import Foundation
import Cocoa
import SwiftUI
import GhosttyKit

/// The terminal controller is an NSWindowController that maps 1:1 to a terminal window.
class TerminalController: NSWindowController, NSWindowDelegate, 
                          TerminalViewDelegate, TerminalViewModel,
                          PasteProtectionViewDelegate
{
    override var windowNibName: NSNib.Name? { "Terminal" }
    
    /// The app instance that this terminal view will represent.
    let ghostty: Ghostty.AppState
    
    /// The currently focused surface.
    var focusedSurface: Ghostty.SurfaceView? = nil

    /// The surface tree for this window.
    @Published var surfaceTree: Ghostty.SplitNode? = nil {
        didSet {
            // If our surface tree becomes nil then it means all our surfaces
            // have closed, so we also close the window.
            if (surfaceTree == nil) { lastSurfaceDidClose() }
        }
    }
    
    /// Fullscreen state management.
    private let fullscreenHandler = FullScreenHandler()
    
    /// True when an alert is active so we don't overlap multiple.
    private var alert: NSAlert? = nil
    
    /// The paste protection window, if shown.
    private var pasteProtection: PasteProtectionController? = nil
    
    init(_ ghostty: Ghostty.AppState, withBaseConfig base: Ghostty.SurfaceConfiguration? = nil) {
        self.ghostty = ghostty
        super.init(window: nil)
        
        // Initialize our initial surface.
        guard let ghostty_app = ghostty.app else { preconditionFailure("app must be loaded") }
        self.surfaceTree = .leaf(.init(ghostty_app, base))
        
        // Setup our notifications for behaviors
        let center = NotificationCenter.default
        center.addObserver(
            self,
            selector: #selector(onToggleFullscreen),
            name: Ghostty.Notification.ghosttyToggleFullscreen,
            object: nil)
        center.addObserver(
            self,
            selector: #selector(onGotoTab),
            name: Ghostty.Notification.ghosttyGotoTab,
            object: nil)
        center.addObserver(
            self,
            selector: #selector(onConfirmUnsafePaste),
            name: Ghostty.Notification.confirmUnsafePaste,
            object: nil)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) is not supported for this view")
    }
    
    deinit {
        // Remove all of our notificationcenter subscriptions
        let center = NotificationCenter.default
        center.removeObserver(self)
    }

    /// Update the accessory view of each tab according to the keyboard
    /// shortcut that activates it (if any). This is called when the key window
    /// changes and when a window is closed.
    func relabelTabs() {
        guard let windows = self.window?.tabbedWindows else { return }
        guard let cfg = ghostty.config else { return }
        for (index, window) in windows.enumerated().prefix(9) {
            let action = "goto_tab:\(index + 1)"
            let trigger = ghostty_config_trigger(cfg, action, UInt(action.count))
            guard let equiv = Ghostty.keyEquivalentLabel(key: trigger.key, mods: trigger.mods) else {
                continue
            }

            let attributes: [NSAttributedString.Key: Any] = [
                .font: NSFont.labelFont(ofSize: 0),
                .foregroundColor: window.isKeyWindow ? NSColor.labelColor : NSColor.secondaryLabelColor,
            ]
            let attributedString = NSAttributedString(string: " \(equiv) ", attributes: attributes)
            let text = NSTextField(labelWithAttributedString: attributedString)
            window.tab.accessoryView = text
        }
    }

    //MARK: - NSWindowController
    
    override func windowWillLoad() {
        // We do NOT want to cascade because we handle this manually from the manager.
        shouldCascadeWindows = false
    }
    
    override func windowDidLoad() {
        guard let window = window else { return }

        // If window decorations are disabled, remove our title
        if (!ghostty.windowDecorations) { window.styleMask.remove(.titled) }
        
        // If we aren't in full screen, then we want to disable tabbing (see comment
        // in the delegate function)
        if (!window.styleMask.contains(.fullScreen)) { disableTabbing() }
        
        // Terminals typically operate in sRGB color space and macOS defaults
        // to "native" which is typically P3. There is a lot more resources
        // covered in thie GitHub issue: https://github.com/mitchellh/ghostty/pull/376
        window.colorSpace = NSColorSpace.sRGB
        
        // Center the window to start, we'll move the window frame automatically
        // when cascading.
        window.center()
        
        // Initialize our content view to the SwiftUI root
        window.contentView = NSHostingView(rootView: TerminalView(
            ghostty: self.ghostty,
            viewModel: self,
            delegate: self
        ))
    }
    
    // Shows the "+" button in the tab bar, responds to that click.
    override func newWindowForTab(_ sender: Any?) {
        // Trigger the ghostty core event logic for a new tab.
        guard let surface = self.focusedSurface?.surface else { return }
        ghostty.newTab(surface: surface)
    }
    
    //MARK: - NSWindowDelegate
    
    // This is called when performClose is called on a window (NOT when close()
    // is called directly). performClose is called primarily when UI elements such
    // as the "red X" are pressed.
    func windowShouldClose(_ sender: NSWindow) -> Bool {
        // We must have a window. Is it even possible not to?
        guard let window = self.window else { return true }
        
