class BulletTrain::Themes::Light::CustomThemeFileReplacer

def adjust_directory_hierarchy(file_name, theme_name)
  file_name.match?("lib/bullet_train/themes/#{theme_name}") ? file_name.gsub(/\/app/, "") : file_name
end

def build_main_app_file_name(original_theme, custom_theme, custom_gem_file)
  main_app_file = custom_gem_file
  custom_gem_file_hierarchy = custom_gem_file.split("/")
  if custom_gem_file_hierarchy.last.match?(original_theme)
    custom_gem_file_hierarchy.last.gsub!(original_theme, custom_theme)
    main_app_file = custom_gem_file_hierarchy.join("/")
  end
  main_app_file
end

def constantize_from_snake_case(str)
  str.split(/[_|-]/).map(&:capitalize).join
end

def default_files_to_replace(original_theme)
  # TODO: Add this file and the FileReplacer module once they're added to the main branch.
  [
    "/bullet_train-themes-#{original_theme}.gemspec",
    "/app/assets/config/bullet_train_themes_#{original_theme}_manifest.js",
    "/lib/tasks/bullet_train/themes/#{original_theme}_tasks.rake",
    "/test/bullet_train/themes/#{original_theme}_test.rb"
  ].map { |file| @repo_path + file }
end

def directories_to_remove_from_main_app(custom_theme)
  [
    "./app/assets/stylesheets/#{custom_theme}/",
    "./app/views/themes/#{custom_theme}/",
    "./app/lib/"
  ].map { |directory| directory unless directory == "./app/lib/" && Dir.empty?(directory) }
end

def ejected_files_to_replace(original_theme, custom_theme)
  [
    Dir.glob("#{@repo_path}/app/assets/stylesheets/#{custom_theme}/**/*.css"),
    Dir.glob("#{@repo_path}/app/assets/stylesheets/#{custom_theme}/**/*.scss"),
    Dir.glob("#{@repo_path}/app/views/themes/#{custom_theme}/**/*.html.erb"),
    "/app/javascript/application.#{original_theme}.js",
    "/tailwind.#{original_theme}.config.js",
    "/app/lib/bullet_train/themes/#{original_theme}.rb",
    # The Glob up top doesn't grab the #{original_theme}.tailwind.css file, so we set that here.
    "/app/assets/stylesheets/#{original_theme}.tailwind.css",
    "/tailwind.mailer.#{original_theme}.config.js"
  ].flatten.map { |file| file.match?(/^#{@repo_path}/) ? file : @repo_path + file }
end

def files_to_remove_from_main_app(custom_theme)
  [
    Dir.glob("./app/assets/stylesheets/#{custom_theme}/**/*.css"),
    Dir.glob("./app/assets/stylesheets/#{custom_theme}/**/*.scss"),
    "./app/assets/stylesheets/#{custom_theme}.tailwind.css",
    "./app/javascript/application.#{custom_theme}.js",
    "./app/lib/bullet_train/themes/#{custom_theme}.rb",
    Dir.glob("./app/views/themes/#{custom_theme}/**/*.html.erb"),
    "./tailwind.mailer.#{custom_theme}.config.js",
    "./tailwind.#{custom_theme}.config.js",
  ].flatten
end

def files_whose_contents_need_to_be_replaced(custom_theme)
  [
    "/app/assets/stylesheets/#{custom_theme}.tailwind.css",
    "/app/views/themes/#{custom_theme}/layouts/_account.html.erb",
    "/app/views/themes/#{custom_theme}/layouts/_devise.html.erb",
    "/bin/rails",
    "/lib/bullet_train/themes/#{custom_theme}/engine.rb",
    "/lib/bullet_train/themes/#{custom_theme}/version.rb",
    "/lib/bullet_train/themes/#{custom_theme}.rb",
    "/lib/tasks/bullet_train/themes/#{custom_theme}_tasks.rake",
    "/test/bullet_train/themes/#{custom_theme}_test.rb",
    "/test/dummy/app/views/layouts/mailer.html.erb",
    "/test/dummy/config/application.rb",
    "/bullet_train-themes-#{custom_theme}.gemspec",
    "/Gemfile",
    "/README.md"
  ].map { |file| @repo_path + file }
end

def initialize(custom_theme)
  @repo_path = "./local/bullet_train-themes-#{custom_theme}"
end

