import SwiftUI

// ═══════════════════════════════════════════════════════════════════════════════
// NTS Anchor View — 36 Global Atomic Time Servers
// Montana Protocol v3.17.0
//
// Визуализация NTS-якорей: каждое τ₂ окно привязано к глобальному
// атомному времени через TLS 1.3 handshake с 36 серверами (RFC 8915).
// ═══════════════════════════════════════════════════════════════════════════════

struct NTSAnchorView: View {
    @EnvironmentObject var engine: PresenceEngine
    @Environment(\.dismiss) private var dismiss
    @State private var showSidebar = false

    // Data
    @State private var ntsStatus: [String: Any] = [:]
    @State private var serverList: [[String: Any]] = []
    @State private var regions: [String: Any] = [:]
    @State private var latestAnchor: [String: Any]? = nil
    @State private var attestations: [[String: Any]] = []
    @State private var isLoading = true
    @State private var errorText = ""
    @State private var selectedRegion: String? = nil

    // Colors
    private let cyan = Color(red: 0, green: 0.83, blue: 1)
    private let gold = Color(red: 0.85, green: 0.68, blue: 0.25)
    private let cardBg = Color(red: 0.09, green: 0.09, blue: 0.12)
    private let green = Color(red: 0.2, green: 0.85, blue: 0.4)

    // Region display order
    private let regionOrder = ["GLOBAL", "EU", "RU", "US", "SA", "ASIA", "OCEANIA", "POLES"]
    private let regionEmoji: [String: String] = [
        "GLOBAL": "\u{1F310}", "EU": "\u{1F1EA}\u{1F1FA}", "RU": "\u{1F1F7}\u{1F1FA}",
        "US": "\u{1F1FA}\u{1F1F8}", "SA": "\u{1F30E}", "ASIA": "\u{1F30F}",
        "OCEANIA": "\u{1F30F}", "POLES": "\u{2744}\u{FE0F}"
    ]
    private let regionNames: [String: String] = [
        "GLOBAL": "Global", "EU": "Europe", "RU": "Russia",
        "US": "USA", "SA": "South America", "ASIA": "Asia",
        "OCEANIA": "Oceania", "POLES": "Poles"
    ]

    var body: some View {
        ZStack(alignment: .leading) {
            VStack(spacing: 0) {
                // Burger menu
                HStack {
                    Button(action: { withAnimation(.easeInOut(duration: 0.3)) { showSidebar = true } }) {
                        Image(systemName: "line.3.horizontal")
                            .font(.system(size: 18, weight: .medium))
                            .foregroundColor(gold)
                            .padding(8)
                    }
                    .buttonStyle(.plain)
                    Spacer()
                }
                .padding(.horizontal, 20)
                .padding(.top, 24)

                // Header
                HStack(spacing: 6) {
                    Image(systemName: "shield.checkered")
                        .foregroundColor(cyan)
                        .font(.system(size: 16))
                    Text("NTS Anchor")
                        .font(.system(size: 14, weight: .bold))
                    Text("36 Atomic Servers")
                        .font(.system(size: 10))
                        .foregroundColor(.secondary)
                    Spacer()
                    Button(action: { loadData() }) {
                        Image(systemName: "arrow.clockwise")
                            .foregroundColor(.secondary)
                    }
                    .buttonStyle(.plain)
                    Button(action: { dismiss() }) {
                        Image(systemName: "xmark.circle.fill")
                            .foregroundColor(.secondary)
                    }
                    .buttonStyle(.plain)
                }
                .padding(.horizontal, 20)
                .padding(.top, 4)
                .padding(.bottom, 8)

                Divider()

                if isLoading {
                    Spacer()
                    ProgressView().controlSize(.small)
                    Text("Loading NTS status...")
                        .font(.caption).foregroundColor(.secondary)
                    Spacer()
                } else if !errorText.isEmpty {
                    Spacer()
                    VStack(spacing: 8) {
                        Image(systemName: "exclamationmark.triangle")
                            .font(.system(size: 24)).foregroundColor(.orange)
                        Text(errorText)
                            .font(.caption).foregroundColor(.red)
                            .multilineTextAlignment(.center)
                    }
                    Spacer()
                } else {
                    ScrollView {
                        VStack(spacing: 12) {
                            // Status card
                            statusCard

                            // Region grid
                            regionGrid

                            // Latest anchor details
                            if let anchor = latestAnchor {
                                anchorDetailCard(anchor)
                            }

                            // Server list
                            serverListSection
                        }
                        .padding(.horizontal, 20)
                        .padding(.top, 12)
                        .padding(.bottom, 20)
                    }
                }
            }
            .background(Color.black)

            // Sidebar
            if showSidebar {
                SharedSidebar(isVisible: $showSidebar)
                    .environmentObject(engine)
            }
        }
        .onAppear { loadData() }
    }

