//
//  MainWindowController.swift
//  Evergreen
//
//  Created by Brent Simmons on 8/1/15.
//  Copyright © 2015 Ranchero Software, LLC. All rights reserved.
//

import AppKit
import Data
import Account

private let kWindowFrameKey = "MainWindow"

class MainWindowController : NSWindowController, NSUserInterfaceValidations {

	var isOpen: Bool {
		return isWindowLoaded && window!.isVisible
	}

	var isDisplayingSheet: Bool {
		if let _ = window?.attachedSheet {
			return true
		}
		return false
	}

	// MARK: NSWindowController

	private let windowAutosaveName = NSWindow.FrameAutosaveName(rawValue: kWindowFrameKey)
	private var unreadCount: Int = 0 {
		didSet {
			if unreadCount != oldValue {
				updateWindowTitle()
			}
		}
	}

	static var didPositionWindowOnFirstRun = false

	override func windowDidLoad() {

		super.windowDidLoad()

		if !AppDefaults.shared.showTitleOnMainWindow {
			window?.titleVisibility = .hidden
		}

		window?.setFrameUsingName(windowAutosaveName, force: true)
		if AppDefaults.shared.isFirstRun && !MainWindowController.didPositionWindowOnFirstRun {

			if let window = window {
				let point = NSPoint(x: 128, y: 64)
				let size = NSSize(width: 1000, height: 700)
				let minSize = NSSize(width: 600, height: 600)
				window.setPointAndSizeAdjustingForScreen(point: point, size: size, minimumSize: minSize)
				MainWindowController.didPositionWindowOnFirstRun = true
			}
		}

		detailSplitViewItem?.minimumThickness = 384
		
		NotificationCenter.default.addObserver(self, selector: #selector(applicationWillTerminate(_:)), name: NSApplication.willTerminateNotification, object: nil)

		NotificationCenter.default.addObserver(self, selector: #selector(appNavigationKeyPressed(_:)), name: .AppNavigationKeyPressed, object: nil)

		NotificationCenter.default.addObserver(self, selector: #selector(refreshProgressDidChange(_:)), name: .AccountRefreshDidBegin, object: nil)
		NotificationCenter.default.addObserver(self, selector: #selector(refreshProgressDidChange(_:)), name: .AccountRefreshDidFinish, object: nil)
		NotificationCenter.default.addObserver(self, selector: #selector(refreshProgressDidChange(_:)), name: .AccountRefreshProgressDidChange, object: nil)

		NotificationCenter.default.addObserver(self, selector: #selector(unreadCountDidChange(_:)), name: .UnreadCountDidChange, object: nil)

		DispatchQueue.main.async {
			self.updateWindowTitle()
		}
	}

	func saveState() {

		// TODO: save width of split view and anything else that should be saved.

		
	}

	// MARK: Sidebar

	func selectedObjectsInSidebar() -> [AnyObject]? {

		return sidebarViewController?.selectedObjects
	}

	// MARK: Notifications

	@objc func applicationWillTerminate(_ note: Notification) {

		window?.saveFrame(usingName: windowAutosaveName)
	}

	@objc func appNavigationKeyPressed(_ note: Notification) {

		guard let navigationKey = note.userInfo?[UserInfoKey.navigationKeyPressed] as? Int else {
			return
		}
		guard let contentView = window?.contentView, let view = note.object as? NSView, view.isDescendant(of: contentView) else {
			return
		}

		if navigationKey == NSRightArrowFunctionKey {
			handleRightArrowFunctionKey(in: view)
		}
		if navigationKey == NSLeftArrowFunctionKey {
			handleLeftArrowFunctionKey(in: view)
		}
	}

	@objc func refreshProgressDidChange(_ note: Notification) {
		
		performSelectorCoalesced(#selector(MainWindowController.makeToolbarValidate(_:)), with: nil, delay: 0.1)
	}

