"""remove SLA tracking

Revision ID: d4e5g6h7i8j9
Revises: a1b2c3d4e5f2
Create Date: 2026-08-31

SLA is being removed entirely. Drops the SLA-specific complaint columns
(first response, due instants, materialized durations) and the per-priority
sla_policies table. `reported_at`, `resolved_at` and `closed_at` stay — they
are plain timestamps, not SLA machinery.
"""
from typing import Sequence, Union

import sqlalchemy as sa
from alembic import op


revision: str = 'd4e5g6h7i8j9'
down_revision: Union[str, None] = 'a1b2c3d4e5f2'
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    op.drop_table('sla_policies')
    op.drop_column('complaints', 'first_response_at')
    op.drop_column('complaints', 'sla_response_due_at')
    op.drop_column('complaints', 'sla_resolution_due_at')
    op.drop_column('complaints', 'response_minutes')
    op.drop_column('complaints', 'resolution_minutes')


def downgrade() -> None:
    op.add_column(
        'complaints',
        sa.Column('resolution_minutes', sa.Integer(), nullable=True),
    )
    op.add_column(
        'complaints',
        sa.Column('response_minutes', sa.Integer(), nullable=True),
    )
    op.add_column(
        'complaints',
        sa.Column('sla_resolution_due_at', sa.DateTime(timezone=True), nullable=True),
    )
    op.add_column(
        'complaints',
        sa.Column('sla_response_due_at', sa.DateTime(timezone=True), nullable=True),
    )
    op.add_column(
        'complaints',
        sa.Column('first_response_at', sa.DateTime(timezone=True), nullable=True),
    )
    op.create_table(
        'sla_policies',
        sa.Column('id', sa.Integer(), nullable=False),
        sa.Column(
            'priority',
            sa.Enum(name='complaint_priority', create_type=False),
            nullable=False,
        ),
        sa.Column('response_minutes', sa.Integer(), nullable=False),
        sa.Column('resolution_minutes', sa.Integer(), nullable=False),
        sa.Column(
            'created_at',
            sa.DateTime(timezone=True),
            server_default=sa.text('now()'),
            nullable=False,
        ),
        sa.Column(
            'updated_at',
            sa.DateTime(timezone=True),
            server_default=sa.text('now()'),
            nullable=False,
        ),
        sa.PrimaryKeyConstraint('id', name=op.f('pk_sla_policies')),
        sa.UniqueConstraint('priority', name=op.f('uq_sla_policies_priority')),
    )
    op.create_index(
        op.f('ix_sla_policies_created_at'), 'sla_policies', ['created_at'], unique=False
    )