extension UIFont {
    
    func sizeOfString(string: NSString, constrainedToWidth width: Double) -> CGSize {
        return string.boundingRectWithSize(CGSize(width: width, height: DBL_MAX), options: NSStringDrawingOptions.UsesLineFragmentOrigin, attributes: [NSFontAttributeName: self], context: nil).size
    }
    
}

extension String {
    
    static private var kPBegin = "<p>"
    static private var kPEnd = "</p>"
    static private var kBBegin = "<b>"
    static private var kBEnd = "</b>"
    static private var kBr = "<br>"
    static private var kNewLine = "\n"
    static private var kSpaceSymbol = " "
    static private var kPreBegin = "<pre>"
    static private var kPreEnd = "</pre>"
    static private var kTableBegin = "<table"
    static private var kTableEnd = "</table>"
    
    static func replaceHTMLTablesWithFormattedText(htmlText: String?) -> String? {
        if nil == htmlText {
            return htmlText
        }
        
        let font = UIFont.systemFontOfSize(12)
        let compareWidth = 10000.0
        
        var result: NSString = htmlText!
        var rangeStart = result.rangeOfString(kTableBegin, options: [.CaseInsensitiveSearch])
        while rangeStart.location != NSNotFound {
            let rangeEnd = result.rangeOfString(kTableEnd, options: [.CaseInsensitiveSearch])
            if rangeEnd.location != NSNotFound {
                let rangeTable = NSMakeRange(rangeStart.location, rangeEnd.location+rangeEnd.length - rangeStart.location)
                let stringTable = result.substringWithRange(rangeTable)
                
                let html = Ji(htmlString: stringTable)
                if let table = html?.rootNode?.firstChild?.firstChild, body = table.firstChild { // html->body->table->tbody->...
                    var data = [[String]]()
                    let trs = body.children
                    if let maxTds = trs.first?.children.count {
                        for i in 0...maxTds-1 {
                            var columnData = [String]()
                            for tr in trs {
                                let tds = tr.children
                                if i < tds.count {
                                    let td = tds[i]
                                    if let content = String.stringByStripHTML(td.content) {
                                        columnData.append(content)
                                    }
                                    continue
                                }
                                columnData.append("")
                            }
                            data.append(columnData)
                        }
                    }
                    
                    var fixedTable = kBr
                    if data.count > 0 {
                        for i in 0...data[0].count-1 { // columns
                            var maxLength: CGFloat = 0
                            for j in 0...data.count-1 { // rows
                                let string = data[i][j]
                                let length = font.sizeOfString(string, constrainedToWidth: compareWidth).width
                                if length > maxLength {
                                    maxLength = length
                                }
                            }
                            for j in 0...data.count-1 {
                                let string = data[i][j]
                                let length = font.sizeOfString(string, constrainedToWidth: compareWidth).width
                                var spaces = maxLength - length
                                if spaces > 0 {
                                    spaces /= font.sizeOfString(kSpaceSymbol, constrainedToWidth: compareWidth).width
                                    let count = Int(spaces)
                                    if count > 0 {
                                        data[i][j] = string + String(count: count, repeatedValue: kSpaceSymbol.characters.first!)
                                    }
                                }
                            }
                        }
                        
                        for i in 0...data.count-1 { // rows
                            var row = [String]()
                            for j in 0...data[0].count-1 { // columns
                                row.append(data[j][i])
                            }
                            fixedTable += kPreBegin + row.joinWithSeparator(kSpaceSymbol + kSpaceSymbol) + kPreEnd + kBr
                        }
                    }
                    
                    result = result.stringByReplacingOccurrencesOfString(stringTable, withString: fixedTable)
                } else {
                    return result as String
                }
                
                rangeStart = result.rangeOfString(kTableBegin, options: [.CaseInsensitiveSearch])
            } else {
                return result as String
            }
        }
        return result as String
    }
    
  }