class Bundler::Resolver

def self.platform_sort_key(platform)
  # Prefer specific platform to not specific platform
  return ["99-LAST", "", "", ""] if Gem::Platform::RUBY == platform
  ["00", *platform.to_a.map {|part| part || "" }]
end

def self.resolve(requirements, index, source_requirements = {}, base = [], gem_version_promoter = GemVersionPromoter.new, additional_base_requirements = [], platforms = nil)
  base = SpecSet.new(base) unless base.is_a?(SpecSet)
  resolver = new(index, source_requirements, base, gem_version_promoter, additional_base_requirements, platforms)
  result = resolver.start(requirements)
  SpecSet.new(result)
end

def after_resolution
  Bundler.ui.info ""
end

def amount_constrained(dependency)
  @amount_constrained ||= {}
  @amount_constrained[dependency.name] ||= begin
    if (base = @base[dependency.name]) && !base.empty?
      dependency.requirement.satisfied_by?(base.first.version) ? 0 : 1
    else
      all = index_for(dependency).search(dependency.name).size
      if all <= 1
        all - 1_000_000
      else
        search = search_for(dependency)
        search = @prerelease_specified[dependency.name] ? search.count : search.count {|s| !s.version.prerelease? }
        search - all
      end
    end
  end
end

def before_resolution
  Bundler.ui.info "Resolving dependencies...", debug?
end

def debug(depth = 0)
  return unless debug?
  debug_info = yield
  debug_info = debug_info.inspect unless debug_info.is_a?(String)
  puts debug_info.split("\n").map {|s| depth == 0 ? "BUNDLER: #{s}" : "BUNDLER(#{depth}): #{s}" }
end

def debug?
  return @debug_mode if defined?(@debug_mode)
  @debug_mode =
    ENV["BUNDLER_DEBUG_RESOLVER"] ||
    ENV["BUNDLER_DEBUG_RESOLVER_TREE"] ||
    ENV["DEBUG_RESOLVER"] ||
    ENV["DEBUG_RESOLVER_TREE"] ||
    false
end

def dependencies_equal?(dependencies, other_dependencies)
  dependencies.map(&:dep) == other_dependencies.map(&:dep)
end

def dependencies_for(specification)
  all_dependencies = specification.dependencies_for_activated_platforms
  if @variant_specific_names.include?(specification.name)
    @variant_specific_names |= all_dependencies.map(&:name) - @generic_names
  else
    generic_names, variant_specific_names = specification.partitioned_dependency_names_for_activated_platforms
    @variant_specific_names |= variant_specific_names - @generic_names
    @generic_names |= generic_names
  end
  all_dependencies
end

def formatted_versions_with_platforms(versions_with_platforms)
  version_platform_strs = versions_with_platforms.map do |vwp|
    version = vwp.first
    platform = vwp.last
    version_platform_str = String.new(version.to_s)
    version_platform_str << " #{platform}" unless platform.nil? || platform == Gem::Platform::RUBY
    version_platform_str
  end
  version_platform_strs.join(", ")
end

def index_for(dependency)
  source = @source_requirements[dependency.name]
  if source
    source.specs
  elsif @lockfile_uses_separate_rubygems_sources
    Index.build do |idx|
      if dependency.all_sources
        dependency.all_sources.each {|s| idx.add_source(s.specs) if s }
      else
        idx.add_source @source_requirements[:default].specs
      end
    end
  else
    @index
  end
end

