# frozen_string_literal: true

require 'digest/sha1'

# Public: Keeps track of watched files and triggers builds as needed.
class ViteRuby::Builder
  def initialize(vite_ruby)
    @vite_ruby = vite_ruby
  end

  # Public: Checks if the watched files have changed since the last compilation,
  # and triggers a Vite build if any files have changed.
  def build(*args)
    last_build = last_build_metadata(ssr: args.include?('--ssr'))

    if args.delete('--force') || last_build.stale? || config.manifest_paths.empty?
      stdout, stderr, status = build_with_vite(*args)
      log_build_result(stdout, stderr, status)
      record_build_metadata(last_build, errors: stderr, success: status.success?)
      status.success?
    elsif last_build.success
      logger.debug "Skipping vite build. Watched files have not changed since the last build at #{ last_build.timestamp }"
      true
    else
      logger.error "Skipping vite build. Watched files have not changed since the build failed at #{ last_build.timestamp } ❌"
      false
    end
  end

  # Internal: Reads the result of the last compilation from disk.
  def last_build_metadata(ssr: false)
    ViteRuby::Build.from_previous(last_build_path(ssr: ssr), watched_files_digest)
  end

private

  extend Forwardable

  def_delegators :@vite_ruby, :config, :logger, :run

  # Internal: Writes a digest of the watched files to disk for future checks.
  def record_build_metadata(build, **attrs)
    config.build_cache_dir.mkpath
    build.with_result(**attrs).write_to_cache
  end

  # Internal: The file path where metadata of the last build is stored.
  def last_build_path(ssr:)
    config.build_cache_dir.join("last#{ '-ssr' if ssr }-build-#{ config.mode }.json")
  end

  # Internal: Returns a digest of all the watched files, allowing to detect
  # changes, and skip Vite builds if no files have changed.
  def watched_files_digest
    config.within_root do
      files = Dir[*config.watched_paths].reject { |f| File.directory?(f) }
      file_ids = files.sort.map { |f| "#{ File.basename(f) }/#{ Digest::SHA1.file(f).hexdigest }" }
      Digest::SHA1.hexdigest(file_ids.join('/'))
    end
  end

  # Public: Initiates a Vite build command to generate assets.
  def build_with_vite(*args)
    logger.info 'Building with Vite ⚡️'

    run(['build', *args])
  end

  # Internal: Outputs the build results.
  #
  # NOTE: By default it also outputs the manifest entries.
  def log_build_result(_stdout, stderr, status)
    if status.success?
      logger.info "Build with Vite complete: #{ config.build_output_dir }"
      logger.error stderr unless stderr.empty?
    else
      logger.error stderr
      logger.error status
      logger.error 'Build with Vite failed! ❌'
      logger.error '❌ Check that vite and vite-plugin-ruby are in devDependencies and have been installed. ' if stderr.include?('ERR! canceled')
    end
  end
end