    // ─── Status Card ──────────────────────────────────────────────

    private var statusCard: some View {
        VStack(spacing: 8) {
            HStack {
                let enabled = ntsStatus["nts_enabled"] as? Bool ?? false
                Circle()
                    .fill(enabled ? green : .red)
                    .frame(width: 8, height: 8)
                Text(enabled ? "NTS Active" : "NTS Disabled")
                    .font(.system(size: 11, weight: .bold))
                    .foregroundColor(enabled ? green : .red)
                Spacer()
                let coverage = ntsStatus["coverage"] as? String ?? "0/0"
                Text(coverage)
                    .font(.system(size: 11, weight: .bold, design: .monospaced))
                    .foregroundColor(gold)
                Text("anchored")
                    .font(.system(size: 9))
                    .foregroundColor(.secondary)
            }

            HStack(spacing: 16) {
                statPill(
                    label: "Servers",
                    value: "\(serverList.count)",
                    icon: "server.rack"
                )
                statPill(
                    label: "Regions",
                    value: "\(regions.count)",
                    icon: "globe"
                )
                let anchors = ntsStatus["total_anchors"] as? Int ?? 0
                statPill(
                    label: "Anchors",
                    value: "\(anchors)",
                    icon: "lock.shield"
                )
            }
        }
        .padding(12)
        .background(cardBg)
        .cornerRadius(10)
    }

    private func statPill(label: String, value: String, icon: String) -> some View {
        HStack(spacing: 4) {
            Image(systemName: icon)
                .font(.system(size: 9))
                .foregroundColor(cyan)
            Text(value)
                .font(.system(size: 12, weight: .bold, design: .monospaced))
            Text(label)
                .font(.system(size: 9))
                .foregroundColor(.secondary)
        }
        .frame(maxWidth: .infinity)
    }

    // ─── Region Grid ──────────────────────────────────────────────

    private var regionGrid: some View {
        VStack(alignment: .leading, spacing: 6) {
            Text("REGIONS")
                .font(.system(size: 9, weight: .bold))
                .foregroundColor(.secondary)

            LazyVGrid(columns: [
                GridItem(.flexible()), GridItem(.flexible()),
                GridItem(.flexible()), GridItem(.flexible())
            ], spacing: 6) {
                ForEach(regionOrder, id: \.self) { region in
                    let count = serverCountForRegion(region)
                    if count > 0 {
                        regionCell(region: region, count: count)
                    }
                }
            }
        }
    }

    private func regionCell(region: String, count: Int) -> some View {
        let isSelected = selectedRegion == region
        return VStack(spacing: 2) {
            Text(regionEmoji[region] ?? "")
                .font(.system(size: 16))
            Text("\(count)")
                .font(.system(size: 12, weight: .bold, design: .monospaced))
            Text(regionNames[region] ?? region)
                .font(.system(size: 8))
                .foregroundColor(.secondary)
        }
        .frame(maxWidth: .infinity)
        .padding(.vertical, 6)
        .background(isSelected ? cyan.opacity(0.15) : cardBg)
        .cornerRadius(8)
        .overlay(
            RoundedRectangle(cornerRadius: 8)
                .stroke(isSelected ? cyan : Color.clear, lineWidth: 1)
        )
        .onTapGesture {
            withAnimation(.easeInOut(duration: 0.2)) {
                selectedRegion = selectedRegion == region ? nil : region
            }
        }
    }

    // ─── Anchor Detail Card ───────────────────────────────────────

    private func anchorDetailCard(_ anchor: [String: Any]) -> some View {
        VStack(alignment: .leading, spacing: 8) {
            HStack {
                Image(systemName: "lock.shield.fill")
                    .foregroundColor(gold)
                Text("Latest NTS Anchor")
                    .font(.system(size: 11, weight: .bold))
                Spacer()
            }

            if let contentHash = anchor["content_hash"] as? String {
                hashRow(label: "Content Hash", hash: contentHash)
            }
            if let anchorHash = anchor["anchor_hash"] as? String {
                hashRow(label: "Anchor Hash", hash: anchorHash)
            }

            HStack(spacing: 12) {
                if let servers = anchor["server_count"] as? Int {
                    detailPill(icon: "server.rack", value: "\(servers)", label: "servers")
                }
                if let regionCount = anchor["region_count"] as? Int {
                    detailPill(icon: "globe", value: "\(regionCount)", label: "regions")
                }
                if let spreadNs = anchor["timestamp_spread_ns"] as? Int {
                    let spreadMs = Double(spreadNs) / 1_000_000.0
                    detailPill(icon: "clock", value: String(format: "%.1fms", spreadMs), label: "spread")
                }
            }

            // Attestation list
            if let atts = anchor["attestations"] as? [[String: Any]], !atts.isEmpty {
                VStack(alignment: .leading, spacing: 2) {
                    Text("ATTESTATIONS (\(atts.count))")
                        .font(.system(size: 8, weight: .bold))
                        .foregroundColor(.secondary)
                        .padding(.top, 4)