def indicate_progress
  Bundler.ui.info ".", false unless debug?
end

def initialize(index, source_requirements, base, gem_version_promoter, additional_base_requirements, platforms)
  @index = index
  @source_requirements = source_requirements
  @base = base
  @resolver = Molinillo::Resolver.new(self, self)
  @search_for = {}
  @base_dg = Molinillo::DependencyGraph.new
  @base.each do |ls|
    dep = Dependency.new(ls.name, ls.version)
    @base_dg.add_vertex(ls.name, DepProxy.get_proxy(dep, ls.platform), true)
  end
  additional_base_requirements.each {|d| @base_dg.add_vertex(d.name, d) }
  @platforms = platforms
  @resolving_only_for_ruby = platforms == [Gem::Platform::RUBY]
  @gem_version_promoter = gem_version_promoter
  @use_gvp = Bundler.feature_flag.use_gem_version_promoter_for_major_updates? || !@gem_version_promoter.major?
  @lockfile_uses_separate_rubygems_sources = Bundler.feature_flag.disable_multisource?
  @variant_specific_names = []
  @generic_names = []
end

def name_for(dependency)
  dependency.name
end

def name_for_explicit_dependency_source
  Bundler.default_gemfile.basename.to_s
rescue StandardError
  "Gemfile"
end

def name_for_locking_dependency_source
  Bundler.default_lockfile.basename.to_s
rescue StandardError
  "Gemfile.lock"
end

def relevant_sources_for_vertex(vertex)
  if vertex.root?
    [@source_requirements[vertex.name]]
  elsif @lockfile_uses_separate_rubygems_sources
    vertex.recursive_predecessors.map do |v|
      @source_requirements[v.name]
    end << @source_requirements[:default]
  end
end

def requirement_satisfied_by?(requirement, activated, spec)
  requirement.matches_spec?(spec) || spec.source.is_a?(Source::Gemspec)
end

def search_for(dependency_proxy)
  platform = dependency_proxy.__platform
  dependency = dependency_proxy.dep
  name = dependency.name
  search_result = @search_for[dependency_proxy] ||= begin
    index = index_for(dependency)
    results = index.search(dependency, @base[name])
    if vertex = @base_dg.vertex_named(name)
      locked_requirement = vertex.payload.requirement
    end
    if !@prerelease_specified[name] && (!@use_gvp || locked_requirement.nil?)
      # Move prereleases to the beginning of the list, so they're considered
      # last during resolution.
      pre, results = results.partition {|spec| spec.version.prerelease? }
      results = pre + results
    end
    spec_groups = if results.any?
      nested = []
      results.each do |spec|
        version, specs = nested.last
        if version == spec.version
          specs << spec
        else
          nested << [spec.version, [spec]]
        end
      end
      nested.reduce([]) do |groups, (version, specs)|
        next groups if locked_requirement && !locked_requirement.satisfied_by?(version)
        specs_by_platform = Hash.new do |current_specs, current_platform|
          current_specs[current_platform] = select_best_platform_match(specs, current_platform)
        end
        spec_group_ruby = SpecGroup.create_for(specs_by_platform, [Gem::Platform::RUBY], Gem::Platform::RUBY)
        groups << spec_group_ruby if spec_group_ruby
        next groups if @resolving_only_for_ruby
        spec_group = SpecGroup.create_for(specs_by_platform, @platforms, platform)
        groups << spec_group if spec_group
        groups
      end
    else
      []
    end
    # GVP handles major itself, but it's still a bit risky to trust it with it
    # until we get it settled with new behavior. For 2.x it can take over all cases.
    if !@use_gvp
      spec_groups
    else
      @gem_version_promoter.sort_versions(dependency, spec_groups)
    end
  end
  unless search_result.empty?
    specific_dependency = @variant_specific_names.include?(name)
    return search_result unless specific_dependency
    search_result.each do |sg|
      if @generic_names.include?(name)
        @variant_specific_names -= [name]
        sg.activate_all_platforms!
      else
        sg.activate_platform!(platform)
      end
    end
  end
  search_result
end

def sort_dependencies(dependencies, activated, conflicts)
  dependencies.sort_by do |dependency|
    dependency.all_sources = relevant_sources_for_vertex(activated.vertex_named(dependency.name))
    name = name_for(dependency)
    vertex = activated.vertex_named(name)
    [
      @base_dg.vertex_named(name) ? 0 : 1,
      vertex.payload ? 0 : 1,
      vertex.root? ? 0 : 1,
      amount_constrained(dependency),
      conflicts[name] ? 0 : 1,
      vertex.payload ? 0 : search_for(dependency).count,
      self.class.platform_sort_key(dependency.__platform),
    ]
  end
end