	@objc func unreadCountDidChange(_ note: Notification) {

		if note.object is AccountManager {
			unreadCount = AccountManager.shared.unreadCount
		}
	}

	// MARK: Toolbar
	
	@objc func makeToolbarValidate(_ sender: Any?) {
		
		window?.toolbar?.validateVisibleItems()
	}

	// MARK: NSUserInterfaceValidations
	
	public func validateUserInterfaceItem(_ item: NSValidatedUserInterfaceItem) -> Bool {
		
		if item.action == #selector(openArticleInBrowser(_:)) {
			return currentLink != nil
		}
		
		if item.action == #selector(nextUnread(_:)) {
			return canGoToNextUnread()
		}
		
		if item.action == #selector(markAllAsRead(_:)) {
			return canMarkAllAsRead()
		}

		if item.action == #selector(markRead(_:)) {
			return canMarkRead()
		}

		if item.action == #selector(markOlderArticlesAsRead(_:)) {
			return canMarkOlderArticlesAsRead()
		}

		if item.action == #selector(toolbarShowShareMenu(_:)) {
			return canShowShareMenu()
		}

		if item.action == #selector(toggleSidebar(_:)) {

			guard let splitViewItem = sidebarSplitViewItem else {
				return false
			}

			let sidebarIsShowing = !splitViewItem.isCollapsed
			if let menuItem = item as? NSMenuItem {
				let title = sidebarIsShowing ? NSLocalizedString("Hide Sidebar", comment: "Menu item") : NSLocalizedString("Show Sidebar", comment: "Menu item")
				menuItem.title = title
			}

			return true
		}

		return true
	}

	// MARK: - Actions

	@IBAction func scrollOrGoToNextUnread(_ sender: Any?) {

		guard let detailViewController = detailViewController else {
			return
		}

		detailViewController.canScrollDown { (canScroll) in

			canScroll ? detailViewController.scrollPageDown(sender) : self.nextUnread(sender)
		}
	}


	@IBAction func showAddFolderWindow(_ sender: Any?) {

		appDelegate.showAddFolderSheetOnWindow(window!)
	}

	@IBAction func showAddFeedWindow(_ sender: Any?) {

		appDelegate.showAddFeedSheetOnWindow(window!, urlString: nil, name: nil)
	}

	@IBAction func openArticleInBrowser(_ sender: Any?) {
		
		if let link = currentLink {
			Browser.open(link)
		}		
	}

	@IBAction func openInBrowser(_ sender: Any?) {

		openArticleInBrowser(sender)
	}

	func makeTimelineViewFirstResponder() {

		guard let window = window, let timelineViewController = timelineViewController else {
			return
		}
		window.makeFirstResponderUnlessDescendantIsFirstResponder(timelineViewController.tableView)
	}

	@IBAction func nextUnread(_ sender: Any?) {
		
		guard let timelineViewController = timelineViewController, let sidebarViewController = sidebarViewController else {
			return
		}
		
		if timelineViewController.canGoToNextUnread() {
			goToNextUnreadInTimeline()
		}
		else if sidebarViewController.canGoToNextUnread() {
			sidebarViewController.goToNextUnread()
			if timelineViewController.canGoToNextUnread() {
				goToNextUnreadInTimeline()
			}
		}
	}

	func goToNextUnreadInTimeline() {

		guard let timelineViewController = timelineViewController else {
			return
		}

		if timelineViewController.canGoToNextUnread() {
			timelineViewController.goToNextUnread()
			makeTimelineViewFirstResponder()
		}
	}
	
