class WebMock::VersionChecker

def check_version!
  warn_about_too_low if too_low?
  warn_about_too_high if too_high?
  warn_about_unsupported_version if unsupported_version?
end

def colorize(text, color_code)
  "#{color_code}#{text}\e[0m"
end

def compare_version
  case
    when @major < @min_major then :too_low
    when @major == @min_major && @minor < @min_minor then :too_low
    when @major == @min_major && @minor == @min_minor && @patch < @min_patch then :too_low
    when @max_major && @major > @max_major then :too_high
    when @max_major && @major == @max_major && @max_minor && @minor > @max_minor then :too_high
    else :ok
  end
end

def initialize(library_name, library_version, min_patch_level, max_minor_version = nil, unsupported_versions = [])
  @library_name, @library_version = library_name, library_version
  @min_patch_level, @max_minor_version = min_patch_level, max_minor_version
  @unsupported_versions = unsupported_versions || []
  @major,     @minor,     @patch     = parse_version(library_version)
  @min_major, @min_minor, @min_patch = parse_version(min_patch_level)
  if max_minor_version
    @max_major, @max_minor           = parse_version(max_minor_version)
  else
    @max_major, @max_minor           = nil, nil
  end
  @comparison_result = compare_version
end

def parse_version(version)
  version.split('.').map { |v| v.to_i }
end

def too_high?
  @comparison_result == :too_high
end

def too_low?
  @comparison_result == :too_low
end

def unsupported_version?
  @unsupported_versions.include?(@library_version)
end

def version_requirement
  req = ">= #{@min_patch_level}"
  req += ", < #{@max_major}.#{@max_minor + 1}" if @max_minor
  req += ", except versions #{@unsupported_versions.join(',')}" unless @unsupported_versions.empty?
  req
end

def warn_about_too_high
  warn_in_red "You are using #{@library_name} #{@library_version}. " +
              "WebMock is known to work with #{@library_name} #{version_requirement}. " +
              "It may not work with this version."
end

def warn_about_too_low
  warn_in_red "You are using #{@library_name} #{@library_version}. " +
              "WebMock supports version #{version_requirement}."
end

def warn_about_unsupported_version
  warn_in_red "You are using #{@library_name} #{@library_version}. " +
              "WebMock does not support this version. " +
              "WebMock supports versions #{version_requirement}."
end

def warn_in_red(text)
  Kernel.warn colorize(text, "\e[31m")
end