//
//  PreviewViewControllerProvider.swift
//  Tusker
//
//  Created by Shadowfacts on 10/10/18.
//  Copyright © 2018 Shadowfacts. All rights reserved.
//

import UIKit
import SafariServices
import Pachyderm

protocol MenuPreviewProvider: AnyObject {
    
    typealias PreviewProviders = (content: UIContextMenuContentPreviewProvider, actions: () -> [UIMenuElement])
    
    var navigationDelegate: TuskerNavigationDelegate? { get }
    
    func getPreviewProviders(for location: CGPoint, sourceViewController: UIViewController) -> PreviewProviders?
    
}

protocol CustomPreviewPresenting {
    func presentFromPreview(presenter: UIViewController)
}

extension MenuPreviewProvider {
    
    private var mastodonController: MastodonController? { navigationDelegate?.apiController }
    
    // Default no-op implementation
    func getPreviewProviders(for location: CGPoint, sourceViewController: UIViewController) -> PreviewProviders? {
        return nil
    }
    
    func actionsForProfile(accountID: String, sourceView: UIView?) -> [UIMenuElement] {
        guard let mastodonController = mastodonController,
            let account = mastodonController.persistentContainer.account(for: accountID) else { return [] }
        
        guard let loggedInAccountID = mastodonController.accountInfo?.id else {
            // user is logged out
            return [
                openInSafariAction(url: account.url),
                createAction(identifier: "share", title: "Share", systemImageName: "square.and.arrow.up", handler: { [weak self, weak sourceView] (_) in
                    guard let self = self else { return }
                    self.navigationDelegate?.showMoreOptions(forAccount: accountID, sourceView: sourceView)
                })
            ]
        }
        
        var actionsSection: [UIMenuElement] = [
            createAction(identifier: "sendmessage", title: "Send Message", systemImageName: "envelope", handler: { [weak self] (_) in
                guard let self = self else { return }
                self.navigationDelegate?.compose(mentioningAcct: account.acct)
            }),
        ]
        
        if accountID != mastodonController.account.id {
            actionsSection.append(UIDeferredMenuElement({ (elementHandler) in
                guard let mastodonController = self.mastodonController else {
                    elementHandler([])
                    return
                }
                let request = Client.getRelationships(accounts: [account.id])
                // talk about callback hell :/
                mastodonController.run(request) { [weak self] (response) in
                    guard let self = self,
                          case let .success(results, _) = response,
                          let relationship = results.first else {
                              elementHandler([])
                              return
                          }
                    let following = relationship.following
                    DispatchQueue.main.async {
                        let action = self.createAction(identifier: "follow", title: following ? "Unfollow" : "Follow", systemImageName: following ? "person.badge.minus" : "person.badge.plus", handler: { (_) in
                            let request = (following ? Account.unfollow : Account.follow)(accountID)
                            mastodonController.run(request) { (response) in
                                switch response {
                                case .failure(_):
                                    fatalError()
                                case let .success(relationship, _):
                                    mastodonController.persistentContainer.addOrUpdate(relationship: relationship)
                                }
                            }
                        })
                        elementHandler([
                            action
                        ])
                    }
                }
            }))
        }
        
        var shareSection = [
            openInSafariAction(url: account.url),
            createAction(identifier: "share", title: "Share", systemImageName: "square.and.arrow.up", handler: { [weak self, weak sourceView] (_) in
                guard let self = self else { return }
                self.navigationDelegate?.showMoreOptions(forAccount: accountID, sourceView: sourceView)
            })
        ]
        
        addOpenInNewWindow(actions: &shareSection, activity: UserActivityManager.showProfileActivity(id: accountID, accountID: loggedInAccountID))
        
        return [
            UIMenu(title: "", image: nil, identifier: nil, options: [.displayInline], children: shareSection),
            UIMenu(title: "", image: nil, identifier: nil, options: [.displayInline], children: actionsSection),
        ]
    }
    