	@IBAction func markAllAsRead(_ sender: Any?) {
		
		timelineViewController?.markAllAsRead()
	}

	@IBAction func markRead(_ sender: Any?) {

		timelineViewController?.markSelectedArticlesAsRead(sender)
	}

	@IBAction func markUnread(_ sender: Any?) {

		timelineViewController?.markSelectedArticlesAsUnread(sender)
	}

	@IBAction func markAllAsReadAndGoToNextUnread(_ sender: Any?) {

		markAllAsRead(sender)
		nextUnread(sender)
	}

	@IBAction func markUnreadAndGoToNextUnread(_ sender: Any?) {

		markUnread(sender)
		nextUnread(sender)
	}

	@IBAction func markReadAndGoToNextUnread(_ sender: Any?) {

		markUnread(sender)
		nextUnread(sender)
	}

	@IBAction func toggleSidebar(_ sender: Any?) {
		
		splitViewController!.toggleSidebar(sender)
	}

	@IBAction func markOlderArticlesAsRead(_ sender: Any?) {

		timelineViewController?.markOlderArticlesAsRead()
	}

	@IBAction func navigateToTimeline(_ sender: Any?) {

		timelineViewController?.focus()
	}

	@IBAction func navigateToSidebar(_ sender: Any?) {

		sidebarViewController?.focus()
	}

	@IBAction func goToPreviousSubscription(_ sender: Any?) {

		sidebarViewController?.outlineView.selectPreviousRow(sender)
	}

	@IBAction func goToNextSubscription(_ sender: Any?) {

		sidebarViewController?.outlineView.selectNextRow(sender)
	}

	@IBAction func gotoToday(_ sender: Any?) {

		sidebarViewController?.gotoToday(sender)
	}

	@IBAction func gotoAllUnread(_ sender: Any?) {

		sidebarViewController?.gotoAllUnread(sender)
	}

	@IBAction func gotoStarred(_ sender: Any?) {

		sidebarViewController?.gotoStarred(sender)
	}

	@IBAction func toolbarShowShareMenu(_ sender: Any?) {

		guard let selectedArticles = selectedArticles, !selectedArticles.isEmpty else {
			assertionFailure("Expected toolbarShowShareMenu to be called only when there are selected articles.")
			return
		}
		guard let shareToolbarItem = shareToolbarItem else {
			assertionFailure("Expected toolbarShowShareMenu to be called only by the Share item in the toolbar.")
			return
		}
		guard let view = shareToolbarItem.view else {
			// TODO: handle menu form representation
			return
		}

		let items = selectedArticles.map { ArticlePasteboardWriter(article: $0) }
		let sharingServicePicker = NSSharingServicePicker(items: items)
		sharingServicePicker.delegate = self
		sharingServicePicker.show(relativeTo: view.bounds, of: view, preferredEdge: .minY)
	}

	private func canShowShareMenu() -> Bool {

		guard let selectedArticles = selectedArticles else {
			return false
		}
		return !selectedArticles.isEmpty
	}
}

// MARK: - NSSharingServicePickerDelegate

extension MainWindowController: NSSharingServicePickerDelegate {

	func sharingServicePicker(_ sharingServicePicker: NSSharingServicePicker, sharingServicesForItems items: [Any], proposedSharingServices proposedServices: [NSSharingService]) -> [NSSharingService] {

		let sendToServices = appDelegate.sendToCommands.compactMap { (sendToCommand) -> NSSharingService? in

			guard let object = items.first else {
				return nil
			}
			guard sendToCommand.canSendObject(object, selectedText: nil) else {
				return nil
			}

			let image = sendToCommand.image ?? appDelegate.genericFeedImage ?? NSImage()
			return NSSharingService(title: sendToCommand.title, image: image, alternateImage: nil) {
				sendToCommand.sendObject(object, selectedText: nil)
			}
		}
		return proposedServices + sendToServices
	}
}

// MARK: - NSToolbarDelegate

extension NSToolbarItem.Identifier {
	static let Share = NSToolbarItem.Identifier("share")
}

extension MainWindowController: NSToolbarDelegate {

	func toolbarWillAddItem(_ notification: Notification) {

		// The share button should send its action on mouse down, not mouse up.

		guard let item = notification.userInfo?["item"] as? NSToolbarItem else {
			return
		}
		guard item.itemIdentifier == .Share, let button = item.view as? NSButton else {
			return
		}

		button.sendAction(on: .leftMouseDown)
	}
}


// MARK: - Scripting Access

/*
    the ScriptingMainWindowController protocol exposes a narrow set of accessors with
    internal visibility which are very similar to some private vars.
    
