module Embulk
  def self.new_plugin(name, language, category)
    require 'embulk/data/package_data'
    require 'embulk/version'
    require 'fileutils'

    embulk_category = category
    embulk_category = :input if category == :file_input
    embulk_category = :output if category == :file_output

    name = name.gsub(/[^a-zA-Z0-9_]+/, '_')  # replace '-' to '_'

    full_project_name = "embulk-#{embulk_category}-#{name}"
    plugin_dir = "lib/embulk"
    plugin_path = "#{plugin_dir}/#{embulk_category}/#{name}.rb"

    if File.exist?(full_project_name)
      raise "./#{full_project_name} already exists. Please delete it first."
    end
    FileUtils.mkdir_p(full_project_name)

    puts "Creating #{full_project_name}/"

    success = false
    begin
      #
      # Generate gemspec
      #
      author = `git config user.name`.strip
      author = "YOUR_NAME" if author.empty?
      email = `git config user.email`.strip
      email = "YOUR_NAME" if email.empty?

      # variables used in erb templates
      ruby_class_name = name.split('_').map {|a| a.capitalize }.join
      java_iface_name = category.to_s.split('_').map {|a| a.capitalize }.join
      java_class_name = name.split('_').map {|a| a.capitalize }.join + java_iface_name + "Plugin"
      java_package_name = "org.embulk.#{embulk_category}.#{name}"
      display_name = name.split('_').map {|a| a.capitalize }.join(' ')
      display_category = category.to_s.gsub('_', ' ')

      extra_guess_erb = {}

      case category
      when :input
        description = %[Loads records from #{display_name}.]
      when :file_input
        description = %[Reads files stored on #{display_name}.]
      when :parser
        description = %[Parses #{display_name} files read by other file input plugins.]
        extra_guess_erb["ruby/parser_guess.rb.erb"] = "#{plugin_dir}/guess/#{name}.rb"
      when :decoder
        description = %[Decodes #{display_name}-encoded files read by other file input plugins.]
        extra_guess_erb["ruby/decoder_guess.rb.erb"] = "#{plugin_dir}/guess/#{name}.rb"
      when :output
        description = %[Dumps records to #{display_name}.]
      when :file_output
        description = %[Stores files on #{display_name}.]
      when :formatter
        description = %[Formats #{display_name} files for other file output plugins.]
      when :encoder
        description = %[Encodes files using #{display_name} for other file output plugins.]
      when :filter
        description = %[#{display_name}]
      end

      #
      # Generate project repository
      #
      pkg = Embulk::PackageData.new("new", full_project_name, binding())

      pkg.cp_erb("README.md.erb", "README.md")
      pkg.cp("LICENSE.txt", "LICENSE.txt")
      pkg.cp_erb("gitignore.erb", ".gitignore")

      case language
      when :ruby
        pkg.cp("ruby/Rakefile", "Rakefile")
        pkg.cp("ruby/Gemfile", "Gemfile")
        pkg.cp_erb("ruby/gemspec.erb", "#{full_project_name}.gemspec")
        pkg.cp_erb("ruby/#{category}.rb.erb", plugin_path)

      when :java
        pkg.cp("java/gradle/wrapper/gradle-wrapper.jar", "gradle/wrapper/gradle-wrapper.jar")
        pkg.cp("java/gradle/wrapper/gradle-wrapper.properties", "gradle/wrapper/gradle-wrapper.properties")
        pkg.cp("java/gradlew.bat", "gradlew.bat")
        pkg.cp("java/gradlew", "gradlew")
        pkg.set_executable("gradlew")
        pkg.cp_erb("java/build.gradle.erb", "build.gradle")
        pkg.cp_erb("java/plugin_loader.rb.erb", plugin_path)
        pkg.cp_erb("java/#{category}.java.erb", "src/main/java/#{java_package_name.gsub(/\./, '/')}/#{java_class_name}.java")
        pkg.cp_erb("java/test.java.erb", "src/test/java/#{java_package_name.gsub(/\./, '/')}/Test#{java_class_name}.java")
      end

      extra_guess_erb.each_pair do |erb,dest|
        pkg.cp_erb(erb, dest)
      end

      puts ""
      puts "Plugin template is successfully generated."

      case language
      when :ruby
        puts "Next steps:"
        puts ""
        puts "  $ cd #{full_project_name}"
        puts "  $ rake"
      when :java
        puts "Next steps:"
        puts ""
        puts "  $ cd #{full_project_name}"
        puts "  $ ./gradlew package"
      end

      success = true
      puts ""
    ensure
      FileUtils.rm_rf full_project_name unless success
    end
  end
end