"""Функции работы с БД для GPS-треков (ET-008)."""
import json
import os
import sqlite3
from datetime import datetime, timezone
from typing import Optional

from src.api.gps_tracks.models import TrackInsert


_MIGRATION_PATH = os.path.join(
    os.path.dirname(__file__), "../../../migrations/gps_tracks_001_init.sql"
)


def open_db(db_path: str) -> sqlite3.Connection:
    """Открывает соединение с SQLite БД."""
    conn = sqlite3.connect(db_path)
    conn.row_factory = sqlite3.Row
    conn.execute("PRAGMA journal_mode=WAL")
    conn.execute("PRAGMA foreign_keys=ON")
    return conn


def init_db(conn: sqlite3.Connection) -> None:
    """Применяет миграцию SQL для создания схемы."""
    migration_path = os.path.abspath(_MIGRATION_PATH)
    with open(migration_path, "r", encoding="utf-8") as f:
        sql = f.read()
    # Выполняем каждый statement отдельно (executescript не поддерживает параметры,
    # но зато не требует явного commit)
    conn.executescript(sql)
    conn.commit()


def _now_iso() -> str:
    return datetime.now(timezone.utc).strftime("%Y-%m-%dT%H:%M:%SZ")


def upsert_track(
    conn: sqlite3.Connection,
    track: TrackInsert,
    dedup_key: str,
    source_priority: int,
) -> str:
    """Вставляет или обновляет трек в БД.

    При коллизии dedup_key:
    - UNION sources (без дублей)
    - UNION external_urls (без дублей)
    - Метаданные обновляются если новый source_priority < существующего

    Returns:
        "inserted" или "updated"
    """
    cur = conn.cursor()
    now = _now_iso()

    # Проверяем существующую запись
    cur.execute(
        "SELECT id, sources_json, external_urls_json, name, description, activity_type, "
        "user, created_at, source_priority FROM tracks WHERE dedup_key = ?",
        (dedup_key,),
    )
    existing = cur.fetchone()

    if existing is None:
        # INSERT новой записи
        sources = [track.source_id]
        ext_urls = [track.external_url] if track.external_url else []

        cur.execute(
            """
            INSERT INTO tracks (
                dedup_key, name, description, activity_type, user, created_at,
                length_m, points_count, min_lon, min_lat, max_lon, max_lat,
                geom, sources_json, external_urls_json, tags_json,
                inserted_at, updated_at, source_priority
            ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
            """,
            (
                dedup_key,
                track.name,
                track.description,
                track.activity_type,
                track.user,
                track.created_at,
                track.length_m,
                track.points_count,
                track.min_lon,
                track.min_lat,
                track.max_lon,
                track.max_lat,
                track.geom_wkb,
                json.dumps(sources),
                json.dumps(ext_urls),
                json.dumps(track.tags) if track.tags else json.dumps([]),
                now,
                now,
                source_priority,
            ),
        )
        conn.commit()
        return "inserted"
    else:
        # UPDATE: мержим sources и external_urls
        existing_sources = json.loads(existing["sources_json"] or "[]")
        existing_urls = json.loads(existing["external_urls_json"] or "[]")

        # Union без дублей, сохраняя порядок
        merged_sources = list(dict.fromkeys(existing_sources + [track.source_id]))
        new_urls = [track.external_url] if track.external_url else []
        merged_urls = list(dict.fromkeys(existing_urls + new_urls))

        # Получаем текущий source_priority (может отсутствовать в старых записях)
        existing_priority = existing["source_priority"] if "source_priority" in existing.keys() else 999

        # Обновляем метаданные только если новый источник имеет более высокий приоритет
        if source_priority < existing_priority:
            cur.execute(
                """
                UPDATE tracks SET
                    name = ?,
                    description = ?,
                    activity_type = ?,
                    user = ?,
                    created_at = ?,
                    sources_json = ?,
                    external_urls_json = ?,
                    updated_at = ?,
                    source_priority = ?
                WHERE dedup_key = ?
                """,
                (
                    track.name,
                    track.description,
                    track.activity_type,
                    track.user,
                    track.created_at,
                    json.dumps(merged_sources),
                    json.dumps(merged_urls),
                    now,
                    source_priority,
                    dedup_key,
                ),
            )
        else:
            # Только обновляем sources/urls и updated_at
            cur.execute(
                """
                UPDATE tracks SET
                    sources_json = ?,
                    external_urls_json = ?,
                    updated_at = ?
                WHERE dedup_key = ?
                """,
                (
                    json.dumps(merged_sources),
                    json.dumps(merged_urls),
                    now,
                    dedup_key,
                ),
            )
        conn.commit()
        return "updated"


def get_tracks_in_bbox(
    conn: sqlite3.Connection,
    west: float,
    south: float,
    east: float,
    north: float,
    activities: Optional[list] = None,
    sources: Optional[list] = None,
    limit: int = 500,
) -> tuple:
    """Возвращает треки в указанном bbox.

    Returns:
        (tracks: list[sqlite3.Row], total_count: int)
    """
    cur = conn.cursor()

    # Базовое условие bbox
    conditions = [
        "min_lon <= :east",
        "max_lon >= :west",
        "min_lat <= :north",
        "max_lat >= :south",
    ]
    params: dict = {"west": west, "south": south, "east": east, "north": north}

    # Фильтр по activity_type
    if activities:
        placeholders = ",".join(f":act{i}" for i in range(len(activities)))
        conditions.append(f"activity_type IN ({placeholders})")
        for i, act in enumerate(activities):
            params[f"act{i}"] = act

    where_clause = " AND ".join(conditions)

    # Подсчёт общего числа (без фильтра по source, он применяется постфактум)
    count_sql = f"SELECT COUNT(*) as cnt FROM tracks WHERE {where_clause}"
    cur.execute(count_sql, params)
    total_count = cur.fetchone()["cnt"]

    # Основной запрос
    select_sql = f"""
        SELECT id, dedup_key, name, description, activity_type, user,
               created_at, length_m, points_count,
               min_lon, min_lat, max_lon, max_lat,
               sources_json, external_urls_json, tags_json,
               inserted_at, updated_at, geom
        FROM tracks
        WHERE {where_clause}
        LIMIT :limit
    """
    params["limit"] = limit
    cur.execute(select_sql, params)
    rows = cur.fetchall()

    # Постфильтрация по sources (если задан)
    if sources:
        filtered = []
        for row in rows:
            row_sources = json.loads(row["sources_json"] or "[]")
            if any(s in row_sources for s in sources):
                filtered.append(row)
        rows = filtered

    return rows, total_count