require 'fileutils'
require 'set'
require 'socket'
require 'tmpdir'

require 'fig'
require 'fig/at_exit'
require 'fig/file_not_found_error'
require 'fig/logging'
require 'fig/not_yet_parsed_package'
require 'fig/package_cache'
require 'fig/package_descriptor'
require 'fig/parser'
require 'fig/repository_error'
require 'fig/repository_package_publisher'
require 'fig/url'

module Fig; end

# Overall management of a repository.  Handles local operations itself;
# defers remote operations to others.
class Fig::Repository
  METADATA_SUBDIRECTORY     = '_meta'
  PACKAGE_FILE_IN_REPO      = '.fig'
  RESOURCES_FILE            = 'resources.tar.gz'
  VERSION_FILE_NAME         = 'repository-format-version'
  LOCAL_VERSION_SUPPORTED   = 2
  REMOTE_VERSION_SUPPORTED  = 1

  def initialize(
    application_configuration,
    options,
    operating_system,
    local_repository_directory,
    remote_repository_url,
    parser,
    publish_listeners
  )
    @application_configuration    = application_configuration
    @options                      = options
    @operating_system             = operating_system
    @local_repository_directory   = local_repository_directory
    @remote_repository_url        = remote_repository_url
    @parser                       = parser
    @publish_listeners            = publish_listeners

    initialize_local_repository()
    reset_cached_data()
  end

  def reset_cached_data()
    @package_cache = Fig::PackageCache.new()
  end

  def list_packages
    check_local_repository_format

    results = []
    if File.exist?(local_package_directory)
      @operating_system.list(local_package_directory).each do
        |name|

        @operating_system.list(
          File.join local_package_directory(), name
        ).each do
          |version|

          results << Fig::PackageDescriptor.format(name, version, nil)
        end
      end
    end

    return results
  end

  def list_remote_packages
    check_remote_repository_format()

    paths = @operating_system.download_list(remote_repository_url())

    return paths.reject { |path| path =~ %r< ^ #{METADATA_SUBDIRECTORY} / >xs }
  end

  def get_package(
    descriptor,
    allow_any_version = false
  )
    check_local_repository_format()

    if not descriptor.version
      if allow_any_version
        package = @package_cache.get_any_version_of_package(descriptor.name)
        if package
          Fig::Logging.warn(
            "Picked version #{package.version} of #{package.name} at random."
          )
          return package
        end
      end

      raise Fig::RepositoryError.new(
        %Q<Cannot retrieve "#{descriptor.name}" without a version.>
      )
    end

    package = @package_cache.get_package(descriptor.name, descriptor.version)
    return package if package

    Fig::Logging.debug \
      "Considering #{Fig::PackageDescriptor.format(descriptor.name, descriptor.version, nil)}."

    if should_update?(descriptor)
      check_remote_repository_format()

      update_package(descriptor)
    end

    return read_local_package(descriptor)
  end

  def clean(descriptor)
    check_local_repository_format()

    @package_cache.remove_package(descriptor.name, descriptor.version)

    nuke_package descriptor

    return
  end

  def publish_package(
    package_statements, descriptor, local_only, source_package, was_forced
  )
    check_local_repository_format()
    if not local_only
      check_remote_repository_format()
    end

    publisher = Fig::RepositoryPackagePublisher.new
    publisher.application_configuration    = @application_configuration
    publisher.options                      = @options
    publisher.operating_system             = @operating_system
    publisher.publish_listeners            = @publish_listeners
    publisher.package_statements           = package_statements
    publisher.descriptor                   = descriptor
    publisher.source_package               = source_package
    publisher.was_forced                   = was_forced
    publisher.base_temp_dir                = base_temp_dir
    publisher.runtime_for_package          = runtime_for_package(descriptor)
    publisher.local_directory_for_package  =
      local_directory_for_package(descriptor)
    publisher.remote_directory_for_package =
      remote_directory_for_package(descriptor)
    publisher.local_only                   = local_only
    publisher.local_fig_file_for_package =
      local_fig_file_for_package(descriptor)
    publisher.remote_fig_file_for_package =
      remote_fig_file_for_package(descriptor)

    return publisher.publish_package()
  end

  def update_unconditionally()
    @update_condition = :unconditionally
  end

  def update_if_missing()
    @update_condition = :if_missing
  end

  private

  attr_reader :remote_repository_url

  def initialize_local_repository()
    FileUtils.mkdir_p(@local_repository_directory)

    version_file = local_version_file()
    if not File.exist?(version_file)
      File.open(version_file, 'w') { |handle| handle.write(LOCAL_VERSION_SUPPORTED) }
    end

