import Foundation

/// The persisted sub/dub choices: a global default plus per-series overrides.
/// Keyed by normalized show name so a choice survives across episodes and app
/// restarts. anime defaults to `sub` at resolve time even without an override.
public struct TrackPreferences: Codable, Sendable, Equatable {
    public var globalDefault: DubSub
    public var perSeries: [String: DubSub]

    public init(globalDefault: DubSub = .dub, perSeries: [String: DubSub] = [:]) {
        self.globalDefault = globalDefault
        self.perSeries = perSeries
    }

    static func key(_ name: String) -> String {
        name.lowercased().trimmingCharacters(in: .whitespaces)
    }

    /// Resolve the effective choice: explicit per-series override wins; otherwise
    /// anime defaults to `sub`; otherwise the global default (`dub` — native audio,
    /// no forced subs, which is right for English-language content).
    public func choice(series: String?, category: String?) -> DubSub {
        if let series, let explicit = perSeries[Self.key(series)] { return explicit }
        if category == "anime" { return .sub }
        return globalDefault
    }

    public mutating func setSeries(_ name: String, _ choice: DubSub) {
        perSeries[Self.key(name)] = choice
    }
}

/// JSON store at `~/.local/state/tv-anarchy/track-prefs.json`. Mirrors
/// PlayerStatusCache's load/save shape.
public enum TrackPreferenceStore {
    private static var url: URL {
        FileManager.default.homeDirectoryForCurrentUser
            .appendingPathComponent(".local/state/tv-anarchy/track-prefs.json")
    }

    public static func load() -> TrackPreferences {
        guard let data = try? Data(contentsOf: url),
              let prefs = try? JSONDecoder().decode(TrackPreferences.self, from: data) else {
            return TrackPreferences()
        }
        return prefs
    }

    public static func save(_ prefs: TrackPreferences) {
        guard let data = try? JSONEncoder().encode(prefs) else { return }
        try? FileManager.default.createDirectory(at: url.deletingLastPathComponent(),
                                                 withIntermediateDirectories: true)
        try? data.write(to: url, options: .atomic)
    }
}