"""
통계 사전 집계 — prediction_stats_hourly/daily/monthly 갱신.

hourly: 매 분석 사이클마다 (최근 48h 보존)
daily: 매일 01:00 또는 분석 사이클 후
monthly: daily 합산
"""
import json
import logging
from datetime import date, datetime, timedelta, timezone
from typing import Optional

from config import qualified_table
from db.kcgdb import get_conn

logger = logging.getLogger(__name__)

STATS_HOURLY = qualified_table('prediction_stats_hourly')
STATS_DAILY = qualified_table('prediction_stats_daily')
STATS_MONTHLY = qualified_table('prediction_stats_monthly')
VAR_TABLE = qualified_table('vessel_analysis_results')
EVENTS_TABLE = qualified_table('prediction_events')
ENF_TABLE = qualified_table('enforcement_records')

# 한국 표준시 (운영 기준 — 일/월 집계 경계)
_KST = timezone(timedelta(hours=9))


def _jsonb(d: dict) -> str:
    return json.dumps(d, ensure_ascii=False)


def _aggregate_one_hour(conn, hour_start: datetime, updated_at: datetime) -> dict:
    """단일 hour 의 stats_hourly 레코드를 UPSERT.

    Why separate: prediction 5분 사이클이 평균 13분 소요라 한 사이클이 hour 경계를
    넘나드는 경우가 흔하다 (예: 12:55 시작 → 13:08 완료). 이때 사이클 안에서 생성된
    이벤트(occurred_at=12:57)가 마지막으로 stats_aggregate_hourly 를 돌렸을 때
    now_kst=13:08 이면 **13:00 hour 만** UPSERT 되고 12:00 hour 는 이전 사이클이
    남긴 stale snapshot 을 유지 → 새 카테고리·이벤트 누락.
    해결: 현재 + 이전 hour 를 모두 재집계 (UPSERT idempotent).
    """
    hour_end = hour_start + timedelta(hours=1)
    cur = conn.cursor()
    try:
        cur.execute(
            f"SELECT COUNT(*) FROM {VAR_TABLE} WHERE analyzed_at >= %s AND analyzed_at < %s",
            (hour_start, hour_end)
        )
        total = cur.fetchone()[0] or 0

        cur.execute(
            f"""SELECT risk_level, COUNT(*) FROM {VAR_TABLE}
                WHERE analyzed_at >= %s AND analyzed_at < %s AND risk_level IS NOT NULL
                GROUP BY risk_level""",
            (hour_start, hour_end)
        )
        by_risk = dict(cur.fetchall())

        cur.execute(
            f"""SELECT zone_code, COUNT(*) FROM {VAR_TABLE}
                WHERE analyzed_at >= %s AND analyzed_at < %s AND zone_code IS NOT NULL
                GROUP BY zone_code""",
            (hour_start, hour_end)
        )
        by_zone = dict(cur.fetchall())

        cur.execute(
            f"SELECT COUNT(*) FROM {EVENTS_TABLE} WHERE occurred_at >= %s AND occurred_at < %s",
            (hour_start, hour_end)
        )
        events = cur.fetchone()[0] or 0

        cur.execute(
            f"""SELECT category, COUNT(*) FROM {EVENTS_TABLE}
                WHERE occurred_at >= %s AND occurred_at < %s AND category IS NOT NULL
                GROUP BY category""",
            (hour_start, hour_end)
        )
        by_category = dict(cur.fetchall())

        cur.execute(
            f"""SELECT COUNT(*) FROM {EVENTS_TABLE}
                WHERE occurred_at >= %s AND occurred_at < %s AND level = 'CRITICAL'""",
            (hour_start, hour_end)
        )
        critical = cur.fetchone()[0] or 0

        cur.execute(
            f"""INSERT INTO {STATS_HOURLY}
                (stat_hour, total_detections, by_category, by_zone, by_risk_level,
                 event_count, critical_count, updated_at)
                VALUES (%s, %s, %s, %s, %s, %s, %s, %s)
                ON CONFLICT (stat_hour) DO UPDATE SET
                    total_detections = EXCLUDED.total_detections,
                    by_category = EXCLUDED.by_category,
                    by_zone = EXCLUDED.by_zone,
                    by_risk_level = EXCLUDED.by_risk_level,
                    event_count = EXCLUDED.event_count,
                    critical_count = EXCLUDED.critical_count,
                    updated_at = EXCLUDED.updated_at""",
            (hour_start, total, _jsonb(by_category), _jsonb(by_zone),
             _jsonb(by_risk), events, critical, updated_at)
        )
    finally:
        cur.close()

