// Copyright 2023 RisingWave Labs
//
// 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 pgwire::pg_response::{PgResponse, StatementType};
use risingwave_pb::catalog::connection::Info as ConnectionInfo;
use risingwave_pb::catalog::connection_params::ConnectionType;
use risingwave_sqlparser::ast::ObjectName;

use super::RwPgResponse;
use crate::binder::Binder;
use crate::catalog::root_catalog::SchemaPath;
use crate::error::{ErrorCode, Result};
use crate::handler::HandlerArgs;

pub async fn handle_drop_connection(
    handler_args: HandlerArgs,
    connection_name: ObjectName,
    if_exists: bool,
    cascade: bool,
) -> Result<RwPgResponse> {
    let session = handler_args.session;
    let db_name = &session.database();
    let (schema_name, connection_name) =
        Binder::resolve_schema_qualified_name(db_name, &connection_name)?;
    let search_path = session.config().search_path();
    let user_name = &session.user_name();

    let schema_path = SchemaPath::new(schema_name.as_deref(), &search_path, user_name);

    let (connection_id, is_iceberg_connection) = {
        let reader = session.env().catalog_reader().read_guard();
        let (connection, schema_name) =
            match reader.get_connection_by_name(db_name, schema_path, connection_name.as_str()) {
                Ok((c, s)) => (c, s),
                Err(e) => {
                    return if if_exists {
                        Ok(RwPgResponse::builder(StatementType::DROP_CONNECTION)
                            .notice(format!(
                                "connection \"{}\" does not exist, skipping",
                                connection_name
                            ))
                            .into())
                    } else {
                        Err(e.into())
                    };
                }
            };
        session.check_privilege_for_drop_alter(schema_name, &**connection)?;

        // Check if this is an Iceberg connection
        let is_iceberg = match &connection.info {
            ConnectionInfo::ConnectionParams(params) => {
                params.connection_type == ConnectionType::Iceberg as i32
            }
            _ => false,
        };

        (connection.id, is_iceberg)
    };

    // Ban DROP CASCADE for Iceberg connections
    if is_iceberg_connection && cascade {
        return Err(ErrorCode::NotSupported(
            "DROP CONNECTION CASCADE".to_owned(),
            "Please drop dependent objects manually before dropping the Iceberg connection, or use DROP CONNECTION without CASCADE".to_owned(),
        )
        .into());
    }

    let catalog_writer = session.catalog_writer()?;
    catalog_writer
        .drop_connection(connection_id, cascade)
        .await?;

    Ok(PgResponse::empty_result(StatementType::DROP_CONNECTION))
}
