#!/usr/bin/env ruby

require 'gitlab'

#
# Configure credentials to be used with gitlab gem
#
Gitlab.configure do |config|
  config.endpoint       = 'https://gitlab.com/api/v4'
  config.private_token  = ENV["DOCS_API_TOKEN"]  # GitLab Docs bot access token which has only Developer access to gitlab-docs
end

#
# The remote docs project
#
GITLAB_DOCS_REPO = 'gitlab-com/gitlab-docs'.freeze

#
# Truncate the remote docs branch name if it's more than 63 characters
# otherwise we hit the filesystem limit and the directory name where
# NGINX serves the site won't match the branch name.
#
def docs_branch
  # The maximum string length a file can have on a filesystem (ext4)
  # is 63 characters. Let's use something smaller to be 100% sure.
  max = 42
  # Prefix the remote branch with 'preview-' in order to avoid
  # name conflicts in the rare case the branch name already
  # exists in the docs repo and truncate to max length.
  "preview-#{ENV["CI_COMMIT_REF_SLUG"]}"[0...max]
end

#
# Dummy way to find out in which repo we are, CE or EE
#
def ee?
  File.exist?('CHANGELOG-EE.md')
end

#
# Create a remote branch in gitlab-docs
#
def create_remote_branch
  Gitlab.create_branch(GITLAB_DOCS_REPO, docs_branch, 'master')
  puts "Remote branch '#{docs_branch}' created"
rescue Gitlab::Error::BadRequest
  puts "Remote branch '#{docs_branch}' already exists"
end

#
# Remove a remote branch in gitlab-docs
#
def remove_remote_branch
  Gitlab.delete_branch(GITLAB_DOCS_REPO, docs_branch)
  puts "Remote branch '#{docs_branch}' deleted"
end

#
# Trigger a pipeline in gitlab-docs
#
def trigger_pipeline
  # Overriding vars in https://gitlab.com/gitlab-com/gitlab-docs/blob/master/.gitlab-ci.yml
  param_name = ee? ? 'BRANCH_EE' : 'BRANCH_CE'

  # The review app URL
  app_url = "http://#{docs_branch}.#{ENV["DOCS_REVIEW_APPS_DOMAIN"]}/#{ee? ? 'ee' : 'ce'}"

  # Create the pipeline
  puts "=> Triggering a pipeline..."
  pipeline = Gitlab.run_trigger(GITLAB_DOCS_REPO, ENV["CI_JOB_TOKEN"], docs_branch, { param_name => ENV["CI_COMMIT_REF_NAME"] })

  puts "=> Pipeline created:"
  puts ""
  puts "https://gitlab.com/gitlab-com/gitlab-docs/pipelines/#{pipeline.id}"
  puts ""
  puts "=> Preview your changes live at:"
  puts ""
  puts app_url
  puts ""
end

#
# When the first argument is deploy then create the branch and trigger pipeline
# When it is 'stop', it deleted the remote branch. That way, we ensure there
# are no stale remote branches and the Review server doesn't fill.
#
case ARGV[0]
when 'deploy'
  create_remote_branch
  trigger_pipeline
when 'cleanup'
  remove_remote_branch
else
  puts "Please provide a valid option:
  deploy  - Creates the remote branch and triggers a pipeline
  cleanup - Deletes the remote branch and stops the Review App"
end