class RuboCop::Cop::Layout::SpaceInsideBlockBraces

def adjacent_braces(left_brace, right_brace)
  return if style_for_empty_braces != :space
  offense(left_brace.begin_pos, right_brace.end_pos,
          'Space missing inside empty braces.')
end

def autocorrect(range)
  lambda do |corrector|
    case range.source
    when /\s/ then corrector.remove(range)
    when '{}' then corrector.replace(range, '{ }')
    when '{|' then corrector.replace(range, '{ |')
    else           corrector.insert_before(range, ' ')
    end
  end
end

def braces_with_contents_inside(node, inner)
  args_delimiter = node.arguments.loc.begin # Can be ( | or nil.
  check_left_brace(inner, node.loc.begin, args_delimiter)
  check_right_brace(inner, node.loc.end, node.single_line?)
end

def check_inside(node, left_brace, right_brace)
  if left_brace.end_pos == right_brace.begin_pos
    adjacent_braces(left_brace, right_brace)
  else
    range = range_between(left_brace.end_pos, right_brace.begin_pos)
    inner = range.source
    if inner =~ /\S/
      braces_with_contents_inside(node, inner)
    elsif style_for_empty_braces == :no_space
      offense(range.begin_pos, range.end_pos,
              'Space inside empty braces detected.')
    end
  end
end

def check_left_brace(inner, left_brace, args_delimiter)
  if inner =~ /\A\S/
    no_space_inside_left_brace(left_brace, args_delimiter)
  else
    space_inside_left_brace(left_brace, args_delimiter)
  end
end

def check_right_brace(inner, right_brace, single_line)
  if single_line && inner =~ /\S$/
    no_space(right_brace.begin_pos, right_brace.end_pos,
             'Space missing inside }.')
  else
    space_inside_right_brace(right_brace)
  end
end

def no_space(begin_pos, end_pos, msg)
  if style == :space
    offense(begin_pos, end_pos, msg) { opposite_style_detected }
  else
    correct_style_detected
  end
end

def no_space_inside_left_brace(left_brace, args_delimiter)
  if pipe?(args_delimiter)
    if left_brace.end_pos == args_delimiter.begin_pos &&
       cop_config['SpaceBeforeBlockParameters']
      offense(left_brace.begin_pos, args_delimiter.end_pos,
              'Space between { and | missing.') do
        opposite_style_detected
      end
    end
  else
    # We indicate the position after the left brace. Otherwise it's
    # difficult to distinguish between space missing to the left and to
    # the right of the brace in autocorrect.
    no_space(left_brace.end_pos, left_brace.end_pos + 1,
             'Space missing inside {.')
  end
end

def offense(begin_pos, end_pos, msg, &block)
  range = range_between(begin_pos, end_pos)
  add_offense(range, location: range, message: msg, &block)
end

def on_block(node)
  return if node.keywords?
  left_brace = node.loc.begin
  right_brace = node.loc.end
  check_inside(node, left_brace, right_brace)
end

def pipe?(args_delimiter)
  args_delimiter && args_delimiter.is?('|')
end

def space(begin_pos, end_pos, msg)
  if style == :no_space
    offense(begin_pos, end_pos, msg) { opposite_style_detected }
  else
    correct_style_detected
  end
end

def space_inside_left_brace(left_brace, args_delimiter)
  if pipe?(args_delimiter)
    unless cop_config['SpaceBeforeBlockParameters']
      offense(left_brace.end_pos, args_delimiter.begin_pos,
              'Space between { and | detected.') do
        opposite_style_detected
      end
    end
  else
    brace_with_space = range_with_surrounding_space(range: left_brace,
                                                    side: :right)
    space(brace_with_space.begin_pos + 1, brace_with_space.end_pos,
          'Space inside { detected.')
  end
end

def space_inside_right_brace(right_brace)
  brace_with_space = range_with_surrounding_space(range: right_brace,
                                                  side: :left)
  space(brace_with_space.begin_pos, brace_with_space.end_pos - 1,
        'Space inside } detected.')
end

def style_for_empty_braces
  case cop_config['EnforcedStyleForEmptyBraces']
  when 'space'    then :space
  when 'no_space' then :no_space
  else raise 'Unknown EnforcedStyleForEmptyBraces selected!'
  end
end