import Foundation

extension String {

    var nonEmpty: String? {
        self.isEmpty ? nil : self
    }

    var trimmed: String {
        trimmingCharacters(in: .whitespacesAndNewlines)
    }

    func indented(by indentation: String) -> String {
        components(separatedBy: "\n").joined(separator: "\n" + indentation)
    }

    var withoutEmptyLines: String {
        components(separatedBy: "\n")
            .filter { !$0.trimmed.isEmpty }
            .joined(separator: "\n")
    }

    func dropAfterLast(_ separator: String) -> String {
        components(separatedBy: separator).dropLast().joined(separator: separator)
    }

    func dropBeforeFirst(_ separator: String) -> String {
        components(separatedBy: separator).dropFirst().joined(separator: separator)
    }

    func lastComponentAfter(_ separator: String) -> String {
        components(separatedBy: separator).last!
    }

    func insert(_ content: String, beforeLast separator: String) -> String {
        let parts = components(separatedBy: separator)
        return parts.dropLast().joined(separator: separator) + content + separator + parts.last!
    }

    func dropAfterFirst<T>(_ separator: T) -> String where T: StringProtocol {
        components(separatedBy: separator).first!
    }

    func between(_ start: String, and end: String) -> String {
        dropBeforeFirst(start).dropAfterFirst(end)
    }
}

extension Substring {

    func between(_ start: String, and end: String) -> String {
        components(separatedBy: start).last!
            .components(separatedBy: end).first!
    }
}