from fastapi import APIRouter, HTTPException
import pkgutil
import importlib
from pathlib import Path
from typing import List

from bd import Settings
from sqlalchemy import create_engine
from sqlalchemy.exc import SQLAlchemyError
from pydantic import BaseModel

router = APIRouter(tags=["db"])


def _iter_table_modules() -> List[str]:
    try:
        import bd.tables as tables_pkg
        pkg_paths = getattr(tables_pkg, "__path__", None)
        if not pkg_paths:
            pkg_paths = [str(Path(__file__).resolve().parent.parent / "bd" / "tables")]
    except Exception:
        pkg_paths = [str(Path(__file__).resolve().parent.parent / "bd" / "tables")]

    names = []
    for finder, name, ispkg in pkgutil.iter_modules(pkg_paths):
        names.append(name)
    return names


def collect_metadatas():
    metadatas = []
    for mod_name in _iter_table_modules():
        try:
            module = importlib.import_module(f"bd.tables.{mod_name}")
        except Exception:
            continue
        Base = getattr(module, "Base", None)
        if Base is not None and hasattr(Base, "metadata"):
            metadatas.append(Base.metadata)
    return metadatas


@router.post("/db/create-tables")
async def create_tables():
    """Создаёт все таблицы, описанные в модулях `db.tables`.

    Endpoint вызывается по нажатию кнопки в UI (POST).
    """
    settings = Settings()
    db_url = settings.DATABASE_URL_syncpg
    engine = create_engine(db_url, future=True)

    metadatas = collect_metadatas()
    if not metadatas:
        raise HTTPException(status_code=400, detail="No table metadata found in db.tables")

    # deduplicate metadata objects (multiple modules may expose the same Base.metadata)
    unique = []
    seen = set()
    for md in metadatas:
        if id(md) not in seen:
            seen.add(id(md))
            unique.append(md)

    try:
        for md in unique:
            md.create_all(bind=engine)
        return {"status": "ok", "detail": f"Created {len(unique)} metadata groups"}
    except SQLAlchemyError as e:
        raise HTTPException(status_code=500, detail=str(e))


class ClearDBIn(BaseModel):
    confirm: bool


@router.post("/db/clear")
async def clear_tables(payload: ClearDBIn):
    """Полная очистка всех таблиц, описанных в `bd.tables`.

    Требуется явное подтверждение: POST с телом {"confirm": true}.
    """
    if not payload.confirm:
        raise HTTPException(status_code=400, detail="Confirmation required")

    settings = Settings()
    db_url = settings.DATABASE_URL_syncpg
    engine = create_engine(db_url, future=True)

    metadatas = collect_metadatas()
    if not metadatas:
        raise HTTPException(status_code=400, detail="No table metadata found in db.tables")

    # deduplicate metadata objects
    unique = []
    seen = set()
    for md in metadatas:
        if id(md) not in seen:
            seen.add(id(md))
            unique.append(md)

    try:
        for md in unique:
            md.drop_all(bind=engine)
        return {"status": "ok", "detail": f"Dropped {len(unique)} metadata groups"}
    except SQLAlchemyError as e:
        raise HTTPException(status_code=500, detail=str(e))