import UIKit

class ViewController: UITableViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        URLSession.shared.dataTask(with: URL(string: "https://app.meinali.com/all/?a=show&c=cailiao&id=291")!) { (data, response, err) in
            if let data = data, let json = try? JSONSerialization.jsonObject(with: data, options: .mutableContainers) as? [String: Any] {
                if let content = (json?["retData"] as? [String: Any])?["content"] as? String {
                    DispatchQueue.main.async {
                        let cell = self.tableView.cellForRow(at: IndexPath(row: 2, section: 0))
                        let html  = """
                            <font style=\"font-size:14px\">\(content)</font>
                            <style>img{display:block;margin:auto;}</style>
                            """.toHTML  // NSAttributedString
                        // 给页面添加行间距和段落间距
                        cell?.textLabel?.attributedText = html?.append(.pClosure { (style) in
                            style.lineSpacing = 5
                            style.paragraphSpacing = 10
                        })
                        cell?.textLabel?.attributedText = html
                        self.tableView.reloadData()
                    }
                }
            }
        }.resume()
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 3
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell")!

        if indexPath.row == 0 {
            
            cell.textLabel?.attributedText = "决斗当日".addAttributes(.font(.systemFont(ofSize: 28)), .color(.blue))
                .add("谢尔兹和林肯按照约定来到密西西比河畔，".addAttributes(.font(.systemFont(ofSize: 17))))
                .add("在岸上对峙。".addAttributes(.backColor(.red)))
                .add("两人都做好了战斗致死的准备。".addAttributes(.strikethrough(.styleSingle)))
                .add("幸运的是，".addAttributes(.font(.systemFont(ofSize: 14)), .color(.white), .backColor(.black)))
                .add("在".addAttributes())
                .add("千钧一发".addAttributes(.font(.systemFont(ofSize: 28)), .underline(.styleSingle)))
                .add("之际，两个人的支持者及时赶到，".addAttributes(.font(.systemFont(ofSize: 14))))
                .add("阻止了悲剧的发生。".addAttributes(.font(.systemFont(ofSize: 17)), .color(.yellow), .backColor(.gray)))

        }else if indexPath.row == 1 {

            cell.textLabel?.attributedText = "0.00\n账号余额".addAttributes(.pClosure { (style) in
                style.lineSpacing = 5
                style.alignment = .center
            })
        }

        return cell
    }
}

public enum Attribute {
    /// 前景颜色
    case color(UIColor)
    /// 背景颜色
    case backColor(UIColor)
    /// 字体
    case font(UIFont)
    /// 段落1
    case pStyle(NSMutableParagraphStyle)
    /// 段落2
    case pClosure((NSMutableParagraphStyle) -> Void)
    /// 删除线
    case strikethrough(NSUnderlineStyle)
    /// 删除线颜色
    case strikethroughColor(UIColor)
    /// 删除线加颜色
    case strikethroughWithColor(NSUnderlineStyle, UIColor)
    /// 下划线
    case underline(NSUnderlineStyle)
    /// 下划线颜色
    case underlineColor(UIColor)
    /// 下划线和颜色
    case underlineWithColor(NSUnderlineStyle, UIColor)
}

public extension String {    
    /// 添加多个属性
    func addAttributes(_ attrs: Attribute...) -> NSMutableAttributedString
    /// 添加单个属性，文字默认为黑色
    func addAttributes(_ attrs: Attribute = .color(.black)) -> NSMutableAttributedString
    /// 转换成 HTML 格式的属性字符串
    var toHTML: NSMutableAttributedString?
}

public extension NSMutableAttributedString {
    
    /// 添加属性字符串
    /// 如果传入的属性字符串没有 .font 属性，则同步上一个的 font
    @discardableResult
    func add(_ attrStr: NSAttributedString) -> NSMutableAttributedString
    
    /// 替换指定节点字符串
    func replace(at index: Int, with str: String)
    
    /// 替换指定节点属性字符串
    func replace(at index: Int, with attrString: NSAttributedString)
    
    /// 重置指定节点属性
    func set(_ attrs: Attribute..., at index: Int)
    
    /// 给指定节点字符串追加属性
    func add(_ attrs: Attribute..., at index: Int)
    
    /// 给整段字符串追加属性
    func add(_ attrs: Attribute...)
}

public extension NSAttributedString {
    
    /// 返回指定节点的属性字典
    func attributes(at index: Int) -> [NSAttributedStringKey: Any]
    
    /// 获取指定节点的所在范围
    func range(at index: Int) -> NSRange
    
    /// 返回指定节点的属性字符串
    subscript(index: Int) -> NSAttributedString
    
    /// 返回指定节点的字符串
    subscript(index: Int) -> String
}