import AppKit

import AppKit

class WallpaperManager {
    static let shared = WallpaperManager()
    
    private init() {}
    
    /// Downloads the file to a temporary location and returns the local URL.
    func download(from url: URL) async throws -> URL {
        let (data, _) = try await URLSession.shared.data(from: url)
        
        let filename = url.lastPathComponent
        let tempDir = FileManager.default.temporaryDirectory
        let fileURL = tempDir.appendingPathComponent(filename)
        
        try data.write(to: fileURL)
        return fileURL
    }
    
    /// Sets the desktop image from a local file URL.
    @MainActor
    func setDesktopImage(from fileURL: URL, screen: NSScreen? = nil) throws {
        if let screen = screen {
            try NSWorkspace.shared.setDesktopImageURL(fileURL, for: screen, options: [:])
        } else {
            // Set for all screens or just main? Let's default to main for safety, 
            // but the UI will likely drive this.
            // If no screen specified, maybe set for the 'active' one.
            let targetScreen = NSScreen.main ?? NSScreen.screens.first!
            try NSWorkspace.shared.setDesktopImageURL(fileURL, for: targetScreen, options: [:])
        }
    }
    
    /// Copies the file to the specified destination directory.
    func saveToFolder(from sourceURL: URL, to folderURL: URL) throws {
        // Ensure folder exists
        try FileManager.default.createDirectory(at: folderURL, withIntermediateDirectories: true)
        
        let destinationURL = folderURL.appendingPathComponent(sourceURL.lastPathComponent)
        
        // If file exists, maybe don't overwrite or handle gracefully? 
        // For now, we'll remove it if it exists to ensure we have the fresh one, or just skip.
        if FileManager.default.fileExists(atPath: destinationURL.path) {
            try FileManager.default.removeItem(at: destinationURL)
        }
        
        try FileManager.default.copyItem(at: sourceURL, to: destinationURL)
    }
    
    // Legacy support wrapper (optional, but cleaner to update call sites)
    @MainActor
    func setWallpaper(from url: URL, screen: NSScreen? = nil) async throws {
        let localURL = try await download(from: url)
        try setDesktopImage(from: localURL, screen: screen)
    }
}