import SwiftUI
import UIKit

struct ContentView: View {
    @EnvironmentObject private var client: HoloLakeSyncClient
    @State private var pairingText = ""
    @State private var captureTitle = ""
    @State private var captureBody = ""

    var body: some View {
        NavigationStack {
            ZStack {
                LinearGradient(
                    colors: [HoloLakeDesign.deep, HoloLakeDesign.lake, HoloLakeDesign.violet.opacity(0.78)],
                    startPoint: .topLeading,
                    endPoint: .bottomTrailing
                )
                .ignoresSafeArea()

                ScrollView {
                    VStack(spacing: 16) {
                        header
                        if client.session == nil { pairingCard } else { dashboard }
                        boundaryCard
                    }
                    .padding(.horizontal, 18)
                    .padding(.vertical, 16)
                }
            }
            .toolbar(.hidden, for: .navigationBar)
            .alert("HoloLake", isPresented: Binding(
                get: { client.errorText != nil },
                set: { if !$0 { client.errorText = nil } }
            )) {
                Button("知道了", role: .cancel) { client.errorText = nil }
            } message: {
                Text(client.errorText ?? "")
            }
        }
        .preferredColorScheme(.dark)
    }

    private var header: some View {
        HStack(alignment: .center) {
            VStack(alignment: .leading, spacing: 5) {
                Text("HoloLake").font(.title.weight(.semibold)).tracking(2)
                Text("同一频道 · iPhone 轻入口")
                    .font(.subheadline)
                    .foregroundStyle(HoloLakeDesign.muted)
            }
            Spacer()
            Circle()
                .fill(client.session == nil ? HoloLakeDesign.gold : HoloLakeDesign.mint)
                .frame(width: 11, height: 11)
                .shadow(color: client.session == nil ? HoloLakeDesign.gold : HoloLakeDesign.mint, radius: 8)
        }
        .foregroundStyle(HoloLakeDesign.pearl)
        .padding(.top, 4)
    }

    private var pairingCard: some View {
        LakeCard {
            VStack(alignment: .leading, spacing: 14) {
                Text("连接电脑端").font(.title3.weight(.semibold))
                Text("先在电脑端打开“多端同步”，再扫描配对码或粘贴配对链接。配对密钥只保存在这台 iPhone 的钥匙串。")
                    .font(.subheadline)
                    .foregroundStyle(HoloLakeDesign.muted)

                TextField("hololake://pair?…", text: $pairingText, axis: .vertical)
                    .textInputAutocapitalization(.never)
                    .autocorrectionDisabled()
                    .padding(14)
                    .background(.black.opacity(0.22), in: RoundedRectangle(cornerRadius: 16))

                HStack {
                    Button("从剪贴板读取") {
                        pairingText = UIPasteboard.general.string ?? ""
                    }
                    .buttonStyle(.bordered)

                    Button("校验并配对") {
                        Task { await client.pair(from: pairingText) }
                    }
                    .buttonStyle(.borderedProminent)
                    .tint(HoloLakeDesign.gold)
                    .foregroundStyle(HoloLakeDesign.deep)
                    .disabled(pairingText.isEmpty || client.isWorking)
                }
            }
        }
        .foregroundStyle(HoloLakeDesign.pearl)
    }

    private var dashboard: some View {
        VStack(spacing: 16) {
            LakeCard {
                VStack(alignment: .leading, spacing: 14) {
                    HStack {
                        VStack(alignment: .leading, spacing: 4) {
                            Text(client.session?.desktopName ?? "电脑端")
                                .font(.title3.weight(.semibold))
                            Text(client.stateText)
                                .font(.caption)
                                .foregroundStyle(HoloLakeDesign.muted)
                        }
                        Spacer()
                        Button {
                            Task { await client.sync() }
                        } label: {
                            if client.isWorking {
                                ProgressView()
                            } else {
                                Label("同步", systemImage: "arrow.triangle.2.circlepath")
                            }
                        }
                        .buttonStyle(.borderedProminent)
                        .tint(HoloLakeDesign.mint)
                        .foregroundStyle(HoloLakeDesign.deep)
                        .disabled(client.isWorking)
                    }

                    if let snapshot = client.snapshot {
                        HStack(spacing: 10) {
                            MetricTile(label: "作品", value: "\(snapshot.webNovel.workCount)")
                            MetricTile(label: "章节", value: "\(snapshot.webNovel.chapterCount)")
                            MetricTile(label: "教育表", value: "\(snapshot.education.activeTableCount)")
                        }
                    } else {
                        Text("保持静止；只有你点击同步时才会连接电脑。")
                            .font(.subheadline)
                            .foregroundStyle(HoloLakeDesign.muted)
                    }
                }
            }

            LakeCard {
                VStack(alignment: .leading, spacing: 12) {
                    Text("随手记回频道").font(.headline)
                    TextField("标题（可选）", text: $captureTitle)
                        .padding(12)
                        .background(.black.opacity(0.2), in: RoundedRectangle(cornerRadius: 14))
                    TextField("正文", text: $captureBody, axis: .vertical)
                        .lineLimit(4...10)
                        .padding(12)
                        .background(.black.opacity(0.2), in: RoundedRectangle(cornerRadius: 14))
                    Button("写入电脑端收件箱") {
                        let title = captureTitle
                        let body = captureBody
                        Task {
                            await client.sync(captureTitle: title, captureBody: body)
                            if client.errorText == nil {
                                captureTitle = ""
                                captureBody = ""
                            }
                        }
                    }
                    .buttonStyle(.bordered)
                    .disabled(captureBody.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty || client.isWorking)
                }
            }

            if let works = client.snapshot?.webNovel.works, !works.isEmpty {
                LakeCard {
                    VStack(alignment: .leading, spacing: 12) {
                        Text("最近作品").font(.headline)
                        ForEach(works.prefix(5)) { work in
                            HStack {
                                Text(work.title).lineLimit(1)
                                Spacer()
                                Text(work.status)
                                    .font(.caption)
                                    .foregroundStyle(HoloLakeDesign.muted)
                            }
                            if work.id != works.prefix(5).last?.id {
                                Divider().overlay(.white.opacity(0.12))
                            }
                        }
                    }
                }
            }

            Button("解除本机配对", role: .destructive) {
                client.disconnect()
            }
            .font(.footnote)
        }
        .foregroundStyle(HoloLakeDesign.pearl)
    }

    private var boundaryCard: some View {
        VStack(alignment: .leading, spacing: 6) {
            Text("HLP-IOS-CLIENT-001")
                .font(.caption2.monospaced())
                .foregroundStyle(HoloLakeDesign.gold)
            Text("手机是同一频道的远程身体入口，不复制电脑桌面，不在电脑离线时执行人格或行业任务。")
                .font(.caption)
                .foregroundStyle(HoloLakeDesign.muted)
        }
        .frame(maxWidth: .infinity, alignment: .leading)
        .padding(.horizontal, 4)
    }
}