require 'brakeman/processors/lib/basic_processor'

#Finds method calls matching the given target(s).
#   #-- This should be deprecated --#
#   #--  Do not use for new code  --#
#
#Targets/methods can be:
#
# - nil: matches anything, including nothing
# - Empty array: matches nothing
# - Symbol: matches single target/method exactly
# - Array of symbols: matches against any of the symbols
# - Regular expression: matches the expression
# - Array of regular expressions: matches any of the expressions
#
#If a target is also the name of a class, methods called on instances
#of that class will also be matched, in a very limited way.
#(Any methods called on Klass.new, basically. More useful when used
#in conjunction with AliasProcessor.)
#
#Examples:
#
# #To find any uses of this class:
# FindCall.new :FindCall, nil
#
# #Find system calls without a target
# FindCall.new [], [:system, :exec, :syscall]
#
# #Find all calls to length(), no matter the target
# FindCall.new nil, :length
#
# #Find all calls to sub, sub!, gsub, or gsub!
# FindCall.new nil, /^g?sub!?$/
class Brakeman::FindCall < Brakeman::BasicProcessor

  def initialize targets, methods, tracker
    super tracker
    @calls = []
    @find_targets = targets
    @find_methods = methods
    @current_class = nil
    @current_method = nil
  end

  #Returns a list of results.
  #
  #A result looks like:
  #
  # s(:result, :ClassName, :method_name, s(:call, ...))
  def matches
    @calls
  end

  #Process the given source. Provide either class and method being searched
  #or the template. These names are used when reporting results.
  #
  #Use FindCall#matches to retrieve results.
  def process_source exp
    process exp
  end

  #Process body of method
  def process_defn exp
    process_all exp.body
  end

  alias :process_defs :process_defn

  #Look for matching calls and add them to results
  def process_call exp
    target = get_target exp.target
    method = exp.method

    process_call_args exp

    if match(@find_targets, target) and match(@find_methods, method)
      @calls << Sexp.new(:result, @current_module, @current_class, @current_method, exp).line(exp.line)
    end
    
    exp
  end

  #Process an assignment like a call
  def process_attrasgn exp
    process_call exp
  end

  private

  #Gets the target of a call as a Symbol
  #if possible
  def get_target exp
    if sexp? exp
      case exp.node_type
      when :ivar, :lvar, :const, :lit
        exp.value
      when :colon2
        class_name exp
      else
        exp
      end
    else
      exp
    end
  end

  #Checks if the search terms match the given item
  def match search_terms, item
    case search_terms
    when Symbol
      if search_terms == item
        true
      else
        false
      end
    when Enumerable
      if search_terms.empty?
        item == nil
      end
    end
  end
end