use sea_orm_migration::prelude::*;

#[derive(DeriveMigrationName)]
pub struct Migration;

#[async_trait::async_trait]
impl MigrationTrait for Migration {
    async fn up(&self, manager: &SchemaManager) -> Result<(), DbErr> {
        // 分区表必须用 raw SQL，SeaORM schema builder 不支持 PARTITION BY
        let sql = r#"
            CREATE TABLE IF NOT EXISTS device_readings (
                id              UUID NOT NULL DEFAULT gen_random_uuid(),
                tenant_id       UUID NOT NULL,
                patient_id      UUID NOT NULL,
                device_id       VARCHAR(64),
                device_type     VARCHAR(32) NOT NULL,
                device_model    VARCHAR(64),
                raw_value       JSONB NOT NULL,
                measured_at     TIMESTAMPTZ NOT NULL,
                created_at      TIMESTAMPTZ DEFAULT NOW(),
                deleted_at      TIMESTAMPTZ
            ) PARTITION BY RANGE (measured_at);
        "#;
        manager.get_connection().execute_unprepared(sql).await?;

        // 分区表主键必须包含分区键
        manager
            .get_connection()
            .execute_unprepared("ALTER TABLE device_readings ADD PRIMARY KEY (id, measured_at);")
            .await?;

        // 核心查询索引
        manager.get_connection().execute_unprepared(
            "CREATE INDEX idx_dr_tenant_patient ON device_readings (tenant_id, patient_id, measured_at DESC);"
        ).await?;

        manager.get_connection().execute_unprepared(
            "CREATE INDEX idx_dr_device_type ON device_readings (tenant_id, device_type, measured_at DESC);"
        ).await?;

        // 创建初始分区（当前月 + 未来 3 个月）
        for (suffix, start, end) in [
            ("2026_05", "2026-05-01", "2026-06-01"),
            ("2026_06", "2026-06-01", "2026-07-01"),
            ("2026_07", "2026-07-01", "2026-08-01"),
            ("2026_08", "2026-08-01", "2026-09-01"),
        ] {
            let partition_sql = format!(
                "CREATE TABLE IF NOT EXISTS device_readings_{suffix} PARTITION OF device_readings FOR VALUES FROM ('{start}') TO ('{end}');"
            );
            manager
                .get_connection()
                .execute_unprepared(&partition_sql)
                .await?;
        }

        Ok(())
    }

    async fn down(&self, manager: &SchemaManager) -> Result<(), DbErr> {
        for suffix in ["2026_05", "2026_06", "2026_07", "2026_08"] {
            manager
                .get_connection()
                .execute_unprepared(&format!("DROP TABLE IF EXISTS device_readings_{suffix};"))
                .await
                .ok();
        }
        manager
            .get_connection()
            .execute_unprepared("DROP TABLE IF EXISTS device_readings;")
            .await?;
        Ok(())
    }
}