"""Add invalidation_price fields for BTC bottom-reversal trades.

Revision ID: 010
Revises: 009
Create Date: 2026-05-16 00:00:00.000000

NOTE: `bot_trades.eff_invalidation_price` is ALSO created by migration 009
(two_system_and_frozen_exits). The original 010 added it unconditionally,
which made `alembic upgrade head` on a FRESH database fail at 010 with
"duplicate column name: eff_invalidation_price" (009 already added it).

This revision is now IDEMPOTENT: each column is added only if it is not
already present, so it applies cleanly on both fresh DBs (009 already made
eff_invalidation_price → skip; posts.invalidation_price is new → add) and
DBs that pre-date 009's column. The genuinely-new column introduced by 010
is `posts.invalidation_price`; `eff_invalidation_price` is owned by 009 and
left to 009's downgrade.
"""

from typing import Sequence, Union

import sqlalchemy as sa
from alembic import op
from sqlalchemy import inspect

revision: str = "010"
down_revision: Union[str, None] = "009"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def _columns(table: str) -> set:
    return {c["name"] for c in inspect(op.get_bind()).get_columns(table)}


def upgrade() -> None:
    if "invalidation_price" not in _columns("posts"):
        with op.batch_alter_table("posts") as b:
            b.add_column(sa.Column("invalidation_price", sa.Float(), nullable=True))
    # eff_invalidation_price may already exist (created by 009). Only add it
    # if some older DB reached 010 without it.
    if "eff_invalidation_price" not in _columns("bot_trades"):
        with op.batch_alter_table("bot_trades") as b:
            b.add_column(sa.Column("eff_invalidation_price", sa.Float(), nullable=True))


def downgrade() -> None:
    # Only undo 010's genuine addition. eff_invalidation_price is owned by
    # 009 — dropping it here would double-drop in `downgrade base`.
    if "invalidation_price" in _columns("posts"):
        with op.batch_alter_table("posts") as b:
            b.drop_column("invalidation_price")