//
//  SidebarViewController+ContextualMenus.swift
//  NetNewsWire
//
//  Created by Brent Simmons on 1/28/18.
//  Copyright © 2018 Ranchero Software. All rights reserved.
//

import AppKit
import Articles
import Account
import RSCore

extension SidebarViewController {

	func menu(for objects: [Any]?) -> NSMenu? {

		guard let objects = objects, objects.count > 0 else {
			return menuForNoSelection()
		}

		if objects.count > 1 {
			return menuForMultipleObjects(objects)
		}

		let object = objects.first!

		switch object {
		case is Feed:
			return menuForFeed(object as! Feed)
		case is Folder:
			return menuForFolder(object as! Folder)
		case is PseudoFeed:
			return menuForSmartFeed(object as! PseudoFeed)
		default:
			return nil
		}
	}
}

// MARK: Contextual Menu Actions

extension SidebarViewController {

	@objc func openHomePageFromContextualMenu(_ sender: Any?) {

		guard let menuItem = sender as? NSMenuItem, let urlString = menuItem.representedObject as? String else {
			return
		}
		Browser.open(urlString, inBackground: false)
	}

	@objc func copyURLFromContextualMenu(_ sender: Any?) {

		guard let menuItem = sender as? NSMenuItem, let urlString = menuItem.representedObject as? String else {
			return
		}
		URLPasteboardWriter.write(urlString: urlString, to: NSPasteboard.general)
	}

	@objc func markObjectsReadFromContextualMenu(_ sender: Any?) {

		guard let menuItem = sender as? NSMenuItem, let objects = menuItem.representedObject as? [Any] else {
			return
		}
		
		let articles = unreadArticles(for: objects)
		guard let undoManager = undoManager, let markReadCommand = MarkStatusCommand(initialArticles: Array(articles), markingRead: true, undoManager: undoManager) else {
			return
		}
		runCommand(markReadCommand)
	}

	@objc func deleteFromContextualMenu(_ sender: Any?) {

		guard let menuItem = sender as? NSMenuItem, let objects = menuItem.representedObject as? [AnyObject] else {
			return
		}
		
		let nodes = objects.compactMap { treeController.nodeInTreeRepresentingObject($0) }
		deleteNodes(nodes)
	}

	@objc func renameFromContextualMenu(_ sender: Any?) {

		guard let window = view.window, let menuItem = sender as? NSMenuItem, let object = menuItem.representedObject as? DisplayNameProvider, object is Feed || object is Folder else {
			return
		}

		renameWindowController = RenameWindowController(originalTitle: object.nameForDisplay, representedObject: object, delegate: self)
		guard let renameSheet = renameWindowController?.window else {
			return
		}
		window.beginSheet(renameSheet)
	}
}

extension SidebarViewController: RenameWindowControllerDelegate {

	func renameWindowController(_ windowController: RenameWindowController, didRenameObject object: Any, withNewName name: String) {

		if let feed = object as? Feed {
			feed.rename(to: name) { result in
				switch result {
				case .success:
					break
				case .failure(let error):
					NSApplication.shared.presentError(error)
				}
			}
		} else if let folder = object as? Folder {
			folder.rename(to: name) { result in
				switch result {
				case .success:
					break
				case .failure(let error):
					NSApplication.shared.presentError(error)
				}
			}
		}
	}
}

// MARK: Build Contextual Menus

private extension SidebarViewController {

	func menuForNoSelection() -> NSMenu {

		let menu = NSMenu(title: "")

		menu.addItem(withTitle: NSLocalizedString("New Feed", comment: "Command"), action: #selector(MainWindowController.showAddFeedWindow(_:)), keyEquivalent: "")
		menu.addItem(withTitle: NSLocalizedString("New Folder", comment: "Command"), action: #selector(MainWindowController.showAddFolderWindow(_:)), keyEquivalent: "")

		return menu
	}

	func menuForFeed(_ feed: Feed) -> NSMenu? {

		let menu = NSMenu(title: "")

		if feed.unreadCount > 0 {
			menu.addItem(markAllReadMenuItem([feed]))
			menu.addItem(NSMenuItem.separator())
		}

