"""system_usage_events — were an area's rulings read once its files were
touched? (milestone 444 step 4, #4757)

Revision ID: 0114
Revises: 0113
Create Date: 2026-10-03

The usage twin for Systems, beside note_usage_events and rule_usage_events and
separate from both for the same reason they are separate from each other: a
System id restores through its own map. FK-free like its siblings; no CHECK on
`event`, like its siblings.
"""
import sqlalchemy as sa
from alembic import op

revision = "0114"
down_revision = "0113"
branch_labels = None
depends_on = None


def upgrade() -> None:
    op.create_table(
        "system_usage_events",
        sa.Column("id", sa.BigInteger(), primary_key=True),
        sa.Column(
            "created_at", sa.DateTime(timezone=True), nullable=False,
            server_default=sa.text("now()"),
        ),
        sa.Column("user_id", sa.BigInteger(), nullable=True),
        sa.Column("system_id", sa.BigInteger(), nullable=False),
        sa.Column("event", sa.Text(), nullable=False),
        sa.Column("source", sa.Text(), nullable=False),
        sa.Column("project_id", sa.BigInteger(), nullable=True),
    )
    op.create_index(
        "ix_system_usage_system_event", "system_usage_events", ["system_id", "event"]
    )
    op.create_index("ix_system_usage_created_at", "system_usage_events", ["created_at"])


def downgrade() -> None:
    op.drop_index("ix_system_usage_created_at", table_name="system_usage_events")
    op.drop_index("ix_system_usage_system_event", table_name="system_usage_events")
    op.drop_table("system_usage_events")