//
//  WidgetDataEncoder.swift
//  NetNewsWire
//
//  Created by Stuart Breckenridge on 18/11/20.
//  Copyright © 2020 Ranchero Software. All rights reserved.
//

import Foundation
import WidgetKit
import os.log
import UIKit
import RSCore
import Articles
import Account


public final class WidgetDataEncoder {
	
	private let log = OSLog(subsystem: Bundle.main.bundleIdentifier!, category: "Application")
	private let fetchLimit = 7
	
	private var backgroundTaskID: UIBackgroundTaskIdentifier!
	private lazy var appGroup = Bundle.main.object(forInfoDictionaryKey: "AppGroup") as! String
	private lazy var containerURL = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: appGroup)
	private lazy var dataURL = containerURL?.appendingPathComponent("widget-data.json")
	
	static let shared = WidgetDataEncoder()
	private init () {}
	
	@available(iOS 14, *)
	func encodeWidgetData() throws {
		
		os_log(.debug, log: log, "Starting encoding widget data.")
		
		DispatchQueue.main.async {
			do {
				let unreadArticles = Array(try AccountManager.shared.fetchArticles(.unread(self.fetchLimit))).sortedByDate(.orderedDescending)
				let starredArticles = Array(try AccountManager.shared.fetchArticles(.starred(self.fetchLimit))).sortedByDate(.orderedDescending)
				let todayArticles = Array(try AccountManager.shared.fetchArticles(.today(self.fetchLimit))).sortedByDate(.orderedDescending)
				
				var unread = [LatestArticle]()
				var today = [LatestArticle]()
				var starred = [LatestArticle]()
				
				for article in unreadArticles {
					let latestArticle = LatestArticle(id: article.sortableArticleID,
													  feedTitle: article.sortableName,
													  articleTitle: ArticleStringFormatter.truncatedTitle(article).isEmpty ? ArticleStringFormatter.truncatedSummary(article) : ArticleStringFormatter.truncatedTitle(article),
													  articleSummary: article.summary,
													  feedIcon: article.iconImage()?.image.dataRepresentation(),
													  pubDate: article.datePublished?.description ?? "")
					unread.append(latestArticle)
				}
				
				for article in starredArticles {
					let latestArticle = LatestArticle(id: article.sortableArticleID,
													  feedTitle: article.sortableName,
													  articleTitle: ArticleStringFormatter.truncatedTitle(article).isEmpty ? ArticleStringFormatter.truncatedSummary(article) : ArticleStringFormatter.truncatedTitle(article),
													  articleSummary: article.summary,
													  feedIcon: article.iconImage()?.image.dataRepresentation(),
													  pubDate: article.datePublished?.description ?? "")
					starred.append(latestArticle)
				}
				
				for article in todayArticles {
					let latestArticle = LatestArticle(id: article.sortableArticleID,
													  feedTitle: article.sortableName,
													  articleTitle: ArticleStringFormatter.truncatedTitle(article).isEmpty ? ArticleStringFormatter.truncatedSummary(article) : ArticleStringFormatter.truncatedTitle(article),
													  articleSummary: article.summary,
													  feedIcon: article.iconImage()?.image.dataRepresentation(),
													  pubDate: article.datePublished?.description ?? "")
					today.append(latestArticle)
				}
				
				let latestData = WidgetData(currentUnreadCount: SmartFeedsController.shared.unreadFeed.unreadCount,
											currentTodayCount: SmartFeedsController.shared.todayFeed.unreadCount,
											currentStarredCount: try! SmartFeedsController.shared.starredFeed.fetchArticles().count,
											unreadArticles: unread,
											starredArticles: starred,
											todayArticles:today,
											lastUpdateTime: Date())
				
				
				let encodedData = try JSONEncoder().encode(latestData)
				os_log(.debug, log: self.log, "Finished encoding widget data.")
				
				if self.fileExists() {
					try? FileManager.default.removeItem(at: self.dataURL!)
					os_log(.debug, log: self.log, "Removed widget data from container.")
				}
				if FileManager.default.createFile(atPath: self.dataURL!.path, contents: encodedData, attributes: nil) {
					os_log(.debug, log: self.log, "Wrote widget data to container.")
					WidgetCenter.shared.reloadAllTimelines()
				}
			} catch {
				print(error.localizedDescription)
			}
		}
	}
	
	private func fileExists() -> Bool {
		FileManager.default.fileExists(atPath: dataURL!.path)
	}
	
}