"""replace vision focus with explicit prompt modes

Revision ID: 20260812_0020
Revises: 20260812_0019
"""

from collections.abc import Sequence

from alembic import op
import sqlalchemy as sa


revision: str = "20260812_0020"
down_revision: str | Sequence[str] | None = "20260812_0019"
branch_labels: str | Sequence[str] | None = None
depends_on: str | Sequence[str] | None = None


def upgrade() -> None:
    op.alter_column(
        "assistants",
        "vision_focus_prompt",
        new_column_name="vision_prompt",
    )
    op.add_column(
        "assistants",
        sa.Column(
            "vision_prompt_mode",
            sa.String(length=16),
            server_default="runtime",
            nullable=False,
        ),
    )
    # The previous single-field implementation behaved most like guided mode.
    op.execute(
        "UPDATE assistants SET vision_prompt_mode = 'guided' "
        "WHERE TRIM(vision_prompt) <> ''"
    )


def downgrade() -> None:
    op.drop_column("assistants", "vision_prompt_mode")
    op.alter_column(
        "assistants",
        "vision_prompt",
        new_column_name="vision_focus_prompt",
    )