require_relative '../../spec_helper'
require_relative 'fixtures/classes'

describe "Method#parameters" do
  class MethodSpecs::Methods
    def one_key(a: 1); end
    def one_keyrest(**a); end

    def one_keyreq(a:); end
    def one_nokey(**nil); end

    def one_splat_one_req(*a,b); end
    def one_splat_two_req(*a,b,c); end
    def one_splat_one_req_with_block(*a,b,&blk); end

    def one_opt_with_stabby(a=-> b { true }); end

    def one_unnamed_splat(*); end
    def one_unnamed_keyrest(**); end

    def one_splat_one_block(*args, &block)
      local_is_not_parameter = {}
    end

    def underscore_parameters(_, _, _ = 1, *_, _:, _: 2, **_, &_); end

    define_method(:one_optional_defined_method) {|x = 1|}
  end

  it "returns an empty Array when the method expects no arguments" do
    MethodSpecs::Methods.instance_method(:zero).parameters.should == []
  end

  it "returns [[:req,:name]] for a method expecting one required argument called 'name'" do
    MethodSpecs::Methods.instance_method(:one_req).parameters.should == [[:req,:a]]
  end

  it "returns [[:req,:a],[:req,:b]] for a method expecting two required arguments called 'a' and 'b''" do
    m = MethodSpecs::Methods.instance_method(:two_req)
    m.parameters.should == [[:req,:a], [:req,:b]]
  end

  it "returns [[:block,:blk]] for a method expecting one block argument called 'a'" do
    m = MethodSpecs::Methods.instance_method(:zero_with_block)
    m.parameters.should == [[:block,:blk]]
  end

  it "returns [[:req,:a],[:block,:b] for a method expecting a required argument ('a') and a block argument ('b')" do
    m = MethodSpecs::Methods.instance_method(:one_req_with_block)
    m.parameters.should == [[:req,:a], [:block,:blk]]
  end

  it "returns [[:req,:a],[:req,:b],[:block,:c] for a method expecting two required arguments ('a','b') and a block argument ('c')" do
    m = MethodSpecs::Methods.instance_method(:two_req_with_block)
    m.parameters.should == [[:req,:a], [:req,:b], [:block,:blk]]
  end

  it "returns [[:opt,:a]] for a method expecting one optional argument ('a')" do
    m = MethodSpecs::Methods.instance_method(:one_opt)
    m.parameters.should == [[:opt,:a]]
  end

  it "returns [[:req,:a],[:opt,:b]] for a method expecting one required argument ('a') and one optional argument ('b')" do
    m = MethodSpecs::Methods.instance_method(:one_req_one_opt)
    m.parameters.should == [[:req,:a],[:opt,:b]]
  end

  it "returns [[:req,:a],[:opt,:b]] for a method expecting one required argument ('a') and one optional argument ('b')" do
    m = MethodSpecs::Methods.instance_method(:one_req_one_opt)
    m.parameters.should == [[:req,:a],[:opt,:b]]
  end

  it "returns [[:req,:a],[:opt,:b],[:opt,:c]] for a method expecting one required argument ('a') and two optional arguments ('b','c')" do
    m = MethodSpecs::Methods.instance_method(:one_req_two_opt)
    m.parameters.should == [[:req,:a],[:opt,:b],[:opt,:c]]
  end

  it "returns [[:req,:a],[:req,:b],[:opt,:c]] for a method expecting two required arguments ('a','b') and one optional arguments ('c')" do
    m = MethodSpecs::Methods.instance_method(:two_req_one_opt)
    m.parameters.should == [[:req,:a],[:req,:b],[:opt,:c]]
  end

  it "returns [[:opt,:a],[:block,:b]] for a method expecting one required argument ('a') and one block argument ('b')" do
    m = MethodSpecs::Methods.instance_method(:one_opt_with_block)
    m.parameters.should == [[:opt,:a],[:block,:blk]]
  end

  it "returns [[:req,:a],[:opt,:b],[:block,:c]] for a method expecting one required argument ('a'), one optional argument ('b'), and a block ('c')" do
    m = MethodSpecs::Methods.instance_method(:one_req_one_opt_with_block)
    m.parameters.should == [[:req,:a],[:opt,:b],[:block,:blk]]
  end

  it "returns [[:req,:a],[:opt,:b],[:opt,:c],[:block,:d]] for a method expecting one required argument ('a'), two optional arguments ('b','c'), and a block ('d')" do
    m = MethodSpecs::Methods.instance_method(:one_req_two_opt_with_block)
    m.parameters.should == [[:req,:a],[:opt,:b],[:opt,:c],[:block,:blk]]
  end

  it "returns [[:rest,:a]] for a method expecting a single splat argument ('a')" do
    m = MethodSpecs::Methods.instance_method(:zero_with_splat)
    m.parameters.should == [[:rest,:a]]
  end

