module ShopifyCli
  class Packager
    PACKAGING_DIR = File.join(ShopifyCli::ROOT, "packaging")
    BUILDS_DIR = File.join(PACKAGING_DIR, "builds", ShopifyCli::VERSION)

    def initialize
      FileUtils.mkdir_p(BUILDS_DIR)
    end

    def build_debian
      ensure_program_installed("dpkg-deb", "brew install dpkg")

      root_dir = File.join(PACKAGING_DIR, "debian")
      debian_dir = File.join(root_dir, "shopify-cli", "DEBIAN")
      FileUtils.mkdir_p(debian_dir)

      puts "\nBuilding Debian package"

      puts "Generating metadata files..."
      Dir.glob("#{debian_dir}/*").each { |file| File.delete(file) }

      metadata_files = %w(control preinst prerm)
      metadata_files.each do |file|
        file_path = File.join(debian_dir, file)

        file_contents = File.read(File.join(root_dir, "#{file}.base"))
        file_contents = file_contents.gsub("SHOPIFY_CLI_VERSION", ShopifyCli::VERSION)
        File.open(file_path, "w", 0775) { |f| f.write(file_contents) }
      end

      puts "Building package..."
      Dir.chdir(root_dir)
      raise "Failed to build package" unless system("dpkg-deb", "-b", "shopify-cli")

      output_path = File.join(root_dir, "shopify-cli.deb")
      final_path = File.join(BUILDS_DIR, "shopify-cli-#{ShopifyCli::VERSION}.deb")

      puts "Moving generated package: \n  From: #{output_path}\n  To: #{final_path}\n\n"
      FileUtils.mv(output_path, final_path)
    end

    def build_rpm
      ensure_program_installed("rpmbuild", "brew install rpm")

      root_dir = File.join(PACKAGING_DIR, "rpm")
      rpm_build_dir = File.join(root_dir, "build")
      FileUtils.mkdir_p(rpm_build_dir)

      spec_path = File.join(root_dir, "shopify-cli.spec")
      puts "\nBuilding RPM package"

      puts "Generating spec file..."
      File.delete(spec_path) if File.exist?(spec_path)

      spec_contents = File.read(File.join(root_dir, "shopify-cli.spec.base"))
      spec_contents = spec_contents.gsub("SHOPIFY_CLI_VERSION", ShopifyCli::VERSION)
      File.write(spec_path, spec_contents)

      puts "Building package..."
      Dir.chdir(root_dir)
      system("rpmbuild", "-bb", File.basename(spec_path))

      output_dir = File.join(root_dir, "build", "noarch")

      puts "Moving generated packages: \n  From: #{output_dir}\n  To: #{BUILDS_DIR}\n\n"
      FileUtils.mv(Dir.glob("#{output_dir}/*.rpm"), BUILDS_DIR)
    end

    def build_homebrew
      root_dir = File.join(PACKAGING_DIR, "homebrew")

      build_path = File.join(BUILDS_DIR, "shopify-cli.rb")
      puts "\nBuilding Homebrew package"

      puts "Generating formula..."
      File.delete(build_path) if File.exist?(build_path)

      spec_contents = File.read(File.join(root_dir, "shopify-cli.base.rb"))
      spec_contents = spec_contents.gsub("SHOPIFY_CLI_VERSION", ShopifyCli::VERSION)

      puts "Grabbing sha256 checksum from Rubygems.org"
      require "digest/sha2"
      require "open-uri"
      gem_checksum = open("https://rubygems.org/downloads/shopify-cli-#{ShopifyCli::VERSION}.gem") do |io|
        Digest::SHA256.new.hexdigest(io.read)
      end

      puts "Got sha256 checksum for gem: #{gem_checksum}"
      spec_contents = spec_contents.gsub("SHOPIFY_CLI_GEM_CHECKSUM", gem_checksum)

      puts "Writing generated formula\n  To: #{build_path}\n\n"
      File.write(build_path, spec_contents)
    end

    private

    def ensure_program_installed(program, installation_cmd)
      unless system(program, "--version", out: File::NULL, err: File::NULL)
        raise <<~MESSAGE

          Could not find program #{program} which is required to build the package.
          You can install it by running #{installation_cmd}.

        MESSAGE
      end
    end
  end
end