import Foundation

enum PlaybackState: String {
    case idle
    case buffering
    case ready
    case ended
}

struct PlaybackSnapshot: Equatable {
    var mediaId: String?
    var positionMs: Int64 = 0
    var durationMs: Int64 = -1
    var bufferedPositionMs: Int64 = 0
    var isPlaying = false
    var state: PlaybackState = .idle
    var speed: Float = 1
    var sentenceIndex: Int?
}

struct PlayerConfig {
    var sentenceMode = true
    var defaultSeekStepMs: Int64 = 10_000
    var autoPlay = false
    var continuousPlayback = true
    var minPlaybackSpeed: Float = 0.5
    var maxPlaybackSpeed: Float = 2.0
}

enum LoopMode {
    case off
    case one
    case all
}

enum SwipeAction {
    case none
    case rewind
    case forward
    case previousSentence
    case nextSentence
    case previousSentenceOrRewind
    case nextSentenceOrForward
}

enum GestureKind {
    case singleTap
    case swipeLeft
    case swipeRight
    case longPressSpeed
}

enum SwipeBackResult {
    case restartedCurrent
    case movedPrevious
    case stayedAtFirst
    case rewound
}

enum BoundaryState: Equatable {
    case idle
    case loading(isLocal: Bool)
    case loaded(count: Int)
    case failed(message: String)
}

/// 云端视频必须先完成整文件下载；下载未完成前不允许创建可播放的 AVPlayerItem。
enum VideoCacheState: Equatable {
    case notRequired
    case downloading
    case ready
    case failed(message: String)

    var statusMessage: String? {
        switch self {
        case .notRequired, .ready:
            return nil
        case .downloading:
            return "正在下载完整视频，下载完成后才能播放"
        case .failed(let message):
            return "视频缓存失败：\(message)"
        }
    }
}