  it "returns [[:req,:a],[:rest,:b]] for a method expecting a splat argument ('a') and a required argument ('b')" do
    m = MethodSpecs::Methods.instance_method(:one_req_with_splat)
    m.parameters.should == [[:req,:a],[:rest,:b]]
  end

  it "returns [[:req,:a],[:req,:b],[:rest,:c]] for a method expecting two required arguments ('a','b') and a splat argument ('c')" do
    m = MethodSpecs::Methods.instance_method(:two_req_with_splat)
    m.parameters.should == [[:req,:a],[:req,:b],[:rest,:c]]
  end

  it "returns [[:req,:a],[:opt,:b],[:rest,:c]] for a method expecting a required argument ('a','b'), an optional argument ('b'), and a splat argument ('c')" do
    m = MethodSpecs::Methods.instance_method(:one_req_one_opt_with_splat)
    m.parameters.should == [[:req,:a],[:opt,:b],[:rest,:c]]
  end

  it "returns [[:req,:a],[:req,:b],[:opt,:b],[:rest,:d]] for a method expecting two required arguments ('a','b'), an optional argument ('c'), and a splat argument ('d')" do
    m = MethodSpecs::Methods.instance_method(:two_req_one_opt_with_splat)
    m.parameters.should == [[:req,:a],[:req,:b],[:opt,:c],[:rest,:d]]
  end

  it "returns [[:req,:a],[:opt,:b],[:opt,:c],[:rest,:d]] for a method expecting a required argument ('a'), two optional arguments ('b','c'), and a splat argument ('d')" do
    m = MethodSpecs::Methods.instance_method(:one_req_two_opt_with_splat)
    m.parameters.should == [[:req,:a],[:opt,:b],[:opt,:c],[:rest,:d]]
  end

  it "returns [[:rest,:a],[:block,:b]] for a method expecting a splat argument ('a') and a block argument ('b')" do
    m = MethodSpecs::Methods.instance_method(:zero_with_splat_and_block)
    m.parameters.should == [[:rest,:a],[:block,:blk]]
  end

  it "returns [[:req,:a],[:rest,:b],[:block,:c]] for a method expecting a required argument ('a'), a splat argument ('b'), and a block ('c')" do
    m = MethodSpecs::Methods.instance_method(:one_req_with_splat_and_block)
    m.parameters.should == [[:req,:a],[:rest,:b],[:block,:blk]]
  end

  it "returns [[:req,:a],[:req,:b],[:rest,:c],[:block,:d]] for a method expecting two required arguments ('a','b'), a splat argument ('c'), and a block ('d')" do
    m = MethodSpecs::Methods.instance_method(:two_req_with_splat_and_block)
    m.parameters.should == [[:req,:a],[:req,:b],[:rest,:c],[:block,:blk]]
  end

  it "returns [[:req,:a],[:opt,:b],[:rest,:c],[:block,:d]] for a method expecting a required argument ('a'), a splat argument ('c'), and a block ('d')" do
    m = MethodSpecs::Methods.instance_method(:one_req_one_opt_with_splat_and_block)
    m.parameters.should == [[:req,:a],[:opt,:b],[:rest,:c],[:block,:blk]]
  end

  it "returns [[:req,:a],[:req,:b],[:opt,:c],[:block,:d]] for a method expecting two required arguments ('a','b'), an optional argument ('c'), a splat argument ('d'), and a block ('e')" do
    m = MethodSpecs::Methods.instance_method(:two_req_one_opt_with_splat_and_block)
    m.parameters.should == [[:req,:a],[:req,:b],[:opt,:c],[:rest,:d],[:block,:blk]]
  end

  it "returns [[:rest,:a],[:req,:b]] for a method expecting a splat argument ('a') and a required argument ('b')" do
    m = MethodSpecs::Methods.instance_method(:one_splat_one_req)
    m.parameters.should == [[:rest,:a],[:req,:b]]
  end

  it "returns [[:rest,:a],[:req,:b],[:req,:c]] for a method expecting a splat argument ('a') and two required arguments ('b','c')" do
    m = MethodSpecs::Methods.instance_method(:one_splat_two_req)
    m.parameters.should == [[:rest,:a],[:req,:b],[:req,:c]]
  end

  it "returns [[:rest,:a],[:req,:b],[:block,:c]] for a method expecting a splat argument ('a'), a required argument ('b'), and a block ('c')" do
    m = MethodSpecs::Methods.instance_method(:one_splat_one_req_with_block)
    m.parameters.should == [[:rest,:a],[:req,:b],[:block,:blk]]
  end

  it "returns [[:key,:a]] for a method with a single optional keyword argument" do
    m = MethodSpecs::Methods.instance_method(:one_key)
    m.parameters.should == [[:key,:a]]
  end

  it "returns [[:keyrest,:a]] for a method with a keyword rest argument" do
    m = MethodSpecs::Methods.instance_method(:one_keyrest)
    m.parameters.should == [[:keyrest,:a]]
  end

  it "returns [[:keyreq,:a]] for a method with a single required keyword argument" do
    m = MethodSpecs::Methods.instance_method(:one_keyreq)
    m.parameters.should == [[:keyreq,:a]]
  end

  it "returns [[:nokey]] for a method with a single **nil parameter" do
    m = MethodSpecs::Methods.instance_method(:one_nokey)
    m.parameters.should == [[:nokey]]
  end

  it "works with ->(){} as the value of an optional argument" do
    m = MethodSpecs::Methods.instance_method(:one_opt_with_stabby)
    m.parameters.should == [[:opt,:a]]
  end

