require 'rubygems/test_case'
require 'rubygems/dependency_resolver'

class TestGemDependencyResolver < Gem::TestCase

  def make_dep(name, *req)
    Gem::Dependency.new(name, *req)
  end

  def set(*specs)
    StaticSet.new(specs)
  end

  def assert_set(expected, actual)
    exp = expected.sort_by { |s| s.full_name }
    act = actual.map { |a| a.spec }.sort_by { |s| s.full_name }

    msg = "Set of gems was not the same: #{exp.map { |x| x.full_name}.inspect} != #{act.map { |x| x.full_name}.inspect}"

    assert_equal exp, act, msg
  end

  def test_no_overlap_specificly
    a = util_spec "a", '1'
    b = util_spec "b", "1"

    ad = make_dep "a", "= 1"
    bd = make_dep "b", "= 1"

    deps = [ad, bd]

    s = set(a, b)

    res = Gem::DependencyResolver.new(deps, s)

    assert_set [a, b], res.resolve
  end

  def test_pulls_in_dependencies
    a = util_spec "a", '1'
    b = util_spec "b", "1", "c" => "= 1"
    c = util_spec "c", "1"

    ad = make_dep "a", "= 1"
    bd = make_dep "b", "= 1"

    deps = [ad, bd]

    s = set(a, b, c)

    res = Gem::DependencyResolver.new(deps, s)

    assert_set [a, b, c], res.resolve
  end

  def test_picks_highest_version
    a1 = util_spec "a", '1'
    a2 = util_spec "a", '2'

    s = set(a1, a2)

    ad = make_dep "a"

    res = Gem::DependencyResolver.new([ad], s)

    assert_set [a2], res.resolve
  end

  def test_only_returns_spec_once
    a1 = util_spec "a", "1", "c" => "= 1"
    b1 = util_spec "b", "1", "c" => "= 1"

    c1 = util_spec "c", "1"

    ad = make_dep "a"
    bd = make_dep "b"

    s = set(a1, b1, c1)

    res = Gem::DependencyResolver.new([ad, bd], s)

    assert_set [a1, b1, c1], res.resolve
  end

  def test_picks_lower_version_when_needed
    a1 = util_spec "a", "1", "c" => ">= 1"
    b1 = util_spec "b", "1", "c" => "= 1"

    c1 = util_spec "c", "1"
    c2 = util_spec "c", "2"

    ad = make_dep "a"
    bd = make_dep "b"

    s = set(a1, b1, c1, c2)

    res = Gem::DependencyResolver.new([ad, bd], s)

    assert_set [a1, b1, c1], res.resolve

    cons = res.conflicts

    assert_equal 1, cons.size
    con = cons.first

    assert_equal "c (= 1)", con.dependency.to_s
    assert_equal "c-2", con.activated.full_name
  end

  def test_conflict_resolution_only_effects_correct_spec
    a1 = util_spec "a", "1", "c" => ">= 1"
    b1 = util_spec "b", "1", "d" => ">= 1"

    d3 = util_spec "d", "3", "c" => "= 1"
    d4 = util_spec "d", "4", "c" => "= 1"

    c1 = util_spec "c", "1"
    c2 = util_spec "c", "2"

    ad = make_dep "a"
    bd = make_dep "b"

    s = set(a1, b1, d3, d4, c1, c2)

    res = Gem::DependencyResolver.new([ad, bd], s)

    assert_set [a1, b1, c1, d4], res.resolve

    cons = res.conflicts

    assert_equal 1, cons.size
    con = cons.first

    assert_equal "c (= 1)", con.dependency.to_s
    assert_equal "c-2", con.activated.full_name
  end

  def test_raises_dependency_error
    a1 = util_spec "a", "1", "c" => "= 1"
    b1 = util_spec "b", "1", "c" => "= 2"

    c1 = util_spec "c", "1"
    c2 = util_spec "c", "2"

    ad = make_dep "a"
    bd = make_dep "b"

    s = set(a1, b1, c1, c2)

    r = Gem::DependencyResolver.new([ad, bd], s)

    e = assert_raises Gem::DependencyResolutionError do
      r.resolve
    end

    assert_equal "unable to resolve conflicting dependencies 'c (= 2)' and 'c (= 1)'", e.message

    deps = [make_dep("c", "= 2"), make_dep("c", "= 1")]
    assert_equal deps, e.conflicting_dependencies

    con = e.conflict

    act = con.activated
    assert_equal "c-1", act.spec.full_name

    parent = act.parent
    assert_equal "a-1", parent.spec.full_name

    act = con.requester
    assert_equal "b-1", act.spec.full_name
  end

  def test_raises_when_a_gem_is_missing
    ad = make_dep "a"

    r = Gem::DependencyResolver.new([ad], set)

    e = assert_raises Gem::UnsatisfiableDepedencyError do
      r.resolve
    end

    assert_equal "Unable to resolve dependency: (unknown) requires a (>= 0)",
                 e.message

