HealthKitSteps.swift

//
//  HealthViewController.swift
//  IBScratch
//
//  Created by Don Mag on 11/9/17.
//  Copyright © 2017 DonMag. All rights reserved.
//

import UIKit
import HealthKit

class HealthKitManager {
	
	class var sharedInstance: HealthKitManager {
		struct Singleton {
			static let instance = HealthKitManager()
		}
		
		return Singleton.instance
	}
	
	let healthStore: HKHealthStore? = {
		if HKHealthStore.isHealthDataAvailable() {
			return HKHealthStore()
		} else {
			return nil
		}
	}()
	
	let stepsCount = HKQuantityType.quantityType(forIdentifier: HKQuantityTypeIdentifier.stepCount)
	
}

class HealthViewController: UIViewController {

	var theStepsArray = [Int]()
	
	fileprivate let healthKitManager = HealthKitManager.sharedInstance
	
    override func viewDidLoad() {
        super.viewDidLoad()

		requestHealthKitAuthorization()
    }

}

private extension HealthViewController {
	
	func todayTotalSteps () -> Void{
		let healthStore: HKHealthStore? = {
			if HKHealthStore.isHealthDataAvailable() {
				return HKHealthStore()
			} else {
				return nil
			}
		}()
		let calendar = NSCalendar.current
		let interval = NSDateComponents()
		interval.day = 1
		
		var anchorComponents = calendar.dateComponents([.day, .month, .year], from: NSDate() as Date)
		anchorComponents.hour = 0
		let anchorDate = calendar.date(from: anchorComponents)
		
		guard let stepsCount = healthKitManager.stepsCount else {
			fatalError("*** Unable to create a step count type ***")
		}
		
		// Define 1-day intervals starting from 0:00
		let stepsQuery = HKStatisticsCollectionQuery(quantityType: stepsCount, quantitySamplePredicate: nil, options: .cumulativeSum, anchorDate: anchorDate!, intervalComponents: interval as DateComponents)
		
		stepsQuery.initialResultsHandler = { query, results, error in
			let endDate = NSDate()
			let startDate = calendar.date(byAdding: .day, value: -365, to: endDate as Date, wrappingComponents: false)
			
			if let myResults = results{
				myResults.enumerateStatistics(from: startDate!, to: endDate as Date) { statistics, stop in
					if let quantity = statistics.sumQuantity(){
						
						let steps = quantity.doubleValue(for: HKUnit.count())
						
						// append to array
						self.theStepsArray.append(Int(steps))
						
						// let date = statistics.startDate
						// print(date, "we have steps for this date")
						
					}
					else
					{
						
						self.theStepsArray.append(0)
						
						// let date = statistics.startDate
						// print(date, "no steps for this date")
						
					}
				} //end block
			} //end if leta
			
			// here we have processed all the results
			print(self.theStepsArray)
			print()
			print("Array size is now:", self.theStepsArray.count)
			
			// NOTE: If you are going to update the UI do it in the main thread
			DispatchQueue.main.async {
				//update UI components
			}
			
		}
		healthStore?.execute(stepsQuery)
	}
	
	func requestHealthKitAuthorization() {
		let dataTypesToRead = NSSet(objects: healthKitManager.stepsCount as Any)
		healthKitManager.healthStore?.requestAuthorization(toShare: nil, read: dataTypesToRead as? Set<HKObjectType>, completion: { [unowned self] (success, error) in
			if success {
				
				self.todayTotalSteps()
				
			} else {
				print(error.debugDescription)
			}
		})
	}
	
}