        // If we have no surfaces, close.
        guard let node = self.surfaceTree else { return true }
        
        // If we already have an alert, continue with it
        guard alert == nil else { return false }
        
        // If our surfaces don't require confirmation, close.
        if (!node.needsConfirmQuit()) { return true }
        
        // We require confirmation, so show an alert as long as we aren't already.
        let alert = NSAlert()
        alert.messageText = "Close Terminal?"
        alert.informativeText = "The terminal still has a running process. If you close the " +
        "terminal the process will be killed."
        alert.addButton(withTitle: "Close the Terminal")
        alert.addButton(withTitle: "Cancel")
        alert.alertStyle = .warning
        alert.beginSheetModal(for: window, completionHandler: { response in
            self.alert = nil
            switch (response) {
            case .alertFirstButtonReturn:
                window.close()
                
            default:
                break
            }
        })
            
        self.alert = alert
        
        return false
    }
    
    func windowWillClose(_ notification: Notification) {
        // I don't know if this is required anymore. We previously had a ref cycle between
        // the view and the window so we had to nil this out to break it but I think this
        // may now be resolved. We should verify that no memory leaks and we can remove this.
        self.window?.contentView = nil

        self.relabelTabs()
    }

    func windowDidBecomeKey(_ notification: Notification) {
        self.relabelTabs()
    }
    
    func windowWillExitFullScreen(_ notification: Notification) {
        // See comment in this function
        disableTabbing()
    }
    
    func windowWillEnterFullScreen(_ notification: Notification) {
        // We re-enable the automatic tabbing mode when we enter full screen otherwise
        // every new tab also enters a new screen.
        guard let window = self.window else { return }
        window.tabbingMode = .automatic
    }
    
    private func disableTabbing() {
        // For new windows, explicitly disallow tabbing with other windows.
        // This overrides the value of userTabbingPreference. Rationale:
        // Ghostty provides separate "New Tab" and "New Window" actions so
        // there's no reason to make "New Window" open in a tab.
        guard let window = self.window else { return }
        window.tabbingMode = .disallowed;
    }

    //MARK: - First Responder
    
    @IBAction func newWindow(_ sender: Any?) {
        guard let surface = focusedSurface?.surface else { return }
        ghostty.newWindow(surface: surface)
    }
    
    @IBAction func newTab(_ sender: Any?) {
        guard let surface = focusedSurface?.surface else { return }
        ghostty.newTab(surface: surface)
    }
    
    @IBAction func close(_ sender: Any) {
        guard let surface = focusedSurface?.surface else { return }
        ghostty.requestClose(surface: surface)
    }
    
    @IBAction func closeWindow(_ sender: Any) {
        self.window?.performClose(sender)
    }
    
    @IBAction func splitHorizontally(_ sender: Any) {
        guard let surface = focusedSurface?.surface else { return }
        ghostty.split(surface: surface, direction: GHOSTTY_SPLIT_RIGHT)
    }
    
    @IBAction func splitVertically(_ sender: Any) {
        guard let surface = focusedSurface?.surface else { return }
        ghostty.split(surface: surface, direction: GHOSTTY_SPLIT_DOWN)
    }
    
    @IBAction func splitZoom(_ sender: Any) {
        guard let surface = focusedSurface?.surface else { return }
        ghostty.splitToggleZoom(surface: surface)
    }
    
    @IBAction func splitMoveFocusPrevious(_ sender: Any) {
        splitMoveFocus(direction: .previous)
    }
    
    @IBAction func splitMoveFocusNext(_ sender: Any) {
        splitMoveFocus(direction: .next)
    }
    
    @IBAction func splitMoveFocusAbove(_ sender: Any) {
        splitMoveFocus(direction: .top)
    }
    
    @IBAction func splitMoveFocusBelow(_ sender: Any) {
        splitMoveFocus(direction: .bottom)
    }
    
    @IBAction func splitMoveFocusLeft(_ sender: Any) {
        splitMoveFocus(direction: .left)
    }
    
    @IBAction func splitMoveFocusRight(_ sender: Any) {
        splitMoveFocus(direction: .right)
    }
    
    private func splitMoveFocus(direction: Ghostty.SplitFocusDirection) {
        guard let surface = focusedSurface?.surface else { return }
        ghostty.splitMoveFocus(surface: surface, direction: direction)
    }
    
    @IBAction func toggleGhosttyFullScreen(_ sender: Any) {
        guard let surface = focusedSurface?.surface else { return }
        ghostty.toggleFullscreen(surface: surface)
    }
    
    @IBAction func increaseFontSize(_ sender: Any) {
        guard let surface = focusedSurface?.surface else { return }
        ghostty.changeFontSize(surface: surface, .increase(1))
    }

    @IBAction func decreaseFontSize(_ sender: Any) {
        guard let surface = focusedSurface?.surface else { return }
        ghostty.changeFontSize(surface: surface, .decrease(1))
    }

