// Copyright 2023 Greptime Team
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::sync::Weak;

use common_meta::key::TableMetadataManagerRef;
use snafu::OptionExt;

use crate::CatalogManager;
use crate::error::{GetInformationExtensionSnafu, Result, UpgradeWeakCatalogManagerRefSnafu};
use crate::information_schema::InformationExtensionRef;
use crate::kvbackend::KvBackendCatalogManager;
use crate::system_schema::semantic_graph::EntityGraphProviderRef;

pub mod tables;

/// Try to get the entity-graph provider from a `[CatalogManager]` weak reference.
/// Returns `None` when the manager is not the kv-backed one or the provider has
/// not been injected yet (the computed graph tables then stream empty).
pub fn entity_graph_provider(
    catalog_manager: &Weak<dyn CatalogManager>,
) -> Result<Option<EntityGraphProviderRef>> {
    let catalog_manager = catalog_manager
        .upgrade()
        .context(UpgradeWeakCatalogManagerRefSnafu)?;

    Ok(catalog_manager
        .as_any()
        .downcast_ref::<KvBackendCatalogManager>()
        .and_then(|manager| manager.entity_graph_provider()))
}

/// Try to get the `[InformationExtension]` from `[CatalogManager]` weak reference.
pub fn information_extension(
    catalog_manager: &Weak<dyn CatalogManager>,
) -> Result<InformationExtensionRef> {
    let catalog_manager = catalog_manager
        .upgrade()
        .context(UpgradeWeakCatalogManagerRefSnafu)?;

    let information_extension = catalog_manager
        .as_any()
        .downcast_ref::<KvBackendCatalogManager>()
        .map(|manager| manager.information_extension())
        .context(GetInformationExtensionSnafu)?;

    Ok(information_extension)
}

/// Try to get the `[TableMetadataManagerRef]` from `[CatalogManager]` weak reference.
pub fn table_meta_manager(
    catalog_manager: &Weak<dyn CatalogManager>,
) -> Result<Option<TableMetadataManagerRef>> {
    let catalog_manager = catalog_manager
        .upgrade()
        .context(UpgradeWeakCatalogManagerRefSnafu)?;

    Ok(catalog_manager
        .as_any()
        .downcast_ref::<KvBackendCatalogManager>()
        .map(|manager| manager.table_metadata_manager_ref().clone()))
}
