import Foundation

@Observable
final class WatchProgressStore {
    static let shared = WatchProgressStore()

    private let defaults = UserDefaults.standard
    private let progressKey = "ddys_watch_progress"

    private var progressMap: [String: WatchProgress] {
        get {
            guard let data = defaults.data(forKey: progressKey),
                  let map = try? JSONDecoder().decode([String: WatchProgress].self, from: data) else {
                return [:]
            }
            return map
        }
        set {
            if let data = try? JSONEncoder().encode(newValue) {
                defaults.set(data, forKey: progressKey)
            }
        }
    }

    private init() {}

    func getProgress(for contentId: String, episodeId: Int = 0) -> WatchProgress? {
        let key = "\(contentId)_\(episodeId)"
        return progressMap[key]
    }

    func saveProgress(contentId: String, episodeId: Int = 0, currentTime: Double, duration: Double) {
        let key = "\(contentId)_\(episodeId)"
        let progress = WatchProgress(
            contentId: contentId,
            episodeId: episodeId,
            currentTime: currentTime,
            duration: duration,
            lastWatched: Date()
        )
        var map = progressMap
        map[key] = progress
        progressMap = map
    }

    func clearAll() {
        defaults.removeObject(forKey: progressKey)
    }

    func recentlyWatched(limit: Int = 20) -> [WatchProgress] {
        progressMap.values
            .sorted { $0.lastWatched > $1.lastWatched }
            .prefix(limit)
            .map { $0 }
    }
}

struct WatchProgress: Codable {
    let contentId: String
    let episodeId: Int
    let currentTime: Double
    let duration: Double
    let lastWatched: Date

    var percentage: Double {
        guard duration > 0 else { return 0 }
        return currentTime / duration
    }
}