//
//  CalendarDateCollectionViewCell.swift
//  VDS
//
//  Created by Kanamarlapudi, Vasavi on 24/04/24.
//

import Foundation
import UIKit
import VDSTokens

/// Calendar collection view cell
final class CalendarDateCollectionViewCell: UICollectionViewCell {
    
    ///Identifier for the Calendar Date Cell
    static let identifier: String = String(describing: CalendarDateCollectionViewCell.self)
    
    
    private lazy var dateView = DateView()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func configure(with surface: Surface, indicators: [CalendarBase.CalendarIndicatorModel], text: String, indicatorCount: Int) {
        addSubview(dateView)
        dateView.numberLabel.text = text
        dateView.indicatorCount  = indicatorCount
        dateView.dateIndicators = indicators
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
    }
}

/// Date view to show Date number and indicator if applies
private class DateView : View {
    
    //--------------------------------------------------
    // MARK: - Initializers
    //--------------------------------------------------
    required public init() {
        super.init(frame: .zero)
    }
    
    public override init(frame: CGRect) {
        super.init(frame: .zero)
    }
    
    public required init?(coder: NSCoder) {
        super.init(coder: coder)
    }
    
    //--------------------------------------------------
    // MARK: - Public Properties
    //--------------------------------------------------
    open var indicatorCount: Int = 0
    
    open var dateIndicators: [CalendarBase.CalendarIndicatorModel] = [] { didSet { setNeedsUpdate() } }
    
    open var numberLabel = Label().with {
        $0.translatesAutoresizingMaskIntoConstraints = false
        $0.textAlignment = .center
        $0.textStyle = .bodySmall //isCurrentDate: .boldBodySmall
    }
    
    //--------------------------------------------------
    // MARK: - Private Properties
    //--------------------------------------------------
    internal var containerSize: CGSize { CGSize(width: 40, height: 40) }
    
    internal var containerView = View().with {
        $0.clipsToBounds = true
    }
    
    private lazy var stackView: UIStackView = {
        return UIStackView().with {
            $0.translatesAutoresizingMaskIntoConstraints = false
            $0.axis = .horizontal
            $0.distribution = .fill
            $0.alignment = .center
            $0.spacing = VDSLayout.space1X
            $0.setContentCompressionResistancePriority(.defaultHigh, for: .horizontal)
            $0.setContentHuggingPriority(.defaultHigh, for: .horizontal)
        }
    }()
    
    private lazy var shapeLayer = CAShapeLayer()
    
    private let indicatorColorConfiguration = SurfaceColorConfiguration(VDSColor.elementsSecondaryOnlight, VDSColor.elementsSecondaryOndark)
    
    //--------------------------------------------------
    // MARK: - Lifecycle
    //--------------------------------------------------
    open override func initialSetup() {
        super.initialSetup()
    }
    
    open override func setup() {
        super.setup()
        isAccessibilityElement = false
        addSubview(containerView)
        containerView
            .pinTop()
            .pinBottom()
            .pinLeadingGreaterThanOrEqualTo()
            .pinTrailingLessThanOrEqualTo()
            .height(containerSize.height)
            .width(containerSize.width)
        containerView.centerXAnchor.constraint(equalTo: centerXAnchor).activate()
        
        // Number label
        containerView.addSubview(numberLabel)
        numberLabel.pinToSuperView()
        
        // Indicators
        containerView.addSubview(stackView)
        let topPos = containerSize.height * 0.6
        stackView.pinTop(topPos).pinBottom().pinTopGreaterThanOrEqualTo().pinTrailingLessThanOrEqualTo().pinCenterY()
        stackView.centerXAnchor.constraint(equalTo: centerXAnchor).activate()
    }
    
    open override func updateView() {
        super.updateView()
        numberLabel.surface = surface
        numberLabel.isEnabled = isEnabled
        
        stackView.arrangedSubviews.forEach { $0.removeFromSuperview() }
        if indicatorCount > 0 {
            let width = (indicatorCount * 8) + (Int(VDSLayout.space1X) * (indicatorCount - 1))
            stackView.widthAnchor.constraint(equalToConstant: CGFloat(width)).activate()
            for x in (0...(dateIndicators.count-1)) {
                if (self.numberLabel.text == self.getDay(with: dateIndicators[x].date)) {
                    addIndicator(with: VDSColor.elementsSecondaryOnlight, surface: surface, clearFullCircle: (x == 1), drawSemiCircle: (x == 2))
                }
            }
        }
    }
    
    override open func layoutSubviews() {
        super.layoutSubviews()
    }
    
    open override func reset() {
        super.reset()
        numberLabel.textStyle = .bodySmall
    }
    
    //--------------------------------------------------
    // MARK: - Private Methods
    //--------------------------------------------------
    func addIndicator(with color: UIColor, surface: Surface, clearFullCircle: Bool, drawSemiCircle: Bool) {
        // add indicator
        let indicatorView: View = View().with {
            $0.translatesAutoresizingMaskIntoConstraints = false
            $0.backgroundColor = .clear
            $0.layer.borderWidth = 1.0
        }
        indicatorView.pinLeading().pinTrailing().width(8).height(8).pinCenterY()
        stackView.addArrangedSubview(indicatorView)
        
        // update indicator
        indicatorView.backgroundColor = drawSemiCircle ? .clear : (clearFullCircle ? .clear : color)
        indicatorView.layer.borderColor = indicatorColorConfiguration.getColor(surface).cgColor
        
        self.layoutIfNeeded()
        
        indicatorView.layer.cornerRadius = indicatorView.frame.size.height / 2.0
        
        guard drawSemiCircle else { return }
        
        let center = CGPoint(x: indicatorView.frame.size.width/2, y: indicatorView.frame.size.height/2)
        let path = UIBezierPath()
        path.move(to: center)
        path.addArc(withCenter: center, radius: center.x, startAngle: 2 * .pi, endAngle: .pi, clockwise: true)
        path.close()
        shapeLayer.path = path.cgPath
        shapeLayer.fillColor = color.cgColor
        
        guard indicatorView.layer.sublayers?.contains(shapeLayer) ?? true else { return }
        indicatorView.layer.addSublayer(shapeLayer)
    }
    
    func getDay(with date:Date) -> String {
        if #available(iOS 15.0, *) {
            return date.formatted(.dateTime.day())
        } else {
            // Fallback on earlier versions
            let dateFormatter: DateFormatter = DateFormatter()
            dateFormatter.dateFormat = "d"
            let day: String = dateFormatter.string(from: date)
            return day
        }
    }
    
}