Protocols proposal + dataSource sample implementation

CodeChallenge.xcodeproj/project.pbxproj

@@ -24,6 +24,7 @@
 		8AF0EBB4206F7E6800AF374C /* NSDictionary+Networking.m in Sources */ = {isa = PBXBuildFile; fileRef = 8AF0EBB3206F7E6800AF374C /* NSDictionary+Networking.m */; };
 		8AF0EBB9206F875300AF374C /* Avatar.m in Sources */ = {isa = PBXBuildFile; fileRef = 8AF0EBB5206F875200AF374C /* Avatar.m */; };
 		8AF0EBBA206F875300AF374C /* _Avatar.m in Sources */ = {isa = PBXBuildFile; fileRef = 8AF0EBB6206F875200AF374C /* _Avatar.m */; };
+		8AF0EBC4206F9DD500AF374C /* RepositoriesDataProvider.m in Sources */ = {isa = PBXBuildFile; fileRef = 8AF0EBC3206F9DD500AF374C /* RepositoriesDataProvider.m */; };
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 /* End PBXBuildFile section */
 
@@ -60,6 +61,12 @@
 		8AF0EBB6206F875200AF374C /* _Avatar.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = _Avatar.m; sourceTree = "<group>"; };
 		8AF0EBB7206F875300AF374C /* Avatar.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = Avatar.h; sourceTree = "<group>"; };
 		8AF0EBB8206F875300AF374C /* _Avatar.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = _Avatar.h; sourceTree = "<group>"; };
+		8AF0EBBB206F94DE00AF374C /* NetworkManagerProtocol.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = NetworkManagerProtocol.h; sourceTree = "<group>"; };
+		8AF0EBBD206F973600AF374C /* DataProviderProtocol.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = DataProviderProtocol.h; sourceTree = "<group>"; };
+		8AF0EBBE206F992400AF374C /* BusinessLogicControllerProtocol.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = BusinessLogicControllerProtocol.h; sourceTree = "<group>"; };
+		8AF0EBC0206F99EF00AF374C /* PersistencyManagerProtocol.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = PersistencyManagerProtocol.h; sourceTree = "<group>"; };
+		8AF0EBC2206F9DD500AF374C /* RepositoriesDataProvider.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = RepositoriesDataProvider.h; sourceTree = "<group>"; };
+		8AF0EBC3206F9DD500AF374C /* RepositoriesDataProvider.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = RepositoriesDataProvider.m; sourceTree = "<group>"; };
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@@ -98,6 +105,7 @@
 		6B5FAB5F206F883500371E40 /* Protocols */ = {
 			isa = PBXGroup;
 			children = (
+				8AF0EBC1206F9C0E00AF374C /* Proposal */,
 				6B5FAB5A206F7E2C00371E40 /* FeedProtocol.h */,
 				6B5FAB5E206F870D00371E40 /* FetchDelegate.h */,
 			);
@@ -173,6 +181,19 @@
 			path = Categories;
 			sourceTree = "<group>";
 		};
+		8AF0EBC1206F9C0E00AF374C /* Proposal */ = {
+			isa = PBXGroup;
+			children = (
+				8AF0EBBE206F992400AF374C /* BusinessLogicControllerProtocol.h */,
+				8AF0EBBD206F973600AF374C /* DataProviderProtocol.h */,
+				8AF0EBBB206F94DE00AF374C /* NetworkManagerProtocol.h */,
+				8AF0EBC0206F99EF00AF374C /* PersistencyManagerProtocol.h */,
+				8AF0EBC2206F9DD500AF374C /* RepositoriesDataProvider.h */,
+				8AF0EBC3206F9DD500AF374C /* RepositoriesDataProvider.m */,
+			);
+			path = Proposal;
+			sourceTree = "<group>";
+		};
 		8E9A3E0E896FD7902B4985B0 /* Pods */ = {
 			isa = PBXGroup;
 			children = (
@@ -313,6 +334,7 @@
 				8AF0EBAC206F7C7300AF374C /* Commit.m in Sources */,
 				8AF0EBBA206F875300AF374C /* _Avatar.m in Sources */,
 				8AC26785206EC0550083E45A /* ViewController.m in Sources */,
+				8AF0EBC4206F9DD500AF374C /* RepositoriesDataProvider.m in Sources */,
 				8AC26790206EC0550083E45A /* main.m in Sources */,
 				8AF0EBAE206F7C7300AF374C /* _Commit.m in Sources */,
 				8AC26782206EC0550083E45A /* AppDelegate.m in Sources */,

