import Foundation

class SVGParserRegexHelper {

    fileprivate static let transformAttributePattern = "([a-z]+)\\(((\\-?\\d+\\.?\\d*e?\\-?\\d*\\s*,?\\s*)+)\\)"
    fileprivate static let transformPattern = "\\-?\\d+\\.?\\d*e?\\-?\\d*"
    fileprivate static let textElementPattern = "<text.*?>((?s:.*))<\\/text>"
    fileprivate static let maskIdenitifierPattern = "url\\(#((?s:.*))\\)"
    fileprivate static let unitsIdenitifierPattern = "([a-zA-Z]+)$"

    fileprivate static var transformMatcher: NSRegularExpression?
    fileprivate static var transformAttributeMatcher: NSRegularExpression?
    fileprivate static var textElementMatcher: NSRegularExpression?
    fileprivate static var maskIdenitifierMatcher: NSRegularExpression?
    fileprivate static var unitsMatcher: NSRegularExpression?

    class func getTransformAttributeMatcher() -> NSRegularExpression? {
        if self.transformAttributeMatcher == nil {
            do {
                self.transformAttributeMatcher = try NSRegularExpression(pattern: transformAttributePattern, options: .caseInsensitive)
            } catch {

            }
        }
        return self.transformAttributeMatcher
    }

    class func getTransformMatcher() -> NSRegularExpression? {
        if self.transformMatcher == nil {
            do {
                self.transformMatcher = try NSRegularExpression(pattern: transformPattern, options: .caseInsensitive)
            } catch {

            }
        }
        return self.transformMatcher
    }

    class func getTextElementMatcher() -> NSRegularExpression? {
        if self.textElementMatcher == nil {
            do {
                self.textElementMatcher = try NSRegularExpression(pattern: textElementPattern, options: .caseInsensitive)
            } catch {

            }
        }
        return self.textElementMatcher
    }

    class func getMaskIdenitifierMatcher() -> NSRegularExpression? {
        if self.maskIdenitifierMatcher == nil {
            do {
                self.maskIdenitifierMatcher = try NSRegularExpression(pattern: maskIdenitifierPattern, options: .caseInsensitive)
            } catch {

            }
        }
        return self.maskIdenitifierMatcher
    }
    
    class func getUnitsIdenitifierMatcher() -> NSRegularExpression? {
        if unitsMatcher == nil {
            do {
                unitsMatcher = try NSRegularExpression(pattern: unitsIdenitifierPattern, options: .caseInsensitive)
            } catch {
                
            }
        }
        return unitsMatcher
    }

}