Date Aggregation #swift #dates

DateAggegation.swift

import Cocoa



struct entry {
    let date: Date
    let vol: Measurement<UnitVolume>
}

let entries = [
    entry(date: Date(), vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date(), vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date(), vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date(), vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date(), vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    
    entry(date: Date() - 25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date() - 25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date() - 25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date() - 25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date() - 25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date() - 25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date() - 25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    
    
    entry(date: Date() - 2*25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date() - 2*25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date() - 2*25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date() - 2*25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    
    entry(date: Date() - 3*25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date() - 3*25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    
    entry(date: Date() - 4*25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date() - 4*25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    
    entry(date: Date() - 5*25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date() - 5*25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    
    entry(date: Date() - 6*25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date() - 6*25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    
    entry(date: Date() - 7*25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date() - 7*25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    
    entry(date: Date() - 8*25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
    entry(date: Date() - 8*25*60*60, vol: Measurement(value: 100, unit: UnitVolume.milliliters)),
]


extension Date {
    public func removeTimeStamp() -> Date {
        guard let date = Calendar.current.date(from: Calendar.current.dateComponents([.year, .month, .day], from: self)) else {
            fatalError("Failed to strip time from Date object")
        }
        return date
    }
}

let now = Date()
print("Now: \(now)")

let endOfToday = Calendar.current.date(byAdding: .day, value: 1, to: Date())?.removeTimeStamp().addingTimeInterval(TimeInterval(-1))
print("End of today: \(endOfToday!)")

let sevenDays = entries.filter{ $0.date > Calendar.current.date(byAdding: .day, value: -7, to: endOfToday!)!}
var history = [Date: Measurement<UnitVolume>]()
for entry in sevenDays {
    let date = entry.date.removeTimeStamp()
    if let _ = history[date] {
        history[date]! = history[date]! + entry.vol
    } else {
        history[date] = entry.vol
    }
}

for date in Array(history.keys.sorted().reversed()) {
    print("\(date): \(history[date]!)")
}
print(Locale.current)