def replace_theme(original_theme, custom_theme)
  # Rename the directories
  [
    "/app/assets/stylesheets/bullet_train/themes/#{original_theme}/",
    "/app/assets/stylesheets/#{original_theme}/",
    "/app/views/themes/#{original_theme}/",
    "/lib/bullet_train/themes/#{original_theme}/"
  ].map { |file| @repo_path + file }.each do |original_directory|
    custom_directory = original_directory.gsub(/(.*)(#{original_theme})(\/$)/, '\1' + custom_theme + '\3')
    FileUtils.mv(original_directory, custom_directory)
  end
  # Only compare ejected files.
  files_to_replace =
    ejected_files_to_replace(original_theme, custom_theme).map { |file| {file_name: file, must_compare: true} } +
    default_files_to_replace(original_theme).map { |file| {file_name: file, must_compare: false} }
  # Replace the file contents and rename the files.
  files_to_replace.each do |custom_gem_file|
    # All of the files we want to compare against the fresh gem are in the main app.
    main_app_file = build_main_app_file_name(original_theme, custom_theme, custom_gem_file[:file_name].gsub(@repo_path, "."))
    custom_gem_file[:file_name] = adjust_directory_hierarchy(custom_gem_file[:file_name], original_theme)
    # The content in the main app should replace the cloned gem files.
    begin
      if custom_gem_file[:must_compare] && !BulletTrain::Themes::Light::FileReplacer.files_have_same_content?(custom_gem_file[:file_name], main_app_file)
        BulletTrain::Themes::Light::FileReplacer.replace_content(old: custom_gem_file[:file_name], new: main_app_file)
      end
    rescue Errno::ENOENT => _
      puts "Skipping `#{main_app_file}` because it isn't present."
    end
    # Only rename file names that still have the original theme in them, i.e. - ./tailwind.config.light.js
    if File.basename(custom_gem_file[:file_name]).match?(original_theme)
      main_app_file = adjust_directory_hierarchy(main_app_file, custom_theme)
      new_file_name = main_app_file.gsub(/^\./, @repo_path).gsub(original_theme, custom_theme)
      File.rename(custom_gem_file[:file_name], new_file_name)
    end
  end
  # Change the content of specific files that contain the orignal theme's string.
  # i.e. - `module Light` and `tailwind.light.config`.
  constantized_original = constantize_from_snake_case(original_theme)
  constantized_custom = constantize_from_snake_case(custom_theme)
  files_whose_contents_need_to_be_replaced(custom_theme).each do |file|
    new_lines = []
    File.open(file, "r") do |f|
      new_lines = f.readlines
      new_lines = new_lines.map do |line|
        # We want the original theme it's being edited from when creating a new theme.
        # We also remove mattr_accessor in the eject task, so we need to add it back here.
        if f.path == "#{@repo_path}/lib/bullet_train/themes/#{custom_theme}.rb" && line.match?("class Theme < BulletTrain::Themes::")
          line = "      mattr_accessor :color, default: :blue\n      class Theme < BulletTrain::Themes::#{constantize_from_snake_case(original_theme)}::Theme\n"
        else
          # `_account.html.erb` and `_devise.html.erb` have tailwind classes that contain `light`.
          # We shouldn't be replacing the classes with the custom theme string, so we skip it here.
          # TODO: We should change this Regexp to check if the original theme is prefixed with `-`.
          # If it is, we ignore the string if it's not prefixed with `bullet_train-themes-`,
          line.gsub!(original_theme, custom_theme) unless line.match?("bg-light-gradient")
          line.gsub!(constantized_original, constantized_custom)
        end
        line
      end
    end
    File.open(file, "w") do |f|
      f.puts new_lines.join
    end
  end
  # The contents in this specific main app file don't have the require statements which the gem
  # originally has, so we add those back after moving the main app file contents to the gem.
  new_lines = nil
  File.open("#{@repo_path}/lib/bullet_train/themes/#{custom_theme}.rb", "r") do |file|
    new_lines = file.readlines
    require_lines =
      <<~RUBY
        require "bullet_train/themes/#{custom_theme}/version"
        require "bullet_train/themes/#{custom_theme}/engine"
        require "bullet_train/themes/#{original_theme}"
      RUBY
    new_lines.unshift(require_lines)
  end
  File.open("#{@repo_path}/lib/bullet_train/themes/#{custom_theme}.rb", "w") do |file|
    file.puts new_lines.flatten.join
  end
  # Since we're generating a new gem, it should be version 1.0
  File.open("#{@repo_path}/lib/bullet_train/themes/#{custom_theme}/version.rb", "r") do |file|
    new_lines = file.readlines
    new_lines = new_lines.map { |line| line.match?("VERSION") ? "      VERSION = \"1.0\"\n" : line }
  end
  File.open("#{@repo_path}/lib/bullet_train/themes/#{custom_theme}/version.rb", "w") do |file|
    file.puts new_lines.join
  end
  # Remove files and directories from the main application.
  files_to_remove_from_main_app(custom_theme).each { |file| File.delete(file) }
  directories_to_remove_from_main_app(custom_theme).each do |directory|
    FileUtils.rm_rf(directory) unless directory.nil?
  end
  # Update the author and email.
  # If the developer hasn't set these yet, this should simply return empty strings.
  author = `git config --global user.name`.chomp
  email = `git config --global user.email`.chomp
  File.open("#{@repo_path}/bullet_train-themes-#{custom_theme}.gemspec", "r") do |file|
    new_lines = file.readlines
    new_lines = new_lines.map do |line|
      if line.match?("spec.authors")
        "  spec.authors = [\"#{author}\"]\n"
      elsif line.match?("spec.email")
        "  spec.email = [\"#{email}\"]\n"
      else
        line
      end
    end
  end
  File.open("#{@repo_path}/bullet_train-themes-#{custom_theme}.gemspec", "w") do |file|
    file.puts new_lines.join
  end
end