require "dsl_evaluator/version"

module DslEvaluator
  class Error < StandardError; end

  def evaluate_file(path)
    return unless path && File.file?(path)
    instance_eval(IO.read(path), path)
  rescue Exception => e
    evaluation_error(e)
    puts "\nFull error:"
    raise
  end

  @@backtrace_reject = nil
  def backtrace_reject
    @@backtrace_reject
  end

  def backtrace_reject=(v)
    @@backtrace_reject = v
  end

  # Prints out a user friendly task_definition error message
  def evaluation_error(e)
    lines = e.backtrace
    lines = lines.reject { |l| l.include?(backtrace_reject) } if backtrace_reject
    error_info = lines.first
    path, line_no, _ = error_info.split(':')
    line_no = line_no.to_i
    puts "Error evaluating #{path}:".color(:red)
    puts e.message
    puts "Here's the line in #{path} with the error:\n\n"

    contents = IO.read(path)
    content_lines = contents.split("\n")
    context = 5 # lines of context
    top, bottom = [line_no-context-1, 0].max, line_no+context-1
    spacing = content_lines.size.to_s.size
    content_lines[top..bottom].each_with_index do |line_content, index|
      line_number = top+index+1
      if line_number == line_no
        printf("%#{spacing}d %s\n".color(:red), line_number, line_content)
      else
        printf("%#{spacing}d %s\n", line_number, line_content)
      end
    end
  end

  extend self
end