"""Database helper for packet persistence and retrieval."""

import asyncio
import base64
import json
import logging
from datetime import datetime, timezone
from typing import Any, Dict, List, Optional

import asyncpg
from asyncpg.pool import Pool
from pydantic import ValidationError

from src.Models.packets import PacketDBModel

logger = logging.getLogger("af_packet_sniffer")


def _db_text(value: Any) -> Any:
    if value is None:
        return None
    if isinstance(value, (str, int)):
        return value
    if hasattr(value, "value"):
        return getattr(value, "value")
    return str(value)


def _serialize_row_for_broadcast(row: Dict[str, Any]) -> Dict[str, Any]:
    serialized = dict(row)
    _normalize_json_fields(serialized)

    raw_val = serialized.get("raw")
    if isinstance(raw_val, (bytes, bytearray)):
        serialized["raw_b64"] = base64.b64encode(raw_val).decode("ascii")
        serialized.pop("raw", None)

    for key, value in list(serialized.items()):
        if hasattr(value, "isoformat"):
            serialized[key] = value.isoformat()

    return serialized


def _normalize_json_fields(payload: Dict[str, Any]) -> None:
    for key in ("dpi_metadata", "capture_metadata", "telemetry_metadata"):
        value = payload.get(key)
        if isinstance(value, str):
            try:
                parsed = json.loads(value)
            except json.JSONDecodeError:
                continue
            if isinstance(parsed, dict):
                payload[key] = parsed


class DatabasePool:
    """Asyncpg connection pool wrapper used by the packet APIs."""

    def __init__(self, dsn: str, min_size: int = 1, max_size: int = 5):
        self._dsn = dsn
        self._pool: Optional[Pool] = None
        self._min_size = min_size
        self._max_size = max_size
        self.broadcaster = None
        self._init_lock: Optional[asyncio.Lock] = None

    async def init_pool(self) -> None:
        """Initialize the connection pool once per process."""
        if self._pool is not None:
            return

        if self._init_lock is None:
            self._init_lock = asyncio.Lock()

        async with self._init_lock:
            if self._pool is not None:
                return

            logger.info("Initializing DB pool (dsn=%s)", self._dsn)
            try:
                self._pool = await asyncpg.create_pool(
                    dsn=self._dsn,
                    min_size=self._min_size,
                    max_size=self._max_size,
                )
                logger.info("DB pool initialized")
            except Exception:
                logger.exception("Failed to create DB pool")
                raise

    async def close_pool(self) -> None:
        """Close the pool if present."""
        if self._pool is None:
            return

        try:
            await self._pool.close()
            logger.info("DB pool closed")
        except Exception:
            logger.exception("Error closing DB pool")
        finally:
            self._pool = None

    async def insert_packet(self, pkt_info: Dict[str, Any]) -> None:
        """Insert one packet record and publish it to subscribers."""
        await self.upsert_packet(pkt_info)

    async def upsert_packet(self, pkt_info: Dict[str, Any]) -> None:
        """Insert or update one packet record and publish it to subscribers."""
        if self._pool is None:
            await self.init_pool()

        dpi_metadata = pkt_info.get("dpi_metadata")
        telemetry_metadata = pkt_info.get("telemetry_metadata")

