi

PLANNED_DEBIAN_BEHAVIOR="Unknown"
if dpkg --compare-versions "$VERSION" ge "$MIN_DEBIAN13_FW_VERSION"; then
    if (( DEBIAN_MAJOR == 12 )); then
        PLANNED_DEBIAN_BEHAVIOR="Upgrade Debian 12 -> 13 (trixie) before FileWave install"
    elif (( DEBIAN_MAJOR == 13 )); then
        PLANNED_DEBIAN_BEHAVIOR="Stay on Debian 13 (trixie)"
    else
        PLANNED_DEBIAN_BEHAVIOR="Unsupported Debian major $DEBIAN_MAJOR"
    fi
else
    if (( DEBIAN_MAJOR == 12 )); then
        PLANNED_DEBIAN_BEHAVIOR="Stay on Debian 12 (bookworm)"
    elif (( DEBIAN_MAJOR == 13 )); then
        PLANNED_DEBIAN_BEHAVIOR="Blocked: FileWave $VERSION supported only on Debian 12 (per matrix)"
    else
        PLANNED_DEBIAN_BEHAVIOR="Unsupported Debian major $DEBIAN_MAJOR"
    fi
fi

echo "[SUMMARY] Detected Debian Version: $DEBIAN_VERSION"
echo "[SUMMARY] /boot Usage: $(df -h /boot 2>/dev/null | awk 'NR==2 {print $5}' || echo "n/a")"
echo "[SUMMARY] Installed FileWave Booster Version (fwbooster): $INSTALLED_FWBOOSTER_VERSION"
if [[ "$INSTALLED_FWBOOSTER_VERSION" == "not installed" || "$INSTALLED_FWBOOSTER_VERSION" == "unknown" || -z "$INSTALLED_FWBOOSTER_VERSION" ]]; then
    echo "[SUMMARY] FileWave Booster Presence Check: NO — this system does not appear to have an existing FileWave Booster installation"
else
    echo "[SUMMARY] FileWave Booster Presence Check: YES — existing FileWave Booster installation detected"
fi
echo "[SUMMARY] Target FileWave Version: $VERSION-$REVISION"
echo "[SUMMARY] Server Type: $SERVER_TYPE"
echo "[SUMMARY] Auto-Yes Mode: $auto_yes"
echo "[SUMMARY] Risky Auto-Yes Mode (yesyes): $auto_risky_yes"
echo "[SUMMARY] Planned Debian behavior: $PLANNED_DEBIAN_BEHAVIOR"
echo "[SUMMARY] Beginning validation and upgrade process..."

#################### EARLY DOWNGRADE GUARD ####################
# Block downgrades before doing ANY OS changes. Fresh installs are allowed for FileWave Booster.
INSTALLED_VERSION_EARLY=$(dpkg-query -W -f='${Version}' fwbooster 2>/dev/null || true)
if [[ -n "${INSTALLED_VERSION_EARLY:-}" && "${INSTALLED_VERSION_EARLY}" != "none" ]]; then
    if dpkg --compare-versions "$INSTALLED_VERSION_EARLY" gt "$VERSION"; then
        die "[CHECK] Installed version ($INSTALLED_VERSION_EARLY) is newer than requested ($VERSION). Downgrade is blocked."
    fi
fi
#################### VERSION MATRIX ENFORCEMENT ####################
if dpkg --compare-versions "$VERSION" ge "$MIN_DEBIAN13_FW_VERSION"; then
    if (( DEBIAN_MAJOR == 12 )); then
        upgrade_to_debian13
    elif (( DEBIAN_MAJOR == 13 )); then
        echo "[MATRIX] Debian 13 detected; proceeding with FileWave $VERSION."
    else
        die "[MATRIX] Unsupported Debian major $DEBIAN_MAJOR for FileWave $VERSION. Debian 13 is required."
    fi
else
    if (( DEBIAN_MAJOR != 12 )); then
        die "[MATRIX] FileWave $VERSION is only supported on Debian 12 (per matrix). Current Debian: $DEBIAN_VERSION."
    fi
fi