    return
  end

  def check_local_repository_format()
    version = local_repository_version

    if version != LOCAL_VERSION_SUPPORTED
      message =
        "Local repository is in version #{version} format. This version of fig can only deal with repositories in version #{LOCAL_VERSION_SUPPORTED} format."
      if version < LOCAL_VERSION_SUPPORTED
        message +=
          " Either point $FIG_HOME to a different location or rename or delete #{@local_repository_directory}. (Be mindful of packages that have been published only locally.)"
      end
      Fig::Logging.fatal message
      raise Fig::RepositoryError.new
    end

    return
  end

  def check_remote_repository_format()
    version = remote_repository_version

    if version != REMOTE_VERSION_SUPPORTED
      Fig::Logging.fatal \
        "Remote repository is in version #{version} format. This version of fig can only deal with repositories in version #{REMOTE_VERSION_SUPPORTED} format."
      raise Fig::RepositoryError.new
    end

    return
  end

  def local_repository_version()
    if @local_repository_version.nil?
      version_file = local_version_file()

      @local_repository_version =
        parse_repository_version(version_file, version_file)
    end

    return @local_repository_version
  end

  def local_version_file()
    return File.join(@local_repository_directory, VERSION_FILE_NAME)
  end

  def local_package_directory()
    return File.expand_path(File.join(@local_repository_directory, 'packages'))
  end

  def package_runtime_directory()
    return File.expand_path(File.join(@local_repository_directory, 'runtime'))
  end

  def remote_repository_version()
    if @remote_repository_version.nil?
      temp_dir = base_temp_dir()
      @operating_system.delete_and_recreate_directory(temp_dir)
      remote_version_file = Fig::URL.append_path_components(
        remote_repository_url(), [VERSION_FILE_NAME]
      )
      local_version_file = File.join(temp_dir, "remote-#{VERSION_FILE_NAME}")
      begin
        @operating_system.download(
          remote_version_file, local_version_file, :prompt_for_login
        )
      rescue Fig::FileNotFoundError
        # The download may create an empty file, so get rid of it.
        if File.exist?(local_version_file)
          File.unlink(local_version_file)
        end
      end

      @remote_repository_version =
        parse_repository_version(local_version_file, remote_version_file)
    end

    return @remote_repository_version
  end

  def parse_repository_version(version_file, description)
    if not File.exist?(version_file)
      return 1 # Since there was no version file early in Fig development.
    end

    version_string = IO.read(version_file)
    version_string.strip!()
    if version_string !~ / \A \d+ \z /x
      Fig::Logging.fatal \
        %Q<Could not parse the contents of "#{description}" ("#{version_string}") as a version.>
      raise Fig::RepositoryError.new
    end

    return version_string.to_i()
  end

  def should_update?(descriptor)
    return true if @update_condition == :unconditionally

    return @update_condition == :if_missing && package_missing?(descriptor)
  end

  def read_local_package(descriptor)
    directory = local_directory_for_package(descriptor)
    return read_package_from_directory(directory, descriptor)
  end

  def update_package(descriptor)
    temp_dir = package_download_temp_dir(descriptor)
    begin
      install_package(descriptor, temp_dir)
    rescue Fig::FileNotFoundError => error
      if @updating_package_definition
        Fig::Logging.fatal \
          "Package #{descriptor.to_string} not found in remote repository. (Was looking for #{error.path}.)"
      else
        Fig::Logging.fatal \
          "Part of package #{descriptor.to_string} was not downloadable. (Was attempting to get #{error.path}.)"
      end

      raise Fig::RepositoryError.new
    rescue StandardError => exception
      Fig::Logging.fatal %Q<Install of #{descriptor.to_string} failed: #{exception}>

      raise Fig::RepositoryError.new
    ensure
      FileUtils.rm_rf(temp_dir)
    end

    return
  end

  def install_package(descriptor, temporary_directory)
    remote_fig_file   = remote_fig_file_for_package(descriptor)
    package_directory = local_directory_for_package(descriptor)
    local_fig_file    = fig_file_for_package_download(package_directory)

    if @operating_system.path_up_to_date?(
      remote_fig_file, local_fig_file, :prompt_for_login
    )
      Fig::Logging.debug \
        "Skipping update of #{descriptor.to_string} because it looks like #{local_fig_file} is up-to-date."
      return
    end

    temporary_package = File.join temporary_directory, 'packages'
    temporary_runtime = File.join temporary_directory, 'runtime'
    temp_fig_file   = fig_file_for_package_download(temporary_package)
    set_up_package_download_directories(
      temporary_directory, temporary_package, package_directory
    )

