"""
Database Migration: User Memories Table.
[AC-IDMP-14] 用户级记忆滚动摘要表

创建时间: 2025-03-08
变更说明:
- 新增 user_memories 表用于存储滚动摘要与事实/偏好/未解决问题

执行方式:
- SQLModel 会自动创建表（通过 init_db）
- 此脚本用于手动迁移或回滚

SQL DDL:
```sql
CREATE TABLE user_memories (
    id UUID PRIMARY KEY,
    tenant_id VARCHAR NOT NULL,
    user_id VARCHAR NOT NULL,
    summary TEXT,
    facts JSON,
    preferences JSON,
    open_issues JSON,
    summary_version INTEGER NOT NULL DEFAULT 1,
    last_turn_id VARCHAR,
    expires_at TIMESTAMP,
    created_at TIMESTAMP NOT NULL DEFAULT NOW(),
    updated_at TIMESTAMP NOT NULL DEFAULT NOW()
);

CREATE INDEX ix_user_memories_tenant_user ON user_memories(tenant_id, user_id);
CREATE INDEX ix_user_memories_tenant_user_updated ON user_memories(tenant_id, user_id, updated_at);
```

回滚 SQL:
```sql
DROP TABLE IF EXISTS user_memories;
```
"""

USER_MEMORIES_DDL = """
CREATE TABLE IF NOT EXISTS user_memories (
    id UUID PRIMARY KEY,
    tenant_id VARCHAR NOT NULL,
    user_id VARCHAR NOT NULL,
    summary TEXT,
    facts JSON,
    preferences JSON,
    open_issues JSON,
    summary_version INTEGER NOT NULL DEFAULT 1,
    last_turn_id VARCHAR,
    expires_at TIMESTAMP,
    created_at TIMESTAMP NOT NULL DEFAULT NOW(),
    updated_at TIMESTAMP NOT NULL DEFAULT NOW()
);
"""

USER_MEMORIES_INDEXES = """
CREATE INDEX IF NOT EXISTS ix_user_memories_tenant_user ON user_memories(tenant_id, user_id);
CREATE INDEX IF NOT EXISTS ix_user_memories_tenant_user_updated ON user_memories(tenant_id, user_id, updated_at);
"""

USER_MEMORIES_ROLLBACK = """
DROP TABLE IF EXISTS user_memories;
"""


async def upgrade(conn):
    """执行迁移"""
    await conn.execute(USER_MEMORIES_DDL)
    await conn.execute(USER_MEMORIES_INDEXES)


async def downgrade(conn):
    """回滚迁移"""
    await conn.execute(USER_MEMORIES_ROLLBACK)