import SwiftUI

#if canImport(UIKit)
import WebKit

@MainActor
public struct XWebViewView: UIViewRepresentable {
    private let config: XWebViewConfig

    public init(config: XWebViewConfig? = nil) {
        self.config = config ?? XWebViewBridge.shared.currentConfig()
    }

    public func makeCoordinator() -> Coordinator {
        Coordinator()
    }

    public func makeUIView(context: Context) -> WKWebView {
        let webView = WKWebView(frame: .zero)
        webView.navigationDelegate = context.coordinator
        webView.uiDelegate = context.coordinator
        if let userAgent = config.userAgent {
            webView.customUserAgent = userAgent
        }
        context.coordinator.attach(webView)
        XWebViewBridge.shared.setController(context.coordinator)
        if !config.url.isEmpty, let url = URL(string: config.url) {
            webView.load(URLRequest(url: url))
        }
        return webView
    }

    public func updateUIView(_ webView: WKWebView, context: Context) {
        context.coordinator.attach(webView)
        if webView.url == nil, !config.url.isEmpty, let url = URL(string: config.url) {
            webView.load(URLRequest(url: url))
        }
    }

    public static func dismantleUIView(_ uiView: WKWebView, coordinator: Coordinator) {
        coordinator.detach()
        if XWebViewBridge.shared.currentController() === coordinator {
            XWebViewBridge.shared.setController(nil)
        }
    }

    @MainActor
    public final class Coordinator: NSObject, WKNavigationDelegate, WKUIDelegate, XWebViewController {
        private weak var webView: WKWebView?

        func attach(_ webView: WKWebView) {
            self.webView = webView
        }

        func detach() {
            webView = nil
        }

        public func canGoBack() -> Bool {
            webView?.canGoBack == true
        }

        public func canGoForward() -> Bool {
            webView?.canGoForward == true
        }

        public func currentUrl() -> String? {
            webView?.url?.absoluteString
        }

        public func goBack() {
            webView?.goBack()
        }

        public func goForward() {
            webView?.goForward()
        }

        public func reload() {
            webView?.reload()
        }

        public func load(url: String) {
            guard let url = URL(string: url) else { return }
            webView?.load(URLRequest(url: url))
        }
    }
}

#else

public struct XWebViewView: View {
    private let config: XWebViewConfig

    public init(config: XWebViewConfig? = nil) {
        self.config = config ?? XWebViewBridge.shared.currentConfig()
    }

    public var body: some View {
        VStack(spacing: 12) {
            Text(config.title.isEmpty ? "WebView" : config.title)
                .font(.headline)
            Text("XWebView is available on iOS with UIKit-backed WebView.")
                .font(.subheadline)
                .foregroundStyle(.secondary)
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
    }
}

#endif