        try:
            async with self._pool.acquire() as conn:
                row = await conn.fetchrow(
                    """
                    INSERT INTO packets (
                        correlation_key,
                        packet_id,
                        packet_uid,
                        correlation_source,
                        skb_mark,
                        capture_iface,
                        ingress_if,
                        egress_if,
                        verdict,
                        verdict_reason,
                        verdict_confidence,
                        ingress_seen_at,
                        egress_seen_at,
                        verdict_seen_at,
                        src_mac,
                        dst_mac,
                        eth_type_raw,
                        eth_type,
                        vlan_id,
                        src_ip,
                        dst_ip,
                        ip_proto_raw,
                        ip_proto,
                        src_port,
                        dst_port,
                        length,
                        raw_present,
                        capture_sources,
                        app_protocol,
                        app_master_protocol,
                        app_category,
                        app_confidence,
                        app_hostname,
                        app_is_encrypted,
                        app_risk_score,
                        dpi_metadata,
                        capture_metadata,
                        telemetry_metadata,
                        raw
                    ) VALUES(
                        $1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14,$15,$16,$17,$18,$19,$20,
                        $21,$22,$23,$24,$25,$26,$27,$28,$29,$30,$31,$32,$33,$34,$35,$36::jsonb,
                        $37::jsonb,$38::jsonb,$39
                    )
                    ON CONFLICT (correlation_key) DO UPDATE SET
                        updated_at = NOW(),
                        packet_id = COALESCE(EXCLUDED.packet_id, packets.packet_id),
                        packet_uid = COALESCE(EXCLUDED.packet_uid, packets.packet_uid),
                        correlation_source = COALESCE(EXCLUDED.correlation_source, packets.correlation_source),
                        skb_mark = COALESCE(EXCLUDED.skb_mark, packets.skb_mark),
                        capture_iface = COALESCE(EXCLUDED.capture_iface, packets.capture_iface),
                        ingress_if = COALESCE(EXCLUDED.ingress_if, packets.ingress_if),
                        egress_if = COALESCE(EXCLUDED.egress_if, packets.egress_if),
                        verdict = COALESCE(EXCLUDED.verdict, packets.verdict),
                        verdict_reason = COALESCE(EXCLUDED.verdict_reason, packets.verdict_reason),
                        verdict_confidence = COALESCE(EXCLUDED.verdict_confidence, packets.verdict_confidence),
                        ingress_seen_at = COALESCE(EXCLUDED.ingress_seen_at, packets.ingress_seen_at),
                        egress_seen_at = COALESCE(EXCLUDED.egress_seen_at, packets.egress_seen_at),
                        verdict_seen_at = COALESCE(EXCLUDED.verdict_seen_at, packets.verdict_seen_at),
                        src_mac = COALESCE(EXCLUDED.src_mac, packets.src_mac),
                        dst_mac = COALESCE(EXCLUDED.dst_mac, packets.dst_mac),
                        eth_type_raw = COALESCE(EXCLUDED.eth_type_raw, packets.eth_type_raw),
                        eth_type = COALESCE(EXCLUDED.eth_type, packets.eth_type),
                        vlan_id = COALESCE(EXCLUDED.vlan_id, packets.vlan_id),
                        src_ip = COALESCE(EXCLUDED.src_ip, packets.src_ip),
                        dst_ip = COALESCE(EXCLUDED.dst_ip, packets.dst_ip),
                        ip_proto_raw = COALESCE(EXCLUDED.ip_proto_raw, packets.ip_proto_raw),
                        ip_proto = COALESCE(EXCLUDED.ip_proto, packets.ip_proto),
                        src_port = COALESCE(EXCLUDED.src_port, packets.src_port),
