import SwiftUI
import UIKit

struct OnboardingView: View {
    @EnvironmentObject var daemonConfig: DaemonConfiguration
    @AppStorage("hasCompletedOnboarding") private var hasCompleted = false

    @State private var step        = 0
    @State private var tailscaleIP = ""
    @State private var wcApiKey    = ""
    @State private var testResult: TestResult = .idle

    enum TestResult: Equatable {
        case idle, testing, success, failure(String)
        static func ==(a: TestResult, b: TestResult) -> Bool {
            switch (a,b) {
            case (.idle,.idle),(.testing,.testing),(.success,.success): return true
            case (.failure(let x),.failure(let y)): return x == y
            default: return false
            }
        }
    }

    private let steps = ["Welcome","Connect to Mac","Working Copy","Ready"]

    var body: some View {
        NavigationStack {
            VStack(spacing: 0) {
                // Progress dots
                HStack(spacing: 6) {
                    ForEach(0..<steps.count, id: \.self) { i in
                        Circle().fill(i <= step ? Color.accentColor : Color.secondary.opacity(0.3))
                            .frame(width: 8, height: 8)
                            .animation(.spring, value: step)
                    }
                }.padding(.top, 20)

                // Content
                TabView(selection: $step) {
                    welcomeStep.tag(0)
                    daemonStep.tag(1)
                    workingCopyStep.tag(2)
                    readyStep.tag(3)
                }
                .tabViewStyle(.page(indexDisplayMode: .never))

                // Navigation
                HStack {
                    if step > 0 { Button("Back") { withAnimation { step -= 1 } }.buttonStyle(.bordered) }
                    Spacer()
                    if step < steps.count - 1 {
                        Button("Next") { withAnimation { step += 1 } }
                            .buttonStyle(.borderedProminent)
                            .disabled(step == 1 && testResult != .success)
                    } else {
                        Button("Get Started") { applyAndFinish() }
                            .buttonStyle(.borderedProminent)
                            .disabled(testResult != .success && tailscaleIP.isEmpty)
                    }
                }
                .padding(.horizontal, 24).padding(.bottom, 32)
            }
        }
    }

    // MARK: - Steps

    private var welcomeStep: some View {
        VStack(spacing: 28) {
            Image(systemName: "laptopcomputer.and.ipad").font(.system(size:72,weight:.thin)).foregroundStyle(Color.accentColor).padding(.top,40)
            VStack(spacing:10) {
                Text("Welcome to PadXcode").font(.largeTitle.bold()).multilineTextAlignment(.center)
                Text("A native Swift IDE on your iPad, backed by your Mac.").font(.body).foregroundStyle(.secondary).multilineTextAlignment(.center).padding(.horizontal,24)
            }
            LazyVGrid(columns: [.init(.flexible()),.init(.flexible())], spacing:12) {
                ForEach([("swift","Runestone Editor",.orange),("sparkles","Tree-sitter Syntax",.yellow),
                         ("hammer.fill","xcodebuild Builds",.blue),("iphone.radiowaves.left.and.right","devicectl Deploy",.green),
                         ("wand.and.stars","sourcekit-lsp",.purple),("arrow.triangle.branch","Working Copy Git",.pink)] as [(String,String,Color)], id:\.1) { icon,name,color in
                    HStack(spacing:10) {
                        Image(systemName:icon).font(.title3).foregroundStyle(color).frame(width:32)
                        Text(name).font(.subheadline); Spacer()
                    }.padding(12).background(.quaternary, in: RoundedRectangle(cornerRadius:10))
                }
            }.padding(.horizontal,24)
            Spacer(minLength:40)
        }
    }

    private var daemonStep: some View {
        VStack(spacing: 28) {
            Image(systemName:"network").font(.system(size:72,weight:.thin)).foregroundStyle(.blue).padding(.top,40)
            VStack(spacing:10) {
                Text("Connect to Your Mac").font(.largeTitle.bold()).multilineTextAlignment(.center)
                Text("Enter your Mac's Tailscale IP to connect to the daemon.").font(.body).foregroundStyle(.secondary).multilineTextAlignment(.center).padding(.horizontal,24)
            }
            VStack(spacing:14) {
                VStack(alignment:.leading,spacing:6) {
                    Label("Tailscale IP Address", systemImage:"network").font(.subheadline.bold())
                    TextField("100.x.x.x", text:$tailscaleIP)
                        .textFieldStyle(.roundedBorder).keyboardType(.numbersAndPunctuation)
                        .autocorrectionDisabled().autocapitalization(.none)
                        .onChange(of:tailscaleIP) { _,_ in testResult = .idle }
                }
                GroupBox {
                    VStack(alignment:.leading,spacing:6) {
                        Label("Mac terminal:", systemImage:"terminal").font(.caption.bold())
                        Text("open mac-daemon/PadXcodeDaemon.xcodeproj")
                            .font(.system(.caption,design:.monospaced)).padding(6)
                            .frame(maxWidth:.infinity,alignment:.leading)
                            .background(Color(.secondarySystemBackground),in:RoundedRectangle(cornerRadius:6))
                    }
                }
                Button {
                    Task { await testConnection() }
                } label: {
                    HStack {
                        if case .testing = testResult { ProgressView().scaleEffect(0.8) }
                        Text(testLabel)
                    }.frame(maxWidth:.infinity)
                }
                .buttonStyle(.borderedProminent)
                .disabled(tailscaleIP.isEmpty || testResult == .testing)

