From 100a3d245e9a545271f098b15bc97ab1b22d8082 Mon Sep 17 00:00:00 2001
From: Evan Lucas <evanlucas@me.com>
Date: Tue, 27 Sep 2016 06:05:33 -0500
Subject: [PATCH] bin: add --list flag to list all rules

It is useful to know what rules exist. In the future, these need to be
documented.

Semver: minor
---
 README.md     | 10 ++++++++++
 bin/cmd.js    | 16 ++++++++++++++++
 bin/usage.txt |  1 +
 lib/utils.js  | 16 ++++++++++++++++
 4 files changed, 43 insertions(+)

diff --git a/README.md b/README.md
index 6e9c5ae..75d802d 100644
--- a/README.md
+++ b/README.md
@@ -19,6 +19,16 @@ $ core-validate-commit <sha>
 
 # validate since <sha>
 $ git rev-list <sha>..HEAD | xargs core-validate-commit
+
+# list all rules
+$ core-validate-commit --list
+    fixes-url enforce format of Fixes URLs
+  line-length enforce max length of lines in commit body
+ metadata-end enforce that metadata is at the end of commit messages
+       pr-url enforce PR-URL
+    reviewers enforce having reviewers
+    subsystem enforce subsystem validity
+ title-length enforce max length of commit title
 ```
 
 ## Test
diff --git a/bin/cmd.js b/bin/cmd.js
index efc4812..c3d5a90 100755
--- a/bin/cmd.js
+++ b/bin/cmd.js
@@ -13,17 +13,20 @@ const pretty = require('../lib/format-pretty')
 const formatTap = require('../lib/format-tap')
 const Validator = require('../lib')
 const Tap = require('../lib/tap')
+const utils = require('../lib/utils')
 const knownOpts = { help: Boolean
                   , version: Boolean
                   , 'validate-metadata': Boolean
                   , tap: Boolean
                   , out: path
+                  , list: Boolean
                   }
 const shortHand = { h: ['--help']
                   , v: ['--version']
                   , V: ['--validate-metadata']
                   , t: ['--tap']
                   , o: ['--out']
+                  , l: ['--list']
                   }
 
 const parsed = nopt(knownOpts, shortHand)
@@ -79,6 +82,19 @@ function loadPatch(uri, cb) {
 
 const v = new Validator(parsed)
 
+if (parsed.list) {
+  const ruleNames = Array.from(v.rules.keys())
+  const max = ruleNames.reduce((m, item) => {
+    if (item.length > m) m = item.length
+    return m
+  }, 0)
+
+  for (const rule of v.rules.values()) {
+    utils.describeRule(rule, max)
+  }
+  return
+}
+
 if (parsed.tap) {
   const stream = parsed.out
     ? fs.createWriteStream(parsed.out)
diff --git a/bin/usage.txt b/bin/usage.txt
index d8d936f..0e2efba 100644
--- a/bin/usage.txt
+++ b/bin/usage.txt
@@ -7,6 +7,7 @@ core-validate-commit - Validate the commit message for a particular commit in no
     -v, --version                 show version
     -V, --validate-metadata       validate PR-URL and revieweres (on by default)
     -t, --tap                     output in tap format
+    -l, --list                    list rules and their descriptions
 
   examples:
     Validate a single sha:
diff --git a/lib/utils.js b/lib/utils.js
index 9f766ad..8f32e0c 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -17,6 +17,14 @@ exports.rightPad = function rightPad(str, max) {
   return str
 }
 
+exports.leftPad = function leftPad(str, max) {
+  const diff = max - str.length + 1
+  if (diff > 0) {
+    return `${' '.repeat(diff)}${str}`
+  }
+  return str
+}
+
 exports.header = (sha, status) => {
   switch (status) {
     case 'skip':
@@ -29,3 +37,11 @@ exports.header = (sha, status) => {
       return `${X}  ${chalk.underline(sha)}`
   }
 }
+
+exports.describeRule = function describeRule(rule, max = 20) {
+  if (rule.meta && rule.meta.description) {
+    const desc = rule.meta.description
+    const title = exports.leftPad(rule.id, max)
+    console.log(' %s %s', chalk.red(title), chalk.dim(desc))
+  }
+}