change repo branch (#2202)

* change repo branch

additions:
- A change-repository-branch workflow thats very similar to the workflow in Milestones
- GraphQL query to fetch a repo's branches

modifications:
- a mutable "branch" string in RepositoryOverviewController and RepositoryCodeDirectoryViewController
- updated the V3RepositoryReadME fetch to include a branch parameter
- a protocol RepositoryBranchUpdatable to flag and update the appropriate ViewControllers when a user switches branches
- ContextMenu and UIAlertAction setup
- Removed some outdated code to get a repo's branch name from fetch(page:) in RepositoryOverviewViewController
- Added a line feed.adapter.reloadData() in fetch(page:) because app was crashing intermittently after a user switched branches without that line - was always an IGListKit duplicate identifier error on StyledTextRenderers  -  to reproduce, remove the feed.adapter.reloadData(), go to https://github.com/TheAlgorithms/Python, try to switch branches and the app will crash. I'm working raising an issue for it.

* requested changes

- changed public var to private(set) for var branch: String
- removed wasteful feed.adapter.reloadData() call
- re-formated params in switchBranchAction()

* style nit

Author: BrianLitwin

Classes/Repository/RepositoryBranches/GitHubClient+RepositoryBranches.swift

@@ -0,0 +1,38 @@
+//
+//  GitHubClient+RepoBranches.swift
+//  Freetime
+//
+//  Created by B_Litwin on 9/25/18.
+//  Copyright © 2018 Ryan Nystrom. All rights reserved.
+//
+
+import GitHubAPI
+
+extension GithubClient {
+    
+    func fetchRepositoryBranches(owner: String,
+                                 repo: String,
+                                 completion: @escaping (Result<([String])>)->Void
+    ) {
+        let query = FetchRepositoryBranchesQuery(owner: owner, name: repo)
+        client.query(query, result: { $0.repository }) { result in
+        
+        switch result {
+        case .failure(let error):
+                completion(.error(error))
+    
+        case .success(let repository):
+            var branches: [String] = []
+            repository.refs.map { edges in
+                edges.edges.map { edge in
+                    branches += edge.compactMap {
+                        $0?.node?.name
+                    }
+                }
+            }
+
+            completion(.success(branches))
+            }
+        }
+    }
+}

Classes/Repository/RepositoryBranches/RepositoryBranchUpdatable.swift

@@ -0,0 +1,13 @@
+//
+//  RepositoryBranchUpdatable.swift
+//  Freetime
+//
+//  Created by B_Litwin on 9/28/18.
+//  Copyright © 2018 Ryan Nystrom. All rights reserved.
+//
+
+import UIKit
+
+protocol RepositoryBranchUpdatable: class {
+    func updateBranch(to newBranch: String)
+}

Classes/Repository/RepositoryBranches/RepositoryBranchesCell.swift

@@ -0,0 +1,58 @@
+//
+//  RepoBranchesCell.swift
+//  Freetime
+//
+//  Created by B_Litwin on 9/25/18.
+//  Copyright © 2018 Ryan Nystrom. All rights reserved.
+//
+
+import UIKit
+
+final class RepositoryBranchCell: SelectableCell {
+    public let label = UILabel()
+    private let checkedImageView = UIImageView(image: UIImage(named: "check-small")?.withRenderingMode(.alwaysTemplate))
+    
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+        
+        backgroundColor = nil
+        contentView.backgroundColor = nil
+        
+        contentView.addSubview(checkedImageView)
+        checkedImageView.tintColor = Styles.Colors.Blue.medium.color
+        checkedImageView.snp.makeConstraints { make in
+            make.right.equalTo(-Styles.Sizes.gutter)
+            make.centerY.equalTo(contentView.snp.centerY)
+        }
+        
+        contentView.addSubview(label)
+        label.font = Styles.Text.bodyBold.preferredFont
+        label.textColor = .white
+        label.snp.makeConstraints { make in
+            make.left.equalTo(Styles.Sizes.gutter)
+            make.right.lessThanOrEqualTo(checkedImageView.snp.left)
+            make.centerY.equalTo(contentView.snp.centerY)
+        }
+        
+        let border = contentView.addBorder(.bottom,
+                                           left: Styles.Sizes.gutter,
+                                           right: -Styles.Sizes.gutter
+        )
+        border.backgroundColor = Styles.Colors.Gray.medium.color
+    }
+    
+    func setSelected(_ selected: Bool) {
+        checkedImageView.isHidden = !selected
+    }
+    
+    required init?(coder aDecoder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+    
+    // MARK: Accessibility
+    
+    override var accessibilityLabel: String? {
+        get { return AccessibilityHelper.generatedLabel(forCell: self) }
+        set { }
+    }
+}

