"""Create notifications table for in-app notification centre.

Revision ID: 041
Revises: 040
"""
from alembic import op
import sqlalchemy as sa
from sqlalchemy.dialects.postgresql import JSONB

revision = "041"
down_revision = "040"
branch_labels = None
depends_on = None


def upgrade() -> None:
    op.create_table(
        "notifications",
        sa.Column("id", sa.Integer, primary_key=True, index=True),
        sa.Column(
            "user_id",
            sa.Integer,
            sa.ForeignKey("users.id", ondelete="CASCADE"),
            nullable=False,
        ),
        sa.Column("type", sa.String(50), nullable=False),
        sa.Column("title", sa.String(255), nullable=True),
        sa.Column("message", sa.Text, nullable=True),
        sa.Column("data", JSONB, nullable=True),
        sa.Column("source_type", sa.String(50), nullable=True),
        sa.Column("source_id", sa.Integer, nullable=True),
        sa.Column("is_read", sa.Boolean, nullable=False, server_default="false"),
        sa.Column(
            "created_at",
            sa.DateTime,
            nullable=False,
            server_default=sa.func.now(),
        ),
    )

    # Fast unread count query
    op.execute(
        'CREATE INDEX "ix_notifications_user_unread" ON notifications (user_id, is_read) '
        "WHERE is_read = false"
    )
    # Paginated listing
    op.create_index(
        "ix_notifications_user_created",
        "notifications",
        ["user_id", sa.text("created_at DESC")],
    )


def downgrade() -> None:
    op.drop_index("ix_notifications_user_created", table_name="notifications")
    op.execute('DROP INDEX IF EXISTS "ix_notifications_user_unread"')
    op.drop_table("notifications")