MO_Chat/Frameworks/DesignKit/src/Font/UIFontExtensions.swift

//
//  UIFont+Typography.swift
//  DesignKit
//
//  Created by Jake Lin on 19/10/20.
//

import UIKit
import SwiftUI

public extension UIFont {
    static let designKit = DesignKitTypography()

    struct DesignKitTypography {
        public var display1: UIFont {
            scaled(baseFont: .systemFont(ofSize: 42, weight: .semibold), forTextStyle: .largeTitle, maximumPointSize: 49)
        }

        public var display2: UIFont {
            scaled(baseFont: .systemFont(ofSize: 36, weight: .semibold), forTextStyle: .largeTitle, maximumPointSize: 42)
        }

        public var title1: UIFont {
            scaled(baseFont: .systemFont(ofSize: 24, weight: .semibold), forTextStyle: .title1, maximumPointSize: 29)
        }

        public var title2: UIFont {
            scaled(baseFont: .systemFont(ofSize: 20, weight: .semibold), forTextStyle: .title2, maximumPointSize: 24)
        }

        public var title3: UIFont {
            scaled(baseFont: .systemFont(ofSize: 18, weight: .semibold), forTextStyle: .title3, maximumPointSize: 23)
        }

        public var title4: UIFont {
            scaled(baseFont: .systemFont(ofSize: 14, weight: .regular), forTextStyle: .headline, maximumPointSize: 18)
        }

        public var title5: UIFont {
            scaled(baseFont: .systemFont(ofSize: 12, weight: .regular), forTextStyle: .subheadline, maximumPointSize: 16)
        }

        public var bodyBold: UIFont {
            scaled(baseFont: .systemFont(ofSize: 16, weight: .semibold), forTextStyle: .body, maximumPointSize: 21)
        }

        public var body: UIFont {
            scaled(baseFont: .systemFont(ofSize: 16, weight: .regular), forTextStyle: .body, maximumPointSize: 21)
        }

        public var captionBold: UIFont {
            scaled(baseFont: .systemFont(ofSize: 14, weight: .semibold), forTextStyle: .caption1, maximumPointSize: 20)
        }

        public var caption: UIFont {
            scaled(baseFont: .systemFont(ofSize: 14, weight: .light), forTextStyle: .caption1, maximumPointSize: 20)
        }

        public var small: UIFont {
            scaled(baseFont: .systemFont(ofSize: 12, weight: .light), forTextStyle: .footnote, maximumPointSize: 16)
        }
    }
    static func font(ofSize fontSize: CGFloat, weight: UIFont.Weight = .regular) -> UIFont {
        return .systemFont(ofSize: fontSize, weight: weight)
    }
}

public extension Font {
    static func font(ofSize fontSize: CGFloat, weight: UIFont.Weight = .regular) -> Font {
        return Font(UIFont.systemFont(ofSize: fontSize, weight: weight))
    }
}

private extension UIFont.DesignKitTypography {
    func scaled(baseFont: UIFont, forTextStyle textStyle: UIFont.TextStyle = .body, maximumPointSize: CGFloat? = nil) -> UIFont {
        let fontMetrics = UIFontMetrics(forTextStyle: textStyle)

        if let maximumPointSize = maximumPointSize {
            return fontMetrics.scaledFont(for: baseFont, maximumPointSize: maximumPointSize)
        }
        return fontMetrics.scaledFont(for: baseFont)
    }
}