#################### OPERATOR CONFIRMATION ####################
echo "This script will update your OS and install/upgrade the FileWave Booster package (fwbooster)."
echo "Version: $VERSION, Revision: $REVISION, Server Type: $SERVER_TYPE"
if [[ "$auto_yes" == "true" ]]; then
    confirm="yes"
else
    read -p "Do you wish to proceed? (yes/no): " confirm < /dev/tty
fi
if [[ ! "$confirm" =~ ^[Yy]([Ee][Ss])?$ ]]; then
    echo "Aborting installation as requested."
    exit 0
fi

#################### DOWNLOAD SERVER ####################
if [[ "$SERVER_TYPE" == "beta" ]]; then
    BASE_URL="https://fwbetas.filewave.com"
elif [[ "$SERVER_TYPE" == "dev" ]]; then
    BASE_URL="https://fwdevdl.filewave.com"
else
    BASE_URL="https://fwdl.filewave.com"
fi

#################### MAIN ####################
rm -f /etc/apt/sources.list.d/filewave-beta.list >/dev/null 2>&1 || true
rm -f /etc/apt/sources.list.d/filewave-dev.list >/dev/null 2>&1 || true
rm -f /etc/apt/sources.list.d/filewave-release.list >/dev/null 2>&1 || true

echo "[TOOLS] Installing essential tools..."
apt-get clean || die "[TOOLS] apt-get clean failed."
apt-get update -y || die "[TOOLS] apt-get update failed."
apt-get --fix-broken install -y || die "[TOOLS] apt --fix-broken failed."
apt-get autoremove -y || die "[TOOLS] apt-get autoremove failed."
ensure_boot_space "pre-install kernel space check"
for dep in "python3" "curl" "zip" "gdebi" "wget"; do
    if ! command -v "$dep" >/dev/null 2>&1; then
        echo "[TOOLS] $dep not found. Installing..."
        apt-get update -qq
        DEBIAN_FRONTEND=noninteractive apt-get install -y -q "$dep" || die "[TOOLS] Failed to install $dep."
    fi
done


if ! dpkg-query -W -f='${Status}' net-tools 2>/dev/null | grep -q "install ok installed"; then
    echo "[TOOLS] net-tools not found. Installing..."
    DEBIAN_FRONTEND=noninteractive apt-get install -y -q net-tools || die "[TOOLS] Failed to install net-tools."
fi

#################### INSTALLED VERSION + DOWNGRADE PROTECTION ####################
INSTALLED_VERSION=$(dpkg-query -W -f='${Version}' fwbooster 2>/dev/null || true)

if [[ -z "$INSTALLED_VERSION" || "$INSTALLED_VERSION" == "none" ]]; then
    echo "[CHECK] No fwbooster package detected. This will be treated as a fresh install."
    if [[ "$auto_yes" == "true" ]]; then
        fresh_confirm="yes"
    else
        read -p "Proceed with FRESH install of fwbooster $VERSION? (yes/no): " fresh_confirm < /dev/tty
    fi
    [[ "$fresh_confirm" =~ ^[Yy]([Ee][Ss])?$ ]] || die "[CHECK] Aborting fresh install at user request."
    INSTALLED_VERSION="0.0.0"
fi

if dpkg --compare-versions "$INSTALLED_VERSION" gt "$VERSION"; then
    die "[CHECK] Installed version ($INSTALLED_VERSION) is newer than requested ($VERSION). Downgrade is blocked."
fi

if dpkg --compare-versions "$INSTALLED_VERSION" eq "$VERSION"; then
    echo "[CHECK] Requested version matches installed version ($INSTALLED_VERSION). Proceeding with reinstall."
fi

install_packages() {
    echo "[INSTALL] Downloading and installing FileWave Booster package..."

    local PACKAGE="fwbooster_${VERSION}_amd64.deb"
    DOWNLOAD_DIR="/tmp/filewave_install_$$"
    mkdir -p "$DOWNLOAD_DIR" || die "[INSTALL] Failed to create download directory."

    local PACKAGE_URL="$BASE_URL/$VERSION/$PACKAGE"
    echo "[DOWNLOAD] Validating download exists: $PACKAGE_URL"
    if ! validate_download_exists "$PACKAGE_URL" 2; then
        die "[DOWNLOAD] Package not found at: $PACKAGE_URL (server_type=$SERVER_TYPE). Verify the version/channel and try again."
    fi

    echo "[DOWNLOAD] Downloading $PACKAGE..."
    local ok=false
    for i in {1..3}; do
        if wget -q -O "$DOWNLOAD_DIR/$PACKAGE" "$PACKAGE_URL"; then
            ok=true
            break
        fi
        echo "[DOWNLOAD] Retrying download ($i/3)..."
        sleep 5
    done
    $ok || die "[DOWNLOAD] Failed to download $PACKAGE after multiple attempts."

