# -*- encoding: utf-8 -*-

module Aequitas
  module Context
    # Module with validation context functionality.
    #
    # Contexts are implemented using a thread-local array-based stack.


    # Execute a block of code within a specific validation context
    # 
    # @param [Symbol] context
    #   the context to execute the block of code within
    # 
    # @api semipublic
    def self.in_context(context)
      stack << context
      return_value = yield
    ensure
      stack.pop
      return_value
    end

    # Get the current validation context or nil (if no context is on the stack).
    # 
    # @return [Symbol, NilClass]
    #   The current validation context (for the current thread),
    #   or nil if no current context is on the stack
    def self.current
      stack.last
    end

    # Are there any contexts on the stack?
    # 
    # @return [Boolean]
    #   true/false whether there are any contexts on the context stack
    # 
    # @api semipublic
    def self.any?(&block)
      stack.any?(&block)
    end

    # The (thread-local) validation context stack
    # This allows object graphs to be saved within potentially nested contexts
    # without having to pass the validation context throughout
    # 
    # @api private
    def self.stack
      Thread.current[:dm_validations_context_stack] ||= []
    end

  end # module Context
end # module Aequitas