    func actionsForURL(_ url: URL, sourceView: UIView?) -> [UIAction] {
        return [
           openInSafariAction(url: url),
            createAction(identifier: "share", title: "Share", systemImageName: "square.and.arrow.up", handler: { [weak self, weak sourceView] (_) in
                guard let self = self else { return }
                self.navigationDelegate?.showMoreOptions(forURL: url, sourceView: sourceView)
            })
        ]
    }
    
    func actionsForHashtag(_ hashtag: Hashtag, sourceView: UIView?) -> [UIMenuElement] {
        let account = mastodonController!.accountInfo!
        let saved = SavedDataManager.shared.isSaved(hashtag: hashtag, for: account)
        
        let actionsSection = [
            createAction(identifier: "save", title: saved ? "Unsave Hashtag" : "Save Hashtag", systemImageName: "number", handler: { (_) in
                if saved {
                    SavedDataManager.shared.remove(hashtag: hashtag, for: account)
                } else {
                    SavedDataManager.shared.add(hashtag: hashtag, for: account)
                }
            })
        ]
        
        let shareSection = actionsForURL(hashtag.url, sourceView: sourceView)
        
        return [
            UIMenu(title: "", image: nil, identifier: nil, options: [.displayInline], children: shareSection),
            UIMenu(title: "", image: nil, identifier: nil, options: [.displayInline], children: actionsSection),
        ]
    }
    
    func actionsForStatus(_ status: StatusMO, sourceView: UIView?, includeReply: Bool = true) -> [UIMenuElement] {
        guard let mastodonController = mastodonController else { return [] }
        
        guard let accountID = mastodonController.accountInfo?.id else {
            // user is logged out
            return [
                openInSafariAction(url: status.url!),
                createAction(identifier: "share", title: "Share", systemImageName: "square.and.arrow.up", handler: { [weak self, weak sourceView] (_) in
                    guard let self = self else { return }
                    self.navigationDelegate?.showMoreOptions(forStatus: status.id, sourceView: sourceView)
                })
            ]
        }
        
        let bookmarked = status.bookmarked ?? false
        let muted = status.muted
        
        var actionsSection = [
            createAction(identifier: "bookmark", title: bookmarked ? "Unbookmark" : "Bookmark", systemImageName: bookmarked ? "bookmark.fill" : "bookmark", handler: { [weak self] (_) in
                guard let self = self else { return }
                let request = (bookmarked ? Status.unbookmark : Status.bookmark)(status.id)
                self.mastodonController?.run(request) { (response) in
                    if case let .success(status, _) = response {
                        self.mastodonController?.persistentContainer.addOrUpdate(status: status, incrementReferenceCount: false)
                    }
                }
            }),
            createAction(identifier: "mute", title: muted ? "Unmute" : "Mute", systemImageName: muted ? "speaker" : "speaker.slash", handler: { [weak self] (_) in
                guard let self = self else { return }
                let request = (muted ? Status.unmuteConversation : Status.muteConversation)(status.id)
                self.mastodonController?.run(request) { (response) in
                    if case let .success(status, _) = response {
                        self.mastodonController?.persistentContainer.addOrUpdate(status: status, incrementReferenceCount: false)
                    }
                }
            })
        ]
        
        if includeReply {
            actionsSection.insert(createAction(identifier: "reply", title: "Reply", systemImageName: "arrowshape.turn.up.left", handler: { [weak self] (_) in
                guard let self = self else { return }
                self.navigationDelegate?.compose(inReplyToID: status.id)
            }), at: 0)
        }
        
        if mastodonController.account != nil && mastodonController.account.id == status.account.id {
            let pinned = status.pinned ?? false
            actionsSection.append(createAction(identifier: "pin", title: pinned ? "Unpin from Profile" : "Pin to Profile", systemImageName: pinned ? "pin.slash" : "pin", handler: { [weak self] (_) in
                guard let self = self else { return }
                let request = (pinned ? Status.unpin : Status.pin)(status.id)
                self.mastodonController?.run(request, completion: { [weak self] (response) in
                    guard let self = self else { return }
                    if case let .success(status, _) = response {
                        self.mastodonController?.persistentContainer.addOrUpdate(status: status, incrementReferenceCount: false)
                    }
                })
            }))
        }
        