    echo "[INSTALL] Installing $PACKAGE..."
    DEBIAN_FRONTEND=noninteractive gdebi -n "$DOWNLOAD_DIR/$PACKAGE" || die "[INSTALL] Failed to install $PACKAGE."
}

echo "[INSTALL] Upgrading/installing from $INSTALLED_VERSION to $VERSION..."
install_packages
ensure_boot_space "post FileWave package install kernel space check"
#################### OS PATCH UPGRADE ####################
if [[ "$OS_UPGRADED" == "true" ]]; then
    echo "[OS-UPGRADE] Skipping generic OS upgrade step because Debian 12 -> 13 release upgrade already occurred in this run."
else
    echo "[OS-UPGRADE] This will apply OS updates (apt upgrade). Recommended for security."
    if [[ "$auto_yes" == "true" ]]; then
        upgrade_confirm="yes"
    else
        read -p "Proceed with OS patch upgrade now? (yes/no): " upgrade_confirm < /dev/tty
    fi

    if [[ "$upgrade_confirm" =~ ^[Yy]([Ee][Ss])?$ ]]; then
ensure_boot_space "pre OS patch upgrade kernel space check"
        echo "[OS-UPGRADE] Running apt upgrade..."
        apt-get update -y || die "[OS-UPGRADE] apt-get update failed."
        DEBIAN_FRONTEND=noninteractive apt-get upgrade -y \
            -o Dpkg::Options::="--force-confdef" \
            -o Dpkg::Options::="--force-confold" \
            --autoremove || die "[OS-UPGRADE] apt-get upgrade failed."
    else
        echo "[OS-UPGRADE] Skipping OS patch upgrade at user request."
    fi
fi

#################### REBOOT ####################
echo "[REBOOT] The system should reboot to complete updates."
if [[ "$auto_yes" == "true" ]]; then
    reboot_confirm="yes"
else
    read -p "Reboot now? (yes/no): " reboot_confirm < /dev/tty
fi

if [[ "$reboot_confirm" =~ ^[Yy]([Ee][Ss])?$ ]]; then
    FINAL_FWXSERVER_VERSION=$(dpkg-query -W -f='${Version}' fwbooster 2>/dev/null || echo "unknown")
    echo "[SUMMARY-END] Debian Version After Upgrade: $(grep -E '^VERSION_ID=' /etc/os-release | cut -d= -f2 | tr -d '\"')"
if has_separate_boot; then
    echo "[SUMMARY-END] /boot Usage After Upgrade: $(boot_fs_use_pct)"
else
    echo "[SUMMARY-END] /boot Usage After Upgrade: N/A (no separate /boot filesystem; /boot is on /)"
    echo "[SUMMARY-END] Root FS Usage After Upgrade: $(root_fs_use_pct)"
    echo "[SUMMARY-END] /boot Directory Size After Upgrade: $(boot_dir_size)"
fi
    echo "[SUMMARY-END] FileWave Booster Version Installed (fwbooster): $FINAL_FWXSERVER_VERSION"
    echo "[SUMMARY-END] Major OS Upgrade Performed (Debian 12 -> 13): $OS_UPGRADED"
    echo "[SUMMARY-END] Log File: $LOG_FILE"
    if [[ "${auto_risky_yes:-false}" == "true" ]]; then
    echo "[REBOOT] Rebooting in 0 seconds... (unattended mode)"
    reboot
else
    echo "[REBOOT] Rebooting in 120 seconds... (press Enter to reboot now)"
    # Wait up to 120 seconds for Enter; then reboot automatically.
    if read -r -t 120 _ < /dev/tty; then
        echo "[REBOOT] Rebooting now..."
    else
        echo "[REBOOT] Timeout reached; rebooting now..."
    fi
    reboot
fi
else
    echo "[REBOOT] Skipping reboot. Please reboot manually to apply all changes."
    echo "[REBOOT] Log File: $LOG_FILE"
fi