                    ForEach(Array(atts.prefix(12).enumerated()), id: \.offset) { _, att in
                        attestationRow(att)
                    }
                    if atts.count > 12 {
                        Text("+ \(atts.count - 12) more...")
                            .font(.system(size: 9))
                            .foregroundColor(.secondary)
                    }
                }
            }
        }
        .padding(12)
        .background(cardBg)
        .cornerRadius(10)
    }

    private func attestationRow(_ att: [String: Any]) -> some View {
        let host = att["server_host"] as? String ?? "?"
        let region = att["server_region"] as? String ?? ""
        let tls = att["tls_version"] as? String ?? ""
        let cert = att["cert_fingerprint"] as? String ?? ""

        return HStack(spacing: 4) {
            Circle().fill(green).frame(width: 4, height: 4)
            Text(regionEmoji[region] ?? "")
                .font(.system(size: 8))
            Text(host)
                .font(.system(size: 9, design: .monospaced))
                .foregroundColor(.white)
                .lineLimit(1)
            Spacer()
            Text(tls)
                .font(.system(size: 8))
                .foregroundColor(tls.contains("1.3") ? green : .orange)
            Text(String(cert.prefix(8)))
                .font(.system(size: 8, design: .monospaced))
                .foregroundColor(.secondary)
        }
        .padding(.vertical, 1)
    }

    private func hashRow(label: String, hash: String) -> some View {
        HStack {
            Text(label)
                .font(.system(size: 9))
                .foregroundColor(.secondary)
            Spacer()
            Text(String(hash.prefix(16)) + "...")
                .font(.system(size: 9, design: .monospaced))
                .foregroundColor(cyan)
        }
    }

    private func detailPill(icon: String, value: String, label: String) -> some View {
        HStack(spacing: 3) {
            Image(systemName: icon)
                .font(.system(size: 8))
                .foregroundColor(gold)
            Text(value)
                .font(.system(size: 10, weight: .bold, design: .monospaced))
            Text(label)
                .font(.system(size: 8))
                .foregroundColor(.secondary)
        }
    }

    // ─── Server List ──────────────────────────────────────────────

    private var serverListSection: some View {
        VStack(alignment: .leading, spacing: 6) {
            Text("ALL SERVERS (\(filteredServers.count))")
                .font(.system(size: 9, weight: .bold))
                .foregroundColor(.secondary)

            ForEach(Array(filteredServers.enumerated()), id: \.offset) { idx, server in
                serverRow(server, index: idx + 1)
            }
        }
    }

    private var filteredServers: [[String: Any]] {
        if let region = selectedRegion {
            return serverList.filter { ($0["region"] as? String) == region }
        }
        return serverList
    }

    private func serverRow(_ server: [String: Any], index: Int) -> some View {
        let host = server["host"] as? String ?? "?"
        let region = server["region"] as? String ?? ""
        let org = server["org"] as? String ?? ""
        let country = server["country"] as? String ?? ""
        let port = server["port"] as? Int ?? 4460

        return HStack(spacing: 6) {
            Text("\(index)")
                .font(.system(size: 8, design: .monospaced))
                .foregroundColor(.secondary)
                .frame(width: 18, alignment: .trailing)
            Text(country)
                .font(.system(size: 10))
            VStack(alignment: .leading, spacing: 1) {
                Text(host)
                    .font(.system(size: 9, weight: .medium, design: .monospaced))
                    .foregroundColor(.white)
                    .lineLimit(1)
                Text("\(org) : \(port)")
                    .font(.system(size: 8))
                    .foregroundColor(.secondary)
                    .lineLimit(1)
            }
            Spacer()
            Text(regionNames[region] ?? region)
                .font(.system(size: 8))
                .foregroundColor(cyan)
                .padding(.horizontal, 4)
                .padding(.vertical, 1)
                .background(cyan.opacity(0.1))
                .cornerRadius(3)
        }
        .padding(.vertical, 3)
        .padding(.horizontal, 8)
        .background(cardBg)
        .cornerRadius(6)
    }

    // ─── Data Loading ─────────────────────────────────────────────

    private func loadData() {
        isLoading = true
        errorText = ""
        Task { @MainActor in
            do {
                async let fetchServers = engine.api.fetchNTSServers()
                async let fetchStatus = engine.api.fetchNTSStatus()

                let serversResult = try await fetchServers
                let statusResult = try await fetchStatus

                serverList = serversResult["servers"] as? [[String: Any]] ?? []
                regions = serversResult["regions"] as? [String: Any] ?? [:]
                ntsStatus = statusResult
                latestAnchor = statusResult["latest_anchor"] as? [String: Any]

                isLoading = false
            } catch {
                errorText = "NTS data unavailable"
                isLoading = false
            }
        }
    }

    private func serverCountForRegion(_ region: String) -> Int {
        return serverList.filter { ($0["region"] as? String) == region }.count
    }
}