#!/bin/sh
# nDPId to Netifyd Compatibility Layer
# Translates nDPId events to Netifyd-compatible format
# Copyright (C) 2025 CyberMind.fr

. /lib/functions.sh
. /usr/share/ndpid/functions.sh 2>/dev/null || true

# Configuration
DISTRIBUTOR_SOCK="/var/run/ndpid/distributor.sock"
STATUS_FILE="/var/run/netifyd/status.json"
FLOWS_FILE="/tmp/ndpid-flows.json"
STATS_FILE="/tmp/ndpid-stats.json"
STATS_HISTORY="/tmp/ndpid-stats-history.json"
UPDATE_INTERVAL=1
MAX_HISTORY=1440

# State variables (stored in temp files for shell compatibility)
STATE_DIR="/tmp/ndpid-state"
FLOWS_ACTIVE_FILE="$STATE_DIR/flows_active"
FLOW_COUNT_FILE="$STATE_DIR/flow_count"
STATS_FILE_TMP="$STATE_DIR/stats"

# Initialize state
init_state() {
	mkdir -p "$STATE_DIR"
	mkdir -p "$(dirname "$STATUS_FILE")"
	echo "0" > "$FLOWS_ACTIVE_FILE"
	echo "0" > "$FLOW_COUNT_FILE"
	echo "{}" > "$STATS_FILE_TMP"
}

# Increment counter
inc_counter() {
	local file="$1"
	local val=$(cat "$file" 2>/dev/null || echo 0)
	echo $((val + 1)) > "$file"
}

# Decrement counter
dec_counter() {
	local file="$1"
	local val=$(cat "$file" 2>/dev/null || echo 0)
	[ "$val" -gt 0 ] && val=$((val - 1))
	echo "$val" > "$file"
}

# Get counter value
get_counter() {
	cat "$1" 2>/dev/null || echo 0
}

# Update interface stats
update_iface_stats() {
	local iface="$1"
	local proto="$2"
	local bytes="$3"

	local stats=$(cat "$STATS_FILE_TMP" 2>/dev/null || echo "{}")

	# Use jq to update stats (if available) or simple JSON
	if command -v jq >/dev/null 2>&1; then
		stats=$(echo "$stats" | jq --arg iface "$iface" --arg proto "$proto" --argjson bytes "$bytes" '
			.[$iface] //= {"ip_bytes": 0, "wire_bytes": 0, "tcp": 0, "udp": 0, "icmp": 0} |
			.[$iface].ip_bytes += $bytes |
			.[$iface].wire_bytes += $bytes |
			if $proto == "tcp" then .[$iface].tcp += 1
			elif $proto == "udp" then .[$iface].udp += 1
			elif $proto == "icmp" then .[$iface].icmp += 1
			else . end
		')
		echo "$stats" > "$STATS_FILE_TMP"
	fi
}

# Process a single nDPId event
process_event() {
	local raw="$1"

	# Strip 5-digit length prefix
	local json="${raw:5}"

	# Parse event type
	local event_name=$(echo "$json" | jsonfilter -e '@.flow_event_name' 2>/dev/null)
	[ -z "$event_name" ] && event_name=$(echo "$json" | jsonfilter -e '@.daemon_event_name' 2>/dev/null)

	case "$event_name" in
		new)
			inc_counter "$FLOW_COUNT_FILE"
			inc_counter "$FLOWS_ACTIVE_FILE"
			;;
		end|idle)
			dec_counter "$FLOWS_ACTIVE_FILE"
			;;
		detected|guessed)
			# Extract flow info for stats
			local iface=$(echo "$json" | jsonfilter -e '@.source' 2>/dev/null)
			local proto=$(echo "$json" | jsonfilter -e '@.l4_proto' 2>/dev/null)
			local src_bytes=$(echo "$json" | jsonfilter -e '@.flow_src_tot_l4_payload_len' 2>/dev/null || echo 0)
			local dst_bytes=$(echo "$json" | jsonfilter -e '@.flow_dst_tot_l4_payload_len' 2>/dev/null || echo 0)
			local total_bytes=$((src_bytes + dst_bytes))

			[ -n "$iface" ] && update_iface_stats "$iface" "$proto" "$total_bytes"
			;;
	esac
}

# Generate Netifyd-compatible status.json
generate_status() {
	local flow_count=$(get_counter "$FLOW_COUNT_FILE")
	local flows_active=$(get_counter "$FLOWS_ACTIVE_FILE")
	local stats=$(cat "$STATS_FILE_TMP" 2>/dev/null || echo "{}")
	local uptime=$(($(date +%s) - START_TIME))

	if command -v jq >/dev/null 2>&1; then
		jq -n \
			--argjson flow_count "$flow_count" \
			--argjson flows_active "$flows_active" \
			--argjson stats "$stats" \
			--argjson uptime "$uptime" \
			'{
				flow_count: $flow_count,
				flows_active: $flows_active,
				stats: $stats,
				devices: [],
				dns_hint_cache: { cache_size: 0 },
				uptime: $uptime,
				source: "ndpid-compat"
			}' > "$STATUS_FILE"
	else
		cat > "$STATUS_FILE" << EOF
{
  "flow_count": $flow_count,
  "flows_active": $flows_active,
  "stats": $stats,
  "devices": [],
  "dns_hint_cache": { "cache_size": 0 },
  "uptime": $uptime,
  "source": "ndpid-compat"
}
EOF
	fi
}

# Main loop
main() {
	START_TIME=$(date +%s)

	logger -t ndpid-compat "Starting nDPId compatibility layer"

	# Initialize state
	init_state

	# Check for socat
	if ! command -v socat >/dev/null 2>&1; then
		logger -t ndpid-compat "ERROR: socat not found, using nc fallback"
		USE_NC=1
	fi

	# Wait for distributor socket
	local wait_count=0
	while [ ! -S "$DISTRIBUTOR_SOCK" ] && [ $wait_count -lt 30 ]; do
		sleep 1
		wait_count=$((wait_count + 1))
	done

	if [ ! -S "$DISTRIBUTOR_SOCK" ]; then
		logger -t ndpid-compat "ERROR: Distributor socket not found after 30s"
		exit 1
	fi

	logger -t ndpid-compat "Connected to distributor: $DISTRIBUTOR_SOCK"

	# Background status file updater
	(
		while true; do
			generate_status
			sleep $UPDATE_INTERVAL
		done
	) &
	STATUS_PID=$!
	trap "kill $STATUS_PID 2>/dev/null" EXIT

	# Read events from distributor
	if [ -z "$USE_NC" ]; then
		socat -u UNIX-CONNECT:"$DISTRIBUTOR_SOCK" - | while IFS= read -r line; do
			process_event "$line"
		done
	else
		nc -U "$DISTRIBUTOR_SOCK" | while IFS= read -r line; do
			process_event "$line"
		done
	fi
}

# Run main if not sourced
case "$1" in
	-h|--help)
		echo "Usage: $0 [-d|--daemon]"
		echo "  Translates nDPId events to Netifyd-compatible format"
		exit 0
		;;
	-d|--daemon)
		main &
		echo $! > /var/run/ndpid-compat.pid
		;;
	*)
		main
		;;
esac