// 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 UpdateSearch3: Migration {
    let dropSQL: SQLQueryString = "DROP MATERIALIZED VIEW search"
    
    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(dropSQL).run()
            .flatMap { db.raw("""
            -- v4
            CREATE MATERIALIZED VIEW search AS
            SELECT
              p.id AS package_id,
              p.score,
              r.keywords,
              r.last_commit_date,
              r.license,
              r.name AS repo_name,
              r.owner AS repo_owner,
              r.stars,
              r.last_activity_at,
              r.summary,
              v.package_name
            FROM packages p
              JOIN repositories r ON r.package_id = p.id
              JOIN versions v ON v.package_id = p.id
            WHERE v.reference ->> 'branch' = r.default_branch
            """).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(dropSQL).run()
            .flatMap { db.raw("""
            -- v3
            CREATE MATERIALIZED VIEW search AS
            SELECT
              p.id AS package_id,
              p.score,
              r.keywords,
              r.last_commit_date,
              r.license,
              r.name AS repo_name,
              r.owner AS repo_owner,
              r.stars,
              r.summary,
              v.package_name
            FROM packages p
              JOIN repositories r ON r.package_id = p.id
              JOIN versions v ON v.package_id = p.id
            WHERE v.reference ->> 'branch' = r.default_branch
            """).run() }
    }
}
