//
//  DesignLabel.swift
//  FigmaConvertXib
//
//  Created by Рустам Мотыгуллин on 25.07.2020.
//  Copyright © 2020 mrusta. All rights reserved.
//

import UIKit

@IBDesignable
class DesignLabel: UILabel {
    
    //MARK: Gradient
    @IBInspectable var grColor1: UIColor?
    @IBInspectable var grColor2: UIColor?
    @IBInspectable var grColor3: UIColor?
    @IBInspectable var grColor4: UIColor?
    @IBInspectable var grColor5: UIColor?
    @IBInspectable var grColor6: UIColor?
    
    @IBInspectable var grStartPoint: CGPoint = .zero
    @IBInspectable var grEndPoint:   CGPoint = .zero
    
    @IBInspectable var grRadial: Bool = false /// default: linear
    @IBInspectable var grDrawsOptions: Bool = true
    @IBInspectable var grDebug: Bool = false
    @IBInspectable var grPointPercent: Bool = true
    @IBInspectable var grBlendMode:    Int  = 20    /// заполнители
    
    //MARK: - Shadow
    
    @IBInspectable var shColor: UIColor = .clear
    @IBInspectable var shRadius: CGFloat = 0.0
    @IBInspectable var shOffset: CGSize  = .zero
    
    //MARK: Border
    
    @IBInspectable var brColor: UIColor = .clear
    @IBInspectable var brWidth: CGFloat = 0.0
    
     //MARK: - Draw
    
    override func draw(_ rect: CGRect) {
        super.draw(rect)
        shadow()
        gradient()
        gradientDebug()
        border()
    }
    
    //MARK: - Add Shadow
    
    private func shadow() {
        layer.shadowOpacity = 1.0
        layer.shadowOffset = shOffset
        layer.shadowRadius = shRadius
        layer.shadowColor = shColor.cgColor
    }
    
    //MARK: - Add Border
    
    func border() {
        
        guard brColor != .clear, brWidth != 0.0 else { return }
        
        let borderLabel = UILabel(frame: bounds)
        borderLabel.text = text
        borderLabel.font = font
        borderLabel.textColor = .clear
        borderLabel.numberOfLines = numberOfLines
        borderLabel.backgroundColor = .clear
        
        
        let strokeTextAttributes: [NSAttributedString.Key : Any] = [
            .strokeColor : brColor,
            .strokeWidth : (-1 * (brWidth * 2)),
        ]
        
        borderLabel.attributedText = NSAttributedString(string: text ?? "",
                                                        attributes: strokeTextAttributes)
        
        addSubview(borderLabel)
    }
    
    //MARK: - Add Gradient
    
    func gradient() {
        var colors: [CGColor] = []
        
        if grColor1 != nil || grColor2 != nil || grColor3 != nil || grColor4 != nil || grColor5 != nil {
            
            if let color1 = grColor1 { colors.append(color1.cgColor) }
            if let color2 = grColor2 { colors.append(color2.cgColor) }
            if let color3 = grColor3 { colors.append(color3.cgColor) }
            if let color4 = grColor4 { colors.append(color4.cgColor) }
            if let color5 = grColor5 { colors.append(color5.cgColor) }
            if let color6 = grColor6 { colors.append(color6.cgColor) }
            
        } else { return }
        
        guard let gradient = CGGradient(colorsSpace: CGColorSpaceCreateDeviceRGB(),
                                        colors: colors as CFArray,
                                        locations: nil) else { return }
        
        guard let context = UIGraphicsGetCurrentContext() else { return }
        
        let bMode = CGBlendMode(rawValue: CGBlendMode.RawValue(grBlendMode)) ?? CGBlendMode.sourceAtop
        context.setBlendMode(bMode)

        let options: CGGradientDrawingOptions =
            grDrawsOptions ? [ .drawsBeforeStartLocation, .drawsAfterEndLocation ] : [ ]
        
        
        if grPointPercent {
            grEndPoint = CGPoint(x: grEndPoint.x * frame.width, y: grEndPoint.y * frame.height)
            grStartPoint = CGPoint(x: grStartPoint.x * frame.width, y: grStartPoint.y * frame.height)
        }
        
        //MARK: Gr. Radial / Linear
        if grRadial {
            let x: CGFloat = (grEndPoint.x - grStartPoint.x)
            let y: CGFloat = (grEndPoint.y - grStartPoint.y)
            let distance: CGFloat = sqrt((x * x) + (y * y))
            
            context.drawRadialGradient(gradient,
                                       startCenter: grStartPoint,
                                       startRadius: 0,
                                       endCenter: grStartPoint,
                                       endRadius: distance,
                                       options: options)
        } else {
            context.drawLinearGradient(gradient,
                                       start: grStartPoint,
                                       end: grEndPoint,
                                       options: options)
        }
        context.saveGState()
        
    }

    //MARK: - Gr. Debug
    
    func gradientDebug() {
      guard let context = UIGraphicsGetCurrentContext() else { return }
      guard grDebug else { return }
      
      context.setBlendMode(CGBlendMode.normal)
      context.setLineWidth(3.0)
      context.setFillColor(UIColor.black.cgColor)
      context.setStrokeColor(UIColor.systemRed.cgColor)
      
      let ellipseRadius: CGFloat = 5
      let circleRect = CGRect(x: grStartPoint.x - ellipseRadius,
                              y: grStartPoint.y - ellipseRadius,
                              width: ellipseRadius * 2,
                              height: ellipseRadius * 2)
      
      context.fillEllipse(in: circleRect)
      context.strokeEllipse(in: circleRect)
      context.setStrokeColor(UIColor.green.cgColor)
        
      let circleRect2 = CGRect(x: grEndPoint.x - ellipseRadius,
                              y: grEndPoint.y - ellipseRadius,
                              width: ellipseRadius * 2,
                              height: ellipseRadius * 2)
      
      context.fillEllipse(in: circleRect2)
      context.strokeEllipse(in: circleRect2)
    }
    
}