import SwiftUI

/// Tailscale 连接列表页。可添加多个；每个是一个常驻 tsnet 节点。
struct TailscaleListView: View {
    @ObservedObject var store: TailscaleStore
    @EnvironmentObject var theme: TXThemeManager
    @State private var editing: TailscaleConnection?
    @State private var showEditor = false
    private var p: TXPalette { theme.palette }

    var body: some View {
        ZStack {
            p.bg.ignoresSafeArea()
            ScrollView {
                VStack(alignment: .leading, spacing: TX.Space.s) {
                    if store.connections.isEmpty {
                        TXEmptyState(icon: "network", title: "还没有 Tailscale 连接",
                                     subtitle: "添加一个 tailnet，主机可选择经它连接")
                    } else {
                        ForEach(store.connections) { conn in
                            connRow(conn)
                                .contextMenu {
                                    Button { editing = conn; showEditor = true } label: {
                                        Label("编辑", systemImage: "pencil")
                                    }
                                    Button(role: .destructive) { store.remove(conn) } label: {
                                        Label("删除", systemImage: "trash")
                                    }
                                }
                        }
                    }
                }
                .padding(TX.Space.m)
            }
        }
        .navigationTitle("Tailscale")
        .navigationBarTitleDisplayMode(.inline)
        .toolbarBackground(p.bg, for: .navigationBar)
        .toolbar {
            ToolbarItem(placement: .topBarTrailing) {
                Button { editing = nil; showEditor = true } label: { Image(systemName: "plus") }
            }
        }
        .sheet(isPresented: $showEditor) {
            TailscaleEditorView(existing: editing, store: store)
        }
    }

    private func connRow(_ conn: TailscaleConnection) -> some View {
        HStack(spacing: TX.Space.m) {
            Image(systemName: "network")
                .font(.system(size: 18))
                .foregroundStyle(conn.needsAuthKey ? p.textTertiary : p.mosh)
                .frame(width: 40, height: 40)
                .background(p.surfaceElevated, in: RoundedRectangle(cornerRadius: TX.Radius.chip))
            VStack(alignment: .leading, spacing: 2) {
                Text(conn.name).font(.system(size: 15, weight: .semibold)).foregroundStyle(p.textPrimary)
                Text(conn.needsAuthKey ? "未认证" : (conn.lastSelfIP.map { "已注册 · \($0)" } ?? "已注册"))
                    .font(TX.Font.mono(12))
                    .foregroundStyle(conn.needsAuthKey ? p.warning : p.textSecondary)
            }
            Spacer()
            Circle().fill(conn.needsAuthKey ? p.offline : p.mosh).frame(width: 8, height: 8)
        }
        .padding(TX.Space.m)
        .background(p.surface, in: RoundedRectangle(cornerRadius: TX.Radius.card))
        .overlay(RoundedRectangle(cornerRadius: TX.Radius.card).stroke(p.border, lineWidth: 1))
    }
}

/// Tailscale 连接编辑页：填 name/hostname/authKey → 注册（Up tsnet 节点）→ 显示 SelfIP。
struct TailscaleEditorView: View {
    let existing: TailscaleConnection?
    @ObservedObject var store: TailscaleStore
    /// 保存回调（主机编辑页就地新建时用于自动选中刚建的连接）。
    var onSave: ((TailscaleConnection) -> Void)?

    @EnvironmentObject var theme: TXThemeManager
    @Environment(\.dismiss) private var dismiss

    @State private var name = ""
    @State private var hostname = "terminalx-ipad"
    @State private var authKey = ""
    @State private var registering = false
    @State private var statusText = ""
    @State private var registered = false
    @State private var draft: TailscaleConnection?

