module ActiveSupport::Deprecation::Reporting

def _extract_callstack(callstack)
  warn "Please pass `caller_locations` to the deprecation API" if $VERBOSE
  offending_line = callstack.find { |line| !ignored_callstack(line) } || callstack.first
  if offending_line
    if md = offending_line.match(/^(.+?):(\d+)(?::in `(.*?)')?/)
      md.captures
    else
      offending_line
    end
  end
end

def deprecated_method_warning(method_name, message = nil)
  warning = "#{method_name} is deprecated and will be removed from #{gem_name} #{deprecation_horizon}"
  case message
  when Symbol then "#{warning} (use #{message} instead)"
  when String then "#{warning} (#{message})"
  else warning
  end
end

def deprecation_caller_message(callstack)
  file, line, method = extract_callstack(callstack)
  if file
    if line && method
      "(called from #{method} at #{file}:#{line})"
    else
      "(called from #{file}:#{line})"
    end
  end
end

def deprecation_message(callstack, message = nil)
  message ||= "You are using deprecated behavior which will be removed from the next major or minor release."
  "DEPRECATION WARNING: #{message} #{deprecation_caller_message(callstack)}"
end

def deprecation_warning(deprecated_method_name, message = nil, caller_backtrace = nil)
  caller_backtrace ||= caller_locations(2)
  deprecated_method_warning(deprecated_method_name, message).tap do |msg|
    warn(msg, caller_backtrace)
  end
end

def extract_callstack(callstack)
  return _extract_callstack(callstack) if callstack.first.is_a? String
  offending_line = callstack.find { |frame|
    frame.absolute_path && !ignored_callstack(frame.absolute_path)
  } || callstack.first
  [offending_line.path, offending_line.lineno, offending_line.label]
end

def ignored_callstack(path)
  path.start_with?(RAILS_GEM_ROOT) || path.start_with?(RbConfig::CONFIG["rubylibdir"])
end

def silence
  old_silenced, @silenced = @silenced, true
  yield
ensure
  @silenced = old_silenced
end

def warn(message = nil, callstack = nil)
  return if silenced
  callstack ||= caller_locations(2)
  deprecation_message(callstack, message).tap do |m|
    behavior.each { |b| b.call(m, callstack, deprecation_horizon, gem_name) }
  end
end