CodeChallenge/Protocols/Proposal/BusinessLogicControllerProtocol.h

@@ -0,0 +1,20 @@
+//
+//  BusinessLogicControllerProtocol.h
+//  CodeChallenge
+//
+//  Created by alexey novikov on 31.03.2018.
+//
+
+#import <Foundation/Foundation.h>
+#import "Repository.h"
+
+// This is the top-level abstraction protocol
+// Will be implemented by a business logic controller, which will be accessible from the view controllers.
+// Implementation of such BL controller will incorporate the logic for making network requests (JSON+image data)
+// and persistency.
+
+@protocol BusinessLogicControllerProtocol <NSObject>
+@optional
+    - (void)loadRepositoriesWithOffset:(NSUInteger)offset limit:(NSUInteger)limit;
+    - (void)loadCommitsForRepository:(Repository *)repository limit:(NSUInteger)limit;
+@end

CodeChallenge/Protocols/Proposal/DataProviderProtocol.h

@@ -0,0 +1,38 @@
+//
+//  DataProviderProtocol.h
+//  CodeChallenge
+//
+//  Created by alexey novikov on 31.03.2018.
+//
+
+#import <Foundation/Foundation.h>
+
+@protocol DataConsumer;
+
+
+// for each of two of our UIViewControllers there will be two different objects implementing this protocol.
+// UIViewControllers will have strong references to those objects, and provide a callback reference to themselves via
+// the `dataConsumer` property.
+// Each object that will implement this method will have an NSFetchedResultsController instance inside of it,
+// and will be the delegate for that NSFetchedResultsController. These implementation details are never exposed,
+// thus providing abstraction for the data layer.
+@protocol DataProviderProtocol <NSObject>
+@optional
+    - (id)cellModelAtRow:(NSUInteger)row;
+
+    @property (nonatomic, readonly) NSUInteger numberOfRows;
+
+    // our UIViewController. will be notified in two different cases:
+    // 1. when the incorporated NSFetchedResultsController fires controllerDidChangeContent: or
+    // 2. an image has been downloaded for a row.
+    @property (weak, nonatomic) id<DataConsumer> dataConsumer;
+@end
+
+
+// UIViewControllers will implement this and decide whether or not to reload the data for the entire table,
+// or for just one row, in case of the image download
+@protocol DataConsumer <NSObject>
+    - (void)dataProvider:(id<DataProviderProtocol>)dataProvider didChangeImageForRowAtIndex:(NSUInteger)index;
+    - (void)dataProviderDidChangeData:(id<DataProviderProtocol>)dataProvider
+@end
+

CodeChallenge/Protocols/Proposal/NetworkManagerProtocol.h

@@ -0,0 +1,34 @@
+//
+//  NetworkManagerProtocol.h
+//  CodeChallenge
+//
+//  Created by alexey novikov on 31.03.2018.
+//
+
+#import <Foundation/Foundation.h>
+
+// this protocol describes the low-level network interaction interface that is never exposed to view controllers,
+// but only to the business logic controller.
+// object implementing it will know how to create NSURLSessionTasks, will be aware of the base URL, and will form the request parameters.
+
+typedef void(^DataSuccessBlock)(NSData *imageData)
+typedef void(^SuccessBlock)(NSDictionary *payload);
+typedef void(^FailureBlock)(NSError *error);
+
+@protocol NetworkManagerProtocol <NSObject>
+    - (void)fetchRepositoriesWithOffset:(NSUInteger)offset
+                                  limit:(NSUInteger)limit
+                           successBlock:(SuccessBlock)success
+                           failureBlock:(FailureBlock)failure;
+
+    - (void)fetchCommitsForRepository:(NSString *)repository
+                                limit:(NSUInteger)limit
+                         successBlock:(SuccessBlock)success
+                         failureBlock:(FailureBlock)failure;
+
+    - (void)fetchAvatarForAuthor:(NSString *)author
+                    successBlock:(DataSuccessBlock)success
+                    failureBlock:(FailureBlock)failure;
+
+    - (void)cancelAllRequests;
+@end

