import SwiftUI

struct MessagesView: View {
    @StateObject private var model: MessagesViewModel
    @State private var pendingDeleteMessage: SMSMessage?

    init(model: MessagesViewModel? = nil) {
        _model = StateObject(wrappedValue: model ?? DefaultContainer.makeMessagesModel())
    }

    var body: some View {
        ZStack {
            AITheme.canvas.ignoresSafeArea()
            ScrollView {
                LazyVStack(spacing: 12) {
                    filterBar
                    if let errorMessage = model.errorMessage {
                        AIStatusBanner(errorMessage, tint: AITheme.warning, systemImage: "exclamationmark.triangle")
                    }
                    if model.isLoading && model.filteredRows.isEmpty {
                        AILoadingCard("正在同步消息")
                    }
                    if model.filteredRows.isEmpty && !model.isLoading {
                        AICard {
                            AIEmptyState(
                                systemImage: "message",
                                title: "暂无消息",
                                message: "刷新后从实例同步短信。"
                            )
                        }
                    }
                    ForEach(model.filteredRows) { message in
                        messageCard(message)
                    }
                }
                .padding(16)
            }
        }
        .navigationTitle("消息中心")
        .aiBottomActionBar {
            Button {
                model.showingSendForm = true
            } label: {
                Label("发送消息", systemImage: "paperplane")
            }
            .buttonStyle(AIButtonStyle(kind: .primary, size: .regular, fillsWidth: true))
        }
        .confirmationDialog(
            "删除这条消息？操作不可恢复。",
            isPresented: Binding(
                get: { pendingDeleteMessage != nil },
                set: { if !$0 { pendingDeleteMessage = nil } }
            ),
            titleVisibility: .visible
        ) {
            Button("删除消息", role: .destructive) {
                guard let message = pendingDeleteMessage else { return }
                Task { await model.delete(message) }
            }
            Button("取消", role: .cancel) {}
        }
        .refreshable {
            await model.refresh()
        }
        .task {
            await model.refresh()
        }
        .sheet(isPresented: $model.showingSendForm) {
            SendMessageFormView(model: model)
        }
    }

    private var filterBar: some View {
        AICard {
            VStack(spacing: 10) {
                Picker("方向", selection: $model.direction) {
                    ForEach(MessagesViewModel.DirectionFilter.allCases) { item in
                        Text(item.rawValue).tag(item)
                    }
                }
                .pickerStyle(.segmented)

                Picker("实例", selection: $model.selectedInstanceID) {
                    Text("全部实例").tag(Optional<UUID>.none)
                    ForEach(model.instances) { instance in
                        Text(instance.name).tag(Optional(instance.id))
                    }
                }
                .pickerStyle(.menu)
                .aiSelectSurface()

                AISearchField("搜索号码或内容", text: $model.searchText)
            }
        }
    }

    private func messageCard(_ message: SMSMessage) -> some View {
        AICard {
            VStack(alignment: .leading, spacing: 10) {
                HStack(spacing: 8) {
                    Text(message.phoneNumber.isEmpty ? "未知号码" : message.phoneNumber)
                        .font(.headline)
                    Spacer()
                    AITag(message.direction.label, tint: message.direction == .outgoing ? AITheme.primary : AITheme.success)
                }
                Text(message.content)
                    .font(.subheadline)
                    .foregroundStyle(AITheme.ink)
                    .fixedSize(horizontal: false, vertical: true)
                HStack {
                    Text(message.instanceName)
                        .font(.caption)
                        .foregroundStyle(AITheme.muted)
                        .lineLimit(1)
                        .truncationMode(.middle)
                        .layoutPriority(1)
                    Spacer()
                    Button("删除") {
                        pendingDeleteMessage = message
                    }
                    .buttonStyle(
                        AIButtonStyle(
                            kind: .danger,
                            size: .compact,
                            fixedWidth: AITheme.listActionButtonWidth
                        )
                    )
                }
            }
        }
    }
}