"""
Добавление в SQLite недостающих колонок по ORM-моделям (легаси → рефактор).

Вызывается из единой миграции wesp_2_0 на каждом bind отдельно (recipes / reports).
Не создаёт таблицы и не меняет типы существующих колонок.
"""

from __future__ import annotations

from alembic import op
import sqlalchemy as sa
from sqlalchemy import inspect as sa_inspect
from sqlalchemy.sql import sqltypes


def _bool_server_default(col: sa.Column) -> sa.TextClause:
    if col.default is None:
        return sa.text("0")
    arg = getattr(col.default, "arg", False)
    if callable(arg):
        return sa.text("0")
    return sa.text("1" if arg else "0")


def _int_server_default(col: sa.Column) -> str:
    if col.default is None:
        return "0"
    arg = getattr(col.default, "arg", None)
    if arg is None or callable(arg):
        return "0"
    try:
        return str(int(arg))
    except (TypeError, ValueError):
        return "0"


def _float_server_default(col: sa.Column) -> str:
    if col.default is None:
        return "0"
    arg = getattr(col.default, "arg", None)
    if arg is None or callable(arg):
        return "0"
    try:
        return str(float(arg))
    except (TypeError, ValueError):
        return "0"


def _is_bool_type(t: sa.types.TypeEngine) -> bool:
    return isinstance(t, sqltypes.Boolean)


def _is_int_type(t: sa.types.TypeEngine) -> bool:
    return isinstance(t, sqltypes.Integer)


def _is_float_type(t: sa.types.TypeEngine) -> bool:
    return isinstance(t, (sqltypes.Float, sqltypes.REAL))


def _is_stringy_type(t: sa.types.TypeEngine) -> bool:
    return isinstance(t, (sqltypes.String, sqltypes.Text, sqltypes.Unicode, sqltypes.UnicodeText))


def _is_datetime_type(t: sa.types.TypeEngine) -> bool:
    return isinstance(t, sqltypes.DateTime)


def _add_column_sqlite_safe(op, table: str, col: sa.Column) -> None:
    typ = col.type
    name = col.name

    # В SQLAlchemy по умолчанию nullable=None/True; только явный False — NOT NULL в DDL.
    if col.nullable is not False:
        op.add_column(table, sa.Column(name, typ, nullable=True))
        return

    if col.server_default is not None:
        op.add_column(
            table,
            sa.Column(name, typ, nullable=False, server_default=col.server_default),
        )
        return

    if _is_bool_type(typ):
        op.add_column(
            table,
            sa.Column(name, typ, nullable=False, server_default=_bool_server_default(col)),
        )
        return

    if _is_stringy_type(typ):
        op.add_column(
            table,
            sa.Column(name, typ, nullable=False, server_default=""),
        )
        return

    if _is_int_type(typ):
        op.add_column(
            table,
            sa.Column(
                name,
                typ,
                nullable=False,
                server_default=_int_server_default(col),
            ),
        )
        return

    if _is_float_type(typ):
        op.add_column(
            table,
            sa.Column(
                name,
                typ,
                nullable=False,
                server_default=_float_server_default(col),
            ),
        )
        return

    if _is_datetime_type(typ):
        op.add_column(table, sa.Column(name, typ, nullable=True))
        bind = op.get_bind()
        insp = sa_inspect(bind)
        cols_now = {c["name"] for c in insp.get_columns(table)}
        parts: list[str] = []
        for key in ("created_at", "updated_at"):
            if key in cols_now and key != name:
                parts.append(f'"{key}"')
        if parts:
            expr = "COALESCE(" + ", ".join(parts) + ", CURRENT_TIMESTAMP)"
        else:
            expr = "CURRENT_TIMESTAMP"
        op.execute(
            sa.text(f'UPDATE "{table}" SET "{name}" = {expr} WHERE "{name}" IS NULL')
        )
        with op.batch_alter_table(table) as batch:
            batch.alter_column(name, existing_type=typ, nullable=False)
        return

    op.add_column(table, sa.Column(name, typ, nullable=True))


def apply_legacy_orm_gaps(op, kw: dict) -> None:
    tag = kw.get("tag")
    reports_only = tag == "reports"

    from app import db  # noqa: WPS433 — внутри миграции, после загрузки приложения в env
    import app.models  # noqa: F401, WPS433

    bind = op.get_bind()
    insp = sa_inspect(bind)

    for mapper in db.Model.registry.mappers:
        cls = mapper.class_
        bk = getattr(cls, "__bind_key__", None)
        if reports_only:
            if bk != "reports":
                continue
        else:
            if bk == "reports":
                continue

        # db.Model (Flask-SQLAlchemy) задаёт __abstract__ = True; наследники остаются конкретными.
        if cls.__dict__.get("__abstract__", False):
            continue

        tab = getattr(cls, "__tablename__", None)
        if not tab:
            continue

        if not insp.has_table(tab):
            continue

        existing = {c["name"] for c in insp.get_columns(tab)}

        for col in cls.__table__.columns:
            if col.primary_key:
                continue
            if col.key in existing:
                continue
            _add_column_sqlite_safe(op, tab, col)
            existing.add(col.key)
            from app.services.migration_pace import migration_pause_step

            migration_pause_step(f"column:{tab}.{col.key}")