impl Db {
    pub fn list_flows(&self) -> Result<Vec<Flow>> {
        self.list_payloads(queries::LIST_FLOWS)
    }

    pub fn get_flow(&self, id: &str) -> Result<Option<Flow>> {
        self.get_payload(queries::GET_FLOW, id)
    }

    pub fn replace_flow_outputs(&self, flow: &Flow, schedules: &[Schedule], automations: &[Automation]) -> Result<()> {
        let mut conn = self.lock()?;
        let tx = conn.transaction()?;
        tx.execute(queries::DELETE_SCHEDULES_BY_FLOW_ID, [flow.id.as_str()])?;
        tx.execute(queries::DELETE_AUTOMATIONS_BY_FLOW_ID, [flow.id.as_str()])?;
        for schedule in schedules {
            let payload = Self::to_json(schedule)?;
            tx.execute(queries::UPSERT_SCHEDULE, params![schedule.id, schedule.zone_id, payload, schedule.updated_at.to_rfc3339()])?;
        }
        for item in automations {
            let payload = Self::to_json(item)?;
            tx.execute(queries::UPSERT_AUTOMATION, params![item.id, payload, item.updated_at.to_rfc3339()])?;
        }
        let payload = Self::to_json(flow)?;
        tx.execute(queries::UPSERT_FLOW, params![flow.id, payload, flow.updated_at.to_rfc3339()])?;
        tx.commit()?;
        Ok(())
    }

    pub fn delete_flow(&self, id: &str) -> Result<bool> {
        let mut conn = self.lock()?;
        let tx = conn.transaction()?;
        tx.execute(queries::DELETE_SCHEDULES_BY_FLOW_ID, [id])?;
        tx.execute(queries::DELETE_AUTOMATIONS_BY_FLOW_ID, [id])?;
        let changed = tx.execute(queries::DELETE_FLOW, [id])? > 0;
        tx.commit()?;
        Ok(changed)
    }
}