"""add_performance_indexes

Revision ID: 1174fffbe3e4
Revises: fbf6318a8a36
Create Date: 2025-11-01 04:15:25.367010

"""
from typing import Sequence, Union

import sqlalchemy as sa

from alembic import op

# revision identifiers, used by Alembic.
revision: str = '1174fffbe3e4'
down_revision: Union[str, None] = 'fbf6318a8a36'
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    """Add performance indexes for optimized queries."""

    # Index for session cleanup queries
    # Optimizes: DELETE WHERE is_active = FALSE AND expires_at < now AND created_at < cutoff
    op.create_index(
        'ix_user_sessions_cleanup',
        'user_sessions',
        ['is_active', 'expires_at', 'created_at'],
        unique=False,
        postgresql_where=sa.text('is_active = false')
    )

    # Index for user search queries (basic trigram support without pg_trgm extension)
    # Optimizes: WHERE email ILIKE '%search%' OR first_name ILIKE '%search%'
    # Note: For better performance, consider enabling pg_trgm extension
    op.create_index(
        'ix_users_email_lower',
        'users',
        [sa.text('LOWER(email)')],
        unique=False,
        postgresql_where=sa.text('deleted_at IS NULL')
    )

    op.create_index(
        'ix_users_first_name_lower',
        'users',
        [sa.text('LOWER(first_name)')],
        unique=False,
        postgresql_where=sa.text('deleted_at IS NULL')
    )

    op.create_index(
        'ix_users_last_name_lower',
        'users',
        [sa.text('LOWER(last_name)')],
        unique=False,
        postgresql_where=sa.text('deleted_at IS NULL')
    )

    # Index for organization search
    op.create_index(
        'ix_organizations_name_lower',
        'organizations',
        [sa.text('LOWER(name)')],
        unique=False
    )


def downgrade() -> None:
    """Remove performance indexes."""

    # Drop indexes in reverse order
    op.drop_index('ix_organizations_name_lower', table_name='organizations')
    op.drop_index('ix_users_last_name_lower', table_name='users')
    op.drop_index('ix_users_first_name_lower', table_name='users')
    op.drop_index('ix_users_email_lower', table_name='users')
    op.drop_index('ix_user_sessions_cleanup', table_name='user_sessions')