import Foundation
import UIKit
import WebKit

/**
 * PlatformApi iOS implementation.
 *
 * 组装完整 User-Agent，格式与 Android 端保持一致：
 * `{systemWebViewUA} doublefeel/{versionCode}({versionName})(Apple##Apple##{model}; iOS{osVersion}; {height}x{width})(huawei)`
 */
final class PlatformHostApiImpl: PlatformHostApi {

    // WKWebView 必须在主线程创建，且需保持引用防止释放
    private static let webView: WKWebView = {
        let wv = WKWebView(frame: .zero)
        return wv
    }()

    func getFullUserAgent() throws -> String {
        // 1. 系统 WebView UA（同步读取，WKWebView 已在主线程初始化）
        let systemUa = PlatformHostApiImpl.webView.value(forKey: "userAgent") as? String ?? ""

        // 2. 版本信息（对应 Android versionCode / versionName）
        let info = Bundle.main.infoDictionary
        let versionName = info?["CFBundleShortVersionString"] as? String ?? ""
        let versionCode = info?["CFBundleVersion"] as? String ?? "0"

        // 3. 设备信息
        //    iOS 无 manufacturer/brand 概念，统一用 "Apple"
        let manufacturer = "Apple"
        let brand = "Apple"
        let model = UIDevice.current.model          // "iPhone" / "iPad"
        let osVersion = UIDevice.current.systemVersion.replacingOccurrences(of: ".", with: "")

        // 4. 屏幕物理分辨率：长边为 height，短边为 width
        let bounds = UIScreen.main.bounds
        let scale = UIScreen.main.scale
        let pw = bounds.width * scale
        let ph = bounds.height * scale
        let screenWidth = Int(min(pw, ph))
        let screenHeight = Int(max(pw, ph))

        // 5. 组装 customAgent（与 Android DeviceInfoUtils.userAgent 格式一致）
        let customAgent = "doublefeel/\(versionCode)(\(versionName))"
            + "(\(manufacturer)##\(brand)##\(model); iOS\(osVersion); \(screenHeight)x\(screenWidth))"
            + "(apple)"

        let full = "\(systemUa.trimmingCharacters(in: .whitespaces)) \(customAgent)"
            .trimmingCharacters(in: .whitespaces)
        return full
    }
}