"""
Идемпотентная схема WESP 2.0: недостающие таблицы (ORM) + недостающие колонки.

Используется:
- ревизией Alembic wesp_2_0;
- после каждого upgrade head в create_app — чтобы починить БД после stamp / частичного прогона.
"""

from __future__ import annotations

import importlib.util
from pathlib import Path

from alembic.operations import Operations


def _load_legacy_align():
    root = Path(__file__).resolve().parent.parent / "migrations" / "legacy_orm_schema_align.py"
    spec = importlib.util.spec_from_file_location("legacy_orm_schema_align", root)
    if spec is None or spec.loader is None:
        raise RuntimeError(f"Не найден {root}")
    mod = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(mod)
    return mod


def _table_names_for_bind(*, reports_only: bool) -> set[str]:
    from app import db  # noqa: WPS433

    import app.models  # noqa: F401, WPS433

    names: set[str] = set()
    for mapper in db.Model.registry.mappers:
        cls = mapper.class_
        if cls.__dict__.get("__abstract__", False):
            continue
        bk = getattr(cls, "__bind_key__", None)
        if reports_only:
            if bk != "reports":
                continue
        else:
            if bk == "reports":
                continue
        tab = getattr(cls, "__tablename__", None)
        if tab:
            names.add(tab)
    return names


def run_wesp20_idempotent_sync(op: Operations, kw: dict) -> None:
    from app import db  # noqa: WPS433

    import app.models  # noqa: F401, WPS433

    tag = kw.get("tag")
    reports_only = tag == "reports"
    bind = op.get_bind()
    allowed = _table_names_for_bind(reports_only=reports_only)

    # У Flask-SQLAlchemy отдельный MetaData на каждый bind; db.metadata — только основной.
    meta = db.metadatas["reports"] if reports_only else db.metadatas[None]
    from app.services.migration_pace import migration_pause, migration_pause_step

    for table in meta.sorted_tables:
        if table.name not in allowed:
            continue
        table.create(bind, checkfirst=True)
        migration_pause_step(f"table:{table.name}")

    _load_legacy_align().apply_legacy_orm_gaps(op, kw)
    migration_pause("legacy_align")

    if not reports_only:
        repair_legacy_sync_client_snapshot_cursor(op)
        migration_pause("sync_clients_repair")


def repair_legacy_sync_client_snapshot_cursor(op: Operations) -> int:
    """Старые узлы: personal_snapshot_cursor=0 при завершённом enqueue — новая логика ждёт cursor>=total."""
    from sqlalchemy import inspect, text

    from app.services.sync_manager import SNAPSHOT_MODELS

    bind = op.get_bind()
    if bind.dialect.name != "sqlite":
        return 0
    insp = inspect(bind)
    if not insp.has_table("sync_clients"):
        return 0
    total = len(SNAPSHOT_MODELS)
    result = bind.execute(
        text(
            """
            UPDATE sync_clients
            SET personal_snapshot_cursor = :total
            WHERE personal_snapshot_completed_at IS NOT NULL
              AND COALESCE(personal_snapshot_cursor, 0) < :total
            """
        ),
        {"total": total},
    )
    return int(getattr(result, "rowcount", 0) or 0)