                        dst_port = COALESCE(EXCLUDED.dst_port, packets.dst_port),
                        length = COALESCE(EXCLUDED.length, packets.length),
                        raw_present = COALESCE(EXCLUDED.raw_present, FALSE) OR COALESCE(packets.raw_present, FALSE),
                        capture_sources = (
                            SELECT ARRAY(
                                SELECT DISTINCT source
                                FROM unnest(
                                    COALESCE(packets.capture_sources, ARRAY[]::text[]) ||
                                    COALESCE(EXCLUDED.capture_sources, ARRAY[]::text[])
                                ) AS source
                            )
                        ),
                        app_protocol = COALESCE(EXCLUDED.app_protocol, packets.app_protocol),
                        app_master_protocol = COALESCE(EXCLUDED.app_master_protocol, packets.app_master_protocol),
                        app_category = COALESCE(EXCLUDED.app_category, packets.app_category),
                        app_confidence = COALESCE(EXCLUDED.app_confidence, packets.app_confidence),
                        app_hostname = COALESCE(EXCLUDED.app_hostname, packets.app_hostname),
                        app_is_encrypted = COALESCE(EXCLUDED.app_is_encrypted, packets.app_is_encrypted),
                        app_risk_score = COALESCE(EXCLUDED.app_risk_score, packets.app_risk_score),
                        dpi_metadata = COALESCE(EXCLUDED.dpi_metadata, packets.dpi_metadata),
                        capture_metadata = COALESCE(EXCLUDED.capture_metadata, packets.capture_metadata),
                        telemetry_metadata = COALESCE(EXCLUDED.telemetry_metadata, packets.telemetry_metadata),
                        raw = COALESCE(EXCLUDED.raw, packets.raw)
                    RETURNING *
                    """,
                    pkt_info["correlation_key"],
                    pkt_info.get("packet_id"),
                    pkt_info.get("packet_uid"),
                    pkt_info.get("correlation_source"),
                    pkt_info.get("skb_mark"),
                    pkt_info.get("capture_iface"),
                    pkt_info.get("ingress_if"),
                    pkt_info.get("egress_if"),
                    pkt_info.get("verdict"),
                    pkt_info.get("verdict_reason"),
                    pkt_info.get("verdict_confidence"),
                    pkt_info.get("ingress_seen_at"),
                    pkt_info.get("egress_seen_at"),
                    pkt_info.get("verdict_seen_at"),
                    pkt_info.get("src_mac"),
                    pkt_info.get("dst_mac"),
                    pkt_info.get("eth_type_raw"),
                    _db_text(pkt_info.get("eth_type")),
                    pkt_info.get("vlan_id"),
                    pkt_info.get("src_ip"),
                    pkt_info.get("dst_ip"),
                    pkt_info.get("protocol_raw"),
                    _db_text(pkt_info.get("protocol_name") or pkt_info.get("protocol")),
                    pkt_info.get("src_port"),
                    pkt_info.get("dst_port"),
                    pkt_info.get("length"),
                    pkt_info.get("raw_present"),
                    pkt_info.get("capture_sources"),
                    pkt_info.get("app_protocol"),
                    pkt_info.get("app_master_protocol"),
                    pkt_info.get("app_category"),
                    pkt_info.get("app_confidence"),
                    pkt_info.get("app_hostname"),
                    pkt_info.get("app_is_encrypted"),
                    pkt_info.get("app_risk_score"),
                    json.dumps(dpi_metadata) if dpi_metadata is not None else None,
                    json.dumps(pkt_info.get("capture_metadata")) if pkt_info.get("capture_metadata") is not None else None,
                    json.dumps(telemetry_metadata) if telemetry_metadata is not None else None,
                    pkt_info.get("raw"),
                )
        except Exception:
            logger.exception("DB upsert failed")
            return

