import SwiftUI
import AppIntents

@main
struct BusinessCardClipApp: App {
    @State private var recordName: String?
    @State private var launchErrorMessage: String?
    #if DEBUG
    @State private var debugState: ClipDebugState?
    #endif

    var body: some Scene {
        WindowGroup {
            Group {
                #if DEBUG
                if let debugState {
                    ClipDebugHarnessView(initialState: debugState)
                } else if let recordName {
                    ClipRootView(recordName: recordName)
                } else if let launchErrorMessage {
                    ClipErrorView(message: launchErrorMessage) {
                        self.launchErrorMessage = nil
                    }
                } else {
                    ClipLoadingView()
                }
                #else
                if let recordName {
                    ClipRootView(recordName: recordName)
                } else if let launchErrorMessage {
                    ClipErrorView(message: launchErrorMessage) {
                        self.launchErrorMessage = nil
                    }
                } else {
                    ClipLoadingView()
                }
                #endif
            }
            .onContinueUserActivity(NSUserActivityTypeBrowsingWeb) { activity in
                handleUserActivity(activity)
            }
            .onOpenURL { url in
                handleURL(url)
            }
            .task {
                #if DEBUG
                debugState = parseDebugStateArgument()
                #endif
            }
        }
    }

    private func handleUserActivity(_ activity: NSUserActivity) {
        guard let url = activity.webpageURL else { return }
        handleURL(url)
    }

    private func handleURL(_ url: URL) {
        guard let id = extractRecordName(from: url) else {
            launchErrorMessage = ClipError.invalidRecord.localizedDescription
            return
        }
        
        launchErrorMessage = nil
        recordName = id
    }
    
    private func extractRecordName(from url: URL) -> String? {
        if let components = URLComponents(url: url, resolvingAgainstBaseURL: true),
           let id = components.queryItems?
            .first(where: { $0.name == ClipDesign.URL.recordQueryName })?
            .value,
           !id.isEmpty {
            return id
        }
        
        // Fallback for path-based links (e.g. /clip/{recordName}).
        let candidate = url.lastPathComponent.trimmingCharacters(in: .whitespacesAndNewlines)
        guard !candidate.isEmpty, candidate != "/" else { return nil }
        return candidate
    }
    
    #if DEBUG
    private func parseDebugStateArgument() -> ClipDebugState? {
        let prefix = "--clip-debug="
        guard let argument = ProcessInfo.processInfo.arguments.first(where: { $0.hasPrefix(prefix) }) else {
            return nil
        }
        
        let value = String(argument.dropFirst(prefix.count))
        return ClipDebugState(rawValue: value)
    }
    #endif
}