//
//  DKImageExtensionGallery.swift
//  DKImagePickerController
//
//  Created by ZhangAo on 16/12/2017.
//  Copyright © 2017 ZhangAo. All rights reserved.
//

import Foundation
import DKPhotoGallery

open class DKImageExtensionGallery: DKImageBaseExtension, DKPhotoGalleryDelegate {
    
    open weak var gallery: DKPhotoGallery?
    open var group: DKAssetGroup!
    
    override class func extensionType() -> DKImageExtensionType {
        return .gallery
    }
        
    override open func perform(with extraInfo: [AnyHashable: Any]) {
        guard let groupDetailVC = self.context.groupDetailVC
            , let groupId = extraInfo["groupId"] as? String else { return }
        
        guard let group = context.imagePickerController.groupDataManager.fetchGroup(with: groupId) else {
            assertionFailure("Expect group")
            return
        }
        
        if let gallery = self.createGallery(with: extraInfo, group: group) {
            self.gallery = gallery
            self.group = group
            
            if context.imagePickerController.inline {
                UIApplication.shared.keyWindow!.rootViewController!.present(photoGallery: gallery)
            } else {
                groupDetailVC.present(photoGallery: gallery)
            }
        }
    }
    
    open func createGallery(with extraInfo: [AnyHashable: Any], group: DKAssetGroup) -> DKPhotoGallery? {
        guard let groupDetailVC = self.context.groupDetailVC else { return nil }
        
        let presentationIndex = extraInfo["presentationIndex"] as? Int
        let presentingFromImageView = extraInfo["presentingFromImageView"] as? UIImageView
        
        var items = [DKPhotoGalleryItem]()
        
        for i in 0..<group.totalCount {
            guard let phAsset = context.imagePickerController.groupDataManager.fetchPHAsset(group, index: i) else {
                assertionFailure("Expect phAsset")
                continue
            }
            
            let item = DKPhotoGalleryItem(asset: phAsset)
            
            if i == presentationIndex, let presentingFromImage = presentingFromImageView?.image {
                item.thumbnail = presentingFromImage
            }
            
            items.append(item)
        }
        
        let gallery = DKPhotoGallery()
        gallery.singleTapMode = .toggleControlView
        gallery.items = items
        gallery.galleryDelegate = self
        gallery.presentingFromImageView = presentingFromImageView
        gallery.presentationIndex = presentationIndex ?? 0
        gallery.finishedBlock = { dismissIndex, dismissItem in
            let cellIndex = groupDetailVC.adjustAssetIndex(dismissIndex)
            let cellIndexPath = IndexPath(row: cellIndex, section: 0)
            groupDetailVC.scroll(to: cellIndexPath)
            
            return groupDetailVC.thumbnailImageView(for: cellIndexPath)
        }
        
        return gallery
    }
    
    // MARK: - DKPhotoGalleryDelegate
    
    open lazy var backItem = UIBarButtonItem(image: DKImagePickerControllerResource.photoGalleryBackArrowImage(),
                                           style: .plain,
                                           target: self,
                                           action: #selector(dismissGallery))
    
    open func photoGallery(_ gallery: DKPhotoGallery, didShow index: Int) {
        if let viewController = gallery.topViewController {
            if viewController.navigationItem.rightBarButtonItem == nil {
                let button = UIButton(type: .custom)
                button.titleLabel?.font = UIFont(name: "Helvetica Neue", size: 13)
                button.addTarget(self, action: #selector(DKImageExtensionGallery.selectAssetFromGallery(button:)), for: .touchUpInside)
                button.setTitle("", for: .normal)
                
                button.setBackgroundImage(DKImagePickerControllerResource.photoGalleryCheckedImage(), for: .selected)
                button.setBackgroundImage(DKImagePickerControllerResource.photoGalleryUncheckedImage(), for: .normal)
                
                button.bounds = CGRect(x: 0, y: 0,
                                       width: DKImagePickerControllerResource.photoGalleryCheckedImage().size.width,
                                       height: DKImagePickerControllerResource.photoGalleryCheckedImage().size.height)
                
                let item = UIBarButtonItem(customView: button)
                viewController.navigationItem.rightBarButtonItem = item
            }
            
            if viewController.navigationItem.leftBarButtonItem != self.backItem {
                viewController.navigationItem.leftBarButtonItem = self.backItem
            }
            
            self.updateGalleryAssetSelection()
        }
    }
    
    @objc open func selectAssetFromGallery(button: UIButton) {
        if let gallery = self.gallery {
            let currentIndex = gallery.currentIndex()
            if let asset = self.context.imagePickerController.groupDataManager.fetchAsset(self.group,
                                                                                          index: currentIndex)
            {
                if button.isSelected {
                    self.context.imagePickerController.deselect(asset: asset)
                } else {
                    self.context.imagePickerController.select(asset: asset)
                }

                self.updateGalleryAssetSelection()
            }
        }
    }
    
    open func updateGalleryAssetSelection() {
        if let gallery = self.gallery, let button = gallery.topViewController?.navigationItem.rightBarButtonItem?.customView as? UIButton {
            let currentIndex = gallery.currentIndex()
            
            if let asset = self.context.imagePickerController.groupDataManager.fetchAsset(self.group,
                                                                                          index: currentIndex)
            {
                var labelWidth: CGFloat = 0.0
                if let selectedIndex = self.context.imagePickerController.index(of: asset) {
                    let title = "\(selectedIndex + 1)"
                    button.setTitle(title, for: .selected)
                    button.isSelected = true

                    labelWidth = button.titleLabel!.sizeThatFits(CGSize(width: 100, height: 50)).width + 10
                } else {
                    button.isSelected = false
                    button.sizeToFit()
                }

                button.bounds = CGRect(x: 0, y: 0,
                                       width: max(button.backgroundImage(for: .normal)!.size.width, labelWidth),
                                       height: button.bounds.height)
            }
        }
    }
    
    @objc open func dismissGallery() {
        self.gallery?.dismissGallery()
    }

}