    These would be unnecessary if the similar accessors were marked internal rather than private,
    but for now, we'll keep the stratification of visibility
*/

extension MainWindowController : ScriptingMainWindowController {

    internal var scriptingCurrentArticle: Article? {
        return self.oneSelectedArticle
    }

    internal var scriptingSelectedArticles: [Article] {
        return self.selectedArticles ?? []
    }
}

// MARK: - Private

private extension MainWindowController {
	
	var splitViewController: NSSplitViewController? {
		guard let viewController = contentViewController else {
			return nil
		}
		return viewController.childViewControllers.first as? NSSplitViewController
	}

	var sidebarViewController: SidebarViewController? {
		return splitViewController?.splitViewItems[0].viewController as? SidebarViewController
	}
	
	var timelineViewController: TimelineViewController? {
		return splitViewController?.splitViewItems[1].viewController as? TimelineViewController
	}

	var sidebarSplitViewItem: NSSplitViewItem? {
		return splitViewController?.splitViewItems[0]
	}

	var detailSplitViewItem: NSSplitViewItem? {
		return splitViewController?.splitViewItems[2]
	}
	
	var detailViewController: DetailViewController? {
		return splitViewController?.splitViewItems[2].viewController as? DetailViewController
	}

	var selectedArticles: [Article]? {
		return timelineViewController?.selectedArticles
	}

	var oneSelectedArticle: Article? {
		if let articles = selectedArticles {
			return articles.count == 1 ? articles[0] : nil
		}
		return nil
	}

	var currentLink: String? {
		return oneSelectedArticle?.preferredLink
	}

	func canGoToNextUnread() -> Bool {
		
		guard let timelineViewController = timelineViewController, let sidebarViewController = sidebarViewController else {
			return false
		}

		return timelineViewController.canGoToNextUnread() || sidebarViewController.canGoToNextUnread()
	}
	
	func canMarkAllAsRead() -> Bool {
		
		return timelineViewController?.canMarkAllAsRead() ?? false
	}

	func canMarkRead() -> Bool {

		return timelineViewController?.canMarkSelectedArticlesAsRead() ?? false
	}

	func canMarkOlderArticlesAsRead() -> Bool {

		return timelineViewController?.canMarkOlderArticlesAsRead() ?? false
	}

	func updateWindowTitle() {

		if unreadCount < 1 {
			window?.title = appDelegate.appName!
		}
		else if unreadCount > 0 {
			window?.title = "\(appDelegate.appName!) (\(unreadCount))"
		}
	}

	// MARK: - Toolbar

	private var shareToolbarItem: NSToolbarItem? {
		return existingToolbarItem(identifier: .Share)
	}

	func existingToolbarItem(identifier: NSToolbarItem.Identifier) -> NSToolbarItem? {

		guard let toolbarItems = window?.toolbar?.items else {
			return nil
		}
		for toolbarItem in toolbarItems {
			if toolbarItem.itemIdentifier == identifier {
				return toolbarItem
			}
		}
		return nil
	}

	// MARK: - Navigation

	func handleRightArrowFunctionKey(in view: NSView) {

		guard let outlineView = sidebarViewController?.outlineView, view === outlineView, let timelineViewController = timelineViewController else {
			return
		}
		timelineViewController.focus()
	}

	func handleLeftArrowFunctionKey(in view: NSView) {

		guard let timelineView = timelineViewController?.tableView, view === timelineView, let sidebarViewController = sidebarViewController else {
			return
		}
		sidebarViewController.focus()
	}
}