lint_commit_message

#!/usr/bin/env ruby

require 'shellwords'
require 'json'
require 'jira_ref_parser'
require 'yaml'

GERGICH_GIT_PATH=ENV.fetch("GERGICH_GIT_PATH", ".")

def git(command)
  Dir.chdir(GERGICH_GIT_PATH) do
    `git #{command}`
  end
end

def comment(severity, line, message, link_to_guidelines = false)
  $stderr.puts "line #{line}: [#{severity}]: #{message}"
  if ENV['GERRIT_REFSPEC']
    message += "\n\nHere are some guidelines to keep our git log pretty and useful: http://chris.beams.io/posts/git-commit/" if link_to_guidelines

    # NOTE: add 6 to all line numbers, cuz parent/author/commit/dates/etc
    payload = {path: "/COMMIT_MSG", position: line + 6, severity: severity, message: message}
    `gergich comment #{Shellwords.escape(payload.to_json)}`
  end
end

commit_message = ARGV[0] == "--stdin" ? STDIN.read : git("show --pretty=format:%B -s")

exit if commit_message =~ /\A\[?wip($|[\] :-])/i
lines = commit_message.split(/\n/)
subject = lines.shift

if lines.shift != ""
  comment "error", 2, "add a blank line after the subject line", true
end

SUBJECT_MAX_LINE_LEN = 75
SUBJECT_IDEAL_LINE_LEN = 65

length_exemption_regex = /^Revert/

if subject.size > SUBJECT_MAX_LINE_LEN && subject !~ length_exemption_regex
  comment "error", 1, "subject line can't exceed #{SUBJECT_MAX_LINE_LEN} chars (ideally keep it well under #{SUBJECT_IDEAL_LINE_LEN})", true
elsif subject.size > SUBJECT_IDEAL_LINE_LEN && subject !~ length_exemption_regex
  comment "warn", 1, "subject line shouldn't exceed #{SUBJECT_IDEAL_LINE_LEN} chars", true
end

# not perfect (won't get irregular verbs, only checks first word), but
# close enough... does the right thing on most existing commits
maybe_wrong_tense_regex = /\A(spec: )?[a-z]+([^e]ed|[^aijoqsu]s|ing) /i
actually_ok_regex = /\A
  (spec:\s+)?
  (
    # *ing words
    (brand|br|[^ ]*learn|masquerad|upcom|shard|word|grad)ing |

    # *ed words
    (brand|fail|batch|emb|persist|enrich|(un)?publish|moderat|mut|grad)ed |

    # *s words
    (.*(ion|ment)|observer|alway|outcome|rail|user|spec|student|quizze|alert|plugin|term)s
  )
/xi

maybe_start_with_wrong_tense = subject =~ maybe_wrong_tense_regex &&
                               subject !~ actually_ok_regex
if maybe_start_with_wrong_tense
  comment "warn", 1, "make sure your commit message has an imperative verb (e.g. \"add\" instead of \"adds\", \"added\", or \"adding\")", true
end

has_the_word_i = subject =~ /(\A| )i('m)? /i
if has_the_word_i
  comment "warn", 1, "just say what the commit does, and not in the first person :P", true
end


BODY_IDEAL_LINE_LENGTH = 75

long_lines = lines.each_with_index.select do |line, i|
  line.size > BODY_IDEAL_LINE_LENGTH
end

if long_lines.size > 0
  comment "warn", long_lines.first[1] + 3,
    "try to keep all lines under #{BODY_IDEAL_LINE_LENGTH} characters" +
    (long_lines.size > 1 ? " (note that #{long_lines.size - 1} other long lines follow this one)" : ""), true
end

is_a_selinimum_test = commit_message.split("[selinimum:ignore_intermediate_commits]")
if is_a_selinimum_test.size > 1
  line = is_a_selinimum_test[0].count("\n") + 1
  comment "error", line, "since you're telling selinimum to ignore intermediate commits, this commit may not be safe to merge"
end

starts_with_spec = subject =~ /\Aspec: /i
exit if starts_with_spec # we're trusting you here, don't be evil

commit_files = git("show --pretty=format:"" --name-only").split("\n")
only_affects_specs = commit_files.all? { |f| f =~ %r{\Aspec/} }
if only_affects_specs
  comment "warn", 1, "since your commit only affects specs, please prefix your commit message with \"spec: \""
  exit
end

user_config_file = File.expand_path("../../gems/dr_diff/config/gergich_user_config.yml", __FILE__)
if File.exists?(user_config_file)
  config = YAML.load_file(user_config_file) || {}
  user_list = config['only_report_errors'] || []
  exit if user_list.include?(ENV['GERRIT_EVENT_ACCOUNT_EMAIL'])
end

gh_issue = (commit_message =~ /(?:refs|fixes|closes|resolves|references) gh-\d+/i)
SAFE_PARTS_REGEX = /UTF\-8/
TICKET_REGEX = /([A-Z]+\-[0-9]+)/

issue_ids = JiraRefParser.scan_message_for_issue_ids(commit_message)
if issue_ids.empty? && !gh_issue
  parts = commit_message.gsub(SAFE_PARTS_REGEX, "")
            .split(TICKET_REGEX)
  if parts.size > 1
    jira_hook_words = JiraRefParser::RefKeywords + JiraRefParser::FixKeywords
    comment "warn", parts.first.count("\n") + 1, "the jira hooks won't link this commit to #{parts[1]} unless you use one of the following keywords: #{jira_hook_words.join(", ")}"
  else
    comment "warn", 3, "you should really reference a ticket ლ(ٱ٥ٱლ)"
  end
end

has_a_test_plan = commit_message =~ /test[ -]plan/i
unless has_a_test_plan
  comment "warn", 3, "y u no add test plan? ლ(ಠ益ಠლ)"
end