def start(requirements)
  @gem_version_promoter.prerelease_specified = @prerelease_specified = {}
  requirements.each {|dep| @prerelease_specified[dep.name] ||= dep.prerelease? }
  verify_gemfile_dependencies_are_found!(requirements)
  dg = @resolver.resolve(requirements, @base_dg)
  dg.
    tap {|resolved| validate_resolved_specs!(resolved) }.
    map(&:payload).
    reject {|sg| sg.name.end_with?("\0") }.
    map(&:to_specs).
    flatten
rescue Molinillo::VersionConflict => e
  message = version_conflict_message(e)
  raise VersionConflict.new(e.conflicts.keys.uniq, message)
rescue Molinillo::CircularDependencyError => e
  names = e.dependencies.sort_by(&:name).map {|d| "gem '#{d.name}'" }
  raise CyclicDependencyError, "Your bundle requires gems that depend" \
    " on each other, creating an infinite loop. Please remove" \
    " #{names.count > 1 ? "either " : ""}#{names.join(" or ")}" \
    " and try again."
end

def validate_resolved_specs!(resolved_specs)
  resolved_specs.each do |v|
    name = v.name
    next unless sources = relevant_sources_for_vertex(v)
    sources.compact!
    if default_index = sources.index(@source_requirements[:default])
      sources.delete_at(default_index)
    end
    sources.reject! {|s| s.specs[name].empty? }
    sources.uniq!
    next if sources.size <= 1
    multisource_disabled = Bundler.feature_flag.disable_multisource?
    msg = ["The gem '#{name}' was found in multiple relevant sources."]
    msg.concat sources.map {|s| "  * #{s}" }.sort
    msg << "You #{multisource_disabled ? :must : :should} add this gem to the source block for the source you wish it to be installed from."
    msg = msg.join("\n")
    raise SecurityError, msg if multisource_disabled
    Bundler.ui.warn "Warning: #{msg}"
  end
end

def verify_gemfile_dependencies_are_found!(requirements)
  requirements.each do |requirement|
    name = requirement.name
    next if name == "bundler"
    next unless search_for(requirement).empty?
    cache_message = begin
                        " or in gems cached in #{Bundler.settings.app_cache_path}" if Bundler.app_cache.exist?
                      rescue GemfileNotFound
                        nil
                      end
    if (base = @base[name]) && !base.empty?
      version = base.first.version
      message = "You have requested:\n" \
        "  #{name} #{requirement.requirement}\n\n" \
        "The bundle currently has #{name} locked at #{version}.\n" \
        "Try running `bundle update #{name}`\n\n" \
        "If you are updating multiple gems in your Gemfile at once,\n" \
        "try passing them all to `bundle update`"
    elsif source = @source_requirements[name]
      specs = source.specs[name]
      versions_with_platforms = specs.map {|s| [s.version, s.platform] }
      message = String.new("Could not find gem '#{SharedHelpers.pretty_dependency(requirement)}' in #{source}#{cache_message}.\n")
      message << if versions_with_platforms.any?
        "The source contains the following versions of '#{name}': #{formatted_versions_with_platforms(versions_with_platforms)}"
      else
        "The source does not contain any versions of '#{name}'"
      end
    else
      message = "Could not find gem '#{requirement}' in any of the gem sources " \
        "listed in your Gemfile#{cache_message}."
    end
    raise GemNotFound, message
  end
end

