// // StatusesTable.swift // Evergreen // // Created by Brent Simmons on 5/8/16. // Copyright © 2016 Ranchero Software, LLC. All rights reserved. // import Foundation import RSCore import RSDatabase import Data // Article->ArticleStatus is a to-one relationship. // // CREATE TABLE if not EXISTS statuses (articleID TEXT NOT NULL PRIMARY KEY, read BOOL NOT NULL DEFAULT 0, starred BOOL NOT NULL DEFAULT 0, userDeleted BOOL NOT NULL DEFAULT 0, dateArrived DATE NOT NULL DEFAULT 0, accountInfo BLOB); typealias StatusesCompletionBlock = ([String: ArticleStatus]) -> Void // [articleID: Status] final class StatusesTable: DatabaseTable { let name = DatabaseTableName.statuses private let cache = StatusCache() private let queue: RSDatabaseQueue init(queue: RSDatabaseQueue) { self.queue = queue } // MARK: Cache func cachedStatus(for articleID: String) -> ArticleStatus? { assert(Thread.isMainThread) assert(cache[articleID] != nil) return cache[articleID] } func addIfNotCached(_ statuses: Set) { if statuses.isEmpty { return } if Thread.isMainThread { self.cache.addIfNotCached(statuses) } else { DispatchQueue.main.async { self.cache.addIfNotCached(statuses) } } } // MARK: Creating/Updating func ensureStatusesForArticleIDs(_ articleIDs: Set, _ completion: @escaping StatusesCompletionBlock) { // Adds them to the cache if not cached. assert(Thread.isMainThread) // Check cache. let articleIDsMissingCachedStatus = articleIDsWithNoCachedStatus(articleIDs) if articleIDsMissingCachedStatus.isEmpty { completion(statusesDictionary(articleIDs)) return } // Check database. fetchAndCacheStatusesForArticleIDs(articleIDsMissingCachedStatus) { let articleIDsNeedingStatus = self.articleIDsWithNoCachedStatus(articleIDs) if !articleIDsNeedingStatus.isEmpty { // Create new statuses. self.createAndSaveStatusesForArticleIDs(articleIDsNeedingStatus) } completion(self.statusesDictionary(articleIDs)) } } // MARK: Marking func markArticleIDs(_ articleIDs: Set, _ statusKey: String, _ flag: Bool, _ database: FMDatabase) { // TODO: replace statuses in cache. updateRowsWithValue(NSNumber(value: flag), valueKey: statusKey, whereKey: DatabaseKey.articleID, matches: Array(articleIDs), database: database) } // MARK: Fetching func statusWithRow(_ row: FMResultSet) -> ArticleStatus? { guard let articleID = row.string(forColumn: DatabaseKey.articleID) else { return nil } guard let dateArrived = row.date(forColumn: DatabaseKey.dateArrived) else { return nil } let articleStatus = ArticleStatus(articleID: articleID, dateArrived: dateArrived, row: row) return articleStatus } } // MARK: - Private private extension StatusesTable { // MARK: Cache func articleIDsWithNoCachedStatus(_ articleIDs: Set) -> Set { assert(Thread.isMainThread) return Set(articleIDs.filter { cache[$0] == nil }) } func statusesDictionary(_ articleIDs: Set) -> [String: ArticleStatus] { assert(Thread.isMainThread) var d = [String: ArticleStatus]() for articleID in articleIDs { if let articleStatus = cache[articleID] { d[articleID] = articleStatus } } return d } // MARK: Creating func saveStatuses(_ statuses: Set) { queue.update { (database) in let statusArray = statuses.map { $0.databaseDictionary()! } self.insertRows(statusArray, insertType: .orIgnore, in: database) } } func createAndSaveStatusesForArticleIDs(_ articleIDs: Set) { assert(Thread.isMainThread) let now = Date() let statuses = Set(articleIDs.map { ArticleStatus(articleID: $0, dateArrived: now) }) cache.addIfNotCached(statuses) saveStatuses(statuses) } func fetchAndCacheStatusesForArticleIDs(_ articleIDs: Set, _ completion: @escaping RSVoidCompletionBlock) { queue.fetch { (database) in guard let resultSet = self.selectRowsWhere(key: DatabaseKey.articleID, inValues: Array(articleIDs), in: database) else { completion() return } let statuses = resultSet.mapToSet(self.statusWithRow) DispatchQueue.main.async { self.cache.addIfNotCached(statuses) completion() } } } } private final class StatusCache { // Main thread only. var dictionary = [String: ArticleStatus]() func add(_ statuses: Set) { // Replaces any cached statuses. for status in statuses { self[status.articleID] = status } } func addIfNotCached(_ statuses: Set) { // Does not replace already cached statuses. for status in statuses { let articleID = status.articleID if let _ = self[articleID] { continue } self[articleID] = status } } subscript(_ articleID: String) -> ArticleStatus? { get { return self[articleID] } set { self[articleID] = newValue } } }