#!/bin/bash
# WireGuard Policy Firewall Installer/Uninstaller
# This file is auto-generated. Do not edit directly. Run build.sh or build.bat instead.

set -euo pipefail

if [[ $EUID -ne 0 ]]; then
   echo "This script must be run as root."
   exit 1
fi

if ! command -v wg &>/dev/null; then
    echo "[ERROR] WireGuard is not installed."
    echo "  Debian/Ubuntu: apt install wireguard"
    echo "  RHEL/CentOS:   dnf install wireguard-tools"
    echo "  Arch:          pacman -S wireguard-tools"
    exit 1
fi

if [[ ! -f /etc/wireguard/wg0.conf ]]; then
    echo "[WARN] WireGuard config not found: /etc/wireguard/wg0.conf"
    echo "  PostUp/PostDown hooks will not be added automatically."
    echo "  Create your wg0.conf first, then re-install."
fi

WG_CONF="/etc/wireguard/wg0.conf"

install_hooks() {
    if [[ ! -f "$WG_CONF" ]]; then
        return 0
    fi

    if grep -q "wg-sync-policy.sh" "$WG_CONF" 2>/dev/null; then
        echo "[OK] PostUp/PostDown hooks already present in $WG_CONF"
        return 0
    fi

    echo "Adding PostUp/PostDown hooks to $WG_CONF..."
    cp "$WG_CONF" "${WG_CONF}.bak.$(date +%Y%m%d%H%M%S)"

    local peer_line
    peer_line=$(grep -n '^\[Peer\]' "$WG_CONF" | head -1 | cut -d: -f1)

    if [[ -n "$peer_line" ]]; then
        sed -i "${peer_line}i\\
# WireGuard Policy Firewall hooks\\
PostUp = /usr/local/bin/wg-sync-policy.sh; /usr/local/bin/wg-policy-engine.sh\\
PostDown = /usr/local/bin/wg-policy-cleanup.sh" "$WG_CONF"
    else
        {
            echo ""
            echo "# WireGuard Policy Firewall hooks"
            echo "PostUp = /usr/local/bin/wg-sync-policy.sh; /usr/local/bin/wg-policy-engine.sh"
            echo "PostDown = /usr/local/bin/wg-policy-cleanup.sh"
        } >> "$WG_CONF"
    fi

    echo "[OK] Hooks added to $WG_CONF"
}

remove_hooks() {
    if [[ ! -f "$WG_CONF" ]]; then
        return 0
    fi

    if ! grep -q "wg-sync-policy.sh" "$WG_CONF" 2>/dev/null; then
        return 0
    fi

    echo "Removing PostUp/PostDown hooks from $WG_CONF..."
    cp "$WG_CONF" "${WG_CONF}.bak.$(date +%Y%m%d%H%M%S)"
    sed -i '/# WireGuard Policy Firewall hooks/d' "$WG_CONF"
    sed -i '/wg-sync-policy\.sh/d' "$WG_CONF"
    sed -i '/wg-policy-cleanup\.sh/d' "$WG_CONF"
    echo "[OK] Hooks removed from $WG_CONF"
}

install_policy() {
    echo "Installing WireGuard Policy Firewall..."

    echo "Checking dependencies..."
    apt-get update -y || true
    apt-get install -y jq inotify-tools nftables || true

    echo "Writing scripts to /usr/local/bin/..."

    cat << 'EOF_WG_POLICY_LIB_SH' > /usr/local/bin/wg-policy-lib.sh
#!/bin/bash
# wg-policy-lib.sh — Shared functions for WireGuard Policy Firewall
# Source this file; do not execute directly.

set -euo pipefail

# ============================================================
# CONFIGURATION
# ============================================================
readonly WG_IF="${WG_IF:-wg0}"
readonly NFT_TABLE="wg_policy"
readonly NFT_TABLE_FULL="inet wg_policy"
readonly NFT_SET_V4="wg_allowed_v4"
readonly NFT_SET_V6="wg_allowed_v6"
readonly POLICY_FILE="/etc/wireguard/policy.json"
readonly WG_CONF="/etc/wireguard/wg0.conf"
readonly LOCK_FILE="/var/lock/wg-policy.lock"
readonly BACKUP_DIR="/etc/wireguard/backups"
readonly LOG_PREFIX="WG_DROP"
readonly LOG_RATE="10/minute"
readonly MAX_RETRY=3
readonly RETRY_DELAY=2
readonly DEBOUNCE_SEC=2

# ============================================================
# LOGGING
# ============================================================
log_info()  { echo "[$(date '+%Y-%m-%d %H:%M:%S')] [INFO]  $*"; }
log_warn()  { echo "[$(date '+%Y-%m-%d %H:%M:%S')] [WARN]  $*" >&2; }
log_error() { echo "[$(date '+%Y-%m-%d %H:%M:%S')] [ERROR] $*" >&2; }

