"""PostgreSQL 연결 및 SCAT 데이터 upsert."""

from __future__ import annotations

import json
from typing import Optional

import psycopg2
from psycopg2 import pool

import config
from models import CoastalSection


# ---------------------------------------------------------------------------
# 커넥션 풀 (싱글턴)
# ---------------------------------------------------------------------------
_pool: pool.ThreadedConnectionPool | None = None


def get_pool() -> pool.ThreadedConnectionPool:
    global _pool
    if _pool is None:
        _pool = pool.ThreadedConnectionPool(
            minconn=1,
            maxconn=5,
            host=config.DB_HOST,
            port=config.DB_PORT,
            dbname=config.DB_NAME,
            user=config.DB_USER,
            password=config.DB_PASSWORD,
            options=f'-c search_path={config.DB_SCHEMA},public',
        )
    return _pool


def get_conn():
    return get_pool().getconn()


def put_conn(conn):
    get_pool().putconn(conn)


# ---------------------------------------------------------------------------
# Zone 관리
# ---------------------------------------------------------------------------
def ensure_zone(zone_cd: str, zone_nm: str, jrsd_nm: str) -> int:
    """구역이 없으면 생성, 있으면 SN 반환."""
    conn = get_conn()
    try:
        with conn.cursor() as cur:
            cur.execute(
                'SELECT cst_srvy_zone_sn FROM cst_srvy_zone WHERE zone_cd = %s',
                (zone_cd,),
            )
            row = cur.fetchone()
            if row:
                return row[0]

            cur.execute(
                '''INSERT INTO cst_srvy_zone (zone_cd, zone_nm, jrsd_nm, sect_cnt)
                   VALUES (%s, %s, %s, 0)
                   RETURNING cst_srvy_zone_sn''',
                (zone_cd, zone_nm, jrsd_nm),
            )
            sn = cur.fetchone()[0]
            conn.commit()
            return sn
    finally:
        put_conn(conn)


def update_zone_sect_count(zone_sn: int):
    """구역의 구간 수를 갱신."""
    conn = get_conn()
    try:
        with conn.cursor() as cur:
            cur.execute(
                '''UPDATE cst_srvy_zone
                   SET sect_cnt = (SELECT count(*) FROM cst_sect WHERE cst_srvy_zone_sn = %s)
                   WHERE cst_srvy_zone_sn = %s''',
                (zone_sn, zone_sn),
            )
            conn.commit()
    finally:
        put_conn(conn)


def update_zone_center(zone_sn: int):
    """zone의 sections 좌표 평균으로 LAT_CENTER/LNG_CENTER 갱신."""
    conn = get_conn()
    try:
        with conn.cursor() as cur:
            cur.execute(
                '''UPDATE cst_srvy_zone SET
                       lat_center = sub.avg_lat,
                       lng_center = sub.avg_lng
                   FROM (
                       SELECT AVG(lat) as avg_lat, AVG(lng) as avg_lng
                       FROM cst_sect
                       WHERE cst_srvy_zone_sn = %s AND lat IS NOT NULL
                   ) sub
                   WHERE cst_srvy_zone_sn = %s''',
                (zone_sn, zone_sn),
            )
            conn.commit()
    finally:
        put_conn(conn)


# ---------------------------------------------------------------------------
# Section upsert
# ---------------------------------------------------------------------------
def upsert_section(zone_sn: int, section: CoastalSection) -> int:
    """구간 INSERT 또는 UPDATE (SECT_CD 기준 ON CONFLICT)."""
    conn = get_conn()
    try:
        sensitive = json.dumps(
            [item.model_dump() for item in section.sensitive_info],
            ensure_ascii=False,
        )
        cleanup = json.dumps(section.cleanup_methods, ensure_ascii=False)
        end_crit = json.dumps(section.end_criteria, ensure_ascii=False)
        notes = json.dumps(section.notes, ensure_ascii=False)

        with conn.cursor() as cur:
            cur.execute(
                '''INSERT INTO cst_sect (
                       cst_srvy_zone_sn, sect_cd, sect_nm,
                       cst_tp_cd, esi_cd, esi_num, shore_tp, len_m,
                       lat, lng,
                       access_dc, access_pt,
                       sensitive_info, cleanup_methods, end_criteria, notes,
                       srvy_stts_cd
                   ) VALUES (
                       %s, %s, %s,
                       %s, %s, %s, %s, %s,
                       %s, %s,
                       %s, %s,
                       %s::jsonb, %s::jsonb, %s::jsonb, %s::jsonb,
                       '미조사'
                   )
                   ON CONFLICT (sect_cd) DO UPDATE SET
                       sect_nm = EXCLUDED.sect_nm,
                       cst_tp_cd = EXCLUDED.cst_tp_cd,
                       esi_cd = EXCLUDED.esi_cd,
                       esi_num = EXCLUDED.esi_num,
                       shore_tp = EXCLUDED.shore_tp,
                       len_m = EXCLUDED.len_m,
                       lat = EXCLUDED.lat,
                       lng = EXCLUDED.lng,
                       access_dc = EXCLUDED.access_dc,
                       access_pt = EXCLUDED.access_pt,
                       sensitive_info = EXCLUDED.sensitive_info,
                       cleanup_methods = EXCLUDED.cleanup_methods,
                       end_criteria = EXCLUDED.end_criteria,
                       notes = EXCLUDED.notes
                   RETURNING cst_sect_sn''',
                (
                    zone_sn, section.sect_cd, section.sect_nm,
                    section.cst_tp_cd, section.esi_cd, section.esi_num,
                    section.shore_tp, section.len_m,
                    section.lat, section.lng,
                    section.access_dc, section.access_pt,
                    sensitive, cleanup, end_crit, notes,
                ),
            )
            sn = cur.fetchone()[0]
            conn.commit()
            return sn
    finally:
        put_conn(conn)


def close_pool():
    global _pool
    if _pool:
        _pool.closeall()
        _pool = None