class Solve::Errors::NoSolutionError

def initialize(message = nil, causes = {})
  super(message)
  @message = message
  @missing_artifacts = causes[:missing_artifacts] || []
  @constraints_excluding_all_artifacts = causes[:constraints_excluding_all_artifacts] || []
  @unsatisfiable_demand = causes[:unsatisfiable_demand] || nil
  @artifacts_with_no_satisfactory_version = causes[:artifacts_with_no_satisfactory_version] || []
end

def to_s
  s = ""
  s << "#{@message}\n"
  s << "Missing artifacts: #{missing_artifacts.join(",")}\n" unless missing_artifacts.empty?
  unless constraints_excluding_all_artifacts.empty?
    pretty = constraints_excluding_all_artifacts.map { |constraint| "(#{constraint[0]} #{constraint[1]})" }.join(",")
    s << "Constraints that match no available version: #{pretty}\n"
  end
  s << "Demand that cannot be met: #{unsatisfiable_demand}\n" if unsatisfiable_demand
  unless artifacts_with_no_satisfactory_version.empty?
    s << "Artifacts for which there are conflicting dependencies: #{artifacts_with_no_satisfactory_version.join(",")}"
  end
  s
end