import SwiftUI

struct FleetView: View {
    @StateObject private var model: FleetViewModel
    @Environment(\.refresh) private var refreshEnvironment

    init(model: FleetViewModel? = nil) {
        _model = StateObject(wrappedValue: model ?? DefaultContainer.makeFleetModel())
    }

    var body: some View {
        NavigationStack {
            ZStack {
                AITheme.canvas.ignoresSafeArea()
                ScrollView {
                    LazyVStack(spacing: 12) {
                        searchField
                        if model.rows.isEmpty && !model.isLoading {
                            AICard {
                                VStack(spacing: 10) {
                                    Image(systemName: "server.rack")
                                        .font(.system(size: 28))
                                        .foregroundStyle(AITheme.muted)
                                    Text("暂无实例")
                                        .font(.headline)
                                    Text("添加 SimAdmin 实例后即可开始管理。")
                                        .font(.subheadline)
                                        .foregroundStyle(AITheme.muted)
                                }
                                .frame(maxWidth: .infinity)
                                .padding(.vertical, 18)
                            }
                        }
                        ForEach(model.rows) { row in
                            instanceCard(row)
                        }
                    }
                    .padding(16)
                }
            }
            .navigationTitle("节点总览")
            .toolbar {
                ToolbarItemGroup(placement: .primaryAction) {
                    Button {
                        model.selectionMode.toggle()
                        model.selectedIDs.removeAll()
                    } label: {
                        Label("批量选择", systemImage: model.selectionMode ? "xmark" : "checklist")
                    }
                    .buttonStyle(AIButtonStyle(kind: .secondary, size: .regular))

                    Button {
                        model.showingForm = true
                    } label: {
                        Label("添加实例", systemImage: "plus")
                    }
                    .buttonStyle(AIButtonStyle(kind: .primary, size: .regular))
                }
            }
            .refreshable {
                await model.refresh()
            }
            .task {
                await model.refresh()
            }
            .sheet(isPresented: $model.showingForm) {
                InstanceFormView(model: model)
            }
        }
    }

    private var searchField: some View {
        HStack(spacing: 8) {
            Image(systemName: "magnifyingglass")
                .foregroundStyle(AITheme.muted)
            TextField("搜索实例或地址", text: $model.searchText)
                .textFieldStyle(.plain)
                .onSubmit {
                    Task { await model.refresh() }
                }
        }
        .padding(.horizontal, 14)
        .frame(minHeight: AITheme.buttonHeight)
        .background(AITheme.surface)
        .clipShape(RoundedRectangle(cornerRadius: AITheme.buttonRadius))
        .overlay {
            RoundedRectangle(cornerRadius: AITheme.buttonRadius)
                .strokeBorder(AITheme.line)
        }
    }

    private func instanceCard(_ row: FleetViewModel.Row) -> some View {
        AICard {
            HStack(alignment: .top, spacing: 12) {
                if model.selectionMode {
                    Button {
                        toggle(row.id)
                    } label: {
                        Image(systemName: model.selectedIDs.contains(row.id)
                            ? "checkmark.circle.fill" : "circle")
                            .font(.system(size: 20))
                            .foregroundStyle(model.selectedIDs.contains(row.id) ? AITheme.primary : AITheme.muted)
                    }
                    .buttonStyle(.plain)
                    .frame(width: 32, height: 32)
                }
                VStack(alignment: .leading, spacing: 8) {
                    HStack(spacing: 8) {
                        Text(row.instance.name)
                            .font(.headline)
                            .foregroundStyle(AITheme.ink)
                        Spacer()
                        AITag(row.status.label, tint: statusColor(row.status))
                    }
                    Text(row.instance.origin.absoluteString)
                        .font(.subheadline)
                        .foregroundStyle(AITheme.muted)
                    if !row.instance.tags.isEmpty {
                        HStack(spacing: 6) {
                            ForEach(row.instance.tags, id: \.self) { tag in
                                AITag(tag)
                            }
                        }
                    }
                }
            }
        }
    }

    private func statusColor(_ status: ConnectionStatus) -> Color {
        switch status {
        case .online: return AITheme.success
        case .offline: return AITheme.danger
        case .authRequired: return AITheme.warning
        case .degraded: return AITheme.warning
        case .unknown: return AITheme.muted
        }
    }

    private func toggle(_ id: UUID) {
        if model.selectedIDs.contains(id) {
            model.selectedIDs.remove(id)
        } else {
            model.selectedIDs.insert(id)
        }
    }
}