//
//  Tab.swift
//  VDS
//
//  Created by Matt Bruce on 5/18/23.
//

import Foundation
import VDSColorTokens
import Combine

public class TabItem: View {
    
    //--------------------------------------------------
    // MARK: - Public Properties
    //--------------------------------------------------
    public var label: Label = Label()
    public var orientation: Tabs.Orientation = .horizontal { didSet { setNeedsUpdate() } }
    public var size: Tabs.Size = .medium { didSet { setNeedsUpdate() } }
    public var indicatorPosition: Tabs.IndicatorPosition = .bottom { didSet { setNeedsUpdate() } }
    public var onClick: (() -> Void)?  { didSet { setNeedsUpdate() } }
    public var width: CGFloat?   { didSet { setNeedsUpdate() } }
    public var selected: Bool = false { didSet { setNeedsUpdate() } }
    public var text: String?  { didSet { setNeedsUpdate() } }
    
    //--------------------------------------------------
    // MARK: - Private Properties
    //--------------------------------------------------
    private var labelWidthConstraint: NSLayoutConstraint?
    private var labelLeadingConstraint: NSLayoutConstraint?
    private var labelTopConstraint: NSLayoutConstraint?
    private var labelBottomConstraint: NSLayoutConstraint?

    //--------------------------------------------------
    // MARK: - Configuration
    //--------------------------------------------------
    private var textColorConfiguration: SurfaceColorConfiguration { selected ? textColorSelectedConfiguration : textColorNonSelectedConfiguration }
    private var textColorNonSelectedConfiguration = SurfaceColorConfiguration(VDSColor.elementsSecondaryOnlight , VDSColor.elementsSecondaryOnlight)
    private var textColorSelectedConfiguration = SurfaceColorConfiguration(VDSColor.elementsPrimaryOnlight, VDSColor.elementsPrimaryOndark)
    private var indicatorColorConfiguration = SurfaceColorConfiguration(VDSColor.paletteRed, VDSColor.elementsPrimaryOndark)
    private var indicatorWidth: CGFloat = 4.0
    
    //--------------------------------------------------
    // MARK: - Initializers
    //--------------------------------------------------
    public override init(frame: CGRect) {
        super.init(frame: frame)
    }
   
    public required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    required public convenience init() {
        self.init(frame: .zero)
    }
    
    //--------------------------------------------------
    // MARK: - Overrides
    //--------------------------------------------------
    override public func setup() {
        super.setup()
        addSubview(label)
        backgroundColor = .clear
        label.backgroundColor = .clear
        
        label.translatesAutoresizingMaskIntoConstraints = false
        label.pinTrailing()
        
        labelTopConstraint = label.topAnchor.constraint(equalTo: topAnchor, constant: 0)
        labelTopConstraint?.isActive = true
        
        labelBottomConstraint = label.bottomAnchor.constraint(equalTo: bottomAnchor, constant: 0)
        labelBottomConstraint?.isActive = true
        
        labelLeadingConstraint = label.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 0)
        labelLeadingConstraint?.isActive = true
        
        labelWidthConstraint = label.widthAnchor.constraint(greaterThanOrEqualToConstant: 44.0)
        labelWidthConstraint?.isActive = true
        
        publisher(for: UITapGestureRecognizer())
            .sink { [weak self] _ in
                self?.onClick?()
            }.store(in: &subscribers)
        
    }
    
    public override func updateView() {
        if orientation == .horizontal {
            label.textPosition = .center
        } else {
            label.textPosition = .left
        }
        label.text = text
        label.textStyle = size.textStyle
        label.textColor = textColorConfiguration.getColor(self)
        
        labelWidthConstraint?.isActive = false
        if let width {
            labelWidthConstraint = label.widthAnchor.constraint(equalToConstant: width)
        } else {
            labelWidthConstraint = label.widthAnchor.constraint(greaterThanOrEqualToConstant: 44.0)
        }
        labelWidthConstraint?.isActive = true

        var leadingSpace: CGFloat
        if orientation == .horizontal {
            leadingSpace = 0
        } else {
            leadingSpace = size == .medium ? VDSLayout.Spacing.space4X.value : VDSLayout.Spacing.space6X.value
        }
        labelLeadingConstraint?.constant = leadingSpace

        var otherSpace: CGFloat
        if orientation == .horizontal {
            otherSpace = size == .medium ? VDSLayout.Spacing.space3X.value : VDSLayout.Spacing.space4X.value
        } else {
            otherSpace = VDSLayout.Spacing.space2X.value
        }
        labelTopConstraint?.constant = otherSpace
        labelBottomConstraint?.constant = -otherSpace

        setNeedsLayout()
    }
    
    public override func layoutSubviews() {
        super.layoutSubviews()
        
        removeBorders()

        if selected {
            var indicator: UIRectEdge = .left
            if orientation == .horizontal {
                indicator = indicatorPosition.value
            }
            addBorder(side: indicator, width: indicatorWidth, color: indicatorColorConfiguration.getColor(self))
        }
    }
}