lalkrishna/HTMLBuilder.swift

## HTMLBuilder.swift
//
//  HTMLBuilder.swift
//  HTMLBuilder
//
//  Created by Lal Krishna on 11/03/22.
//  Copyright © 2022 Lal Krishna. All rights reserved.
//

import Foundation
import UIKit

extension HTMLBuilder {
    static func `default`() -> Self {
        let font = UIFont.appFont(style: .regular, ofSize: 22)
        let fontFaces = [
            font.fontName: font.fontName + ".ttf"
        ]
        let builder = HTMLBuilder(defaultFontName: font.fontName, fontFaces: fontFaces)
        return builder
    }
}

struct HTMLBuilder {

    let css: String

    typealias FontName = String
    typealias FontFileName = String

    /// Key-value pair
    /// Example: `[ "Arial-Bold": "Arial_Bold.ttf"`
    var fontFaces: [FontName: FontFileName]

    private var bodyContent: String = ""

    init(defaultFontName: String, fontFaces: [FontName: FontFileName]? = nil, css: String? = nil) {
        self.fontFaces = fontFaces ?? [:]
        self.css = css ?? Self.defaultCSS(defaultFontName: defaultFontName)
    }

    private var attributedText: NSAttributedString? {
        let htmlContent = html
        let htmlData = NSString(string: htmlContent).data(using: String.Encoding.unicode.rawValue)

        let options = [NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.html]

        let attributedString = try? NSAttributedString(data: htmlData!, options: options, documentAttributes: nil)

        return attributedString
    }

    mutating func buildAttributedString(_ htmlContent: String, color: UIColor? = nil) -> NSAttributedString? {
        self.bodyContent = htmlContent
        guard let attributed = attributedText else { return nil }
        guard let color = color else { return attributed }
        let mutable = NSMutableAttributedString(attributedString: attributed)
        mutable.addAttributes([.foregroundColor: color], range: .init(location: 0, length: attributed.length))
        return mutable
    }

    var html: String {
        """
        <html>
            \(head)
            <body>
                \(bodyContent)
            </body>
        </html>
        """
    }

    var head: String {
        """
        </head>
            \(style)
        </head>
        """
    }

    var style: String {
        """
        <style>
            \(fontFacesCSS)
            \(css)
        </style>
        """
    }

    private static func defaultCSS(defaultFontName: String) -> String {
        """
        body {
            font-family: '\(defaultFontName)';
            line-height: 1.6;
        }
        """
    }

//        var css = buildFontFaces()
//        let linkCSS = #"<link rel="stylesheet" type="text/css" href="productDescriptionStyle.css">"#
    var fontFacesCSS: String {
        fontFaces.reduce("") { $0 + "\n" + Self.fontFace(name: $1.key, path: $1.value) }
    }

    mutating func addFontFace(name: String, path: String) {
        fontFaces[name] = path
    }

    private static func fontFace(name: String, path: String) -> String {
        """
        @font-face {
          font-family: '\(name)';
          src: local('\(name)'),url('\(path)')');
        }
        """
    }
}

// Usage
// HTMLBuilder.default().buildAttributedString(htmlContentString, color: UIColor.red)
	//
	// HTMLBuilder.swift
	// HTMLBuilder
	//
	// Created by Lal Krishna on 11/03/22.
	// Copyright © 2022 Lal Krishna. All rights reserved.
	//

	import Foundation
	import UIKit

	extension HTMLBuilder {
	static func `default`() -> Self {
	let font = UIFont.appFont(style: .regular, ofSize: 22)
	let fontFaces = [
	font.fontName: font.fontName + ".ttf"
	]
	let builder = HTMLBuilder(defaultFontName: font.fontName, fontFaces: fontFaces)
	return builder
	}
	}

	struct HTMLBuilder {

	let css: String

	typealias FontName = String
	typealias FontFileName = String

	/// Key-value pair
	/// Example: `[ "Arial-Bold": "Arial_Bold.ttf"`
	var fontFaces: [FontName: FontFileName]

	private var bodyContent: String = ""

	init(defaultFontName: String, fontFaces: [FontName: FontFileName]? = nil, css: String? = nil) {
	self.fontFaces = fontFaces ?? [:]
	self.css = css ?? Self.defaultCSS(defaultFontName: defaultFontName)
	}

	private var attributedText: NSAttributedString? {
	let htmlContent = html
	let htmlData = NSString(string: htmlContent).data(using: String.Encoding.unicode.rawValue)

	let options = [NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.html]

	let attributedString = try? NSAttributedString(data: htmlData!, options: options, documentAttributes: nil)

	return attributedString
	}

	mutating func buildAttributedString(_ htmlContent: String, color: UIColor? = nil) -> NSAttributedString? {
	self.bodyContent = htmlContent
	guard let attributed = attributedText else { return nil }
	guard let color = color else { return attributed }
	let mutable = NSMutableAttributedString(attributedString: attributed)
	mutable.addAttributes([.foregroundColor: color], range: .init(location: 0, length: attributed.length))
	return mutable
	}

	var html: String {
	"""
	<html>
	\(head)
	<body>
	\(bodyContent)
	</body>
	</html>
	"""
	}

	var head: String {
	"""
	</head>
	\(style)
	</head>
	"""
	}

	var style: String {
	"""
	<style>
	\(fontFacesCSS)
	\(css)
	</style>
	"""
	}

	private static func defaultCSS(defaultFontName: String) -> String {
	"""
	body {
	font-family: '\(defaultFontName)';
	line-height: 1.6;
	}
	"""
	}

	// var css = buildFontFaces()
	// let linkCSS = #"<link rel="stylesheet" type="text/css" href="productDescriptionStyle.css">"#
	var fontFacesCSS: String {
	fontFaces.reduce("") { $0 + "\n" + Self.fontFace(name: $1.key, path: $1.value) }
	}

	mutating func addFontFace(name: String, path: String) {
	fontFaces[name] = path
	}

	private static func fontFace(name: String, path: String) -> String {
	"""
	@font-face {
	font-family: '\(name)';
	src: local('\(name)'),url('\(path)')');
	}
	"""
	}
	}

	// Usage
	// HTMLBuilder.default().buildAttributedString(htmlContentString, color: UIColor.red)