# frozen_string_literal: true

class PostReceive
  include ApplicationWorker

  idempotent!
  deduplicate :none
  data_consistency :sticky

  sidekiq_options retry: 3
  include Gitlab::Experiment::Dsl
  include ::Gitlab::ExclusiveLeaseHelpers

  feature_category :source_code_management
  urgency :high
  worker_resource_boundary :cpu
  weight 5
  loggable_arguments 0, 1, 2, 3

  def perform(gl_repository, identifier, changes, push_options = {})
    container, project, repo_type = Gitlab::GlRepository.parse(gl_repository)
    @project = project
    @gl_repository = gl_repository

    if container.nil? || (container.is_a?(ProjectSnippet) && project.nil?)
      log("Triggered hook for non-existing gl_repository \"#{gl_repository}\"")
      return false
    end

    changes = Base64.decode64(changes) unless changes.include?(' ')
    # Use Sidekiq.logger so arguments can be correlated with execution
    # time and thread ID's.
    Sidekiq.logger.info "changes: #{changes.inspect}" if SidekiqLogArguments.enabled?
    post_received = Gitlab::GitPostReceive.new(container, identifier, changes, push_options)

    if repo_type.wiki?
      process_wiki_changes(post_received, container)
    elsif repo_type.project?
      process_project_changes(post_received, container)
    elsif repo_type.snippet?
      process_snippet_changes(post_received, container)
    elsif repo_type.design?
      process_design_management_repository_changes(post_received, container)
    else
      # Other repos don't have hooks for now
    end
  end

  private

  def identify_user(post_received)
    post_received.identify.tap do |user|
      log("Triggered hook for non-existing user \"#{post_received.identifier}\"") unless user
    end
  end

  def process_project_changes(post_received, project)
    user = identify_user(post_received)

    return false unless user

    push_options = post_received.push_options
    changes = post_received.changes

    # We only need to expire certain caches once per push
    expire_caches(post_received, project.repository)
    enqueue_project_cache_update(post_received, project)

    process_ref_changes(project, user, push_options: push_options, changes: changes)
    update_remote_mirrors(post_received, project)
    after_project_changes_hooks(project, user, changes.refs, changes.repository_data)
  end

  def process_wiki_changes(post_received, wiki)
    user = identify_user(post_received)
    return false unless user

    # We only need to expire certain caches once per push
    expire_caches(post_received, wiki.repository)
    wiki.repository.expire_statistics_caches

    ::Git::WikiPushService.new(wiki, user, changes: post_received.changes).execute
  end

  def process_snippet_changes(post_received, snippet)
    user = identify_user(post_received)

    return false unless user

    replicate_snippet_changes(snippet)

    expire_caches(post_received, snippet.repository)
    snippet.touch
    Snippets::UpdateStatisticsService.new(snippet).execute
  end

  def process_design_management_repository_changes(post_received, design_management_repository)
    user = identify_user(post_received)

    return false unless user

    replicate_design_management_repository_changes(design_management_repository)
    expire_caches(post_received, design_management_repository.repository)
  end

  def replicate_snippet_changes(snippet)
    # Used by Gitlab Geo
  end

  def replicate_design_management_repository_changes(design_management_repository)
    # Used by GitLab Geo
  end

  # Expire the repository status, branch, and tag cache once per push.
  def expire_caches(post_received, repository)
    repository.expire_status_cache if repository.empty?
    expire_branch_cache(repository) if post_received.includes_branches?
    expire_tag_cache(repository) if post_received.includes_tags?
  end

  def expire_branch_cache(repository)
    unless Feature.enabled?(:post_receive_sync_refresh_cache, @project)
      repository.expire_branches_cache
      return
    end

    # Consider the scenario where multiple pushes happen in close succession:
    #
    # 1. Job 1 expires cache.
    # 2. Job 1 starts computing branch list.
    # 3. Job 2 starts.
    # 4. Job 2 expires cache (no-op because nothing is there).
    # 5. Job 1 finishes computing branch list, persists cache.
    # 6. Job 2 reads from stale cache instead of loading a fresh branch list.
    #
    # To avoid this, atomically expire and refresh the branch name cache
    # so that tasks such as pipeline creation will find the branch.
    with_lock(:branch) do
      repository.expire_branches_cache
      repository.branch_names
    end
  rescue Gitlab::ExclusiveLeaseHelpers::FailedToObtainLockError
    log("Failed to obtain lease for expiring branch name cache")
    repository.expire_branches_cache
  end

  def expire_tag_cache(repository)
    unless Feature.enabled?(:post_receive_sync_refresh_cache, @project)
      repository.expire_caches_for_tags
      return
    end

    with_lock(:tag) do
      repository.expire_caches_for_tags
      repository.tag_names
    end
  rescue Gitlab::ExclusiveLeaseHelpers::FailedToObtainLockError
    log("Failed to obtain lease for expiring tag name cache")
    repository.expire_caches_for_tags
  end

  def lease_key(ref_type)
    "post_receive:#{@gl_repository}:#{ref_type}"
  end

  def with_lock(ref_type)
    retries = 50
    sleep_interval = cache_ttl.to_f / retries

    in_lock(lease_key(ref_type), ttl: cache_ttl, retries: retries, sleep_sec: sleep_interval) do
      yield
    end
  end

  # Schedule an update for the repository size and commit count if necessary.
  def enqueue_project_cache_update(post_received, project)
    stats_to_invalidate = [:repository_size]
    stats_to_invalidate << :commit_count if post_received.includes_default_branch?

    ProjectCacheWorker.perform_async(
      project.id,
      [],
      stats_to_invalidate,
      true
    )
  end

  def process_ref_changes(project, user, params = {})
    return unless params[:changes].any?

    Git::ProcessRefChangesService.new(project, user, params).execute
  end

  def update_remote_mirrors(post_received, project)
    return unless post_received.includes_branches? || post_received.includes_tags?

    return unless project.has_remote_mirror?

    project.mark_stuck_remote_mirrors_as_failed!
    project.update_remote_mirrors
  end

  def after_project_changes_hooks(project, user, refs, changes)
    repository_update_hook_data = Gitlab::DataBuilder::Repository.update(project, user, changes, refs)
    SystemHooksService.new.execute_hooks(repository_update_hook_data, :repository_update_hooks)
    Gitlab::InternalEvents.track_event('source_code_pushed', project: project, user: user)
  end

  def log(message)
    Gitlab::GitLogger.error("POST-RECEIVE: #{message}")
  end

  def cache_ttl
    ::Gitlab::GitalyClient.fast_timeout * 2
  end
end

PostReceive.prepend_mod_with('PostReceive')