# ============================================================
# VALIDATION
# ============================================================

validate_ipv4() {
    local ip="$1"
    if [[ ! "$ip" =~ ^([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})$ ]]; then
        return 1
    fi
    local IFS='.'
    read -ra octets <<< "$ip"
    for octet in "${octets[@]}"; do
        if [[ "$octet" =~ ^0[0-9] ]]; then
            return 1
        fi
        if (( octet < 0 || octet > 255 )); then
            return 1
        fi
    done
    return 0
}

validate_ipv4_cidr() {
    local cidr="$1"
    local ip prefix

    if [[ "$cidr" == *"/"* ]]; then
        ip="${cidr%%/*}"
        prefix="${cidr##*/}"
    else
        ip="$cidr"
        prefix="32"
    fi

    if ! validate_ipv4 "$ip"; then
        return 1
    fi

    if [[ ! "$prefix" =~ ^[0-9]+$ ]] || (( prefix < 0 || prefix > 32 )); then
        return 1
    fi
    return 0
}

validate_ipv6() {
    local ip="$1"
    if [[ "$ip" =~ ^([0-9a-fA-F]{0,4}:){2,7}[0-9a-fA-F]{0,4}$ ]] || \
       [[ "$ip" =~ ^::([0-9a-fA-F]{0,4}:){0,5}[0-9a-fA-F]{0,4}$ ]] || \
       [[ "$ip" =~ ^([0-9a-fA-F]{0,4}:){1,7}:$ ]] || \
       [[ "$ip" == "::" ]] || \
       [[ "$ip" == "::1" ]]; then
        return 0
    fi
    return 1
}

validate_ipv6_cidr() {
    local cidr="$1"
    local ip prefix

    if [[ "$cidr" == *"/"* ]]; then
        ip="${cidr%%/*}"
        prefix="${cidr##*/}"
    else
        ip="$cidr"
        prefix="128"
    fi

    if ! validate_ipv6 "$ip"; then
        return 1
    fi

    if [[ ! "$prefix" =~ ^[0-9]+$ ]] || (( prefix < 0 || prefix > 128 )); then
        return 1
    fi
    return 0
}

validate_cidr() {
    local cidr="$1"
    if [[ "$cidr" == *":"* ]]; then
        validate_ipv6_cidr "$cidr"
    else
        validate_ipv4_cidr "$cidr"
    fi
}

# ============================================================
# NFTABLES HELPERS
# ============================================================

has_nft() {
    command -v nft &>/dev/null
}

# ============================================================
# RETRY MECHANISM
# ============================================================

retry() {
    local max_attempts="${MAX_RETRY}"
    local delay="${RETRY_DELAY}"
    local attempt=1
    local exit_code=0

    while (( attempt <= max_attempts )); do
        if "$@"; then
            return 0
        fi
        exit_code=$?
        log_warn "Attempt $attempt/$max_attempts failed (exit=$exit_code), retrying in ${delay}s..."
        sleep "$delay"
        (( attempt++ ))
        (( delay *= 2 ))
    done

    log_error "All $max_attempts attempts failed for: $*"
    return "$exit_code"
}

# ============================================================
# LOCK MANAGEMENT
# ============================================================

acquire_lock() {
    local lock_fd=200
    eval "exec ${lock_fd}>\"${LOCK_FILE}\""
    if ! flock -x -w 10 "$lock_fd"; then
        log_error "Failed to acquire lock: ${LOCK_FILE} (timeout 10s)"
        return 1
    fi
    log_info "Lock acquired: ${LOCK_FILE}"
}

release_lock() {
    rm -f "$LOCK_FILE" 2>/dev/null || true
}

# ============================================================
# BACKUP
# ============================================================

backup_policy() {
    mkdir -p "$BACKUP_DIR"
    local timestamp
    timestamp="$(date '+%Y%m%d_%H%M%S')"

    if [[ -f "$POLICY_FILE" ]]; then
        cp "$POLICY_FILE" "${BACKUP_DIR}/policy_${timestamp}.json"
        log_info "Backup created: ${BACKUP_DIR}/policy_${timestamp}.json"
    fi

    local count
    count=$(find "$BACKUP_DIR" -name 'policy_*.json' -type f | wc -l)
    if (( count > 50 )); then
        find "$BACKUP_DIR" -name 'policy_*.json' -type f -printf '%T@ %p\n' \
            | sort -n \
            | head -n $(( count - 50 )) \
            | awk '{print $2}' \
            | xargs rm -f
        log_info "Pruned old backups (kept 50)"
    fi
}

backup_nftables() {
    mkdir -p "$BACKUP_DIR"
    local timestamp
    timestamp="$(date '+%Y%m%d_%H%M%S')"

    if nft list ruleset > "${BACKUP_DIR}/nftables_${timestamp}.rules" 2>/dev/null; then
        log_info "nftables backup: ${BACKUP_DIR}/nftables_${timestamp}.rules"
    fi

    local count
    count=$(find "$BACKUP_DIR" -name 'nftables_*.rules' -type f | wc -l)
    if (( count > 20 )); then
        find "$BACKUP_DIR" -name 'nftables_*.rules' -type f -printf '%T@ %p\n' \
            | sort -n \
            | head -n $(( count - 20 )) \
            | awk '{print $2}' \
            | xargs rm -f
    fi
}