    @updating_package_definition = true
    return if ! @operating_system.download(
      remote_fig_file, temp_fig_file, :prompt_for_login
    )

    package = read_package_from_directory(temporary_package, descriptor)
    @updating_package_definition = false

    download_assets(package, descriptor, temporary_package, temporary_runtime)

    nuke_package descriptor

    FileUtils.mkdir_p File.dirname(package_directory)
    FileUtils.mv temporary_package, package_directory

    runtime_directory = package.runtime_directory
    if File.exists? temporary_runtime
      FileUtils.mkdir_p File.dirname(runtime_directory)
      FileUtils.mv temporary_runtime, runtime_directory
    else
      FileUtils.mkdir_p runtime_directory
    end

    return
  end

  def read_package_from_directory(directory, descriptor)
    dot_fig_file = File.join(directory, PACKAGE_FILE_IN_REPO)
    if not File.exist?(dot_fig_file)
      message =
        %Q<Fig file not found for package "#{descriptor.name || '<unnamed>'}". There is nothing in "#{dot_fig_file}".>
      if ! @update_condition
        message +=
          ' You might want to try specifying the --update or --update-if-missing options.'
      end

      Fig::Logging.fatal message
      raise Fig::RepositoryError.new
    end

    return read_package_from_file(dot_fig_file, descriptor)
  end

  def read_package_from_file(file_name, descriptor)
    if not File.exist?(file_name)
      Fig::Logging.fatal "Package not found: #{descriptor.to_string()}"
      raise Fig::RepositoryError.new
    end
    content = File.read(file_name)

    unparsed_package = Fig::NotYetParsedPackage.new
    unparsed_package.descriptor         = descriptor
    unparsed_package.working_directory  =
      unparsed_package.include_file_base_directory =
      runtime_for_package(descriptor)
    unparsed_package.source_description = descriptor.to_string()
    unparsed_package.unparsed_text      = content

    package = @parser.parse_package(unparsed_package)

    @package_cache.add_package(package)

    return package
  end

  def set_up_package_download_directories(
    temporary_directory, temporary_package, package_directory
  )
    FileUtils.rm_rf temporary_directory
    if File.exist? package_directory
      FileUtils.mkdir_p File.dirname(temporary_package)
      FileUtils.cp_r(
        package_directory, temporary_package, :preserve => true
      )
    else
      FileUtils.mkdir_p temporary_package
    end

    return
  end

  def download_assets(package, descriptor, temporary_package, temporary_runtime)
    remote_package_directory = remote_directory_for_package(descriptor)
    package.archive_locations.each do
      |archive_location|

      if not Fig::URL.is_url?(archive_location)
        archive_location = Fig::URL.append_path_components(
          remote_package_directory, [archive_location]
        )
      end
      @operating_system.download_and_unpack_archive(
        archive_location, temporary_package, temporary_runtime
      )
    end
    package.resource_locations.each do
      |resource_location|

      if not Fig::URL.is_url?(resource_location)
        resource_location = Fig::URL.append_path_components(
          remote_package_directory, [resource_location]
        )
      end

      basename, path =
        @operating_system.download_resource(
          resource_location, temporary_package
        )

      @operating_system.copy path, File.join(temporary_runtime, basename)
    end

    return
  end

  def remote_fig_file_for_package(descriptor)
    return Fig::URL.append_path_components(
      remote_directory_for_package(descriptor), [PACKAGE_FILE_IN_REPO]
    )
  end

  def local_fig_file_for_package(descriptor)
    File.join(local_directory_for_package(descriptor), PACKAGE_FILE_IN_REPO)
  end

  def fig_file_for_package_download(package_download_dir)
    File.join(package_download_dir, PACKAGE_FILE_IN_REPO)
  end

  def remote_directory_for_package(descriptor)
    return Fig::URL.append_path_components(
      remote_repository_url(), [descriptor.name, descriptor.version]
    )
  end

  def local_directory_for_package(descriptor)
    return File.join(
      local_package_directory, descriptor.name, descriptor.version
    )
  end

  def runtime_for_package(descriptor)
    return File.join(
      package_runtime_directory, descriptor.name, descriptor.version
    )
  end

  # Note that we use a temporary directory within the repository so that we
  # don't need to worry about crossing file-system boundaries.  If we stored
  # things in /tmp, we couldn't do true file moves, just copies and deletes,
  # and there would be race conditions and other not-fun things to worry about.
  def base_temp_dir()
    File.join(@local_repository_directory, 'tmp')
  end

  def package_download_temp_dir(descriptor)
    base_directory = File.join(base_temp_dir(), 'package-download')
    FileUtils.mkdir_p(base_directory)

    return Dir.mktmpdir(
      "#{descriptor.name}.version.#{descriptor.version}+", base_directory
    )
  end

  def package_missing?(descriptor)
    not File.exist?(local_fig_file_for_package(descriptor))
  end

  def nuke_package(descriptor)
    FileUtils.rm_rf runtime_for_package(descriptor)
    FileUtils.rm_rf local_directory_for_package(descriptor)

    return
  end
end