TimeTicksView.swift

//
//  TimeTicksView.swift
//  MyAlarmVideo
//
//  Created by Pavel Alexeev on 13.04.2020.
//  Copyright © 2020 Pavel Alexeev. All rights reserved.
//

import Foundation
import UIKit

class TimeTicksView: UIView
{
    var slices: [VideoSlice] {
        didSet {
            update()
        }
    }
    
    private lazy var ticks = (0..<10).map {_ in
        TimeTickView(frame: CGRect(x: 0, y: 0, width: width, height: 22))
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    init(frame: CGRect, slices: [VideoSlice]) {
        self.slices = slices
        
        super.init(frame: frame)
    }
    
    func update() {
        let nearestHour = Date().nearestHour
        var currentDate = nearestHour + 30*60
        var currentY: CGFloat = 0
        
        while currentY < height {
            let localY = Self.yPosition(for: currentDate)
            let globalY = convert(CGPoint(x: 0, y: localY), to: nil).y
    
            currentY = localY
            
            if globalY > 0 && localY >= 0 {
                addTick(at: currentDate)
            }
            if globalY > UIScreen.main.bounds.height {
                break
            }
    
            currentDate -= 30*60
        }
    }
    
    private func availableTick() -> TimeTickView? {
        for tick in ticks {
            if !tick.isVisibleToUser {
                return tick
            }
        }
        print("No available tick!")
        return nil
    }

    @discardableResult
    private func addTick(at date: Date) -> UIView? {
        // проверяем, может такой уже есть
        for tick in ticks {
            if tick.date == date {
                return tick
            }
        }
        
        // переиспользуем
        if let tick = availableTick() {
            tick.date = date
            addSubview(tick)
            return tick
        }
        
        return nil
    }
    
    private static func yPosition(for date: Date) -> CGFloat {
        return date.timeIntervalToNow.toPoints()
    }
    
    class TimeTickView: UIView {
        var date: Date = Date() {
            didSet {
                guard oldValue != date else {
                    return
                }
                
                y = TimeTicksView.yPosition(for: date) - 11
                label.text = Self.dateFormatter.string(from: date)
                if label.text == "00:00" {
                    dayLabel.isVisible = true
                    // отнимаем одну секунду, чтобы в 00:00 показывалось вчера
                    dayLabel.text = (date - 1).userFriendlyDateString
                } else {
                    dayLabel.isVisible = false
                }
            }
        }
        
        private static let dateFormatter = DateFormatter(format: "HH:mm")
        
        private var label = UILabel()
        private var dayLabel = UILabel()
        
        override init(frame: CGRect) {
            super.init(frame: frame)
    
            label.frame = CGRect(x: 0, y: 0, width: 44, height: 22)
            label.lineBreakMode = .byClipping
            label.font = .monospacedDigitSystemFont(ofSize: 14, weight: .regular)
            label.textColor = .buttonDisabled
            
            addSubview(label)
    
            let tick = UIView(frame: CGRect(x: label.right, y: 11, width: frame.width - label.right, height: 1))
            tick.backgroundColor = .timeTicks
            tick.autoresizingMask = [.flexibleLeftMargin, .flexibleTopMargin, .flexibleBottomMargin]
            addSubview(tick)
            
            // выводим день напротив метки
            dayLabel.frame = CGRect(x: tick.right + 16, y: label.y, width: 200, height: label.height)
            dayLabel.autoresizingMask = [.flexibleLeftMargin, .flexibleTopMargin, .flexibleBottomMargin]
            dayLabel.lineBreakMode = .byClipping
            dayLabel.font = .systemFont(ofSize: 14)
            dayLabel.textColor = label.textColor
            addSubview(dayLabel)
        }
    
        required init?(coder: NSCoder) {
            fatalError("init(coder:) has not been implemented")
        }
    }
}