import AppKit
import SwiftUI
import SkyLightWindow
import Defaults
import QuartzCore

@MainActor
final class LockScreenWeatherPanelManager {
    static let shared = LockScreenWeatherPanelManager()

    private var window: NSWindow?
    private var hasDelegated = false
    private(set) var latestFrame: NSRect?
    private var lastSnapshot: LockScreenWeatherSnapshot?
    private var lastContentSize: CGSize?
    private var screenChangeObserver: NSObjectProtocol?
    private var workspaceObservers: [NSObjectProtocol] = []

    private init() {
        registerScreenChangeObservers()
    }

    func show(with snapshot: LockScreenWeatherSnapshot) {
        render(snapshot: snapshot, makeVisible: true)
    }

    func update(with snapshot: LockScreenWeatherSnapshot) {
        render(snapshot: snapshot, makeVisible: false)
    }

    func hide() {
        guard let window else { return }
        window.orderOut(nil)
        window.contentView = nil
        latestFrame = nil
        lastSnapshot = nil
        lastContentSize = nil
    }

    private func render(snapshot: LockScreenWeatherSnapshot, makeVisible: Bool) {
        guard let screen = NSScreen.main else { return }
        if !makeVisible, window == nil {
            return
        }

        let view = LockScreenWeatherWidget(snapshot: snapshot)
        let hostingView = NSHostingView(rootView: view)
        let fittingSize = hostingView.fittingSize
        hostingView.frame = NSRect(origin: .zero, size: fittingSize)

        let targetFrame = frame(for: fittingSize, snapshot: snapshot, on: screen)
        let window = ensureWindow()
        window.setFrame(targetFrame, display: true)
        latestFrame = targetFrame
        window.contentView = hostingView
        lastSnapshot = snapshot
        lastContentSize = fittingSize

        if makeVisible {
            window.orderFrontRegardless()
        }
    }

    private func ensureWindow() -> NSWindow {
        if let window {
            return window
        }

        let frame = NSRect(origin: .zero, size: CGSize(width: 110, height: 40))
        let newWindow = NSWindow(
            contentRect: frame,
            styleMask: [.borderless, .nonactivatingPanel],
            backing: .buffered,
            defer: false
        )

        newWindow.isReleasedWhenClosed = false
        newWindow.isOpaque = false
        newWindow.backgroundColor = .clear
        newWindow.hasShadow = false
        newWindow.ignoresMouseEvents = true
        newWindow.level = NSWindow.Level(rawValue: Int(CGShieldingWindowLevel()))
        newWindow.collectionBehavior = [.canJoinAllSpaces, .stationary, .fullScreenAuxiliary]

        ScreenCaptureVisibilityManager.shared.register(newWindow, scope: .entireInterface)

        window = newWindow
        if !hasDelegated {
            SkyLightOperator.shared.delegateWindow(newWindow)
            hasDelegated = true
        }
        return newWindow
    }

    private func frame(for size: CGSize, snapshot: LockScreenWeatherSnapshot, on screen: NSScreen) -> NSRect {
        let screenFrame = screen.frame
        let originX = screenFrame.midX - (size.width / 2)
        let verticalOffset = screenFrame.height * 0.15
        let maxY = screenFrame.maxY - size.height - 48
        let baseY = min(maxY, screenFrame.midY + verticalOffset)
        let loweredY = baseY - 36

        let inlineLift: CGFloat = snapshot.widgetStyle == .inline ? 44 : 0
        let userOffset = CGFloat(Defaults[.lockScreenWeatherVerticalOffset])
        let clampedOffset = min(max(userOffset, -160), 160)
        let adjustedY = loweredY + inlineLift + clampedOffset
        let upperClampedY = min(maxY, adjustedY)
        let clampedY = max(screenFrame.minY + 80, upperClampedY)
        return NSRect(x: originX, y: clampedY, width: size.width, height: size.height)
    }

    func refreshPositionForOffsets(animated: Bool = true) {
        guard let window, let snapshot = lastSnapshot else { return }
        guard let screen = NSScreen.main else { return }
        let size = lastContentSize ?? window.frame.size
        let targetFrame = frame(for: size, snapshot: snapshot, on: screen)
        latestFrame = targetFrame

        if animated {
            NSAnimationContext.runAnimationGroup { context in
                context.duration = 0.22
                context.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
                window.animator().setFrame(targetFrame, display: true)
            }
        } else {
            window.setFrame(targetFrame, display: true)
        }
    }

    private func registerScreenChangeObservers() {
        screenChangeObserver = NotificationCenter.default.addObserver(
            forName: NSApplication.didChangeScreenParametersNotification,
            object: nil,
            queue: .main
        ) { [weak self] _ in
            self?.handleScreenGeometryChange(reason: "screen-parameters")
        }

        let workspaceCenter = NSWorkspace.shared.notificationCenter
        let wakeObserver = workspaceCenter.addObserver(
            forName: NSWorkspace.screensDidWakeNotification,
            object: nil,
            queue: .main
        ) { [weak self] _ in
            self?.handleScreenGeometryChange(reason: "screens-did-wake")
        }

        workspaceObservers = [wakeObserver]
    }

    private func handleScreenGeometryChange(reason: String) {
        guard window?.isVisible == true else { return }
        refreshPositionForOffsets(animated: false)
        print("LockScreenWeatherPanelManager: realigned window due to \(reason)")
    }
}