# ============================================================
# DETECTION HELPERS
# ============================================================

detect_lan_subnets() {
    ip -o -4 route show scope link \
        | awk '{print $1}' \
        | grep -E '^(10\.|172\.(1[6-9]|2[0-9]|3[01])\.|192\.168\.)' \
        | sort -u
}

detect_wg_subnet() {
    local family="${1:-inet}"
    if [[ "$family" == "inet6" ]]; then
        ip -o -6 addr show "$WG_IF" 2>/dev/null \
            | awk '{print $4; exit}'
    else
        ip -o -4 addr show "$WG_IF" 2>/dev/null \
            | awk '{print $4; exit}'
    fi
}

detect_default_if() {
    local def_if
    def_if=$(ip -4 route ls 2>/dev/null | grep default | grep -Po '(?<=dev )(\S+)' | head -1 || true)
    if [[ -z "$def_if" ]]; then
        echo "eth0"
    else
        echo "$def_if"
    fi
}

# ============================================================
# HEALTH CHECK
# ============================================================

health_check() {
    local status=0
    local report=""

    # 1. Check interface exists
    if ip link show "$WG_IF" &>/dev/null; then
        report+="[OK] Interface $WG_IF is UP\n"
    else
        report+="[FAIL] Interface $WG_IF not found\n"
        status=1
    fi

    # 2. Check policy.json exists and is valid
    if [[ -f "$POLICY_FILE" ]] && jq empty "$POLICY_FILE" 2>/dev/null; then
        local client_count
        client_count=$(jq '(.clients // {}) | length' "$POLICY_FILE")
        report+="[OK] policy.json valid ($client_count clients)\n"
    else
        report+="[FAIL] policy.json missing or corrupt\n"
        status=1
    fi

    # 3. Check nftables table exists
    if nft list table "$NFT_TABLE_FULL" &>/dev/null; then
        local rule_count
        rule_count=$(nft list chain "$NFT_TABLE_FULL" forward 2>/dev/null | grep -c '^\s*' || echo 0)
        report+="[OK] Table $NFT_TABLE active ($rule_count rules)\n"
    else
        report+="[WARN] Table $NFT_TABLE not found\n"
        status=1
    fi

    # 4. Check forward chain exists in table
    if nft list chain "$NFT_TABLE_FULL" forward &>/dev/null; then
        report+="[OK] Forward chain exists in $NFT_TABLE\n"
    else
        report+="[WARN] Forward chain not found in $NFT_TABLE\n"
        status=1
    fi

    # 5. Check nftables sets
    for set_name in "$NFT_SET_V4" "$NFT_SET_V6"; do
        if nft list set "$NFT_TABLE_FULL" "$set_name" &>/dev/null; then
            local entry_count
            entry_count=$(nft list set "$NFT_TABLE_FULL" "$set_name" 2>/dev/null | grep -c '^\s*' || echo 0)
            report+="[OK] Set $set_name active ($entry_count entries)\n"
        else
            report+="[INFO] Set $set_name not created (may not be needed)\n"
        fi
    done

    # 6. Check watcher service
    if systemctl is-active --quiet wg-policy.service 2>/dev/null; then
        report+="[OK] wg-policy.service is running\n"
    else
        report+="[INFO] wg-policy.service not running\n"
    fi

    # 7. Check lock file not stale
    if [[ -f "$LOCK_FILE" ]]; then
        local lock_age
        lock_age=$(( $(date +%s) - $(stat -c %Y "$LOCK_FILE" 2>/dev/null || echo 0) ))
        if (( lock_age > 300 )); then
            report+="[WARN] Stale lock file (${lock_age}s old)\n"
        else
            report+="[OK] Lock file age: ${lock_age}s\n"
        fi
    else
        report+="[OK] No stale lock file\n"
    fi

    echo -e "$report"
    return $status
}

EOF_WG_POLICY_LIB_SH

    cat << 'EOF_WG_POLICY_ENGINE_SH' > /usr/local/bin/wg-policy-engine.sh
#!/bin/bash
# wg-policy-engine.sh — Applies nftables rules from policy.json

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "${SCRIPT_DIR}/wg-policy-lib.sh"

NFT_FILE="/tmp/wg-policy.nft"
NFT_BACKUP="/tmp/wg-policy-backup.nft"

# ============================================================
# ROLLBACK
# ============================================================

rollback() {
    log_error "ROLLBACK triggered! Restoring previous ruleset..."
    trap - ERR

    nft delete table "$NFT_TABLE_FULL" 2>/dev/null || true

    if [[ -f "$NFT_BACKUP" ]]; then
        if nft -f "$NFT_BACKUP" 2>/dev/null; then
            log_info "Rollback: restored from backup"
        else
            log_error "Rollback: failed to restore from backup"
        fi
    fi
}

