# encoding: UTF-8
# frozen_string_literal: true

# Refinements
# =======================================================================

using NRSER
using NRSER::Types


# Definitions
# =======================================================================

module NRSER::Rash::CLI
  
  # Call a Rash function.
  # 
  # @param [String] name
  #   Name of the function.
  # 
  # @param [Array<String>] argv
  #   The shell arguments.
  # 
  def self.call name, argv

    logger.trace "calling #{ name.inspect }, argv: #{ argv.inspect }"
    # look for options
    options = {}
    args = argv.reject do |arg|
      # long options of form '--<name>=<value>'
      if m = arg.match(/\A--([^=]*)(=?)(.*)/)
        options[m[1].to_sym] = if m[2] == ''
          true
        else
          m[3]
        end
        true
      # short options of form '-<char>'
      elsif arg.start_with? '-'
        arg[1..-1].each_char do |char|
          options[char] = true
        end
        true
      end
    end
    logger.debug "options: #{ options.inspect }"
    # options are the last arg, unless we didn't find any
    #
    # NOTE: this causes functions without an optional `options` arg
    #       on the end to raise an exception when called with any options.
    #       
    #       i think this is the correct behavior: the function can't handle
    #       options, and should error out.
    args << options unless options.empty?

    NRSER::Rash.load_functions
    if name.include? '.'
      namespace, method_name = name.split '.'
      namespace = namespace.split '::'
    else
      namespace = []
      method_name = name
    end
    mod = NRSER::Rash::Functions
    namespace.each do |submod_name|
      mod = mod.const_get(submod_name.capitalize)
    end
    begin
      rtn = mod.method(method_name).call *args
    rescue Exception => error
      if NRSER::Rash.config( 'PRINT_ERRORS' ).truthy?
        if NRSER::Rash.config( 'STACKTRACE' ).truthy?
          raise error
        else
          logger.fatal error
          # this is the error code that ruby seems to exit with when you
          # don't check the exception
          exit 1
        end
      end
    end
    logger.debug "return value: #{ rtn.inspect }"
    if formatted = format(rtn)
      puts formatted
    end
    exit 0
  end

  # formats an object to write to `$stdout`.
  # returns `nil` if there's nothing to write (different than returning '',
  # indicating the empty string should be written).
  def self.format(obj)
    # TODO: should formatter be overridable with a env var?
    # formatter = begin config('FORMATTER'); rescue NameError => e; nil; end
    # logger.debug "formatter: #{ formatter.inspect }"
    if obj.rash_formatter
      # there is some sort of formatting info
      # even if the value is a string, we want to follow the instructions
      # hell, maybe we want to write the string out as json or something :/
      if obj.rash_formatter.respond_to? :call
        # the value responds to `call`, so call it to get the value
        # TODO: should we check that it returns a `String`?
        obj.rash_formatter.call(obj)
      # NOTE: `Object.singleton_methods` returns an array of strings in 1.8
      #       and an array of symbols in 1.9, so use strings to work in
      #       both.
      elsif NRSER::Rash::Formatters.
          singleton_methods.
          map {|_| _.to_s }.
          include? obj.rash_formatter.to_s
        # it's a symbol that identifies on of the {NRSER::Rash::Formatters}
        # class methods, so call that
        NRSER::Rash::Formatters.send obj.rash_formatter, obj
      else
        # whatever, call the default
        NRSER::Rash::Formatters.send config('DEFAULT_FORMATTER'), obj
      end
    else
      # there is no formatting info
      if obj.is_a? String
        # in the case that a method passed back a `String`, i think we should
        # consider it formatted and just print it
        obj
      elsif obj.nil?
        # the result is nil and there has been no attempt to format it in
        # a specific way that some program might need to recongize or
        # something. at this point, i'm going to say that the function
        # took some successful action and doesn't have anyhting to say about
        # it, which i think means we shouldn't print anything
      else
        # otherwise, send it to the default formatter
        NRSER::Rash::Formatters.send config('DEFAULT_FORMATTER'), obj
      end
    end
  end
  
end # module NRSER::Rash::CLI