import Foundation

/// 一个 Tailscale 连接（= 一个常驻 tsnet 节点）。可添加多个；host 可绑定其一作为出口。
/// 每连接独立 stateDir（`tsnet-<uuid>`，创建即固化、终身不变——tsnet 无文件锁，同 Dir 双 Up 会损坏状态）。
struct TailscaleConnection: Identifiable, Codable, Equatable {
    let id: UUID
    var name: String
    /// tailnet 内展示的主机名。
    var hostname: String
    /// tsnet 状态目录名（Application Support 下），创建即固化。
    let stateDirName: String
    /// true = 从未注册 或 被 tailnet 清理 → 需重填 authKey 才能 Up。
    var needsAuthKey: Bool
    /// 展示用缓存：上次 Up 后的本节点 tailnet IP。
    var lastSelfIP: String?

    init(id: UUID = UUID(), name: String, hostname: String = "terminalx-ipad",
         needsAuthKey: Bool = true, lastSelfIP: String? = nil) {
        self.id = id
        self.name = name
        self.hostname = hostname
        self.stateDirName = "tsnet-\(id.uuidString)"
        self.needsAuthKey = needsAuthKey
        self.lastSelfIP = lastSelfIP
    }
}

/// Tailscale 连接列表持久化（tailnets.json）。本体无机密（authKey 默认注册后即丢弃）。
@MainActor
final class TailscaleStore: ObservableObject {
    @Published private(set) var connections: [TailscaleConnection] = []

    private let url: URL

    init() {
        let base = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)[0]
        try? FileManager.default.createDirectory(at: base, withIntermediateDirectories: true)
        url = base.appendingPathComponent("tailnets.json")
        load()
    }

    func add(_ conn: TailscaleConnection) { connections.append(conn); save() }

    func update(_ conn: TailscaleConnection) {
        guard let i = connections.firstIndex(where: { $0.id == conn.id }) else { return }
        connections[i] = conn
        save()
    }

    func remove(_ conn: TailscaleConnection) {
        connections.removeAll { $0.id == conn.id }
        save()
        // 删连接 → 删其 tsnet 状态目录，避免残留身份。
        let base = NSSearchPathForDirectoriesInDomains(.applicationSupportDirectory, .userDomainMask, true)[0]
        try? FileManager.default.removeItem(atPath: base + "/" + conn.stateDirName)
    }

    func connection(id: UUID?) -> TailscaleConnection? {
        guard let id else { return nil }
        return connections.first { $0.id == id }
    }

    #if DEBUG
    /// 无头 UI 验证：注入示意 tailnet（**不写盘**，不污染真实 tailnets.json）。
    func injectFixtureConnections(_ list: [TailscaleConnection]) {
        connections = list
    }
    #endif

    private func load() {
        guard let data = try? Data(contentsOf: url),
              let decoded = try? JSONDecoder().decode([TailscaleConnection].self, from: data) else { return }
        connections = decoded
    }

    private func save() {
        guard let data = try? JSONEncoder().encode(connections) else { return }
        try? data.write(to: url, options: .atomic)
    }
}