    return {
        'hour': hour_start.isoformat(),
        'detections': total,
        'events': events,
        'critical': critical,
        'categories': len(by_category),
        'zones': len(by_zone),
    }


def aggregate_hourly(target_hour: Optional[datetime] = None) -> dict:
    """현재 + 이전 hour 를 함께 재집계 (경계 누락 방지).

    반환값은 **현재 hour** 결과 (하위 호환). 이전 hour 갱신은 부수효과.
    target_hour 가 지정된 경우 그 시점 ± 1h 를 재집계.

    DB 컬럼은 모두 timestamptz 이므로 aware datetime 이면 안전 비교됨.
    운영자/대시보드 표기와 stat_hour boundary 가 일치하도록 KST 기준.
    """
    if target_hour is not None:
        if target_hour.tzinfo is None:
            target_hour = target_hour.replace(tzinfo=_KST)
        now_kst = target_hour.astimezone(_KST)
    else:
        now_kst = datetime.now(_KST)
    current_hour = now_kst.replace(minute=0, second=0, microsecond=0)
    previous_hour = current_hour - timedelta(hours=1)
    updated_at = datetime.now(timezone.utc)

    with get_conn() as conn:
        # 이전 hour 먼저 재집계 (경계 누락 복구)
        _aggregate_one_hour(conn, previous_hour, updated_at)
        # 현재 hour — 반환값 대상
        result = _aggregate_one_hour(conn, current_hour, updated_at)

        # 48시간 이전 정리 (세션 재사용)
        cutoff = updated_at - timedelta(hours=48)
        cur = conn.cursor()
        try:
            cur.execute(f"DELETE FROM {STATS_HOURLY} WHERE stat_hour < %s", (cutoff,))
        finally:
            cur.close()
        conn.commit()
    logger.info(f'stats_aggregator hourly: {result}')
    return result


def aggregate_daily(target_date: Optional[date] = None) -> dict:
    """지정 날짜 기준 daily 집계 (KST 기준)."""
    d = target_date or datetime.now(_KST).date()
    # KST 자정을 TIMESTAMPTZ로 표현 (UTC -9시간)
    day_start = datetime(d.year, d.month, d.day, tzinfo=_KST)
    day_end = day_start + timedelta(days=1)
    now = datetime.now(timezone.utc)

    with get_conn() as conn:
        cur = conn.cursor()

        # 총 탐지
        cur.execute(
            f"SELECT COUNT(*) FROM {VAR_TABLE} WHERE analyzed_at >= %s AND analyzed_at < %s",
            (day_start, day_end)
        )
        total = cur.fetchone()[0] or 0

        # 위반 유형별 (unnest)
        cur.execute(
            f"""SELECT unnest(violation_categories) AS vt, COUNT(*)
                FROM {VAR_TABLE}
                WHERE analyzed_at >= %s AND analyzed_at < %s AND violation_categories IS NOT NULL
                GROUP BY vt""",
            (day_start, day_end)
        )
        by_violation = dict(cur.fetchall())

        # 위험 레벨별
        cur.execute(
            f"""SELECT risk_level, COUNT(*) FROM {VAR_TABLE}
                WHERE analyzed_at >= %s AND analyzed_at < %s AND risk_level IS NOT NULL
                GROUP BY risk_level""",
            (day_start, day_end)
        )
        by_risk = dict(cur.fetchall())

        # 이벤트
        cur.execute(
            f"SELECT COUNT(*) FROM {EVENTS_TABLE} WHERE occurred_at >= %s AND occurred_at < %s",
            (day_start, day_end)
        )
        event_count = cur.fetchone()[0] or 0

        cur.execute(
            f"""SELECT COUNT(*) FROM {EVENTS_TABLE}
                WHERE occurred_at >= %s AND occurred_at < %s AND level = 'CRITICAL'""",
            (day_start, day_end)
        )
        critical = cur.fetchone()[0] or 0

