// ConnectivityView.swift
// Jarvis — server address, a Remote Access card (Use <provider> when remote +
// host + live status), and an Auto-connect automation card. The app can't start
// the VPN tunnel (iOS), so when the remote is down we offer a one-tap jump.

import SwiftUI

struct ConnectivityView: View {
    @EnvironmentObject var connectivity: ConnectivitySettings
    @EnvironmentObject var manager: ConnectivityManager
    @Environment(\.dismiss) private var dismiss

    private var directReach: Reachability {
        manager.status[connectivity.directHost.trimmingCharacters(in: .whitespaces)] ?? .unknown
    }
    private var remoteReach: Reachability {
        manager.status[connectivity.remoteHost.trimmingCharacters(in: .whitespaces)] ?? .unknown
    }
    private var providerName: String { connectivity.provider.displayName }

    var body: some View {
        ZStack {
            Color.black.ignoresSafeArea()
            ScrollView {
                VStack(alignment: .leading, spacing: 26) {
                    header
                    serverSection
                    remoteAccessSection
                    automationSection
                    providerSection
                    actions
                }
                .padding(.horizontal, 20)
                .padding(.vertical, 12)
            }
        }
        .preferredColorScheme(.dark)
        .presentationDragIndicator(.visible)
        .task { await recheck() }
    }

    // MARK: - Header

    private var header: some View {
        HStack {
            Text("Connectivity")
                .font(.system(size: 22, weight: .heavy))
                .foregroundStyle(.white)
            Spacer()
            Button { dismiss() } label: {
                Image(systemName: "xmark")
                    .font(.system(size: 15, weight: .bold))
                    .foregroundStyle(Color(hex: "888888"))
                    .frame(width: 44, height: 44)
            }
        }
        .padding(.top, 8)
    }

    // MARK: - Server (LAN)

    private var serverSection: some View {
        VStack(alignment: .leading, spacing: 10) {
            sectionLabel("SERVER")
            Card {
                cardRow(icon: "server.rack") {
                    fieldStack(title: "Direct (LAN) host",
                               text: $connectivity.directHost,
                               placeholder: "192.168.30.50:8080",
                               reach: directReach)
                }
            }
        }
    }

    // MARK: - Remote access

    private var remoteAccessSection: some View {
        VStack(alignment: .leading, spacing: 10) {
            sectionLabel("REMOTE ACCESS")
            Card {
                VStack(spacing: 0) {
                    cardRow(icon: "globe.badge.chevron.backward") {
                        Toggle(isOn: $connectivity.remoteEnabled) {
                            VStack(alignment: .leading, spacing: 3) {
                                Text("Use \(providerName) when remote")
                                    .font(.system(size: 16, weight: .heavy))
                                    .foregroundStyle(.white)
                                Text("Connects via VPN when not on home network")
                                    .font(.system(size: 12))
                                    .foregroundStyle(Color(hex: "888888"))
                                    .fixedSize(horizontal: false, vertical: true)
                            }
                        }
                        .tint(Palette.orange)
                    }

                    if connectivity.remoteEnabled {
                        divider
                        cardRow(icon: "externaldrive.connected.to.line.below") {
                            fieldStack(title: "\(providerName) host",
                                       text: $connectivity.remoteHost,
                                       placeholder: connectivity.provider.remoteHint,
                                       reach: remoteReach)
                        }
                        divider
                        statusRow
                    }
                }
            }
        }
    }

    private var statusRow: some View {
        HStack(spacing: 10) {
            dot(for: connectivity.remoteEnabled ? remoteReach : .unknown)
            Text(statusText)
                .font(.system(size: 14, weight: .bold))
                .foregroundStyle(statusColor)
            Spacer()
            if remoteReach != .reachable && connectivity.provider.canOpenApp {
                Button { connectivity.provider.openApp() } label: {
                    Text("Open \(providerName)")
                        .font(.system(size: 13, weight: .bold))
                        .foregroundStyle(.black)
                        .padding(.horizontal, 14)
                        .frame(height: 36)
                        .background(Palette.orange)
                        .clipShape(Capsule())
                }
            }
        }
        .padding(.vertical, 12)
        .padding(.horizontal, 14)
    }

    private var statusText: String {
        switch remoteReach {
        case .reachable:   return "\(providerName) connected"
        case .checking:    return "Checking \(providerName)…"
        default:           return "\(providerName) not active"
        }
    }
    private var statusColor: Color {
        switch remoteReach {
        case .reachable: return Color(hex: "33C25E")
        case .checking:  return Palette.healthFailing
        default:         return Color(hex: "888888")
        }
    }

