import SwiftUI
import WebKit

private struct RemotePDFView: View {
    let url: URL
    @Binding var isLoading: Bool
    @Binding var hasError: Bool

    var body: some View {
        RemotePDFRepresentable(url: url, isLoading: $isLoading, hasError: $hasError)
    }
}

#if canImport(UIKit)
private struct RemotePDFRepresentable: UIViewRepresentable {
    let url: URL
    @Binding var isLoading: Bool
    @Binding var hasError: Bool

    func makeUIView(context: Context) -> WKWebView {
        let webView = WKWebView()
        webView.navigationDelegate = context.coordinator
        webView.load(URLRequest(url: url))
        return webView
    }

    func updateUIView(_ uiView: WKWebView, context: Context) {}

    func makeCoordinator() -> RemotePDFCoordinator {
        RemotePDFCoordinator(isLoading: $isLoading, hasError: $hasError)
    }
}
#elseif canImport(AppKit)
private struct RemotePDFRepresentable: NSViewRepresentable {
    let url: URL
    @Binding var isLoading: Bool
    @Binding var hasError: Bool

    func makeNSView(context: Context) -> WKWebView {
        let webView = WKWebView()
        webView.navigationDelegate = context.coordinator
        webView.load(URLRequest(url: url))
        return webView
    }

    func updateNSView(_ nsView: WKWebView, context: Context) {}

    func makeCoordinator() -> RemotePDFCoordinator {
        RemotePDFCoordinator(isLoading: $isLoading, hasError: $hasError)
    }
}
#endif

private final class RemotePDFCoordinator: NSObject, WKNavigationDelegate {
    @Binding var isLoading: Bool
    @Binding var hasError: Bool

    init(isLoading: Binding<Bool>, hasError: Binding<Bool>) {
        self._isLoading = isLoading
        self._hasError = hasError
    }

    func webView(_ webView: WKWebView, didStartProvisionalNavigation navigation: WKNavigation!) {
        isLoading = true
        hasError = false
    }

    func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
        isLoading = false
    }

    func webView(_ webView: WKWebView, didFail navigation: WKNavigation!, withError error: Error) {
        isLoading = false
        hasError = true
    }

    func webView(_ webView: WKWebView, didFailProvisionalNavigation navigation: WKNavigation!, withError error: Error) {
        isLoading = false
        hasError = true
    }
}

private struct LegalDocumentScreen: View {
    let title: String
    let headerTitle: String
    let document: LegalDocument
    @Environment(\.colorScheme) var colorScheme
    @Environment(\.dismiss) var dismiss
    @State private var isLoading = true
    @State private var hasError = false

    var body: some View {
        VStack(spacing: 0) {
            screenHeader
                .padding(24)

            ZStack {
                RemotePDFView(url: document.url, isLoading: $isLoading, hasError: $hasError)

                if isLoading {
                    ProgressView()
                }

                if hasError {
                    VStack(spacing: 8) {
                        Text("Não foi possível carregar \(title.lowercased()).")
                            .font(AppTypography.body)
                            .foregroundStyle(AppColors.textPrimary)
                            .multilineTextAlignment(.center)
                    }
                    .padding(24)
                }
            }
        }
        .background((colorScheme == .dark ? Color.black : AppColors.backgroundLight).ignoresSafeArea())
        .appHiddenNavigationBar()
        .navigationBarBackButtonHidden(true)
    }

    private var screenHeader: some View {
        ZStack {
            Text(headerTitle)
                .font(AppTypography.heading2)
                .foregroundStyle(AppColors.textPrimary)
            HStack {
                Button(action: { dismiss() }) {
                    Image(systemName: "chevron.left")
                        .font(.system(size: 24, weight: .semibold))
                        .foregroundStyle(AppColors.textPrimary)
                        .frame(width: 52, height: 52)
                        .background(AppColors.surface)
                        .clipShape(Circle())
                        .shadow(color: .black.opacity(0.06), radius: 8, y: 2)
                }
                .buttonStyle(.plain)
                Spacer()
            }
        }
    }
}

struct TermsOfUseView: View {
    var body: some View {
        LegalDocumentScreen(title: "os Termos de Uso", headerTitle: "Termos de Uso", document: .terms)
    }
}

struct PrivacyPolicyView: View {
    var body: some View {
        LegalDocumentScreen(title: "a Política de Privacidade", headerTitle: "Privacidade", document: .privacyPolicy)
    }
}