# ============================================================
# RULESET GENERATION
# ============================================================

generate_ruleset() {
    local WG_SUBNET="$1"
    local WG_SUBNET_V6="$2"
    local LAN_SUBNETS="$3"
    local DEF_IF="$4"

    cat > "$NFT_FILE" << 'HEADER'
#!/usr/sbin/nft -f
flush ruleset

table inet wg_policy {

    set wg_allowed_v4 {
        type ipv4_addr . ipv4_addr
        flags interval
    }

    set wg_allowed_v6 {
        type ipv6_addr . ipv6_addr
        flags interval
    }

    chain forward {
        type filter hook forward priority filter; policy accept;

        ct state established,related accept

        iifname "wg0" ip saddr . ip daddr @wg_allowed_v4 accept
        iifname "wg0" ip6 saddr . ip6 daddr @wg_allowed_v6 accept

HEADER

    # Client isolation (IPv4)
    if [[ -n "$WG_SUBNET" ]]; then
        cat >> "$NFT_FILE" << EOF

        /* isolation: WG client to WG client */
        iifname "wg0" ip saddr $WG_SUBNET ip daddr $WG_SUBNET ct state new drop
EOF
    fi

    # Client isolation (IPv6)
    if [[ -n "$WG_SUBNET_V6" ]]; then
        cat >> "$NFT_FILE" << EOF

        /* IPv6 isolation */
        iifname "wg0" ip6 saddr $WG_SUBNET_V6 ip6 daddr $WG_SUBNET_V6 ct state new drop
        iifname "wg0" ip6 saddr $WG_SUBNET_V6 ip6 daddr fe80::/10 drop
        iifname "wg0" ip6 saddr $WG_SUBNET_V6 ip6 daddr fc00::/7 drop
EOF
    fi

    # LAN block (IPv4)
    if [[ -n "$WG_SUBNET" && -n "$LAN_SUBNETS" ]]; then
        local lan_list=""
        while IFS= read -r subnet; do
            [[ -z "$subnet" ]] && continue
            [[ "$subnet" == "$WG_SUBNET" ]] && continue
            if [[ -n "$lan_list" ]]; then
                lan_list+=", $subnet"
            else
                lan_list="$subnet"
            fi
        done <<< "$LAN_SUBNETS"

        if [[ -n "$lan_list" ]]; then
            cat >> "$NFT_FILE" << EOF

        /* LAN block */
        iifname "wg0" ip saddr $WG_SUBNET ip daddr { $lan_list } drop
EOF
        fi
    fi

    # Internet access per client (inline in chain)
    while IFS= read -r client_ip; do
        [[ -z "$client_ip" ]] && continue
        cat >> "$NFT_FILE" << EOF

        /* internet access: $client_ip */
        iifname "wg0" ip saddr $client_ip accept
EOF
    done < <(jq -r '
        .clients // {} | to_entries[] |
        select(.value.internet == "true") |
        .key
    ' "$POLICY_FILE" 2>/dev/null)

    while IFS= read -r client_ip; do
        [[ -z "$client_ip" ]] && continue
        cat >> "$NFT_FILE" << EOF

        /* internet access v6: $client_ip */
        iifname "wg0" ip6 saddr $client_ip accept
EOF
    done < <(jq -r '
        .clients // {} | to_entries[] |
        select(.value.internet == "true") |
        select(.key | test(":")) |
        .key
    ' "$POLICY_FILE" 2>/dev/null)

    # Log + drop (final rule)
    cat >> "$NFT_FILE" << EOF

        /* log + drop */
        iifname "wg0" limit rate ${LOG_RATE} log prefix "${LOG_PREFIX}: " drop
    }

    chain postrouting {
        type nat hook postrouting priority srcnat; policy accept;
        oifname "${DEF_IF}" masquerade
    }
}
EOF
}

# ============================================================
# MAIN
# ============================================================

main() {
    log_info "Starting policy engine..."

    # === VALIDATE ===
    if ! ip link show "$WG_IF" &>/dev/null; then
        log_error "Interface $WG_IF is not running. Aborting policy engine."
        exit 1
    fi

    if [[ ! -f "$POLICY_FILE" ]]; then
        log_error "Policy file not found: $POLICY_FILE"
        exit 1
    fi

    if ! jq empty "$POLICY_FILE" 2>/dev/null; then
        log_error "policy.json is corrupt"
        exit 1
    fi

    # Backup current nftables state
    backup_nftables

    # Set trap for rollback on failure
    trap 'rollback' ERR

    # === DETECT SUBNETS ===
    local WG_SUBNET WG_SUBNET_V6 LAN_SUBNETS DEF_IF

    WG_SUBNET="$(detect_wg_subnet inet)"
    WG_SUBNET_V6="$(detect_wg_subnet inet6)"
    LAN_SUBNETS="$(detect_lan_subnets)"
    DEF_IF="$(detect_default_if)"

    if [[ -z "$WG_SUBNET" ]]; then
        log_warn "Interface $WG_IF has no IPv4, skipping client isolation"
    else
        log_info "WG IPv4 subnet: $WG_SUBNET"
    fi

    if [[ -n "$WG_SUBNET_V6" ]]; then
        log_info "WG IPv6 subnet: $WG_SUBNET_V6"
    fi

    if [[ -n "$LAN_SUBNETS" ]]; then
        log_info "Detected LAN subnets:"
        echo "$LAN_SUBNETS" | while read -r s; do log_info "  $s"; done
    fi