  # define_method variants
  it "returns [] for a define_method method with explicit no-args || specification" do
    m = MethodSpecs::Methods.instance_method(:zero_defined_method)
    m.parameters.should == []
  end

  it "returns [[:rest, :x]] for a define_method method with rest arg 'x' only" do
    m = MethodSpecs::Methods.instance_method(:zero_with_splat_defined_method)
    m.parameters.should == [[:rest, :x]]
  end

  it "returns [[:req, :x]] for a define_method method expecting one required argument 'x'" do
    m = MethodSpecs::Methods.instance_method(:one_req_defined_method)
    m.parameters.should == [[:req, :x]]
  end

  it "returns [[:req, :x], [:req, :y]] for a define_method method expecting two required arguments 'x' and 'y'" do
    m = MethodSpecs::Methods.instance_method(:two_req_defined_method)
    m.parameters.should == [[:req, :x], [:req, :y]]
  end

  it "returns [] for a define_method method with no args specification" do
    m = MethodSpecs::Methods.instance_method(:no_args_defined_method)
    m.parameters.should == []
  end

  it "returns [[:req]] for a define_method method with a grouping as its only argument" do
    m = MethodSpecs::Methods.instance_method(:two_grouped_defined_method)
    m.parameters.should == [[:req]]
  end

  it "returns [[:opt, :x]] for a define_method method with an optional argument 'x'" do
    m = MethodSpecs::Methods.instance_method(:one_optional_defined_method)
    m.parameters.should == [[:opt, :x]]
  end

  it "returns [[:rest]] for a Method generated by respond_to_missing?" do
    m = MethodSpecs::Methods.new
    m.method(:handled_via_method_missing).parameters.should == [[:rest]]
  end

  ruby_version_is '3.2' do
    it "adds rest arg with name * for \"star\" argument" do
      m = MethodSpecs::Methods.new
      m.method(:one_unnamed_splat).parameters.should == [[:rest, :*]]
    end

    it "adds keyrest arg with ** as a name for \"double star\" argument" do
      m = MethodSpecs::Methods.new
      m.method(:one_unnamed_keyrest).parameters.should == [[:keyrest, :**]]
    end
  end

  ruby_version_is ''...'3.2' do
    it "adds nameless rest arg for \"star\" argument" do
      m = MethodSpecs::Methods.new
      m.method(:one_unnamed_splat).parameters.should == [[:rest]]
    end

    it "adds nameless keyrest arg for \"double star\" argument" do
      m = MethodSpecs::Methods.new
      m.method(:one_unnamed_keyrest).parameters.should == [[:keyrest]]
    end
  end

  ruby_version_is '3.1' do
    it "adds block arg with name & for anonymous block argument" do
      object = Object.new

      eval(<<~RUBY).should == [[:block, :&]]
        def object.foo(&)
        end
        object.method(:foo).parameters
      RUBY
    end
  end

  it "returns the args and block for a splat and block argument" do
    m = MethodSpecs::Methods.new
    m.method(:one_splat_one_block).parameters.should == [[:rest, :args], [:block, :block]]
  end

  it "returns [] for a Method generated by attr_reader" do
    m = MethodSpecs::Methods.new
    m.method(:reader).parameters.should == []
  end

  it "return [[:req]] for a Method generated by attr_writer" do
    m = MethodSpecs::Methods.new
    m.method(:writer=).parameters.should == [[:req]]
  end

  it "returns all parameters defined with the name _ as _" do
    m = MethodSpecs::Methods.instance_method(:underscore_parameters)
    m.parameters.should == [
      [:req, :_],
      [:req, :_],
      [:opt, :_],
      [:rest, :_],
      [:keyreq, :_],
      [:key, :_],
      [:keyrest, :_],
      [:block, :_]
    ]
  end

  it "returns [[:rest]] for core methods with variable-length argument lists" do
    # delete! takes rest args
    "foo".method(:delete!).parameters.should == [[:rest]]
  end

  it "returns [[:rest]] or [[:opt]] for core methods with optional arguments" do
    # pop takes 1 optional argument
    [
      [[:rest]],
      [[:opt]]
    ].should include([].method(:pop).parameters)
  end

  it "returns [[:req]] for each parameter for core methods with fixed-length argument lists" do
    "foo".method(:+).parameters.should == [[:req]]
  end
end