    private var p: TXPalette { theme.palette }
    private var canRegister: Bool { !name.isEmpty && (!authKey.isEmpty || registered) }

    var body: some View {
        NavigationStack {
            ZStack {
                p.bg.ignoresSafeArea()
                Form {
                    Section("连接") {
                        TXTextField(title: "名称", text: $name, placeholder: "公司 tailnet")
                        TXTextField(title: "本节点主机名", text: $hostname)
                    }
                    Section {
                        TXTextField(title: "Auth Key（tskey-…）", text: $authKey, secure: true)
                        Button {
                            register()
                        } label: {
                            HStack {
                                if registering { ProgressView().controlSize(.small) }
                                Text(registering ? "注册中…" : "注册 / 连接测试")
                            }
                        }
                        .disabled(!canRegister || registering)
                        .txRow(p)
                    } header: {
                        Text("认证")
                    } footer: {
                        Text("Auth key 仅用于首次注册，注册成功后不保存（节点身份持久化在设备本地）。")
                    }
                    if !statusText.isEmpty {
                        Section {
                            Text(statusText)
                                .font(.system(size: 13))
                                .foregroundStyle(registered ? p.accent : p.warning)
                                .txRow(p)
                        }
                    }
                }
                .scrollContentBackground(.hidden)
            }
            .navigationTitle(existing == nil ? "添加 Tailscale" : "编辑 Tailscale")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .cancellationAction) {
                    Button("取消") { dismiss() }.tint(p.textSecondary)
                }
                ToolbarItem(placement: .confirmationAction) {
                    Button("完成") { finish() }.tint(p.accent)
                }
            }
            .toolbarBackground(p.bg, for: .navigationBar)
            .toolbarBackground(.visible, for: .navigationBar)
            .onAppear(perform: populate)
        }
        .tint(p.accent)
    }

    private func populate() {
        guard let c = existing else { return }
        name = c.name; hostname = c.hostname
        registered = !c.needsAuthKey
        draft = c
        if registered { statusText = c.lastSelfIP.map { "已注册 · \($0)" } ?? "已注册" }
    }

    /// 注册：经 TsnetRegistry Up 该连接的节点（后台阻塞），成功后 SelfIP 落库、needsAuthKey=false。
    private func register() {
        // 确定连接身份（新建则造一个，固化 stateDir）。
        let conn = draft ?? existing ?? {
            let c = TailscaleConnection(name: name, hostname: hostname)
            return c
        }()
        draft = conn
        registering = true; statusText = ""
        let connID = conn.id, dir = conn.stateDirName, host = hostname, key = authKey
        Task.detached {
            do {
                let node = try TsnetRegistry.shared.node(
                    connID: connID, stateDirName: dir, hostname: host, authKey: key, timeoutMs: 45000)
                let ip = node.selfIP()
                await MainActor.run {
                    registering = false; registered = true
                    statusText = ip.isEmpty ? "已注册（IP 获取中）" : "已注册 · \(ip)"
                    // 落库（保留同一 id/stateDir）。
                    let updated = TailscaleConnection(id: connID, name: name.isEmpty ? "tailnet" : name,
                                                      hostname: host, needsAuthKey: false,
                                                      lastSelfIP: ip.isEmpty ? nil : ip)
                    persist(updated)
                }
            } catch {
                await MainActor.run {
                    registering = false
                    statusText = "注册失败：\(error.localizedDescription)"
                }
            }
        }
    }

    /// 完成：若已注册则确保落库；未注册也保存 meta（needsAuthKey=true，供之后再认证）。
    private func finish() {
        let base = draft ?? existing
        let conn: TailscaleConnection
        if let base {
            conn = TailscaleConnection(id: base.id, name: name.isEmpty ? "tailnet" : name,
                                       hostname: hostname, needsAuthKey: !registered,
                                       lastSelfIP: registered ? base.lastSelfIP : nil)
        } else {
            conn = TailscaleConnection(name: name.isEmpty ? "tailnet" : name,
                                       hostname: hostname, needsAuthKey: !registered)
        }
        persist(conn)
        dismiss()
    }

    private func persist(_ conn: TailscaleConnection) {
        if store.connections.contains(where: { $0.id == conn.id }) { store.update(conn) }
        else { store.add(conn) }
        draft = conn
        onSave?(conn)
    }
}