// Copyright 2020-2021 Dave Verwer, Sven A. Schmidt, and other contributors.
//
// 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.

import Fluent
import SQLKit


struct AddLastActivityAtToRepositories: Migration {
    func prepare(on database: Database) -> EventLoopFuture<Void> {
        guard let db = database as? SQLDatabase else {
            fatalError("Database must be an SQLDatabase ('as? SQLDatabase' must succeed)")
        }

        return db.raw("""
            ALTER TABLE repositories
            ADD COLUMN last_activity_at TIMESTAMPTZ GENERATED ALWAYS AS (
                GREATEST(last_commit_date, last_issue_closed_at, last_pull_request_closed_at)
            ) STORED;
            """).run()
    }
    
    func revert(on database: Database) -> EventLoopFuture<Void> {
        guard let db = database as? SQLDatabase else {
            fatalError("Database must be an SQLDatabase ('as? SQLDatabase' must succeed)")
        }

        return db.raw("""
            ALTER TABLE repositories DROP COLUMN last_activity_at;
            """).run()
    }
}
