# frozen_string_literal: true

module Gem
  ##
  # Provides 3 methods for declaring when something is going away.
  #
  # <tt>deprecate(name, repl, year, month)</tt>:
  #     Indicate something may be removed on/after a certain date.
  #
  # <tt>rubygems_deprecate(name, replacement=:none)</tt>:
  #     Indicate something will be removed in the next major RubyGems version,
  #     and (optionally) a replacement for it.
  #
  # +rubygems_deprecate_command+:
  #     Indicate a RubyGems command (in +lib/rubygems/commands/*.rb+) will be
  #     removed in the next RubyGems version.
  #
  # Also provides +skip_during+ for temporarily turning off deprecation warnings.
  # This is intended to be used in the test suite, so deprecation warnings
  # don't cause test failures if you need to make sure stderr is otherwise empty.
  #
  #
  # Example usage of +deprecate+ and +rubygems_deprecate+:
  #
  #     class Legacy
  #       def self.some_class_method
  #         # ...
  #       end
  #
  #       def some_instance_method
  #         # ...
  #       end
  #
  #       def some_old_method
  #         # ...
  #       end
  #
  #       extend Gem::Deprecate
  #       deprecate :some_instance_method, "X.z", 2011, 4
  #       rubygems_deprecate :some_old_method, "Modern#some_new_method"
  #
  #       class << self
  #         extend Gem::Deprecate
  #         deprecate :some_class_method, :none, 2011, 4
  #       end
  #     end
  #
  #
  # Example usage of +rubygems_deprecate_command+:
  #
  #     class Gem::Commands::QueryCommand < Gem::Command
  #       extend Gem::Deprecate
  #       rubygems_deprecate_command
  #
  #       # ...
  #     end
  #
  #
  # Example usage of +skip_during+:
  #
  #     class TestSomething < Gem::Testcase
  #       def test_some_thing_with_deprecations
  #         Gem::Deprecate.skip_during do
  #           actual_stdout, actual_stderr = capture_output do
  #             Gem.something_deprecated
  #           end
  #           assert_empty actual_stdout
  #           assert_equal(expected, actual_stderr)
  #         end
  #       end
  #     end

  module Deprecate
    def self.skip # :nodoc:
      @skip ||= false
    end

    def self.skip=(v) # :nodoc:
      @skip = v
    end

    ##
    # Temporarily turn off warnings. Intended for tests only.

    def skip_during
      original = Gem::Deprecate.skip
      Gem::Deprecate.skip = true
      yield
    ensure
      Gem::Deprecate.skip = original
    end

    def self.next_rubygems_major_version # :nodoc:
      Gem::Version.new(Gem.rubygems_version.segments.first).bump
    end

    ##
    # Simple deprecation method that deprecates +name+ by wrapping it up
    # in a dummy method. It warns on each call to the dummy method
    # telling the user of +repl+ (unless +repl+ is :none) and the
    # year/month that it is planned to go away.

    def deprecate(name, repl, year, month)
      class_eval do
        old = "_deprecated_#{name}"
        alias_method old, name
        define_method name do |*args, &block|
          klass = is_a? Module
          target = klass ? "#{self}." : "#{self.class}#"
          msg = [
            "NOTE: #{target}#{name} is deprecated",
            repl == :none ? " with no replacement" : "; use #{repl} instead",
            Kernel.format(". It will be removed on or after %4d-%02d.", year, month),
            "\n#{target}#{name} called from #{Gem.location_of_caller.join(":")}",
          ]
          warn "#{msg.join}." unless Gem::Deprecate.skip
          send old, *args, &block
        end
        ruby2_keywords name if respond_to?(:ruby2_keywords, true)
      end
    end

    ##
    # Simple deprecation method that deprecates +name+ by wrapping it up
    # in a dummy method. It warns on each call to the dummy method
    # telling the user of +repl+ (unless +repl+ is :none) and the
    # Rubygems version that it is planned to go away.

    def rubygems_deprecate(name, replacement = :none, version = nil)
      class_eval do
        old = "_deprecated_#{name}"
        alias_method old, name
        define_method name do |*args, &block|
          klass = is_a? Module
          target = klass ? "#{self}." : "#{self.class}#"
          version ||= Gem::Deprecate.next_rubygems_major_version
          msg = [
            "NOTE: #{target}#{name} is deprecated",
            replacement == :none ? " with no replacement" : "; use #{replacement} instead",
            ". It will be removed in Rubygems #{version}",
            "\n#{target}#{name} called from #{Gem.location_of_caller.join(":")}",
          ]
          warn "#{msg.join}." unless Gem::Deprecate.skip
          send old, *args, &block
        end
        ruby2_keywords name if respond_to?(:ruby2_keywords, true)
      end
    end

    # Deprecation method to deprecate Rubygems commands
    def rubygems_deprecate_command(version = nil)
      class_eval do
        define_method "deprecated?" do
          true
        end

        define_method "deprecation_warning" do
          version ||= Gem::Deprecate.next_rubygems_major_version
          msg = [
            "#{command} command is deprecated",
            ". It will be removed in Rubygems #{version}.\n",
          ]

          alert_warning msg.join.to_s unless Gem::Deprecate.skip
        end
      end
    end

    module_function :rubygems_deprecate, :rubygems_deprecate_command, :skip_during
  end
end