    # === BASE ROUTING & NAT ===
    sysctl -w net.ipv4.ip_forward=1 >/dev/null 2>&1 || true
    sysctl -w net.ipv6.conf.all.forwarding=1 >/dev/null 2>&1 || true

    # === BACKUP EXISTING TABLE ===
    if nft list table "$NFT_TABLE_FULL" &>/dev/null; then
        nft list table "$NFT_TABLE_FULL" > "$NFT_BACKUP" 2>/dev/null || true
        log_info "Backed up existing table to $NFT_BACKUP"
    fi

    # === DELETE OLD TABLE ===
    nft delete table "$NFT_TABLE_FULL" 2>/dev/null || true

    # === GENERATE AND LOAD NEW RULESET ===
    generate_ruleset "$WG_SUBNET" "$WG_SUBNET_V6" "$LAN_SUBNETS" "$DEF_IF"
    log_info "Generated ruleset: $NFT_FILE"

    nft -f "$NFT_FILE"
    log_info "Loaded nftables ruleset from $NFT_FILE"

    # === POPULATE SETS ===
    log_info "Populating whitelist sets..."

    local v4_count=0
    local v6_count=0

    while IFS= read -r line; do
        [[ -z "$line" ]] && continue
        local client_ip target
        client_ip=$(echo "$line" | awk '{print $1}')
        target=$(echo "$line" | awk '{print $2}')
        [[ -z "$client_ip" || -z "$target" ]] && continue

        if [[ "$target" == *":"* ]]; then
            nft add element "$NFT_TABLE_FULL" "$NFT_SET_V6" { "$client_ip" . "$target" } 2>/dev/null || \
                log_warn "Failed to add ${client_ip} . ${target} to set $NFT_SET_V6"
            (( v6_count++ )) || true
        else
            nft add element "$NFT_TABLE_FULL" "$NFT_SET_V4" { "$client_ip" . "$target" } 2>/dev/null || \
                log_warn "Failed to add ${client_ip} . ${target} to set $NFT_SET_V4"
            (( v4_count++ )) || true
        fi
    done < <(jq -r '
        .clients // {} | to_entries[] |
        select(.value.access != null and (.value.access | length > 0)) |
        .key as $ip |
        .value.access[] |
        "\($ip) \(.)"
    ' "$POLICY_FILE" 2>/dev/null)

    log_info "Set $NFT_SET_V4: $v4_count entries, $NFT_SET_V6: $v6_count entries"

    # === CLEANUP BACKUP (success path) ===
    rm -f "$NFT_BACKUP" 2>/dev/null || true

    # Disable ERR trap (success path)
    trap - ERR

    # === VERIFY ===
    local rule_count
    rule_count=$(nft list chain "$NFT_TABLE_FULL" forward 2>/dev/null | grep -c '^\s*' || echo 0)
    log_info "Policy applied. Table: $NFT_TABLE, Rules: $rule_count"

    echo "[OK] nftables policy applied. Table: $NFT_TABLE"
}

main "$@"

EOF_WG_POLICY_ENGINE_SH

    cat << 'EOF_WG_POLICY_CLEANUP_SH' > /usr/local/bin/wg-policy-cleanup.sh
#!/bin/bash
# wg-policy-cleanup.sh — Clean removal of all policy artifacts

set -uo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "${SCRIPT_DIR}/wg-policy-lib.sh"

main() {
    log_info "Starting cleanup..."

    nft delete table inet wg_policy 2>/dev/null || true
    log_info "Removed nftables table inet wg_policy"

    rm -f "$LOCK_FILE" 2>/dev/null || true

    log_info "Cleanup complete"
}

main "$@"

EOF_WG_POLICY_CLEANUP_SH

    cat << 'EOF_WG_SYNC_POLICY_SH' > /usr/local/bin/wg-sync-policy.sh
#!/bin/bash
# wg-sync-policy.sh — Reads wg0.conf, validates, generates policy.json atomically
# Fixed: IP validation, atomic write, proper locking, error handling

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "${SCRIPT_DIR}/wg-policy-lib.sh"

# ============================================================
# MAIN
# ============================================================

main() {
    log_info "Starting policy sync..."