        if status.poll != nil {
            actionsSection.insert(createAction(identifier: "refresh", title: "Refresh Poll", systemImageName: "arrow.clockwise", handler: { [weak self] (_) in
                guard let mastodonController = self?.mastodonController else { return }
                let request = Client.getStatus(id: status.id)
                mastodonController.run(request, completion: { (response) in
                    if case let .success(status, _) = response {
                        // todo: this shouldn't really use the viewContext, but for some reason saving the
                        // backgroundContext with the new version of the status isn't updating the viewContext
                        mastodonController.persistentContainer.addOrUpdate(status: status, incrementReferenceCount: false, context: mastodonController.persistentContainer.viewContext)
                    }
                })
            }), at: 0)
        }
        
        var shareSection = [
            openInSafariAction(url: status.url!),
            createAction(identifier: "share", title: "Share", systemImageName: "square.and.arrow.up", handler: { [weak self, weak sourceView] (_) in
                guard let self = self else { return }
                self.navigationDelegate?.showMoreOptions(forStatus: status.id, sourceView: sourceView)
            }),
        ]
        
        addOpenInNewWindow(actions: &shareSection, activity: UserActivityManager.showConversationActivity(mainStatusID: status.id, accountID: accountID))
        
        return [
            UIMenu(title: "", image: nil, identifier: nil, options: [.displayInline], children: shareSection),
            UIMenu(title: "", image: nil, identifier: nil, options: [.displayInline], children: actionsSection),
        ]
    }

    private func createAction(identifier: String, title: String, systemImageName: String?, handler: @escaping UIActionHandler) -> UIAction {
        let image: UIImage?
        if let name = systemImageName {
            image = UIImage(systemName: name)
        } else {
            image = nil
        }
        return UIAction(title: title, image: image, identifier: UIAction.Identifier(identifier), discoverabilityTitle: nil, attributes: [], state: .off, handler: handler)
    }
    
    private func openInSafariAction(url: URL) -> UIAction {
        return createAction(identifier: "openinsafari", title: "Open in Safari", systemImageName: "safari", handler: { [weak self] (_) in
            self?.navigationDelegate?.selected(url: url, allowUniversalLinks: false)
        })
    }
    
    private func addOpenInNewWindow(actions: inout [UIAction], activity: @escaping @autoclosure () -> NSUserActivity) {
        #if SDK_IOS_15
        if #available(iOS 15.0, *) {
            let options = UIWindowScene.ActivationRequestOptions()
            options.preferredPresentationStyle = .automatic
            actions.append(UIWindowScene.ActivationAction { (_) in
                return .init(userActivity: activity(), options: options, preview: nil)
            })
        } else if UIDevice.current.userInterfaceIdiom == .pad || UIDevice.current.userInterfaceIdiom == .mac {
            actions.append(createAction(identifier: "new_window", title: "Open in New Window", systemImageName: "rectangle.badge.plus", handler: { (_) in
                UIApplication.shared.requestSceneSessionActivation(nil, userActivity: activity(), options: nil, errorHandler: nil)
            }))
        }
        #else
        if UIDevice.current.userInterfaceIdiom == .pad || UIDevice.current.userInterfaceIdiom == .mac {
            actions.append(createAction(identifier: "new_window", title: "Open in New Window", systemImageName: "rectangle.badge.plus", handler: { (_) in
                UIApplication.shared.requestSceneSessionActivation(nil, userActivity: activity(), options: nil, errorHandler: nil)
            }))
        }
        #endif
    }
    
}

extension LargeImageViewController: CustomPreviewPresenting {
    func presentFromPreview(presenter: UIViewController) {
        presenter.present(self, animated: true)
    }
}

extension GalleryViewController: CustomPreviewPresenting {
    func presentFromPreview(presenter: UIViewController) {
        presenter.present(self, animated: true)
    }
}

extension SFSafariViewController: CustomPreviewPresenting {
    func presentFromPreview(presenter: UIViewController) {
        presenter.present(self, animated: true)
    }
}