		if let homePageURL = feed.homePageURL, let _ = URL(string: homePageURL) {
			let item = menuItem(NSLocalizedString("Open Home Page", comment: "Command"), #selector(openHomePageFromContextualMenu(_:)), homePageURL)
			menu.addItem(item)
			menu.addItem(NSMenuItem.separator())
		}

		let copyFeedURLItem = menuItem(NSLocalizedString("Copy Feed URL", comment: "Command"), #selector(copyURLFromContextualMenu(_:)), feed.url)
		menu.addItem(copyFeedURLItem)

		if let homePageURL = feed.homePageURL {
			let item = menuItem(NSLocalizedString("Copy Home Page URL", comment: "Command"), #selector(copyURLFromContextualMenu(_:)), homePageURL)
			menu.addItem(item)
		}
		menu.addItem(NSMenuItem.separator())

		menu.addItem(renameMenuItem(feed))
		menu.addItem(deleteMenuItem([feed]))

		return menu
	}

	func menuForFolder(_ folder: Folder) -> NSMenu? {

		let menu = NSMenu(title: "")

		if folder.unreadCount > 0 {
			menu.addItem(markAllReadMenuItem([folder]))
			menu.addItem(NSMenuItem.separator())
		}

		menu.addItem(renameMenuItem(folder))
		menu.addItem(deleteMenuItem([folder]))

		return menu.numberOfItems > 0 ? menu : nil
	}

	func menuForSmartFeed(_ smartFeed: PseudoFeed) -> NSMenu? {

		let menu = NSMenu(title: "")

		if smartFeed.unreadCount > 0 {
			menu.addItem(markAllReadMenuItem([smartFeed]))
		}
		return menu.numberOfItems > 0 ? menu : nil
	}

	func menuForMultipleObjects(_ objects: [Any]) -> NSMenu? {

		let menu = NSMenu(title: "")

		if anyObjectInArrayHasNonZeroUnreadCount(objects) {
			menu.addItem(markAllReadMenuItem(objects))
		}

		if allObjectsAreFeedsAndOrFolders(objects) {
			menu.addSeparatorIfNeeded()
			menu.addItem(deleteMenuItem(objects))
		}

		return menu.numberOfItems > 0 ? menu : nil
	}

	func markAllReadMenuItem(_ objects: [Any]) -> NSMenuItem {

		return menuItem(NSLocalizedString("Mark All as Read", comment: "Command"), #selector(markObjectsReadFromContextualMenu(_:)), objects)
	}

	func deleteMenuItem(_ objects: [Any]) -> NSMenuItem {

		return menuItem(NSLocalizedString("Delete", comment: "Command"), #selector(deleteFromContextualMenu(_:)), objects)
	}

	func renameMenuItem(_ object: Any) -> NSMenuItem {

		return menuItem(NSLocalizedString("Rename", comment: "Command"), #selector(renameFromContextualMenu(_:)), object)
	}

	func anyObjectInArrayHasNonZeroUnreadCount(_ objects: [Any]) -> Bool {

		for object in objects {
			if let unreadCountProvider = object as? UnreadCountProvider {
				if unreadCountProvider.unreadCount > 0 {
					return true
				}
			}
		}
		return false
	}

	func allObjectsAreFeedsAndOrFolders(_ objects: [Any]) -> Bool {

		for object in objects {
			if !objectIsFeedOrFolder(object) {
				return false
			}
		}
		return true
	}

	func objectIsFeedOrFolder(_ object: Any) -> Bool {

		return object is Feed || object is Folder
	}

	func menuItem(_ title: String, _ action: Selector, _ representedObject: Any) -> NSMenuItem {

		let item = NSMenuItem(title: title, action: action, keyEquivalent: "")
		item.representedObject = representedObject
		item.target = self
		return item
	}

	func unreadArticles(for objects: [Any]) -> Set<Article> {

		var articles = Set<Article>()
		for object in objects {
			if let articleFetcher = object as? ArticleFetcher {
				articles.formUnion(articleFetcher.fetchUnreadArticles())
			}
		}
		return articles
	}
}