LeadKit/TIMapUtils/Sources/Drawing/Operations/CurrentLocationDrawingOperation.swift

//
//  Copyright (c) 2023 Touch Instinct
//
//  Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the Software), to deal
//  in the Software without restriction, including without limitation the rights
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//  copies of the Software, and to permit persons to whom the Software is
//  furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in
//  all copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED AS IS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//  THE SOFTWARE.
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import CoreGraphics

public struct CurrentLocationDrawingOperation: DrawingOperation {
    public enum Defaults {
        public static var iconSize: CGSize {
            CGSize(width: 27, height: 27)
        }

        public static var borderWidth: CGFloat {
            2
        }
    }

    public var iconSize: CGSize
    public var borderWidth: CGFloat
    public var mainColor: CGColor
    public var borderColor: CGColor
    public var backgroundColor: CGColor
    public var showHeadingArrow: Bool

    private var innerCircleSize: CGSize {
        CGSize(width: innerBorderSize.width - borderWidth,
               height: innerBorderSize.height - borderWidth)
    }

    private var innerBorderSize: CGSize {
        CGSize(width: outerBorderSize.width - borderWidth,
               height: outerBorderSize.height - borderWidth)
    }

    private var outerBorderSize: CGSize {
        CGSize(width: iconSize.width - 8,
               height: iconSize.height - 8)
    }

    private var innerCircleOrigin: CGPoint {
        CGPoint(x: (iconSize.width - innerCircleSize.width) / 2,
                y: (iconSize.height - innerCircleSize.height) / 2)
    }

    private var innerBorderOrigin: CGPoint {
        CGPoint(x: (iconSize.width - innerBorderSize.width) / 2,
                y: (iconSize.height - innerBorderSize.height) / 2)
    }

    private var outerBorderOrigin: CGPoint {
        CGPoint(x: (iconSize.width - outerBorderSize.width) / 2,
                y: (iconSize.height - outerBorderSize.height) / 2)
    }

    private var iconRect: CGRect {
        CGRect(origin: .zero,
               size: iconSize)
    }

    private  var innerCircleRect: CGRect {
        CGRect(origin: innerCircleOrigin,
               size: innerCircleSize)
    }

    private var innerBorderRect: CGRect {
        CGRect(origin: innerBorderOrigin,
               size: innerBorderSize)
    }

    private var outerBorderRect: CGRect {
        CGRect(origin: outerBorderOrigin,
               size: outerBorderSize)
    }

    public init(iconSize: CGSize = Defaults.iconSize,
                borderWidth: CGFloat = Defaults.borderWidth,
                mainColor: CGColor,
                borderColor: CGColor,
                showHeadingArrow: Bool = true) {

        self.iconSize = iconSize
        self.borderWidth = borderWidth
        self.mainColor = mainColor
        self.borderColor = borderColor
        self.backgroundColor = mainColor.copy(alpha: 0.3) ?? mainColor
        self.showHeadingArrow = showHeadingArrow
    }

    public func affectedArea(in context: CGContext? = nil) -> CGRect {
        iconRect
    }

    public func apply(in context: CGContext) {
        let backgroundDrawing = SolidFillDrawingOperation(color: backgroundColor,
                                                          ellipseRect: iconRect)

        let innerCircleDrawing = SolidFillDrawingOperation(color: mainColor,
                                                           ellipseRect: innerCircleRect)

        let innerBorderDrawing = BorderDrawingOperation(frameableContentRect: innerBorderRect,
                                                        border: borderWidth,
                                                        color: borderColor,
                                                        radius: min(innerBorderSize.width, innerBorderSize.height) / 2,
                                                        exteriorBorder: false)

        let outerBorderDrawing = BorderDrawingOperation(frameableContentRect: outerBorderRect,
                                                        border: borderWidth,
                                                        color: backgroundColor,
                                                        radius: min(outerBorderSize.width, outerBorderSize.height) / 2,
                                                        exteriorBorder: false)

        // flip horizontally

        context.translateBy(x: 0, y: iconSize.height)
        context.scaleBy(x: 1, y: -1)

        backgroundDrawing.apply(in: context)

        context.setFillColor(mainColor)
        context.setLineWidth(.zero)

        guard showHeadingArrow else {
            innerCircleDrawing.apply(in: context)

            innerBorderDrawing.apply(in: context)

            return
        }

        context.addLines(between: [
            CGPoint(x: innerBorderRect.minX, y: innerBorderRect.midY),
            CGPoint(x: iconRect.midX, y: iconRect.maxY),
            CGPoint(x: innerBorderRect.maxX, y: innerBorderRect.midY)
        ])

        context.drawPath(using: .fillStroke)

        innerCircleDrawing.apply(in: context)

        innerBorderDrawing.apply(in: context)

        context.setBlendMode(.destinationAtop)
        outerBorderDrawing.apply(in: context)
    }
}