#!/usr/bin/env ruby
require 'fileutils'
class RenameModule
  attr_reader :current_module_name, :new_module_name, :dir
  def initialize(current_module_name:,
                 new_module_name:,
                 dir:
                )
    @current_module_name = current_module_name
    @new_module_name = new_module_name
    @dir = dir
  end

  def rename
      puts "[rename-module] "
      puts "[rename-module] Rename module #{current_module_name} to module #{new_module_name} in #{dir}"
      puts "[rename-module]"
      rename_in_dir
  end

  def rename_in_dir
    Dir["#{dir}/**/*.elm"].each do |file|
      _as_ = false
      processed_file = []
      IO.readlines(file).each do |line|
        if line =~ /module\s+#{current_module_name}\s/
          p new_line = line.sub(current_module_name, new_module_name)
          processed_file << new_line
        elsif line =~ /import\s+#{current_module_name}\s/
          if line =~ /\sas\s/
            _as_ = true
          end
          p new_line = line.sub(current_module_name, new_module_name)
          processed_file << new_line
        else
          # somewhere below imports
          # if _as_ is false then the module can be referenced directly
          # using . operater ie
          # \sModuleName\.
          if line =~ /\s#{current_module_name}\./
            new_line =  line.sub(/ #{current_module_name}\./," #{new_module_name}.")
            processed_file << new_line
          elsif line =~ /\(#{current_module_name}\./
              new_line =  line.sub(/\(#{current_module_name}\./,"(#{new_module_name}.")
              processed_file << new_line
          else
            processed_file << line
          end
        end
      end
      if File.basename(file) =~/#{current_module_name}.elm/
        p new_file = file.sub(current_module_name,new_module_name)

        IO.write(new_file,
                 processed_file.join(''))
        FileUtils.rm file
      else
        IO.write(file,
                 processed_file.join(''))
      end
    end
  end
end
current_module_name = ARGV.shift
new_module_name     = ARGV.shift
dir                 = ARGV.shift

if current_module_name && new_module_name && dir
 RenameModule.new(current_module_name: current_module_name,
                  new_module_name: new_module_name,
                  dir: dir).rename

else
 puts "[rename-module]"
 puts "[rename-module] Expecting 3 arguments"
 puts "[rename-module]"
 puts "[rename-modlue] Usage Example:"
 puts "[rename-module]"
 puts "[rename-module] .\\rename-module CurrentModuleName NewModuleName srcDirectory"
 puts "[rename-module]"
 exit(-1)
end