import Foundation

/// A screen identified across restarts and machines: by name first, position as fallback.
/// (CGDirectDisplayIDs differ between Macs and can change after a reboot.)
public struct ScreenRef: Codable, Hashable, Sendable {
    public var name: String
    /// Position in the system's screen list (0 = main screen).
    public var index: Int

    public init(name: String, index: Int) {
        self.name = name
        self.index = index
    }
}

/// One NDI source fullscreen on one screen.
public struct VideoAssignment: Codable, Hashable, Sendable {
    public var screen: ScreenRef
    public var source: Source

    public init(screen: ScreenRef, source: Source) {
        self.screen = screen
        self.source = source
    }
}

/// One audio source on one output channel.
public struct AudioAssignment: Codable, Hashable, Sendable {
    public enum SourceSpec: Codable, Hashable, Sendable {
        case ndi(name: String)
        /// Input device by UID; the name is the fallback when the UID changes (e.g. other USB port).
        case input(uid: String, name: String)
    }

    public var source: SourceSpec
    public var deviceUID: String
    public var deviceName: String
    public var channel: Int // 0-based
    public var selection: ChannelSelection
    public var gainDB: Float
    public var muted: Bool

    public init(source: SourceSpec, deviceUID: String, deviceName: String, channel: Int,
                selection: ChannelSelection = .mono, gainDB: Float = 0, muted: Bool = false) {
        self.source = source
        self.deviceUID = deviceUID
        self.deviceName = deviceName
        self.channel = channel
        self.selection = selection
        self.gainDB = gainDB
        self.muted = muted
    }

    /// Identity of the route (what goes where), without its settings.
    public var key: String {
        let sourceKey = switch source {
        case .ndi(let name): "ndi:\(name)"
        case .input(let uid, _): "input:\(uid)"
        }
        return "\(sourceKey)→\(deviceUID)#\(channel)"
    }
}

/// Everything one Mac outputs.
public struct MachineConfig: Codable, Hashable, Sendable {
    public var video: [VideoAssignment]
    public var audio: [AudioAssignment]

    public init(video: [VideoAssignment] = [], audio: [AudioAssignment] = []) {
        self.video = video
        self.audio = audio
    }

    public static let empty = MachineConfig()
}

/// A complete setup of the control Mac and its nodes, e.g. "OP-Live".
public struct Scene: Codable, Identifiable, Hashable, Sendable {
    public var id: UUID
    public var name: String
    public var control: MachineConfig
    /// Node name (computer name) → what that node shows.
    public var nodes: [String: MachineConfig]

    public init(id: UUID = UUID(), name: String, control: MachineConfig = .empty, nodes: [String: MachineConfig] = [:]) {
        self.id = id
        self.name = name
        self.control = control
        self.nodes = nodes
    }
}