                if case .failure(let m) = testResult {
                    Label(m, systemImage:"xmark.circle").font(.caption).foregroundStyle(.red)
                }
                if case .success = testResult {
                    Label("Connected to daemon ✓", systemImage:"checkmark.circle.fill").font(.caption).foregroundStyle(.green)
                }
            }
            .padding(20).background(.regularMaterial, in:RoundedRectangle(cornerRadius:14)).padding(.horizontal,24)
            Spacer(minLength:40)
        }
    }

    private var workingCopyStep: some View {
        VStack(spacing: 28) {
            Image(systemName:"arrow.triangle.branch").font(.system(size:72,weight:.thin)).foregroundStyle(.purple).padding(.top,40)
            VStack(spacing:10) {
                Text("Working Copy (Optional)").font(.largeTitle.bold()).multilineTextAlignment(.center)
                Text("Connect Working Copy to commit and push from within PadXcode.").font(.body).foregroundStyle(.secondary).multilineTextAlignment(.center).padding(.horizontal,24)
            }
            VStack(spacing:14) {
                let installed = UIApplication.shared.canOpenURL(URL(string:"working-copy://")!)
                if installed {
                    Label("Working Copy detected ✓", systemImage:"checkmark.circle.fill").foregroundStyle(.green).font(.subheadline)
                } else {
                    Label("Working Copy not installed", systemImage:"exclamationmark.triangle").foregroundStyle(.orange).font(.subheadline)
                }
                VStack(alignment:.leading,spacing:6) {
                    Label("API Key", systemImage:"key.fill").font(.subheadline.bold())
                    SecureField("Paste from Working Copy → Settings → Advanced", text:$wcApiKey)
                        .textFieldStyle(.roundedBorder).autocorrectionDisabled().autocapitalization(.none)
                }
                Text("For local git over Tailscale: clone via SSH in Working Copy using ssh://user@100.x.x.x/path/to/repo.git")
                    .font(.caption).foregroundStyle(.secondary).multilineTextAlignment(.center)
            }
            .padding(20).background(.regularMaterial, in:RoundedRectangle(cornerRadius:14)).padding(.horizontal,24)
            Spacer(minLength:40)
        }
    }

    private var readyStep: some View {
        VStack(spacing: 28) {
            Image(systemName:"checkmark.seal.fill").font(.system(size:72,weight:.thin)).foregroundStyle(.green).padding(.top,40)
            VStack(spacing:10) {
                Text("You're All Set").font(.largeTitle.bold()).multilineTextAlignment(.center)
                Text("Open a project and start building.").font(.body).foregroundStyle(.secondary)
            }
            VStack(spacing:10) {
                summaryRow("network",       .blue,   "Mac Daemon",    tailscaleIP.isEmpty ? "Not configured" : tailscaleIP)
                summaryRow("arrow.triangle.branch", .purple, "Working Copy", wcApiKey.isEmpty ? "Not configured" : "Connected")
                summaryRow("wand.and.stars", .yellow, "sourcekit-lsp", "Auto-starts with project")
                summaryRow("hammer.fill",   .orange, "Build & Deploy", "Ready")
            }
            .padding(20).background(.regularMaterial, in:RoundedRectangle(cornerRadius:14)).padding(.horizontal,24)
            Spacer(minLength:40)
        }
    }

    private func summaryRow(_ icon: String, _ color: Color, _ label: String, _ value: String) -> some View {
        HStack {
            Image(systemName:icon).foregroundStyle(color).frame(width:24)
            Text(label).font(.subheadline)
            Spacer()
            Text(value).font(.subheadline).foregroundStyle(.secondary)
        }
    }

    // MARK: - Actions

    private var testLabel: String {
        switch testResult {
        case .testing: return "Testing…"; case .success: return "Connected ✓"; default: return "Test Connection"
        }
    }

    private func testConnection() async {
        testResult = .testing
        let host = tailscaleIP.trimmingCharacters(in:.whitespaces)
        guard let url = URL(string:"http://\(host):8080/health") else { testResult = .failure("Invalid IP"); return }
        var req = URLRequest(url:url); req.timeoutInterval = 4
        do {
            let (_,resp) = try await URLSession.shared.data(for:req)
            testResult = (resp as? HTTPURLResponse)?.statusCode == 200 ? .success : .failure("Unexpected response")
        } catch { testResult = .failure(error.localizedDescription) }
    }

    private func applyAndFinish() {
        daemonConfig.host = tailscaleIP.trimmingCharacters(in:.whitespaces)
        daemonConfig.port = 8080
        if !wcApiKey.isEmpty { UserDefaults.standard.set(wcApiKey, forKey:"workingCopyAPIKey") }
        hasCompleted = true
    }
}