Classes/Repository/RepositoryBranches/RepositoryBranchesSectionController.swift

@@ -0,0 +1,43 @@
+//
+//  RepoBranchesSectionController.swift
+//  Freetime
+//
+//  Created by B_Litwin on 9/25/18.
+//  Copyright © 2018 Ryan Nystrom. All rights reserved.
+//
+
+import UIKit
+import IGListKit
+
+protocol RepositoryBranchSectionControllerDelegate: class {
+    func didSelect(value: RepositoryBranchViewModel)
+}
+
+final class RepositoryBranchSectionController: ListSwiftSectionController<RepositoryBranchViewModel> {
+    
+    public weak var delegate: RepositoryBranchSectionControllerDelegate?
+    
+    override func createBinders(from value: RepositoryBranchViewModel) -> [ListBinder] {
+        return [
+            binder(
+                value,
+                cellType: ListCellType.class(RepositoryBranchCell.self),
+                size: {
+                    return CGSize(
+                        width: $0.collection.containerSize.width,
+                        height: Styles.Sizes.tableCellHeightLarge
+                    )
+            },
+                configure: {
+                    $0.label.text = $1.value.branch
+                    $0.setSelected($1.value.selected)
+            },
+                didSelect: { [weak self] context in
+                    guard let strongSelf = self else { return }
+                    context.deselect(animated: true)
+                    strongSelf.delegate?.didSelect(value: context.value)
+            })
+        ]
+    }
+}
+

Classes/Repository/RepositoryBranches/RepositoryBranchesViewController.swift

@@ -0,0 +1,85 @@
+//
+//  RepoBranchesViewController.swift
+//  Freetime
+//
+//  Created by B_Litwin on 9/25/18.
+//  Copyright © 2018 Ryan Nystrom. All rights reserved.
+//
+
+import UIKit
+import Squawk
+import IGListKit
+
+final class RepositoryBranchesViewController: BaseListViewController2<String>,
+BaseListViewController2DataSource,
+RepositoryBranchSectionControllerDelegate
+{
+
+    private let owner: String
+    private let repo: String
+    private let client: GithubClient
+    private var branches: [String] = []
+    public var branch: String
+    
+    init(branch: String,
+         owner: String,
+         repo: String,
+         client: GithubClient
+        )
+    {
+        self.branch = branch
+        self.owner = owner
+        self.repo = repo
+        self.client = client
+        super.init(emptyErrorMessage: "Couldn't load repository branches")
+        
+        title = NSLocalizedString("Branches", comment: "")
+        preferredContentSize = Styles.Sizes.contextMenuSize
+        feed.collectionView.backgroundColor = Styles.Colors.menuBackgroundColor.color
+        dataSource = self
+    }
+    
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        navigationController?.navigationBar.titleTextAttributes = [.foregroundColor: UIColor.white]
+        addMenuDoneButton()
+    }
+    
+    required init?(coder aDecoder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+    
+    override func fetch(page: String?) {
+        client.fetchRepositoryBranches(owner: owner,
+                                 repo: repo
+            )
+        {  [weak self] result in
+            switch result {
+            case .success(let branches):
+                self?.branches = branches
+            case .error:
+                Squawk.showError(message: "Couldn't fetch repository branches")
+            }
+            self?.update(animated: true)
+        }
+    }
+    
+    func models(adapter: ListSwiftAdapter) -> [ListSwiftPair] {
+        guard feed.status == .idle else { return [] }
+        return branches.map {
+            let value = RepositoryBranchViewModel(branch: $0,
+                                                  selected: $0 == self.branch)
+            
+            return ListSwiftPair(value) { [weak self] in
+                let controller = RepositoryBranchSectionController()
+                controller.delegate = self
+                return controller
+            }
+        }
+    }
+    
+    func didSelect(value: RepositoryBranchViewModel) {
+        self.branch = value.branch
+        fetch(page: nil)
+    }
+}

