require 'polyglot'
require 'treetop'
require 'awesome_print'
require 'rest_client'
require File.join(File.dirname(__FILE__), 'scope')
require File.join(File.dirname(__FILE__), 'extended_value')
require File.join(File.dirname(__FILE__), 'webhook')
require File.join(File.dirname(__FILE__), 'errors/parse_error')
require File.join(File.dirname(__FILE__), 'errors/run_error')

Treetop.load File.join(File.dirname(__FILE__), 'expressive_grammar.treetop')

module Expressive
  def self.run(source_code, scope = TopLevel.new )
    program = parse(source_code)
    begin
      program.eval(scope)
    rescue Exception => e
      raise RunError, "Error running '#{source_code}':  #{$!}", $!.backtrace
    end
  end

  def self.parse(expressions)
    parser = ::ExpressiveParser.new
    begin
      parser.parse(expressions)
    rescue Exception => e
      if expressions.nil?
        message = "Error parsing nil expression:  #{$!}"
      else
        message = "Error parsing '#{expressions}':  #{$!}"
      end
      raise ParseError, message, $!.backtrace
    end
  end

  def self.all_symbols
    %w(+ - * / = ~ set sum $sub post >= > < <= and or if date datetime get put lookup $lookup $head $tail $reverse round $round $days_ago $hours_ago $minutes_ago $append $id $hash $concat $split $sms $hval $index $random $join $not $include $string $float $integer $id)
  end

  module Boolean
    def eval(scope = nil)
     'true' == text_value
    end
  end

  module IntegerValue
    def eval(scope = nil)
      text_value.to_i
    end
  end

  module FloatValue
    def eval(scope = nil)
      text_value.to_f
    end
  end

  module StringValue
    def eval(scope = nil)
      text_value.gsub('"', '')
    end
  end

  class Program < Treetop::Runtime::SyntaxNode
    def eval(scope)
      elements.map {|e|
        e.eval(scope)
      }.last
    end
  end

  class List < Treetop::Runtime::SyntaxNode
    def statements
      elements[1].elements.map {|e| e.data }
    end

    def eval(scope)
      first_elem = statements.first.eval(scope)
      if first_elem.is_a? Function
        first_elem.call(scope, statements[1..-1])
      else
        statements.map {|stat| stat.eval(scope) }
      end
    end
  end

  class Statement < Treetop::Runtime::SyntaxNode
    def data
      elements[1]
    end

    def eval(scope)
      data.eval(scope)
    end
  end

  class Identifier < Treetop::Runtime::SyntaxNode
    def eval(scope)
      scope[text_value]
    end
  end

  class Function
    def initialize(&block)
      @block = block
    end

    def call(scope, statements)
      parameters = statements.map {|c| c.eval(scope)}
      @block.call(*parameters)
    end
  end

  class Syntax < Function
    def call(scope, statements)
      @block.call(scope, statements)
    end
  end
end