import SwiftUI

struct NotificationsView: View {
    @StateObject private var model: NotificationsViewModel

    init(model: NotificationsViewModel? = nil) {
        _model = StateObject(wrappedValue: model ?? DefaultContainer.makeNotificationsModel())
    }

    var body: some View {
        ZStack {
            AITheme.canvas.ignoresSafeArea()
            ScrollView {
                LazyVStack(spacing: 12) {
                    if let actionMessage = model.actionMessage {
                        AICard {
                            Text(actionMessage)
                                .font(.subheadline)
                                .foregroundStyle(AITheme.success)
                        }
                    }
                    if let errorMessage = model.errorMessage {
                        AICard {
                            Text(errorMessage)
                                .font(.subheadline)
                                .foregroundStyle(AITheme.warning)
                        }
                    }

                    if let overview = model.overview {
                        stats(overview)
                        devices(overview)
                        channels(overview)
                        queue(overview)
                        logs(overview)
                    } else if model.isLoading {
                        AICard {
                            ProgressView("正在加载通知中心...")
                                .frame(maxWidth: .infinity)
                                .padding(.vertical, 22)
                        }
                    } else {
                        empty
                    }
                }
                .padding(16)
            }
        }
        .navigationTitle("通知中心")
        .toolbar {
            ToolbarItemGroup(placement: .primaryAction) {
                Button {
                    Task { await model.retryAll() }
                } label: {
                    Label("立即投递", systemImage: "paperplane")
                }
                .buttonStyle(AIButtonStyle(kind: .primary, size: .regular))
                .disabled(model.isLoading)
            }
        }
        .refreshable {
            await model.refresh()
        }
        .task {
            await model.refresh()
        }
    }

    private var empty: some View {
        AICard {
            VStack(spacing: 10) {
                Image(systemName: "bell")
                    .font(.system(size: 28))
                    .foregroundStyle(AITheme.muted)
                Text("暂无通知数据")
                    .font(.headline)
                Text("下拉刷新后从已配置实例同步。")
                    .font(.subheadline)
                    .foregroundStyle(AITheme.muted)
            }
            .frame(maxWidth: .infinity)
            .padding(.vertical, 18)
        }
    }

    private func stats(_ overview: NotificationOverview) -> some View {
        LazyVGrid(columns: [GridItem(.flexible()), GridItem(.flexible())], spacing: 12) {
            statCard("通道", "\(overview.config.channelEnabled)/\(overview.config.channelCount)", "已启用/总数", AITheme.primary)
            statCard("规则", "\(overview.config.ruleEnabled)/\(overview.config.ruleCount)", "已启用/总数", AITheme.primary)
            statCard("队列", "\(overview.queue.pending + overview.queue.retrying)", "等待与重试", AITheme.warning)
            statCard("失败", "\(overview.queue.failed + overview.logs.failed)", "队列与投递", AITheme.danger)
        }
    }

    private func statCard(_ title: String, _ value: String, _ detail: String, _ tint: Color) -> some View {
        AICard {
            VStack(alignment: .leading, spacing: 6) {
                Text(title)
                    .font(.caption)
                    .foregroundStyle(AITheme.muted)
                Text(value)
                    .font(.title2.weight(.bold))
                    .foregroundStyle(tint)
                Text(detail)
                    .font(.caption)
                    .foregroundStyle(AITheme.muted)
            }
            .frame(maxWidth: .infinity, alignment: .leading)
        }
    }

    private func devices(_ overview: NotificationOverview) -> some View {
        AICard {
            VStack(alignment: .leading, spacing: 10) {
                title("实例状态")
                if overview.devices.isEmpty {
                    Text("尚未添加实例。")
                        .font(.subheadline)
                        .foregroundStyle(AITheme.muted)
                } else {
                    ForEach(overview.devices) { device in
                        HStack(spacing: 8) {
                            Text(device.name)
                                .font(.subheadline)
                            Spacer()
                            AITag(deviceState(device.state), tint: deviceTint(device.state))
                        }
                    }
                }
            }
        }
    }

    private func channels(_ overview: NotificationOverview) -> some View {
        AICard {
            VStack(alignment: .leading, spacing: 10) {
                title("通道类型")
                if overview.config.channelTypes.isEmpty {
                    Text("实例未配置通知通道。")
                        .font(.subheadline)
                        .foregroundStyle(AITheme.muted)
                } else {
                    ForEach(overview.config.channelTypes) { channel in
                        HStack(spacing: 8) {
                            Text(channelTypeLabel(channel.type))
                                .font(.subheadline)
                            Spacer()
                            AITag("\(channel.enabled)/\(channel.total)", tint: channel.enabled > 0 ? AITheme.success : AITheme.muted)
                        }
                    }
                }
            }
        }
    }

