//
//  Badge.swift
//  VDS
//
//  Created by Matt Bruce on 9/22/22.
//

import Foundation
import UIKit
import VDSColorTokens
import VDSFormControlsTokens
import Combine

/// Badges are visual labels used to convey status or highlight supplemental information.
@objc(VDSBadge)
open class Badge: View {
    //--------------------------------------------------
    // MARK: - Enums
    //--------------------------------------------------
    public enum FillColor: String, CaseIterable {
        case red, yellow, green, orange, blue, black, white
    }
    
    //--------------------------------------------------
    // MARK: - Public Properties
    //--------------------------------------------------
    
    /// Label used to render text
    open var label = Label().with {
        $0.lineBreakMode = .byTruncatingTail
        $0.setContentCompressionResistancePriority(.required, for: .vertical)
        $0.setContentHuggingPriority(.defaultHigh, for: .vertical)
        $0.setContentCompressionResistancePriority(.required, for: .horizontal)
        $0.setContentHuggingPriority(.defaultHigh, for: .horizontal)
        $0.textPosition = .left
        $0.textStyle = .boldBodySmall
    }
    
    /// This will render the badges fill color based on the available options.
    /// When used in conjunction with the surface prop, this fill color will change its tint automatically based on a light or dark surface.
    open var fillColor: FillColor = .red { didSet { setNeedsUpdate() }}
    
    /// The text that will be shown in the label.
    open var text: String = "" { didSet { setNeedsUpdate() }}
    
    /// When applied, this property takes a px value  that will restrict the width at that point.
    open var maxWidth: CGFloat? { didSet { setNeedsUpdate() }}
    
    /// This will restrict the badge height to a specific number of lines. If the text overflows the allowable space, ellipsis will show.
    open var numberOfLines: Int = 1 { didSet { setNeedsUpdate() }}
    
    //--------------------------------------------------
    // MARK: - Constraints
    //--------------------------------------------------
    private var labelWidthConstraint: NSLayoutConstraint?
    
    private var widthConstraint: NSLayoutConstraint {
        // Determine which constraint to activate based on the maxWidth and minWidth properties
        if let maxWidth = maxWidth, maxWidth > minWidth {
            // Apply maximum width constraint if set and greater than minWidth
            return label.widthAnchor.constraint(lessThanOrEqualToConstant: maxWidth)
        } else {
            // Apply minimum width constraint
            return label.widthAnchor.constraint(greaterThanOrEqualToConstant: minWidth)
        }
    }
    
    //--------------------------------------------------
    // MARK: - Configuration
    //--------------------------------------------------
    private var minWidth: CGFloat = 23.0
    private var labelInset: UIEdgeInsets = .init(top: 2,
                                                 left: VDSLayout.Spacing.space1X.value,
                                                 bottom: 2,
                                                 right: VDSLayout.Spacing.space1X.value)
    
    /// ColorConfiguration that is mapped to the 'fillColor' for the surface.
    private var backgroundColorConfiguration: AnyColorable = {
        let config = KeyedColorConfiguration<Badge, FillColor>(keyPath: \.fillColor)
        config.setSurfaceColors(VDSColor.backgroundBrandhighlight, VDSColor.backgroundBrandhighlight, forKey: .red)
        config.setSurfaceColors(VDSColor.paletteYellow53, VDSColor.paletteYellow53, forKey: .yellow)
        config.setSurfaceColors(VDSColor.paletteGreen26, VDSColor.paletteGreen36, forKey: .green)
        config.setSurfaceColors(VDSColor.paletteOrange41, VDSColor.paletteOrange58, forKey: .orange)
        config.setSurfaceColors(VDSColor.paletteBlue38, VDSColor.paletteBlue46, forKey: .blue)
        config.setSurfaceColors(VDSColor.backgroundPrimaryDark, VDSColor.backgroundPrimaryDark, forKey: .black)
        config.setSurfaceColors(VDSColor.backgroundPrimaryLight, VDSColor.backgroundPrimaryLight, forKey: .white)
        return config.eraseToAnyColorable()
    }()
    
    /// ColorConfiguration for the Text.
    private var textColorConfiguration = ViewColorConfiguration()
    
    /// Updates the textColorConfiguration based on the fillColor.
    public func updateTextColorConfig() {
        textColorConfiguration.reset()
        
        switch fillColor {
            
        case .red, .black:
            textColorConfiguration.setSurfaceColors(VDSColor.elementsPrimaryOndark, VDSColor.elementsPrimaryOndark, forDisabled: false)
            textColorConfiguration.setSurfaceColors(VDSColor.elementsPrimaryOndark, VDSColor.elementsPrimaryOndark, forDisabled: true)
            
        case .yellow, .white:
            textColorConfiguration.setSurfaceColors(VDSColor.elementsPrimaryOnlight, VDSColor.elementsPrimaryOnlight, forDisabled: false)
            textColorConfiguration.setSurfaceColors(VDSColor.elementsPrimaryOnlight, VDSColor.elementsPrimaryOnlight, forDisabled: true)
            
        case .orange, .green, .blue:
            textColorConfiguration.setSurfaceColors(VDSColor.elementsPrimaryOndark, VDSColor.elementsPrimaryOnlight, forDisabled: false)
            textColorConfiguration.setSurfaceColors(VDSColor.elementsPrimaryOndark, VDSColor.elementsPrimaryOnlight, forDisabled: true)
        }
    }
    
    //--------------------------------------------------
    // MARK: - Lifecycle
    //--------------------------------------------------
    
    open override func setup() {
        super.setup()
        
        accessibilityElements = [label]
        layer.cornerRadius = 2
        
        addSubview(label)
        label.pinToSuperView(labelInset)
        
    }
    
    /// Resets to default settings.
    open override func reset() {
        super.reset()
        shouldUpdateView = false
        label.reset()
        label.lineBreakMode = .byTruncatingTail
        label.textPosition = .left
        label.textStyle = .boldBodySmall
        fillColor = .red
        text = ""
        maxWidth = nil
        numberOfLines = 1
        shouldUpdateView = true
        setNeedsUpdate()
    }
    
    /// Function used to make changes to the View based off a change events or from local properties.
    open override func updateView() {
        super.updateView()
        
        updateTextColorConfig()
        
        backgroundColor = backgroundColorConfiguration.getColor(self)
        
        labelWidthConstraint?.isActive = false
        labelWidthConstraint = widthConstraint
        labelWidthConstraint?.isActive = true
        
        label.textColorConfiguration = textColorConfiguration.eraseToAnyColorable()
        label.numberOfLines = numberOfLines
        label.text = text
        label.surface = surface
        label.disabled = disabled
        
    }
}