    @IBAction func resetFontSize(_ sender: Any) {
        guard let surface = focusedSurface?.surface else { return }
        ghostty.changeFontSize(surface: surface, .reset)
    }
    
    @IBAction func toggleTerminalInspector(_ sender: Any) {
        guard let surface = focusedSurface?.surface else { return }
        ghostty.toggleTerminalInspector(surface: surface)
    }
    
    //MARK: - TerminalViewDelegate
    
    func focusedSurfaceDidChange(to: Ghostty.SurfaceView?) {
        self.focusedSurface = to
    }
    
    func titleDidChange(to: String) {
        self.window?.title = to
    }
    
    func cellSizeDidChange(to: NSSize) {
        guard ghostty.windowStepResize else { return }
        self.window?.contentResizeIncrements = to
    }
    
    func lastSurfaceDidClose() {
        self.window?.close()
    }
    
    //MARK: - Paste Protection
    
    func pasteProtectionComplete(_ action: PasteProtectionView.Action) {
        // End our paste protection no matter what
        guard let pp = self.pasteProtection else { return }
        self.pasteProtection = nil
        
        // Close the sheet
        if let ppWindow = pp.window {
            window?.endSheet(ppWindow)
        }
        
        let str: String
        switch (action) {
        case .cancel:
            str = ""
            
        case .paste:
            str = pp.contents
        }
        
        Ghostty.AppState.completeClipboardRequest(pp.surface, data: str, state: pp.state, confirmed: true)
    }
    
    //MARK: - Notifications
    
    @objc private func onGotoTab(notification: SwiftUI.Notification) {
        guard let target = notification.object as? Ghostty.SurfaceView else { return }
        guard target == self.focusedSurface else { return }
        guard let window = self.window else { return }
        
        // Get the tab index from the notification
        guard let tabIndexAny = notification.userInfo?[Ghostty.Notification.GotoTabKey] else { return }
        guard let tabIndex = tabIndexAny as? Int32 else { return }
        
        guard let windowController = window.windowController else { return }
        guard let tabGroup = windowController.window?.tabGroup else { return }
        let tabbedWindows = tabGroup.windows
        
        // This will be the index we want to actual go to
        let finalIndex: Int
        
        // An index that is invalid is used to signal some special values.
        if (tabIndex <= 0) {
            guard let selectedWindow = tabGroup.selectedWindow else { return }
            guard let selectedIndex = tabbedWindows.firstIndex(where: { $0 == selectedWindow }) else { return }
            
            if (tabIndex == GHOSTTY_TAB_PREVIOUS.rawValue) {
                finalIndex = selectedIndex - 1
            } else if (tabIndex == GHOSTTY_TAB_NEXT.rawValue) {
                finalIndex = selectedIndex + 1
            } else {
                return
            }
        } else {
            // Tabs are 0-indexed here, so we subtract one from the key the user hit.
            finalIndex = Int(tabIndex - 1)
        }
        
        guard finalIndex >= 0 && finalIndex < tabbedWindows.count else { return }
        let targetWindow = tabbedWindows[finalIndex]
        targetWindow.makeKeyAndOrderFront(nil)
    }

    
    @objc private func onToggleFullscreen(notification: SwiftUI.Notification) {
        guard let target = notification.object as? Ghostty.SurfaceView else { return }
        guard target == self.focusedSurface else { return }
        
        // We need a window to fullscreen
        guard let window = self.window else { return }
        
        // Check whether we use non-native fullscreen
        guard let useNonNativeFullscreenAny = notification.userInfo?[Ghostty.Notification.NonNativeFullscreenKey] else { return }
        guard let useNonNativeFullscreen = useNonNativeFullscreenAny as? ghostty_non_native_fullscreen_e else { return }
        self.fullscreenHandler.toggleFullscreen(window: window, nonNativeFullscreen: useNonNativeFullscreen)
        
        // For some reason focus always gets lost when we toggle fullscreen, so we set it back.
        if let focusedSurface {
            Ghostty.moveFocus(to: focusedSurface)
        }
    }
    
    @objc private func onConfirmUnsafePaste(notification: SwiftUI.Notification) {
        guard let target = notification.object as? Ghostty.SurfaceView else { return }
        guard target == self.focusedSurface else { return }
        guard let surface = target.surface else { return }
        
        // We need a window
        guard let window = self.window else { return }
        
        // Check whether we use non-native fullscreen
        guard let str = notification.userInfo?[Ghostty.Notification.UnsafePasteStrKey] as? String else { return }
        guard let state = notification.userInfo?[Ghostty.Notification.UnsafePasteStateKey] as? UnsafeMutableRawPointer? else { return }
        
        // If we already have a paste protection view up, we ignore this request.
        // This shouldn't be possible...
        guard self.pasteProtection == nil else {
            Ghostty.AppState.completeClipboardRequest(surface, data: "", state: state, confirmed: true)
            return
        }
        
        // Show our paste confirmation
        self.pasteProtection = PasteProtectionController(
            surface: surface,
            contents: str,
            state: state,
            delegate: self
        )
        window.beginSheet(self.pasteProtection!.window!)
    }
}