module JosieHealth
  module Utils
    struct Result(T)
      getter data : T?
      getter error : String?
      getter status_code : Int32

      def initialize(@data : T?, @error : String?, @status_code : Int32 = 200)
      end

      def self.success(data : T, status_code : Int32 = 200) : Result(T)
        Result(T).new(data: data, error: nil, status_code: status_code)
      end

      def self.error(message : String, status_code : Int32 = 500) : Result(T)
        Result(T).new(data: nil, error: message, status_code: status_code)
      end

      def self.not_found(message : String = "Not found") : Result(T)
        Result(T).new(data: nil, error: message, status_code: 404)
      end

      def success? : Bool
        @error.nil? && @data != nil
      end

      def failure? : Bool
        !success?
      end

      def unwrap! : T
        @data.not_nil!
      end

      def unwrap_or(default : T) : T
        @data || default
      end

      def map(&block : T -> U) : Result(U) forall U
        if d = @data
          Result(U).success(yield d, @status_code)
        else
          Result(U).new(data: nil, error: @error, status_code: @status_code)
        end
      end
    end
  end
end