Support mail composer with activity indicator

EYSupportMailComposer.h

// erkanyildiz
// 20170828-2105+0900
//
// EYSupportMailComposer.h

#import <Foundation/Foundation.h>

@interface EYSupportMailComposer : NSObject

+ (void)presentMailComposerOnViewController:(UIViewController *)viewController withEmail:(NSString *)email;

@end

EYSupportMailComposer.m

// erkanyildiz
// 20170828-2105+0900
//
// EYSupportMailComposer.h

#import "EYSupportMailComposer.h"
#import <MessageUI/MessageUI.h>
#import <sys/utsname.h>
#import "EYUtils.h"


@interface EYSupportMailComposer () <MFMailComposeViewControllerDelegate>
@end


@implementation EYSupportMailComposer

static EYSupportMailComposer *delegateInstance;

+ (void)presentMailComposerOnViewController:(UIViewController *)viewController withEmail:(NSString *)email
{
    MFMailComposeViewController *mc = MFMailComposeViewController.new;

    if(!mc)
        return;

    NSString* appName = [NSBundle.mainBundle objectForInfoDictionaryKey:(NSString*)kCFBundleNameKey];
    NSString* appVersion = [NSBundle.mainBundle objectForInfoDictionaryKey:@"CFBundleShortVersionString"];
    NSString* osVersion = UIDevice.currentDevice.systemVersion;
    struct utsname deviceInfo;
    uname(&deviceInfo);
    NSString* deviceModel = [NSString stringWithCString:deviceInfo.machine encoding:NSUTF8StringEncoding];

    NSString* systemInfo = [NSString stringWithFormat:@"\n\n"
                                                 "---System Info---\n"
                                                 "App Name: %@\n"
                                                 "App Version: %@\n"
                                                 "iOS Version: %@\n"
                                                 "Device Model: %@\n"
                                                 "Locale ID: %@",
                                                 appName,
                                                 appVersion,
                                                 osVersion,
                                                 deviceModel,
                                                 NSLocale.currentLocale.localeIdentifier];
    
    [mc setSubject: [NSString stringWithFormat:@"Feedback %@ %@", appName, appVersion]];
    [mc setToRecipients:@[email]];
    [mc setMessageBody:systemInfo isHTML:NO];
    delegateInstance = EYSupportMailComposer.new;
    [mc setMailComposeDelegate:delegateInstance];

    [viewController showActivityIndicator];

    [viewController presentViewController:mc animated:YES completion:^
    {
        [viewController hideActivityIndicator];
    }];
}


- (void)mailComposeController:(MFMailComposeViewController *)controller
          didFinishWithResult:(MFMailComposeResult)result
                        error:(NSError *)error
{
    [controller dismissViewControllerAnimated:YES completion:nil];
}

@end