        # 단속
        cur.execute(
            f"SELECT COUNT(*) FROM {ENF_TABLE} WHERE enforced_at >= %s AND enforced_at < %s",
            (day_start, day_end)
        )
        enf_count = cur.fetchone()[0] or 0

        # 오탐
        cur.execute(
            f"""SELECT COUNT(*) FROM {EVENTS_TABLE}
                WHERE occurred_at >= %s AND occurred_at < %s AND status = 'FALSE_POSITIVE'""",
            (day_start, day_end)
        )
        fp = cur.fetchone()[0] or 0

        # AI 정확도
        accuracy = round((1 - fp / max(event_count, 1)) * 100, 2) if event_count > 0 else None

        cur.execute(
            f"""INSERT INTO {STATS_DAILY}
                (stat_date, total_detections, by_violation_type, by_risk_level,
                 event_count, critical_event_count, enforcement_count,
                 false_positive_count, ai_accuracy_pct, updated_at)
                VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s)
                ON CONFLICT (stat_date) DO UPDATE SET
                    total_detections = EXCLUDED.total_detections,
                    by_violation_type = EXCLUDED.by_violation_type,
                    by_risk_level = EXCLUDED.by_risk_level,
                    event_count = EXCLUDED.event_count,
                    critical_event_count = EXCLUDED.critical_event_count,
                    enforcement_count = EXCLUDED.enforcement_count,
                    false_positive_count = EXCLUDED.false_positive_count,
                    ai_accuracy_pct = EXCLUDED.ai_accuracy_pct,
                    updated_at = EXCLUDED.updated_at""",
            (d, total, _jsonb(by_violation), _jsonb(by_risk),
             event_count, critical, enf_count, fp, accuracy, now)
        )
        conn.commit()

    result = {'date': d.isoformat(), 'detections': total, 'events': event_count, 'accuracy': accuracy}
    logger.info(f'stats_aggregator daily: {result}')
    return result


def aggregate_monthly(target_month: Optional[date] = None) -> dict:
    """지정 월 기준 monthly 집계 (daily 합산, KST 기준)."""
    d = target_month or datetime.now(_KST).date().replace(day=1)
    month_start = d.replace(day=1)
    if month_start.month == 12:
        month_end = month_start.replace(year=month_start.year + 1, month=1)
    else:
        month_end = month_start.replace(month=month_start.month + 1)
    now = datetime.now(timezone.utc)

    with get_conn() as conn:
        cur = conn.cursor()

        cur.execute(
            f"""SELECT
                    COALESCE(SUM(total_detections), 0),
                    COALESCE(SUM(event_count), 0),
                    COALESCE(SUM(critical_event_count), 0),
                    COALESCE(SUM(enforcement_count), 0),
                    COALESCE(SUM(false_positive_count), 0)
                FROM {STATS_DAILY}
                WHERE stat_date >= %s AND stat_date < %s""",
            (month_start, month_end)
        )
        row = cur.fetchone()
        total_det, evt, crit, enf, fp = row

        accuracy = round((1 - fp / max(evt, 1)) * 100, 2) if evt > 0 else None

        cur.execute(
            f"""INSERT INTO {STATS_MONTHLY}
                (stat_month, total_detections, total_enforcements,
                 event_count, critical_event_count, false_positive_count,
                 ai_accuracy_pct, updated_at)
                VALUES (%s, %s, %s, %s, %s, %s, %s, %s)
                ON CONFLICT (stat_month) DO UPDATE SET
                    total_detections = EXCLUDED.total_detections,
                    total_enforcements = EXCLUDED.total_enforcements,
                    event_count = EXCLUDED.event_count,
                    critical_event_count = EXCLUDED.critical_event_count,
                    false_positive_count = EXCLUDED.false_positive_count,
                    ai_accuracy_pct = EXCLUDED.ai_accuracy_pct,
                    updated_at = EXCLUDED.updated_at""",
            (month_start, total_det, enf, evt, crit, fp, accuracy, now)
        )
        conn.commit()

    result = {'month': month_start.isoformat(), 'detections': total_det, 'enforcements': enf}
    logger.info(f'stats_aggregator monthly: {result}')
    return result