    private func queue(_ overview: NotificationOverview) -> some View {
        AICard {
            VStack(alignment: .leading, spacing: 10) {
                HStack {
                    title("最近队列")
                    Spacer()
                    Text("\(overview.queue.total) 项")
                        .font(.caption)
                        .foregroundStyle(AITheme.muted)
                }
                if overview.queue.items.isEmpty {
                    Text("队列为空。")
                        .font(.subheadline)
                        .foregroundStyle(AITheme.muted)
                } else {
                    ForEach(overview.queue.items) { item in
                        VStack(alignment: .leading, spacing: 8) {
                            HStack(spacing: 8) {
                                Text(eventTypeLabel(item.eventType))
                                    .font(.subheadline.weight(.semibold))
                                Spacer()
                                AITag(statusLabel(item.status), tint: statusTint(item.status))
                            }
                            Text("\(item.instanceName) · \(item.createdAt)")
                                .font(.caption)
                                .foregroundStyle(AITheme.muted)
                            HStack(spacing: 8) {
                                Button {
                                    Task { await model.retryQueue(item) }
                                } label: {
                                    Label("重试", systemImage: "arrow.clockwise")
                                }
                                .buttonStyle(AIButtonStyle(kind: .secondary, size: .compact))
                                .disabled(model.busyQueueID == item.id)

                                Button {
                                    Task { await model.deleteQueue(item) }
                                } label: {
                                    Label("删除", systemImage: "trash")
                                }
                                .buttonStyle(AIButtonStyle(kind: .danger, size: .compact))
                            }
                        }
                        .padding(.bottom, 4)
                    }
                }
            }
        }
    }

    private func logs(_ overview: NotificationOverview) -> some View {
        AICard {
            VStack(alignment: .leading, spacing: 10) {
                HStack {
                    title("投递日志")
                    Spacer()
                    Text("\(overview.logs.total) 条")
                        .font(.caption)
                        .foregroundStyle(AITheme.muted)
                }
                if overview.logs.entries.isEmpty {
                    Text("暂无投递日志。")
                        .font(.subheadline)
                        .foregroundStyle(AITheme.muted)
                } else {
                    ForEach(overview.logs.entries) { entry in
                        VStack(alignment: .leading, spacing: 6) {
                            HStack(spacing: 8) {
                                Text(eventTypeLabel(entry.eventType))
                                    .font(.subheadline.weight(.semibold))
                                Spacer()
                                AITag(statusLabel(entry.status), tint: statusTint(entry.status))
                            }
                            Text("\(entry.channelName ?? "未指定通道") · \(entry.createdAt)")
                                .font(.caption)
                                .foregroundStyle(AITheme.muted)
                        }
                        .padding(.bottom, 4)
                    }
                }
            }
        }
    }

    private func title(_ text: String) -> some View {
        Text(text)
            .font(.headline)
            .foregroundStyle(AITheme.ink)
    }

    private func deviceState(_ state: NotificationDeviceState) -> String {
        switch state {
        case .ready: return "在线"
        case .unauthorized: return "需登录"
        case .unavailable: return "离线"
        case .failed: return "异常"
        }
    }

    private func deviceTint(_ state: NotificationDeviceState) -> Color {
        switch state {
        case .ready: return AITheme.success
        case .unauthorized: return AITheme.warning
        case .unavailable: return AITheme.muted
        case .failed: return AITheme.danger
        }
    }

    private func channelTypeLabel(_ type: String) -> String {
        switch type {
        case "webhook": return "Webhook"
        case "bark": return "Bark"
        case "pushplus": return "PushPlus"
        case "wecom_app": return "企业微信应用"
        case "wecom_robot": return "企业微信机器人"
        case "dingtalk_robot": return "钉钉机器人"
        case "dingtalk_app": return "钉钉应用"
        case "feishu_robot": return "飞书机器人"
        case "telegram": return "Telegram"
        case "email": return "邮件"
        case "serverchan": return "Server 酱"
        default: return type
        }
    }

    private func eventTypeLabel(_ value: String) -> String {
        switch value {
        case "sms": return "短信"
        case "ddns": return "DDNS"
        case "version": return "版本"
        case "system": return "系统"
        case "device": return "设备"
        case "automation": return "自动化"
        default: return value
        }
    }

    private func statusLabel(_ value: String) -> String {
        switch value {
        case "success", "succeeded": return "成功"
        case "failed": return "失败"
        case "pending": return "等待"
        case "sending": return "发送中"
        case "retrying": return "重试中"
        case "cancelled": return "已取消"
        case "unmatched": return "未匹配"
        case "no_available_channel": return "无可用通道"
        case "quiet_hours": return "免打扰"
        default: return value
        }
    }

    private func statusTint(_ value: String) -> Color {
        switch value {
        case "success", "succeeded": return AITheme.success
        case "pending", "sending", "retrying": return AITheme.warning
        case "failed": return AITheme.danger
        default: return AITheme.muted
        }
    }
}