NetNewsWire/Frameworks/Database/AuthorsTable.swift

//
//  AuthorsTable.swift
//  Database
//
//  Created by Brent Simmons on 7/13/17.
//  Copyright © 2017 Ranchero Software. All rights reserved.
//

import Foundation
import RSDatabase
import Data

// article->authors is a many-to-many relationship.
// There’s a lookup table relating authorID and articleID.
//
// CREATE TABLE if not EXISTS authors (authorID TEXT NOT NULL PRIMARY KEY, name TEXT, url TEXT, avatarURL TEXT, emailAddress TEXT);
// CREATE TABLE if not EXISTS authorLookup (authorID TEXT NOT NULL, articleID TEXT NOT NULL, PRIMARY KEY(authorID, articleID));


final class AuthorsTable: DatabaseRelatedObjectsTable {
	
	let name: String
	let databaseIDKey = DatabaseKey.authorID
	var cache = [String: Author]()

	init(name: String) {

		self.name = name
	}
	
	// MARK: DatabaseRelatedObjectsTable

	func objectWithRow(_ row: FMResultSet) -> DatabaseObject? {
	
		if let author = Author.authorWithRow(row) {
			return author as DatabaseObject
		}
		return nil
	}
	
	func save(_ objects: [DatabaseObject], in database: FMDatabase) {

		let attachments = objects.map { $0 as! Author }

		// Authors in cache must already exist in database. Filter them out.
		let authorsToSave = Set(attachments.filter { (attachment) -> Bool in
			if let _ = cache[attachment.attachmentID] {
				return false
			}
			return true
		})

		cacheAttachments(attachmentsToSave)

		insertRows(attachmentsToSave.databaseDictionaries(), insertType: .orIgnore, in: database)
}
}