    # Validate prerequisites
    if [[ ! -f "$WG_CONF" ]]; then
        log_error "WireGuard config not found: $WG_CONF"
        exit 1
    fi

    if ! command -v jq &>/dev/null; then
        log_error "jq is required but not installed"
        exit 1
    fi

    # Acquire lock
    acquire_lock
    trap 'release_lock' EXIT

    # Backup current policy
    backup_policy

    # Temporary file for atomic write
    local tmp_policy
    tmp_policy="$(mktemp /tmp/wg-policy.XXXXXX)"
    trap "rm -f \"$tmp_policy\" 2>/dev/null; release_lock" EXIT

    echo '{"clients":{}}' > "$tmp_policy"

    # Parse peers from wg0.conf
    # AWK extracts IP and #Access comment per [Peer] block
    local parse_errors=0

    awk '
    BEGIN { RS="\n\\[Peer\\]\n"; FS="\n" }
    NR>1 {
        ip=""; access=""; internet="false"
        for(i=1;i<=NF;i++){
            if($i ~ /^AllowedIPs/) {
                split($i,a," = ")
                gsub(/ /,"",a[2])
                split(a[2],b,",")
                split(b[1],c,"/")
                ip=c[1]
            }
            if($i ~ /^#Access/) {
                sub(/^#Access[ \t]*=?[ \t]*/, "", $i)
                access=$i
            }
            if($i ~ /^#Internet/) {
                if(tolower($i) ~ /true|yes|1|allow/) {
                    internet="true"
                }
            }
        }
        if(ip!="" && ip!="0.0.0.0" && ip!="::") {
            printf "%s|%s|%s\n", ip, access, internet
        }
    }
    ' "$WG_CONF" | while IFS="|" read -r ip access_string internet_flag; do

        # === VALIDATE CLIENT IP ===
        if ! validate_cidr "$ip"; then
            log_warn "Invalid client IP skipped: '$ip'"
            (( parse_errors++ )) || true
            continue
        fi

        # === PARSE AND VALIDATE ACCESS TARGETS ===
        local ACCESS_JSON="[]"

        if [[ -n "$access_string" ]]; then
            # Split by ; and , then validate each entry
            local valid_targets=()
            local IFS_OLD="$IFS"
            IFS=';,'
            read -ra targets <<< "$access_string"
            IFS="$IFS_OLD"

            for target in "${targets[@]}"; do
                # Trim whitespace
                target="$(echo "$target" | sed 's/^[[:space:]]*//;s/[[:space:]]*$//')"

                [[ -z "$target" ]] && continue

                if validate_cidr "$target"; then
                    valid_targets+=("$target")
                else
                    log_warn "Invalid access target skipped for $ip: '$target'"
                    (( parse_errors++ )) || true
                fi
            done

            if (( ${#valid_targets[@]} > 0 )); then
                ACCESS_JSON=$(printf '%s\n' "${valid_targets[@]}" | jq -R . | jq -s .)
            fi
        fi

        # Write to temp policy
        jq --arg ip "$ip" --argjson access "$ACCESS_JSON" --argjson internet "$internet_flag" \
           '.clients[$ip] = {"name": $ip, "access": $access, "internet": $internet}' \
           "$tmp_policy" > "${tmp_policy}.tmp" && mv "${tmp_policy}.tmp" "$tmp_policy"

    done

    # Validate JSON before atomic move
    if ! jq empty "$tmp_policy" 2>/dev/null; then
        log_error "Generated JSON is invalid, aborting. Check $tmp_policy"
        exit 1
    fi

    # Atomic move (same filesystem = atomic rename)
    mv -f "$tmp_policy" "$POLICY_FILE"
    log_info "policy.json updated successfully"

    if (( parse_errors > 0 )); then
        log_warn "$parse_errors validation errors encountered (see warnings above)"
    fi

    local client_count
    client_count=$(jq '(.clients // {}) | length' "$POLICY_FILE")
    log_info "Total clients in policy: $client_count"
}

main "$@"

EOF_WG_SYNC_POLICY_SH

    cat << 'EOF_WG_SYNC_WATCH_SH' > /usr/local/bin/wg-sync-watch.sh
#!/bin/bash
# wg-sync-watch.sh — Watches wg0.conf for changes with debounce
# Fixed: proper debounce, error isolation, health reporting

set -uo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "${SCRIPT_DIR}/wg-policy-lib.sh"

SYNC_SCRIPT="/usr/local/bin/wg-sync-policy.sh"
ENGINE_SCRIPT="/usr/local/bin/wg-policy-engine.sh"
HEALTH_INTERVAL=300  # Health check every 5 minutes
LAST_HEALTH=0

# === Validate prerequisites ===
if ! command -v inotifywait &>/dev/null; then
    log_error "inotifywait not found. Install: apt install inotify-tools"
    exit 1
fi

if [[ ! -f "$WG_CONF" ]]; then
    log_error "WireGuard config not found: $WG_CONF"
    exit 1
fi

# === Main watcher loop ===
log_info "Monitoring $WG_CONF for changes (debounce: ${DEBOUNCE_SEC}s)..."
log_info "Health check interval: ${HEALTH_INTERVAL}s"

inotifywait -m -e close_write,move,create \
    --format '%e %f' \
    "$(dirname "$WG_CONF")" 2>/dev/null | \
while read -r events filename; do

    # Only react to wg0.conf changes
    [[ "$filename" != "$(basename "$WG_CONF")" ]] && continue

    log_info "Detected change: $events $filename"

    # Debounce: wait until no more events for DEBOUNCE_SEC
    while IFS= read -r -t "$DEBOUNCE_SEC" _dummy; do
        : # Drain events within debounce window
    done

    log_info "Debounce complete, applying changes..."

