Format a file name of a video to the correct Plex format

String+formattedForPlex.swift

extension String {
    var formattedForPlex: String {
        var newName = self
        
        // Remove all text at the end
        let regexEndText = "\\d{3,4}p.+"
        if let range = newName.range(of: regexEndText, options: .regularExpression) {
            newName.removeSubrange(range)
        }
        
        // Add seperators ( - ) before and after the season/episode.
        let regexSeason = "S\\d\\dE\\d\\d"
        if let range = newName.range(of: regexSeason, options: .regularExpression) {
            // Don't append a trailing dash if there's no relevant text (i.e. episode name)
            // after the episode number.
            let trailingDash: String = !(
                // Are the last two characters of string convertible to an Int?
                (Int(newName.suffix(3).dropLast()) != nil) &&
                // Is the third to last character an "E" for "Episode Number?"
                (newName.suffix(4).first == "E")
            ) ? " -" : ""
            
            let seasonEpisodeID = newName[range]
            newName.replaceSubrange(range, with: "- \(seasonEpisodeID)\(trailingDash)")
        }
        
        // Replace all periods with spaces
        newName = newName.replacingOccurrences(of: ".", with: " ")
        // Trim all extreneous whitespace
        return newName.trimmingCharacters(in: .whitespacesAndNewlines)
    }
}