    assert_equal "a (>= 0)", e.dependency.to_s
  end

  def test_raises_when_a_gem_version_is_missing
    a1 = util_spec "a", "1"

    ad = make_dep "a", "= 3"

    r = Gem::DependencyResolver.new([ad], set(a1))

    e = assert_raises Gem::UnsatisfiableDepedencyError do
      r.resolve
    end

    assert_equal "a (= 3)", e.dependency.to_s
  end

  def test_raises_when_possibles_are_exhausted
    a1 = util_spec "a", "1", "c" => ">= 2"
    b1 = util_spec "b", "1", "c" => "= 1"

    c1 = util_spec "c", "1"
    c2 = util_spec "c", "2"
    c3 = util_spec "c", "3"

    s = set(a1, b1, c1, c2, c3)

    ad = make_dep "a"
    bd = make_dep "b"

    r = Gem::DependencyResolver.new([ad, bd], s)

    e = assert_raises Gem::ImpossibleDependenciesError do
      r.resolve
    end

    assert_match "a-1 requires c (>= 2) but it conflicted", e.message

    assert_equal "c (>= 2)", e.dependency.to_s

    s, con = e.conflicts[0]
    assert_equal "c-3", s.full_name
    assert_equal "c (= 1)", con.dependency.to_s
    assert_equal "b-1", con.requester.full_name
  end

  def test_keeps_resolving_after_seeing_satisfied_dep
    a1 = util_spec "a", "1", "b" => "= 1", "c" => "= 1"
    b1 = util_spec "b", "1"
    c1 = util_spec "c", "1"

    ad = make_dep "a"
    bd = make_dep "b"

    s = set(a1, b1, c1)

    r = Gem::DependencyResolver.new([ad, bd], s)

    assert_set [a1, b1, c1], r.resolve
  end

  def test_common_rack_activation_scenario
    rack100 = util_spec "rack", "1.0.0"
    rack101 = util_spec "rack", "1.0.1"

    lib1 =    util_spec "lib", "1", "rack" => ">= 1.0.1"

    rails =   util_spec "rails", "3", "actionpack" => "= 3"
    ap =      util_spec "actionpack", "3", "rack" => ">= 1.0.0"

    d1 = make_dep "rails"
    d2 = make_dep "lib"

    s = set(lib1, rails, ap, rack100, rack101)

    r = Gem::DependencyResolver.new([d1, d2], s)

    assert_set [rails, ap, rack101, lib1], r.resolve

    # check it with the deps reverse too

    r = Gem::DependencyResolver.new([d2, d1], s)

    assert_set [lib1, rack101, rails, ap], r.resolve
  end

  def test_backtracks_to_the_first_conflict
    a1 = util_spec "a", "1"
    a2 = util_spec "a", "2"
    a3 = util_spec "a", "3"
    a4 = util_spec "a", "4"

    d1 = make_dep "a"
    d2 = make_dep "a", ">= 2"
    d3 = make_dep "a", "= 1"

    s = set(a1, a2, a3, a4)

    r = Gem::DependencyResolver.new([d1, d2, d3], s)

    assert_raises Gem::ImpossibleDependenciesError do
      r.resolve
    end
  end

  # actionmailer 2.3.4
  # activemerchant 1.5.0
  # activesupport 2.3.5, 2.3.4
  # Activemerchant needs activesupport >= 2.3.2. When you require activemerchant, it will activate the latest version that meets that requirement which is 2.3.5. Actionmailer on the other hand needs activesupport = 2.3.4. When rubygems tries to activate activesupport 2.3.4, it will raise an error.


  def test_simple_activesupport_problem
    sup1  = util_spec "activesupport", "2.3.4"
    sup2  = util_spec "activesupport", "2.3.5"

    merch = util_spec "activemerchant", "1.5.0", "activesupport" => ">= 2.3.2"
    mail =  util_spec "actionmailer", "2.3.4", "activesupport" => "= 2.3.4"

    s = set(mail, merch, sup1, sup2)

    d1 = make_dep "activemerchant"
    d2 = make_dep "actionmailer"

    r = Gem::DependencyResolver.new([d1, d2], s)

    assert_set [merch, mail, sup1], r.resolve
  end

  def test_second_level_backout
    b1 = new_spec "b", "1", { "c" => ">= 1" }, "lib/b.rb"
    b2 = new_spec "b", "2", { "c" => ">= 2" }, "lib/b.rb"
    c1 = new_spec "c", "1"
    c2 = new_spec "c", "2"
    d1 = new_spec "d", "1", { "c" => "< 2" },  "lib/d.rb"
    d2 = new_spec "d", "2", { "c" => "< 2" },  "lib/d.rb"

    s = set(b1, b2, c1, c2, d1, d2)

    p1 = make_dep "b", "> 0"
    p2 = make_dep "d", "> 0"

    r = Gem::DependencyResolver.new([p1, p2], s)

    assert_set [b1, c1, d2], r.resolve
  end
end