CoreDataWidget+Provider.swift

// The MIT License (MIT)
//
// Copyright (c) 2020-Present Paweł Wiszenko
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

import CoreData
import OSLog
import WidgetKit

extension CoreDataWidget {
    struct Provider: TimelineProvider {
        static let persistenceController = PersistenceController()
        let managedObjectContext = Self.persistenceController.managedObjectContext

        func placeholder(in context: Context) -> Entry {
            .placeholder
        }

        func getSnapshot(in context: Context, completion: @escaping (Entry) -> Void) {
            completion(.placeholder)
        }

        func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> Void) {
            guard let documents = fetchDocuments() else {
                completion(.init(entries: [.empty], policy: .never))
                return
            }
            let documentInfo = Entry.DocumentInfo(
                count: documents.count,
                lastItem: documents.last.map {
                    .init(name: $0.name, creationDate: $0.creationDate)
                }
            )
            let entry = Entry(documentInfo: documentInfo)
            completion(.init(entries: [entry], policy: .never))
        }
    }
}

// MARK: - Helpers

extension CoreDataWidget.Provider {
    private func fetchDocuments() -> [Document]? {
        let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Document")
        do {
            guard let documents = try managedObjectContext.fetch(request) as? [Document] else {
                return nil
            }
            return documents.sorted {
                $0.creationDate < $1.creationDate
            }
        } catch {
            Logger.widgets.error("Error fetching documents: \(error)")
            return nil
        }
    }
}