import Cocoa
import FlutterMacOS
import UniformTypeIdentifiers

/// Registers a method channel for native file picking with hidden files visible.
/// Called from Dart via `ensureInitialized`.
class NativePickerRegistrar: NSObject, FlutterPlugin {
    public static func register(with registrar: FlutterPluginRegistrar) {
        let channel = FlutterMethodChannel(
            name: "com.svrnty.native_picker",
            binaryMessenger: registrar.messenger)
        let instance = NativePickerRegistrar()
        registrar.addMethodCallDelegate(instance, channel: channel)
    }

    public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
        switch call.method {
        case "getDirectoryPath":
            let args = call.arguments as? [String: Any] ?? [:]
            let dialog = NSOpenPanel()

            if let initial = args["initialDirectory"] as? String, !initial.isEmpty {
                dialog.directoryURL = URL(fileURLWithPath: initial)
            }
            dialog.showsHiddenFiles = true
            dialog.canChooseDirectories = true
            dialog.canChooseFiles = false
            dialog.allowsMultipleSelection = false
            dialog.treatsFilePackagesAsDirectories = true
            dialog.message = "Select a folder containing session files"

            guard let window = NSApp.keyWindow else {
                result(FlutterError(code: "NO_WINDOW", message: "No key window found", details: nil))
                return
            }

            dialog.beginSheetModal(for: window) { response in
                if response == .OK, let url = dialog.url {
                    result(url.path)
                } else {
                    result(nil)
                }
            }

        case "pickFiles":
            let args = call.arguments as? [String: Any] ?? [:]
            let dialog = NSOpenPanel()

            if let initial = args["initialDirectory"] as? String, !initial.isEmpty {
                dialog.directoryURL = URL(fileURLWithPath: initial)
            }
            dialog.showsHiddenFiles = true
            dialog.canChooseDirectories = false
            dialog.canChooseFiles = true
            dialog.allowsMultipleSelection = false

            if let extensions = args["allowedExtensions"] as? [String], !extensions.isEmpty {
                if #available(macOS 11.0, *) {
                    let contentTypes = extensions.compactMap { UTType(filenameExtension: $0) }
                    dialog.allowedContentTypes = contentTypes
                } else {
                    dialog.allowedFileTypes = extensions
                }
            }
            dialog.message = "Select a session file"

            guard let window = NSApp.keyWindow else {
                result(FlutterError(code: "NO_WINDOW", message: "No key window found", details: nil))
                return
            }

            dialog.beginSheetModal(for: window) { response in
                if response == .OK, let url = dialog.url {
                    result([url.path])
                } else {
                    result(nil)
                }
            }

        default:
            result(FlutterMethodNotImplemented)
        }
    }
}