//
//  ShowBasedOnVoteLogics.swift
//  Feels (iOS)
//
//  Created by Trey Tartt on 2/17/22.
//

import CoreData
import SwiftUI


//if this is being shown we're missing an entry
// voting time is noon
    // vote for current day
        // today at 11 am -> How as yesterday
        // today at 1 pm -> How is today
    // vote for previous day
        // today at 11 am -> How as 2 days ago
        // today at 1 pm -> How was yesterday
class ShowBasedOnVoteLogics {
    private static var currentVoting: (passTimeToVote: Bool, dayOptions: DayOptions) {
        let passedTimeToVote = UserDefaultsStore.getOnboarding().ableToVoteBasedOnCurentTime()
        let inputDay = UserDefaultsStore.getOnboarding().inputDay
        
        return (passedTimeToVote, inputDay)
    }
    
    static func isMissingCurrentVote() -> Bool {
        var startDate: Date?
        
        switch (currentVoting.passTimeToVote, currentVoting.dayOptions) {
        case (true, .Previous):
            // if we're passed time to vote and the voting type is previous - last vote should be -1
            startDate = Calendar.current.date(byAdding: .day, value: -1, to: Date())!
        case (true, .Today):
            // if we're passed time to vote and the voting type is today - last vote should be current date
            startDate = Date()
        case (false, .Previous):
            // if we're NOT passed time to vote and the voting type is previous - last vote should be 2 days ago
            startDate = Calendar.current.date(byAdding: .day, value: -2, to: Date())!
        case (false, .Today):
            // if we're NOT passed time to vote and the voting type is previous - last vote should be -1
            startDate = Calendar.current.date(byAdding: .day, value: -1, to: Date())!
        }
        
        startDate = Calendar.current.startOfDay(for: startDate!)
        let endDate = Calendar.current.date(byAdding: .day, value: 1, to: startDate!)!

        let fetchRequest = NSFetchRequest<MoodEntry>(entityName: "MoodEntry")
        let fromPredicate = NSPredicate(format: "%@ <= %K", startDate!
                                        as NSDate, #keyPath(MoodEntry.forDate))
        let toPredicate = NSPredicate(format: "%K < %@", #keyPath(MoodEntry.forDate), endDate as NSDate)
        let datePredicate = NSCompoundPredicate(andPredicateWithSubpredicates: [fromPredicate, toPredicate])
        fetchRequest.predicate = datePredicate
        let entries = try! PersistenceController.shared.viewContext.count(for: fetchRequest)
        
        return entries < 1
    }
    
    static func getVotingTitle() -> String {
        switch (currentVoting.passTimeToVote, currentVoting.dayOptions) {
        case (true, .Previous):
            // if we're passed time to vote and the voting type is previous - last vote should be -1
            return "how was yesterday"
        case (true, .Today):
            // if we're passed time to vote and the voting type is previous - last vote should be today
            return "how is today"
        case (false, .Previous):
            // if we're passed time to vote and the voting type is previous - last vote should be -2
            let lastDayVoteShouldExist = ShowBasedOnVoteLogics.getLastDateVoteShouldExist()
            return "how was \(Random.weekdayName(fromDate: lastDayVoteShouldExist))"
        case (false, .Today):
            // if we're passed time to vote and the voting type is previous - last vote should be -1
            return "how as yesterday"
        }
    }
    
    static func dateForHeaderVote() -> Date? {
        var date: Date?
        
        switch (currentVoting.passTimeToVote, currentVoting.dayOptions) {
        case (true, .Previous):
            // if we're passed time to vote and the voting type is previous - last vote should be -1
            date = Calendar.current.date(byAdding: .day, value: -1, to: Date())
        case (true, .Today):
            // if we're passed time to vote and the voting type is previous - last vote should be today
            date = Date()
        case (false, .Previous):
            // if we're passed time to vote and the voting type is previous - last vote should be -2
            date = Calendar.current.date(byAdding: .day, value: -2, to: Date())
        case (false, .Today):
            // if we're passed time to vote and the voting type is previous - last vote should be -1
            date = Calendar.current.date(byAdding: .day, value: -1, to: Date())
        }
        date = Calendar.current.date(byAdding: .day, value: -2, to: Date())
        if let date = date {
            return date
        }
        
        return nil
    }
    
    static func getLastDateVoteShouldExist() -> Date {
        var endDate: Date?
        
        switch (currentVoting.passTimeToVote, currentVoting.dayOptions) {
        case (true, .Previous):
            // if we're passed time to vote and the voting type is previous - last vote should -1
            endDate = Calendar.current.date(byAdding: .day, value: -1, to: Date())!
        case (true, .Today):
            // if we're passed time to vote and the voting type is previous - last vote should be today
            endDate = Date()
        case (false, .Previous):
            // if we're passed time to vote and the voting type is previous - last vote should be -2
            endDate = Calendar.current.date(byAdding: .day, value: -2, to: Date())!
        case (false, .Today):
            // if we're passed time to vote and the voting type is previous - last vote should be -1
            endDate = Calendar.current.date(byAdding: .day, value: -1, to: Date())!
        }
        
        return endDate!
    }
}