        if row:
            persisted = _serialize_row_for_broadcast(dict(row))
            pkt_info.update(persisted)

        if self.broadcaster:
            try:
                self.broadcaster.sync_publish(pkt_info)
            except Exception:
                logger.exception("Failed to publish pkt_info to broadcaster")

    async def backfill_packet_metadata(
        self,
        *,
        iface: str,
        src_ip: str,
        dst_ip: str,
        src_port: int,
        dst_port: int,
        protocol: int,
        length: int,
        observed_at_ms: int,
        enrichment: Dict[str, Any],
        window_ms: int,
    ) -> int:
        """Update recent packet rows after tshark metadata arrives asynchronously."""
        if self._pool is None:
            await self.init_pool()

        lower_bound = datetime.fromtimestamp(max(observed_at_ms - window_ms, 0) / 1000.0, tz=timezone.utc)
        upper_bound = datetime.fromtimestamp(max(observed_at_ms + window_ms, 0) / 1000.0, tz=timezone.utc)
        dpi_metadata = enrichment.get("dpi_metadata")
        capture_sources = [str(source) for source in enrichment.get("capture_sources", []) if source]

        try:
            async with self._pool.acquire() as conn:
                rows = await conn.fetch(
                    """
                    UPDATE packets
                    SET
                        updated_at = NOW(),
                        app_protocol = COALESCE(packets.app_protocol, $10),
                        app_master_protocol = COALESCE(packets.app_master_protocol, $11),
                        app_category = COALESCE(packets.app_category, $12),
                        app_confidence = COALESCE(packets.app_confidence, $13),
                        app_hostname = COALESCE(packets.app_hostname, $14),
                        app_is_encrypted = COALESCE(packets.app_is_encrypted, $15),
                        dpi_metadata = CASE
                            WHEN $16::jsonb IS NULL THEN packets.dpi_metadata
                            WHEN packets.dpi_metadata IS NULL THEN $16::jsonb
                            ELSE packets.dpi_metadata || $16::jsonb
                        END,
                        capture_sources = (
                            SELECT ARRAY(
                                SELECT DISTINCT source
                                FROM unnest(
                                    COALESCE(packets.capture_sources, ARRAY[]::text[]) ||
                                    COALESCE($17::text[], ARRAY[]::text[])
                                ) AS source
                            )
                        )
                    WHERE
                        ip_proto_raw = $1
                        AND (capture_iface = $2 OR ingress_if = $2 OR egress_if = $2)
                        AND src_ip = $3::inet
                        AND dst_ip = $4::inet
                        AND src_port = $5
                        AND dst_port = $6
                        AND length = $7
                        AND timestamp BETWEEN $8 AND $9
                        AND (
                            packets.app_protocol IS NULL
                            OR packets.app_master_protocol IS NULL
                            OR packets.app_category IS NULL
                            OR packets.app_confidence IS NULL
                            OR packets.app_hostname IS NULL
                            OR packets.app_is_encrypted IS NULL
                            OR ($16::jsonb IS NOT NULL)
                            OR (COALESCE(array_length($17::text[], 1), 0) > 0)
                        )
                    RETURNING *
                    """,
                    protocol,
                    iface,
                    src_ip,
                    dst_ip,
                    src_port,
                    dst_port,
                    length,
                    lower_bound,
                    upper_bound,
                    enrichment.get("app_protocol"),
                    enrichment.get("app_master_protocol"),
                    enrichment.get("app_category"),
                    enrichment.get("app_confidence"),
                    enrichment.get("app_hostname"),
                    enrichment.get("app_is_encrypted"),
                    json.dumps(dpi_metadata) if dpi_metadata is not None else None,
                    capture_sources if capture_sources else None,
                )
        except Exception:
            logger.exception("DB packet metadata backfill failed")
            return 0

        if not rows:
            return 0

        updated_count = 0
        for row in rows:
            serialized = _serialize_row_for_broadcast(dict(row))
            updated_count += 1
            if self.broadcaster:
                try:
                    self.broadcaster.sync_publish(serialized)
                except Exception:
                    logger.exception("Failed to publish tshark-enriched packet row")

        return updated_count

    async def fetch_latest(self, limit: int) -> List[PacketDBModel]:
        """Fetch newest packet rows as validated `PacketDBModel` instances."""
        if self._pool is None:
            await self.init_pool()

        async with self._pool.acquire() as conn:
            rows = await conn.fetch(
                """
                SELECT *
                FROM packets
                ORDER BY updated_at DESC, id DESC
                LIMIT $1
                """,
                limit,
            )

        result: List[PacketDBModel] = []
        for row in rows:
            data = dict(row)
            _normalize_json_fields(data)

            raw_val = data.get("raw")
            if isinstance(raw_val, (bytes, bytearray)):
                data["raw_b64"] = base64.b64encode(raw_val).decode("ascii")
                data.pop("raw", None)

            try:
                packet_model = PacketDBModel(**data)
            except ValidationError as exc:
                logger.warning(
                    "Skipping DB row that failed PacketDBModel validation (id=%s): %s",
                    data.get("id"),
                    exc,
                )
                continue

            result.append(packet_model)

        return result

    async def clear_all_packets(self, reset_identity: bool = True) -> bool:
        """Truncate the packet table and optionally reset identity counters."""
        if self._pool is None:
            await self.init_pool()

        restart_clause = "RESTART IDENTITY" if reset_identity else ""
        query = f"TRUNCATE TABLE packets {restart_clause};"

        try:
            async with self._pool.acquire() as conn:
                await conn.execute(query)
                logger.info("Successfully cleared all packets from the database (reset_id=%s)", reset_identity)
                return True
        except Exception:
            logger.exception("Failed to clear packets table")
            return False