import AppKit
import AVFoundation
import MetalKit

final class MainWindowController: NSWindowController, NSWindowDelegate {
    private let mtkView: MTKView
    private let capture: CameraCapture
    let detector: ObjectDetector
    private let edgePass: EdgePass
    private let jarvisPass: JarvisStylePass
    private let asciiPass: AsciiPass
    let renderer: Renderer

    private static let frameDefaultsKey = "VPOC.MainWindowFrame"

    init() {
        guard let device = MTLCreateSystemDefaultDevice() else {
            fatalError("Metal is required: no default system device available.")
        }

        let defaultSize = Theme.Layout.defaultWindowSize
        let minSize = Theme.Layout.minWindowSize

        let styleMask: NSWindow.StyleMask = [.titled, .closable, .miniaturizable, .resizable]
        let window = NSWindow(
            contentRect: NSRect(origin: .zero, size: defaultSize),
            styleMask: styleMask,
            backing: .buffered,
            defer: false
        )
        window.title = "VisionPOC"
        window.minSize = minSize
        window.appearance = NSAppearance(named: .darkAqua)
        window.isReleasedWhenClosed = false
        window.center()

        let view = MTKView(frame: NSRect(origin: .zero, size: defaultSize), device: device)
        view.colorPixelFormat = .bgra8Unorm
        view.preferredFramesPerSecond = Int(Theme.Tick.renderFPS)
        view.framebufferOnly = true
        let bg = Theme.Palette.background
        view.clearColor = MTLClearColor(red: Double(bg.x), green: Double(bg.y), blue: Double(bg.z), alpha: Double(bg.w))
        view.autoResizeDrawable = true
        view.autoresizingMask = [.width, .height]
        window.contentView = view
        self.mtkView = view

        let capture = CameraCapture(device: device)
        let detector = ObjectDetector()
        let edgePass = EdgePass(device: device)
        let jarvisPass = JarvisStylePass()
        guard let asciiPass = AsciiPass(device: device) else {
            fatalError("Failed to build the ASCII atlas.")
        }

        guard let renderer = Renderer(
            view: view,
            device: device,
            capture: capture,
            detector: detector,
            edgePass: edgePass,
            jarvisPass: jarvisPass,
            asciiPass: asciiPass
        ) else {
            fatalError("Failed to initialize Renderer.")
        }

        self.capture = capture
        self.detector = detector
        self.edgePass = edgePass
        self.jarvisPass = jarvisPass
        self.asciiPass = asciiPass
        self.renderer = renderer

        view.delegate = renderer

        super.init(window: window)

        window.delegate = self
        restoreFrame()
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) is not supported")
    }

    override func showWindow(_ sender: Any?) {
        super.showWindow(sender)
        window?.makeKeyAndOrderFront(sender)
        Task { await capture.start() }
    }

    // MARK: - Camera

    var activeCameraUniqueID: String? {
        capture.activeDeviceUniqueID
    }

    func switchCamera(to device: AVCaptureDevice) {
        capture.switchToDevice(device)
    }

    // MARK: - Snapshot

    @MainActor
    func saveSnapshotToDesktop() {
        guard let data = renderer.snapshotPNG() else {
            LogStream.shared.log("snapshot failed (renderer returned nil)", level: .warn, source: .app)
            return
        }
        let df = DateFormatter()
        df.dateFormat = "yyyy-MM-dd-HHmmss"
        let name = "VisionPOC-\(df.string(from: Date())).png"
        let url = OutputLocations.snapshotDirectory().appendingPathComponent(name)
        do {
            try data.write(to: url)
            LogStream.shared.log("saved \(url.lastPathComponent)", level: .info, source: .app)
        } catch {
            LogStream.shared.log("snapshot write failed: \(error)", level: .error, source: .app)
        }
    }

    // MARK: - Window persistence

    private func restoreFrame() {
        guard let window,
              let saved = UserDefaults.standard.string(forKey: MainWindowController.frameDefaultsKey) else {
            return
        }
        let rect = NSRectFromString(saved)
        if rect.size.width > 0 && rect.size.height > 0 {
            window.setFrame(rect, display: false)
        }
    }

    func windowWillClose(_ notification: Notification) {
        guard let window else { return }
        UserDefaults.standard.set(NSStringFromRect(window.frame),
                                  forKey: MainWindowController.frameDefaultsKey)
    }
}