import AppKit
import WebKit

@MainActor
final class RedditShareScriptBridge: NSObject, WKScriptMessageHandler {
    static let shared = RedditShareScriptBridge()

    weak var webView: WKWebView?

    private override init() {
        super.init()
    }

    nonisolated func userContentController(
        _ userContentController: WKUserContentController,
        didReceive message: WKScriptMessage
    ) {
        guard message.name == RedditShareBridgeStyle.messageHandlerName else { return }
        Task { @MainActor in
            handleShareMessage(message)
        }
    }

    private func handleShareMessage(_ message: WKScriptMessage) {
        let targetWebView = webView ?? message.webView
        guard let targetWebView else {
            return
        }

        var items: [Any] = []
        if let payload = message.body as? [String: Any] {
            if let urlString = payload["url"] as? String,
               !urlString.isEmpty,
               let url = URL(string: urlString) {
                items.append(url)
            }
            if let text = payload["text"] as? String, !text.isEmpty {
                items.append(text)
            }
            if let title = payload["title"] as? String, !title.isEmpty {
                items.append(title)
            }
        } else if let urlString = message.body as? String,
                  let url = URL(string: urlString) {
            items.append(url)
        }

        guard !items.isEmpty else {
            resolveShare(on: targetWebView, success: false)
            return
        }

        let picker = NSSharingServicePicker(items: items)
        let anchor = NSRect(
            x: targetWebView.bounds.midX,
            y: targetWebView.bounds.midY,
            width: 1,
            height: 1
        )
        picker.show(relativeTo: anchor, of: targetWebView, preferredEdge: .minY)
        resolveShare(on: targetWebView, success: true)
    }

    private func resolveShare(on webView: WKWebView, success: Bool) {
        webView.evaluateJavaScript(
            "window.__reddoraShareCallback && window.__reddoraShareCallback(\(success));",
            completionHandler: nil
        )
    }
}