class Inspec::DependencyInstaller

def initialize(gem_path = nil, requested_gems = [])
  @dependency_loader = Inspec::DependencyLoader.new
  @gem_path = gem_path || inspec_gem_path
  @requested_gems = requested_gems
end

def install
  requested_gems.each do |requested_gem|
    version = requested_gem[:version].nil? ? "> 0" : requested_gem[:version]
    install_from_remote_gems(requested_gem[:name], { version: version })
  end
end

def install_from_remote_gems(requested_gem_name, opts)
  version = opts[:version].split(",")
  begin
    gem_dependency = Gem::Dependency.new(requested_gem_name, version || "> 0")
    # BestSet is rubygems.org API + indexing, APISet is for custom sources
    sources = if opts[:source]
                Gem::Resolver::APISet.new(URI.join(opts[:source] + "/api/v1/dependencies"))
              else
                Gem::Resolver::BestSet.new
              end
    install_gem_to_gems_dir(gem_dependency, [sources], opts[:update_mode])
  rescue Gem::RemoteFetcher::FetchError => gem_ex
    ex = Inspec::GemDependencyInstallError.new(gem_ex.message)
    ex.gem_name = requested_gem_name
    raise ex
  rescue Gem::Requirement::BadRequirementError => gem_ex
    ex = Inspec::GemDependencyInstallError.new(gem_ex.message)
    ex.gem_name = requested_gem_name
    raise "Unparseable gem dependency '#{version}' for '#{ex.gem_name}'"
  end
end

def install_gem_to_gems_dir(gem_dependency, extra_request_sets = [], update_mode = false)
  # Solve the dependency (that is, find a way to install the new gem and anything it needs)
  request_set = Gem::RequestSet.new(gem_dependency)
  begin
    solution = request_set.resolve
  rescue Gem::UnsatisfiableDependencyError => gem_ex
    ex = Inspec::GemDependencyInstallError.new(gem_ex.message)
    ex.gem_name = gem_dependency.name
    raise ex
  end
  # OK, perform the installation.
  # Ignore deps here, because any needed deps should already be baked into gem_dependency
  request_set.install_into(gem_path, true, ignore_dependencies: true, document: [])
  # Locate the GemVersion for the new dependency and return it
  solution.detect { |g| g.name == gem_dependency.name }.version
end