    # Run sync
    if retry "$SYNC_SCRIPT"; then
        log_info "Sync successful, running engine..."

        # Run engine with retry
        if retry "$ENGINE_SCRIPT"; then
            log_info "Policy engine applied successfully"
        else
            log_error "Policy engine FAILED after retries"
        fi
    else
        log_error "Policy sync FAILED after retries"
    fi

    # Periodic health check
    local now
    now=$(date +%s)
    if (( now - LAST_HEALTH >= HEALTH_INTERVAL )); then
        LAST_HEALTH=$now
        log_info "=== Periodic Health Check ==="
        health_check || log_warn "Health check reported issues"
    fi

done

EOF_WG_SYNC_WATCH_SH

    cat << 'EOF_WG_POLICY_CTL' > /usr/local/bin/wg-policy-ctl
#!/bin/bash
# wg-policy-ctl — CLI management tool for WireGuard Policy Firewall

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "${SCRIPT_DIR}/wg-policy-lib.sh"

usage() {
    cat <<EOF
Usage: $(basename "$0") <command>

Commands:
    status      Show full health check report
    policy      Display current policy.json formatted
    rules       Show current nftables rules
    ipset       Show nftables set contents
    log         Tail WG_DROP logs (last 50 lines)
    reload      Force re-sync and re-apply policy
    backup      Manual backup of policy + nftables
    stats       Show connection and rule statistics
    validate    Validate policy.json without applying
    help        Show this help
EOF
}

cmd_status() {
    echo "========================================="
    echo " WireGuard Policy Firewall Status"
    echo " $(date '+%Y-%m-%d %H:%M:%S')"
    echo "========================================="
    echo ""
    health_check
}

cmd_policy() {
    if [[ -f "$POLICY_FILE" ]]; then
        jq '.' "$POLICY_FILE"
    else
        log_error "policy.json not found"
        exit 1
    fi
}

cmd_rules() {
    echo "=== Table: $NFT_TABLE_FULL ==="
    if nft list table "$NFT_TABLE_FULL" 2>/dev/null; then
        echo ""
    else
        echo "(table not found)"
    fi
}

cmd_ipset() {
    for set_name in "$NFT_SET_V4" "$NFT_SET_V6"; do
        echo "=== nft set: $set_name ==="
        if nft list set "$NFT_TABLE_FULL" "$set_name" 2>/dev/null; then
            echo ""
        else
            echo "(not found)"
            echo ""
        fi
    done
}

cmd_log() {
    echo "=== Recent WG_DROP log entries ==="
    (journalctl -k --no-pager -n 50 2>/dev/null || dmesg | tail -50) | grep "$LOG_PREFIX" || echo "(no entries)"
}

cmd_reload() {
    log_info "Force reloading policy..."
    if retry /usr/local/bin/wg-sync-policy.sh; then
        if retry /usr/local/bin/wg-policy-engine.sh; then
            log_info "Reload complete"
        else
            log_error "Engine failed"
            exit 1
        fi
    else
        log_error "Sync failed"
        exit 1
    fi
}

cmd_backup() {
    backup_policy
    backup_nftables
    log_info "Manual backup complete. Files in: $BACKUP_DIR"
}

cmd_stats() {
    echo "=== Client Count ==="
    jq '(.clients // {}) | length' "$POLICY_FILE" 2>/dev/null || echo "N/A"

    echo ""
    echo "=== Clients with Access ==="
    jq -r '.clients // {} | to_entries[] | select(.value.access | length > 0) | "\(.key): \(.value.access | join(", "))"' "$POLICY_FILE" 2>/dev/null || echo "N/A"

    echo ""
    echo "=== Clients without Access (Internet Only) ==="
    jq -r '.clients // {} | to_entries[] | select(.value.access | length == 0) | .key' "$POLICY_FILE" 2>/dev/null || echo "N/A"

    echo ""
    echo "=== Active nftables rules ==="
    nft list chain "$NFT_TABLE_FULL" forward 2>/dev/null | grep -c '#' || echo "N/A"

    echo ""
    echo "=== nft set entries ==="
    for set_name in "$NFT_SET_V4" "$NFT_SET_V6"; do
        local count
        count=$(nft list set "$NFT_TABLE_FULL" "$set_name" 2>/dev/null | grep -c -E '^\s+[0-9a-f]' || echo 0)
        echo "  $set_name: $count entries"
    done
}

cmd_validate() {
    log_info "Validating policy.json..."

