"""Phase 2 Plan 04: Add escalation_assignee and natural_language_escalation to agents

Revision ID: 003
Revises: 002
Create Date: 2026-03-23

These columns support the human escalation/handoff system:
- escalation_assignee: Slack user ID of the human to DM when escalation triggers
- natural_language_escalation: tenant-level flag enabling NL phrase detection

Both are nullable/defaulted so existing agent rows are unaffected.
"""

from __future__ import annotations

from typing import Sequence, Union

import sqlalchemy as sa
from alembic import op


# revision identifiers, used by Alembic.
revision: str = "003"
down_revision: Union[str, None] = "002"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    # Add escalation_assignee column — nullable TEXT
    op.add_column(
        "agents",
        sa.Column(
            "escalation_assignee",
            sa.Text,
            nullable=True,
            comment="Slack user ID of the human to DM on escalation (e.g. U0HUMANID)",
        ),
    )

    # Add natural_language_escalation column — NOT NULL with default False
    op.add_column(
        "agents",
        sa.Column(
            "natural_language_escalation",
            sa.Boolean,
            nullable=False,
            server_default=sa.text("FALSE"),
            comment="Whether natural language escalation phrases trigger handoff",
        ),
    )


def downgrade() -> None:
    op.drop_column("agents", "natural_language_escalation")
    op.drop_column("agents", "escalation_assignee")