    // MARK: - Automation

    private var automationSection: some View {
        VStack(alignment: .leading, spacing: 10) {
            sectionLabel("AUTOMATION")
            Card {
                VStack(spacing: 0) {
                    cardRow(icon: "wifi") {
                        Toggle(isOn: $connectivity.autoConnect) {
                            VStack(alignment: .leading, spacing: 3) {
                                Text("Auto-connect on network change")
                                    .font(.system(size: 16, weight: .heavy))
                                    .foregroundStyle(.white)
                                Text("Prefers the LAN on a trusted network; switches to \(providerName) when away")
                                    .font(.system(size: 12))
                                    .foregroundStyle(Color(hex: "888888"))
                                    .fixedSize(horizontal: false, vertical: true)
                            }
                        }
                        .tint(Palette.orange)
                    }
                    if connectivity.autoConnect {
                        divider
                        cardRow(icon: "timer") {
                            HStack {
                                Text("Wait before switching")
                                    .font(.system(size: 15, weight: .bold))
                                    .foregroundStyle(.white)
                                Spacer()
                                Stepper(value: $connectivity.switchDelaySeconds, in: 1...60, step: 1) {
                                    Text("\(connectivity.switchDelaySeconds)s")
                                        .font(.system(size: 14, weight: .bold, design: .monospaced))
                                        .foregroundStyle(Palette.orange)
                                }
                                .labelsHidden()
                                .fixedSize()
                                Text("\(connectivity.switchDelaySeconds)s")
                                    .font(.system(size: 14, weight: .bold, design: .monospaced))
                                    .foregroundStyle(Palette.orange)
                                    .frame(width: 36, alignment: .trailing)
                            }
                        }
                    }
                }
            }
            Text("iOS can't start the \(providerName) tunnel for Jarvis — keep the \(providerName) app connected when away. Jarvis only picks the reachable address.")
                .font(.system(size: 11))
                .foregroundStyle(Color(hex: "666666"))
                .lineSpacing(2)
        }
    }

    // MARK: - Provider

    private var providerSection: some View {
        VStack(alignment: .leading, spacing: 10) {
            sectionLabel("PROVIDER")
            ScrollView(.horizontal, showsIndicators: false) {
                HStack(spacing: 8) {
                    ForEach(VPNProvider.allCases) { p in
                        let selected = connectivity.provider == p
                        Button { connectivity.provider = p } label: {
                            Text(p.displayName)
                                .font(.system(size: 13, weight: .bold))
                                .foregroundStyle(selected ? .black : Color(hex: "AAAAAA"))
                                .padding(.horizontal, 14)
                                .frame(height: 34)
                                .background(selected ? Palette.orange : Palette.surface)
                                .clipShape(Capsule())
                        }
                    }
                }
            }
        }
    }

    // MARK: - Actions

    private var actions: some View {
        HStack(spacing: 12) {
            Button { Task { await recheck() } } label: {
                Text("Re-check")
                    .font(.system(size: 15, weight: .bold))
                    .foregroundStyle(.white)
                    .frame(maxWidth: .infinity).frame(height: 50)
                    .background(Palette.surface2)
                    .clipShape(RoundedRectangle(cornerRadius: 14))
            }
            Button { Task { await manager.resolveAndActivate(); await recheck() } } label: {
                Text("Apply")
                    .font(.system(size: 15, weight: .bold))
                    .foregroundStyle(.black)
                    .frame(maxWidth: .infinity).frame(height: 50)
                    .background(connectivity.isConfigured ? Palette.orange : Palette.surface2)
                    .clipShape(RoundedRectangle(cornerRadius: 14))
            }
            .disabled(!connectivity.isConfigured)
        }
    }

    // MARK: - Building blocks

    private func sectionLabel(_ t: String) -> some View {
        Text(t)
            .font(.system(size: 11, weight: .bold, design: .monospaced))
            .kerning(0.8)
            .foregroundStyle(Color(hex: "555555"))
    }

    private func Card<Content: View>(@ViewBuilder _ content: () -> Content) -> some View {
        content()
            .background(Palette.surface)
            .clipShape(RoundedRectangle(cornerRadius: 14))
    }

    private func cardRow<Content: View>(icon: String, @ViewBuilder _ content: () -> Content) -> some View {
        HStack(alignment: .center, spacing: 14) {
            Image(systemName: icon)
                .font(.system(size: 18, weight: .regular))
                .foregroundStyle(Color(hex: "999999"))
                .frame(width: 26)
            content()
        }
        .padding(.horizontal, 14)
        .padding(.vertical, 14)
        .frame(minHeight: 44)
    }

    private var divider: some View {
        Rectangle().fill(Palette.surface2).frame(height: 1).padding(.leading, 54)
    }

    private func fieldStack(title: String, text: Binding<String>, placeholder: String, reach: Reachability) -> some View {
        VStack(alignment: .leading, spacing: 3) {
            Text(title)
                .font(.system(size: 12))
                .foregroundStyle(Color(hex: "888888"))
            HStack(spacing: 8) {
                TextField("", text: text,
                          prompt: Text(placeholder).foregroundColor(Color(hex: "444444")))
                    .font(.system(size: 16, weight: .regular, design: .monospaced))
                    .foregroundStyle(Palette.orange)
                    .autocorrectionDisabled()
                    .textInputAutocapitalization(.never)
                    .keyboardType(.URL)
                if reach != .unknown { dot(for: reach) }
            }
        }
    }

    // MARK: - Reachability helpers

    private func recheck() async {
        await manager.check(connectivity.directHost)
        if connectivity.remoteActiveInPolicy {
            await manager.check(connectivity.remoteHost)
        }
    }

    private func color(for r: Reachability) -> Color {
        switch r {
        case .reachable:   return Color(hex: "33C25E")
        case .unreachable: return Color(hex: "C25555")
        case .checking:    return Palette.healthFailing
        case .unknown:     return Color(hex: "555555")
        }
    }
    private func dot(for r: Reachability) -> some View {
        Circle().fill(color(for: r)).frame(width: 9, height: 9)
    }
}