class Fasterer::Analyzer

def errors
  @errors ||= Fasterer::OffenseCollector.new
end

def initialize(file_path)
  @file_path = file_path.to_s
  @file_content = File.read(file_path)
end

def scan
  sexp_tree = Fasterer::Parser.parse(@file_content)
  traverse_sexp_tree(sexp_tree)
end

def scan_by_token(token, element)
  case token
  when :defn
    scan_method_definitions(element)
  when :call, :iter
    scan_method_calls(element)
  when :for
    scan_for_loop(element)
  when :resbody
    scan_rescue(element)
  end
end

def scan_for_loop(element)
  errors.push(Fasterer::Offense.new(:for_loop_vs_each, element.line))
end

def scan_method_calls(element)
  method_call_scanner = MethodCallScanner.new(element)
  if method_call_scanner.offense_detected?
    errors.push(method_call_scanner.offense)
  end
end

def scan_method_definitions(element)
  method_definition_scanner = MethodDefinitionScanner.new(element)
  if method_definition_scanner.offense_detected?
    errors.push(method_definition_scanner.offense)
  end
end

def scan_rescue(element)
  rescue_call_scanner = RescueCallScanner.new(element)
  if rescue_call_scanner.offense_detected?
    errors.push(rescue_call_scanner.offense)
  end
end

def traverse_sexp_tree(sexp_tree)
  return unless sexp_tree.is_a?(Sexp)
  token = sexp_tree.first
  scan_by_token(token, sexp_tree)
  case token
  when :call, :iter
    method_call = MethodCall.new(sexp_tree)
    traverse_sexp_tree(method_call.receiver_element) if method_call.receiver_element
    traverse_sexp_tree(method_call.arguments_element)
    traverse_sexp_tree(method_call.block_body) if method_call.has_block?
  else
    sexp_tree.each { |element| traverse_sexp_tree(element) }
  end
end