Dangerfile

# Warn if a pull request is too big
MAX_PR_SIZE = 250
EXCLUSIONS = ['Gemfile.lock', '.json', 'spec/fixtures/', '.txt', 'spec/support/vcr_cassettes/', 'app/swagger']

# takes form {"some/file.rb"=>{:insertions=>4, :deletions=>1}}
changed_files = git.diff.stats[:files]

excluded_changed_files = changed_files.select { |key| EXCLUSIONS.any? { |exclusion| key.include?(exclusion) } }
filtered_changed_files = changed_files.reject { |key| EXCLUSIONS.any? { |exclusion| key.include?(exclusion) } }
lines_of_code = filtered_changed_files.sum { |_file, changes| (changes[:insertions] + changes[:deletions]) }

if lines_of_code > MAX_PR_SIZE
  msg = <<~HTML
    You changed `#{lines_of_code}` LoC. This exceeds our desired maximum of `#{MAX_PR_SIZE}`.

    <details><summary>File Summary</summary>

    #### Included Files

    - #{filtered_changed_files.collect { |key, val| "#{key} (+#{val[:insertions]}/-#{val[:deletions]} )" }.join("\n- ")}

    #### Exclusions

    - #{excluded_changed_files.collect { |key, val| "#{key} (+#{val[:insertions]}/-#{val[:deletions]} )" }.join("\n- ")}

    #### 

    _Note: We exclude the following files when considering PR size_

    ```
    #{EXCLUSIONS}

    ```

    </details>

    Big PRs are difficult to review and often become stale. Consider breaking this PR up into smaller ones.

  HTML
  warn(msg)
end

# Warn when a PR includes a simultaneous DB migration and application code changes
all_touched_files  = git.added_files + git.modified_files + git.deleted_files
db_files  = all_touched_files.select { |filepath| filepath.include? "db/" }
app_files = all_touched_files.select { |filepath| filepath.include? "app/" }

if !db_files.empty? && !app_files.empty?
  msg = <<~HTML
    Modified files in `db/` and `app/` inside the same PR!

    <details><summary>File Summary</summary>

    #### db file(s)

    - #{db_files.collect { |filepath| "#{filepath}" }.join("\n- ")} 

    #### app file(s)

    - #{app_files.collect { |filepath| "#{filepath}" }.join("\n- ")} 

    </details>

    Database migrations do not run automatically with vets-api deployments. Application code must always be backwards compatible with the DB, both before and after migrations have been run. For more info: 

    - [guidance on safe db migrations](https://github.com/ankane/strong_migrations#checks)
    - [`vets-api` deployment process](https://github.com/department-of-veterans-affairs/va.gov-team/blob/master/platform/engineering/deployment.md)

  HTML

  # resolves exception... encode': "\xE2" on US-ASCII (Encoding::InvalidByteSequenceError)
  msg.scrub!('_')

  fail(msg)
end