def version_conflict_message(e)
  # only show essential conflicts, if possible
  conflicts = e.conflicts.dup
  if conflicts["bundler"]
    conflicts.replace("bundler" => conflicts["bundler"])
  else
    conflicts.delete_if do |_name, conflict|
      deps = conflict.requirement_trees.map(&:last).flatten(1)
      !Bundler::VersionRanges.empty?(*Bundler::VersionRanges.for_many(deps.map(&:requirement)))
    end
  end
  e = Molinillo::VersionConflict.new(conflicts, e.specification_provider) unless conflicts.empty?
  solver_name = "Bundler"
  possibility_type = "gem"
  e.message_with_trees(
    :solver_name => solver_name,
    :possibility_type => possibility_type,
    :reduce_trees => lambda do |trees|
      # called first, because we want to reduce the amount of work required to find maximal empty sets
      trees = trees.uniq {|t| t.flatten.map {|dep| [dep.name, dep.requirement] } }
      # bail out if tree size is too big for Array#combination to make any sense
      return trees if trees.size > 15
      maximal = 1.upto(trees.size).map do |size|
        trees.map(&:last).flatten(1).combination(size).to_a
      end.flatten(1).select do |deps|
        Bundler::VersionRanges.empty?(*Bundler::VersionRanges.for_many(deps.map(&:requirement)))
      end.min_by(&:size)
      trees.reject! {|t| !maximal.include?(t.last) } if maximal
      trees.sort_by {|t| t.reverse.map(&:name) }
    end,
    :printable_requirement => lambda {|req| SharedHelpers.pretty_dependency(req) },
    :additional_message_for_conflict => lambda do |o, name, conflict|
      if name == "bundler"
        o << %(\n  Current Bundler version:\n    bundler (#{Bundler::VERSION}))
        conflict_dependency = conflict.requirement
        conflict_requirement = conflict_dependency.requirement
        other_bundler_required = !conflict_requirement.satisfied_by?(Gem::Version.new(Bundler::VERSION))
        if other_bundler_required
          o << "\n\n"
          candidate_specs = @source_requirements[:default_bundler].specs.search(conflict_dependency)
          if candidate_specs.any?
            target_version = candidate_specs.last.version
            new_command = [File.basename($PROGRAM_NAME), "_#{target_version}_", *ARGV].join(" ")
            o << "Your bundle requires a different version of Bundler than the one you're running.\n"
            o << "Install the necessary version with `gem install bundler:#{target_version}` and rerun bundler using `#{new_command}`\n"
          else
            o << "Your bundle requires a different version of Bundler than the one you're running, and that version could not be found.\n"
          end
        end
      elsif conflict.locked_requirement
        o << "\n"
        o << %(Running `bundle update` will rebuild your snapshot from scratch, using only\n)
        o << %(the gems in your Gemfile, which may resolve the conflict.\n)
      elsif !conflict.existing
        o << "\n"
        relevant_sources = if conflict.requirement.source
          [conflict.requirement.source]
        elsif conflict.requirement.all_sources
          conflict.requirement.all_sources
        elsif @lockfile_uses_separate_rubygems_sources
          # every conflict should have an explicit group of sources when we
          # enforce strict pinning
          raise "no source set for #{conflict}"
        else
          []
        end.compact.map(&:to_s).uniq.sort
        metadata_requirement = name.end_with?("\0")
        o << "Could not find gem '" unless metadata_requirement
        o << SharedHelpers.pretty_dependency(conflict.requirement)
        o << "'" unless metadata_requirement
        if conflict.requirement_trees.first.size > 1
          o << ", which is required by "
          o << "gem '#{SharedHelpers.pretty_dependency(conflict.requirement_trees.first[-2])}',"
        end
        o << " "
        o << if relevant_sources.empty?
          "in any of the sources.\n"
        elsif metadata_requirement
          "is not available in #{relevant_sources.join(" or ")}"
        else
          "in any of the relevant sources:\n  #{relevant_sources * "\n  "}\n"
        end
      end
    end,
    :version_for_spec => lambda {|spec| spec.version },
    :incompatible_version_message_for_conflict => lambda do |name, _conflict|
      if name.end_with?("\0")
        %(#{solver_name} found conflicting requirements for the #{name} version:)
      else
        %(#{solver_name} could not find compatible versions for #{possibility_type} "#{name}":)
      end
    end
  )
end