    if [[ ! -f "$POLICY_FILE" ]]; then
        log_error "File not found: $POLICY_FILE"
        exit 1
    fi

    if ! jq empty "$POLICY_FILE" 2>/dev/null; then
        log_error "Invalid JSON"
        exit 1
    fi

    local errors=0
    local total=0

    jq -r '.clients // {} | to_entries[] | "\(.key)|\(.value.access // [] | join(","))"' "$POLICY_FILE" | \
    while IFS="|" read -r ip access_str; do
        (( total++ ))

        if ! validate_cidr "$ip"; then
            log_error "Invalid client IP: $ip"
            (( errors++ )) || true
        fi

        if [[ -n "$access_str" ]]; then
            IFS=',' read -ra targets <<< "$access_str"
            for target in "${targets[@]}"; do
                if ! validate_cidr "$target"; then
                    log_error "Invalid access target for $ip: $target"
                    (( errors++ )) || true
                fi
            done
        fi
    done

    if (( errors > 0 )); then
        log_error "Validation failed: $errors errors"
        exit 1
    else
        log_info "Validation passed: $total clients, 0 errors"
    fi
}

# === DISPATCH ===
case "${1:-help}" in
    status)   cmd_status ;;
    policy)   cmd_policy ;;
    rules)    cmd_rules ;;
    ipset)    cmd_ipset ;;
    log)      cmd_log ;;
    reload)   cmd_reload ;;
    backup)   cmd_backup ;;
    stats)    cmd_stats ;;
    validate) cmd_validate ;;
    help|*)   usage ;;
esac

EOF_WG_POLICY_CTL

    echo "Writing systemd units to /etc/systemd/system/..."

    cat << 'EOF_WG_POLICY_SERVICE' > /etc/systemd/system/wg-policy.service
[Unit]
Description=WireGuard Dynamic Policy Firewall Watcher
After=network-online.target wg-quick@wg0.service
Wants=wg-quick@wg0.service network-online.target
StartLimitIntervalSec=60
StartLimitBurst=5

[Service]
Type=simple
ExecStartPre=/usr/local/bin/wg-sync-policy.sh
ExecStart=/usr/local/bin/wg-sync-watch.sh
ExecStopPost=/usr/local/bin/wg-policy-cleanup.sh
Restart=always
RestartSec=10
User=root
StandardOutput=journal
StandardError=journal
SyslogIdentifier=wg-policy

# Hardening
ProtectSystem=strict
ReadWritePaths=/etc/wireguard /var/lock /tmp
ProtectHome=yes
NoNewPrivileges=no
PrivateTmp=yes

[Install]
WantedBy=multi-user.target

EOF_WG_POLICY_SERVICE

    cat << 'EOF_WG_POLICY_HEALTH_SERVICE' > /etc/systemd/system/wg-policy-health.service
[Unit]
Description=WireGuard Policy Health Check

[Service]
Type=oneshot
ExecStart=/bin/bash -c 'source /usr/local/bin/wg-policy-lib.sh && health_check'
StandardOutput=journal
StandardError=journal
SyslogIdentifier=wg-policy-health

EOF_WG_POLICY_HEALTH_SERVICE

    cat << 'EOF_WG_POLICY_HEALTH_TIMER' > /etc/systemd/system/wg-policy-health.timer
[Unit]
Description=WireGuard Policy Health Check Timer

[Timer]
OnBootSec=60
OnUnitActiveSec=300
AccuracySec=30

[Install]
WantedBy=timers.target

EOF_WG_POLICY_HEALTH_TIMER

    chmod +x /usr/local/bin/wg-*.sh /usr/local/bin/wg-policy-ctl

    echo "Reloading systemd daemon..."
    systemctl daemon-reload
    
    echo "Enabling and starting services..."
    systemctl enable --now wg-policy.service
    systemctl enable --now wg-policy-health.timer

    install_hooks

    echo "Installation complete!"
    echo "You can check status with: wg-policy-ctl status"
}

uninstall_policy() {
    echo "Uninstalling WireGuard Policy Firewall..."

    echo "Stopping and disabling services..."
    systemctl disable --now wg-policy.service wg-policy-health.timer wg-policy-health.service 2>/dev/null || true

    echo "Running cleanup script..."
    if [ -x /usr/local/bin/wg-policy-cleanup.sh ]; then
        /usr/local/bin/wg-policy-cleanup.sh || true
    fi

    remove_hooks

    echo "Removing systemd units..."
    rm -f /etc/systemd/system/wg-policy.service
    rm -f /etc/systemd/system/wg-policy-health.service
    rm -f /etc/systemd/system/wg-policy-health.timer
    systemctl daemon-reload

    echo "Removing scripts from /usr/local/bin/..."
    rm -f /usr/local/bin/wg-policy-lib.sh
    rm -f /usr/local/bin/wg-sync-policy.sh
    rm -f /usr/local/bin/wg-policy-engine.sh
    rm -f /usr/local/bin/wg-policy-cleanup.sh
    rm -f /usr/local/bin/wg-sync-watch.sh
    rm -f /usr/local/bin/wg-policy-ctl

    echo "Uninstallation complete!"
}

case "${1:-}" in
    install)
        install_policy
        ;;
    uninstall)
        uninstall_policy
        ;;
    *)
        echo "Usage: $0 {install|uninstall}"
        exit 1
        ;;
esac