Classes/Repository/RepositoryBranches/RepositoryBranchesViewModel.swift

@@ -0,0 +1,25 @@
+//
+//  RepoBranchesViewModel.swift
+//  Freetime
+//
+//  Created by B_Litwin on 9/25/18.
+//  Copyright © 2018 Ryan Nystrom. All rights reserved.
+//
+
+import IGListKit
+
+struct RepositoryBranchViewModel: ListSwiftDiffable {
+    let branch: String
+    let selected: Bool
+    
+    var identifier: String {
+        return branch
+    }
+    
+    func isEqual(to value: ListSwiftDiffable) -> Bool {
+        guard let value = value as? RepositoryBranchViewModel else { return false }
+        return value.branch == branch
+            && value.selected == selected
+    }
+}
+

Classes/Repository/RepositoryCodeDirectoryViewController.swift

@@ -11,10 +11,12 @@ import IGListKit
 
 final class RepositoryCodeDirectoryViewController: BaseListViewController<NSNumber>,
 BaseListViewControllerDataSource,
-ListSingleSectionControllerDelegate {
+ListSingleSectionControllerDelegate,
+RepositoryBranchUpdatable
+{
 
     private let client: GithubClient
-    private let branch: String
+    private var branch: String
     private let path: FilePath
     private let repo: RepositoryDetails
     private var files = [RepositoryFile]()
@@ -177,5 +179,13 @@ extension RepositoryCodeDirectoryViewController {
 
         navigationController?.pushViewController(controller, animated: trueUnlessReduceMotionEnabled)
     }
+    
+    //Mark: RepositoryBranchUpdatable
+    
+    func updateBranch(to newBranch: String) {
+        guard self.branch != newBranch else { return }
+        self.branch = newBranch
+        fetch(page: nil)
+    }
 
 }

Classes/Repository/RepositoryOverviewViewController.swift

@@ -20,11 +20,14 @@ class HackScrollIndicatorInsetsCollectionView: UICollectionView {
 }
 
 class RepositoryOverviewViewController: BaseListViewController<NSString>,
-BaseListViewControllerDataSource {
+BaseListViewControllerDataSource,
+RepositoryBranchUpdatable
+{
 
     private let repo: RepositoryDetails
     private let client: RepositoryClient
     private var readme: RepositoryReadmeModel?
+    private var branch: String
 
 //    lazy var _feed: Feed = { Feed(
 //        viewController: self,
@@ -41,6 +44,7 @@ BaseListViewControllerDataSource {
     init(client: GithubClient, repo: RepositoryDetails) {
         self.repo = repo
         self.client = RepositoryClient(githubClient: client, owner: repo.owner, name: repo.name)
+        self.branch = repo.defaultBranch
         super.init(
             emptyErrorMessage: NSLocalizedString("Cannot load README.", comment: "")
         )
@@ -71,20 +75,13 @@ BaseListViewControllerDataSource {
 //        let contentInset = feed.collectionView.contentInset
         let width = view.bounds.width - Styles.Sizes.gutter * 2
         let contentSizeCategory = UIContentSizeCategory.preferred
+        let branch = self.branch
 
         client.githubClient.client
-            .send(V3RepositoryReadmeRequest(owner: repo.owner, repo: repo.name)) { [weak self] result in
+            .send(V3RepositoryReadmeRequest(owner: repo.owner, repo: repo.name, branch: branch)) { [weak self] result in
             switch result {
             case .success(let response):
                 DispatchQueue.global().async {
-                    let branch: String
-                    if let items = URLComponents(url: response.data.url, resolvingAgainstBaseURL: false)?.queryItems,
-                        let index = items.index(where: { $0.name == "ref" }),
-                        let value = items[index].value {
-                        branch = value
-                    } else {
-                        branch = "master"
-                    }
 
                     let models = MarkdownModels(
                         response.data.content,
@@ -130,5 +127,13 @@ BaseListViewControllerDataSource {
             type: .readme
         )
     }
+    
+    //Mark: RepositoryBranchUpdatable
+    
+    func updateBranch(to newBranch: String) {
+        guard self.branch != newBranch else { return }
+        self.branch = newBranch
+        fetch(page: nil)
+    }
 
 }