"""Sessions and client events for the Sprint-0 parallel batch.

Two tables that the parallel task batch (T3/T4) needs, landed together in one
revision so no task ever writes a migration:

1. ``id_session`` — server-revocable refresh sessions (架构文档 §6.2, FR-ACC-05).
2. ``ob_event``   — client telemetry (架构文档 §6.2, FR-SYS-06).

Partitioning (架构文档 says "按月分区") is deliberately deferred for both —
same call as ``ob_ai_call``: plain tables until volume justifies it.

Reversible: 是。降级直接 drop 两表。
"""

from __future__ import annotations

from collections.abc import Sequence

import sqlalchemy as sa
from alembic import op
from sqlalchemy.dialects import postgresql

revision: str = "0004"
down_revision: str | None = "0003"
branch_labels: str | Sequence[str] | None = None
depends_on: str | Sequence[str] | None = None


def upgrade() -> None:
    op.create_table(
        "id_session",
        sa.Column("session_id", sa.BigInteger(), nullable=False),
        sa.Column("user_id", sa.BigInteger(), nullable=False),
        sa.Column("refresh_token_hash", sa.String(length=64), nullable=False),
        sa.Column("expire_at", sa.DateTime(timezone=True), nullable=False),
        sa.Column("revoked", sa.Boolean(), nullable=False, server_default=sa.text("false")),
        sa.Column("revoked_at", sa.DateTime(timezone=True), nullable=True),
        sa.Column("created_at", sa.DateTime(timezone=True), nullable=False, server_default=sa.func.now()),
        sa.PrimaryKeyConstraint("session_id"),
        sa.UniqueConstraint("refresh_token_hash", name="uq_id_session_token_hash"),
    )
    op.create_index("ix_id_session_user", "id_session", ["user_id"])

    op.create_table(
        "ob_event",
        sa.Column("event_id", sa.BigInteger(), nullable=False),
        sa.Column("user_id", sa.BigInteger(), nullable=False),
        sa.Column("event_name", sa.String(length=64), nullable=False),
        sa.Column("props", postgresql.JSONB(), nullable=False),
        sa.Column("client_ts", sa.DateTime(timezone=True), nullable=True),
        sa.Column("server_ts", sa.DateTime(timezone=True), nullable=False, server_default=sa.func.now()),
        sa.PrimaryKeyConstraint("event_id"),
    )
    op.create_index("ix_ob_event_name_ts", "ob_event", ["event_name", "server_ts"])
    op.create_index("ix_ob_event_user_ts", "ob_event", ["user_id", "server_ts"])


def downgrade() -> None:
    op.drop_index("ix_ob_event_user_ts", table_name="ob_event")
    op.drop_index("ix_ob_event_name_ts", table_name="ob_event")
    op.drop_table("ob_event")
    op.drop_index("ix_id_session_user", table_name="id_session")
    op.drop_table("id_session")