CodeChallenge/Protocols/Proposal/PersistencyManagerProtocol.h

@@ -0,0 +1,19 @@
+//
+//  PersistencyManagerProtocol.h
+//  CodeChallenge
+//
+//  Created by alexey novikov on 31.03.2018.
+//
+
+#import <Foundation/Foundation.h>
+
+// this interface describes the serializer.
+// object implementing it will hide the details of how exactly the JSON is turned into model objects and persisted (=created and/or updated),
+// be it CoreData or plain text files on the disk, thus providing abstraction on this layer.
+
+@protocol PersistencyManagerProtocol <NSObject>
+    - (void)createRepositoryWithPayload:(NSDictionary *)payload;
+    - (void)createCommitWithPayload:(NSDictionary *)payload;
+    - (void)createAvatarWithData:(NSData *)data;
+    - (void)resetStorage;
+@end

CodeChallenge/Protocols/Proposal/RepositoriesDataProvider.h

@@ -0,0 +1,13 @@
+//
+//  RepositoriesDataProvider.h
+//  CodeChallenge
+//
+//  Created by alexey novikov on 31.03.2018.
+//
+
+#import <Foundation/Foundation.h>
+#import "DataProviderProtocol.h"
+
+@interface RepositoriesDataProvider : NSObject<DataProviderProtocol>
+
+@end

CodeChallenge/Protocols/Proposal/RepositoriesDataProvider.m

@@ -0,0 +1,81 @@
+//
+//  RepositoriesDataProvider.m
+//  CodeChallenge
+//
+//  Created by alexey novikov on 31.03.2018.
+//
+
+@class RepositoriesCellModel;
+
+#import <CoreData/CoreData.h>
+#import <MagicalRecord/MagicalRecord.h>
+
+#import "Repository.h"
+#import "RepositoriesDataProvider.h"
+
+@interface RepositoriesDataProvider ()<NSFetchedResultsControllerDelegate>
+    @property (strong, nonatomic) NSFetchedResultsController *fetchController;
+@end
+
+@implementation RepositoriesDataProvider
+
+- (instancetype)init {
+    self = [super init];
+
+    if (self != nil) {
+
+    }
+
+    return self;
+}
+
+#pragma mark - DataProviderProtocol
+- (NSUInteger)numberOfRows {
+    return self.fetchController.fetchedObjects.count;
+}
+
+- (id)cellModelAtRow:(NSUInteger)row {
+    if (row >= self.fetchController.fetchedObjects.count) {
+        return nil;
+    }
+
+    Repository *r = [self.fetchController.fetchedObjects objectAtIndex:row];
+
+    RepositoriesCellModel *cellModel = [[RepositoriesCellModel alloc] initWithRepository:r];
+    return cellModel;
+}
+
+#pragma mark - NSFRC delegate methods
+- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller {
+    [self notifyDataConsumerAboutDataChange];
+}
+
+#pragma mark - private subroutines
+- (void)notifyDataConsumerAboutDataChange {
+    if (self.dataConsumer != nil && [self.dataConsumer respondsToSelector:@selector(dataProviderDidChangeData:)]) {
+        [self.dataConsumer dataProviderDidChangeData:self];
+    }
+}
+
+- (void)notifyDataConsumerAboutImageDownload {
+
+}
+
+#pragma mark - init subroutines
+- (void)initFetchedResultsController {
+    NSPredicate *predicate = [NSPredicate predicateWithFormat:@""];
+
+    self.fetchController = [Repository MR_fetchAllSortedBy:@"rank"
+                                                 ascending:YES
+                                             withPredicate:predicate
+                                                   groupBy:nil
+                                                  delegate:self];
+    NSError *error;
+    [self.fetchController performFetch:&error];
+
+    if (error != nil) {
+        DLog(@"Atata, error: %@", error.localizedDescription);
+    }
+}
+
+@end