From cde390c838dcd775d92e4054d3eeb97c3e7542af Mon Sep 17 00:00:00 2001
From: hypervtechnics <hypervtechnics@gmail.com>
Date: Thu, 31 Mar 2022 15:53:53 +0200
Subject: [PATCH] chore: include feedback from pull request review

issue: #45
---
 README.md     |  2 +-
 sv/config.go  |  2 +-
 sv/message.go | 39 ++++++++++++++++++++++++++++++---------
 3 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/README.md b/README.md
index 210c0dd..726d651 100644
--- a/README.md
+++ b/README.md
@@ -120,7 +120,7 @@ branches: # Git branches config.
 
 commit-message:
     types: [build, ci, chore, docs, feat, fix, perf, refactor, revert, style, test] # Supported commit types.
-    selector: '' # You can put in a regex here to select only a certain part of the commit message.
+    header-selector: '' # You can put in a regex here to select only a certain part of the commit message. Please define a regex group 'header'.
     scope:
         # Define supported scopes, if blank, scope will not be validated, if not, only scope listed will be valid.
         # Don't forget to add "" on your list if you need to define scopes and keep it optional.
diff --git a/sv/config.go b/sv/config.go
index 64437cd..264755b 100644
--- a/sv/config.go
+++ b/sv/config.go
@@ -5,7 +5,7 @@ package sv
 // CommitMessageConfig config a commit message.
 type CommitMessageConfig struct {
 	Types  []string                             `yaml:"types,flow"`
-	MessageSelector string                      `yaml:"selector"`
+	HeaderSelector string                       `yaml:"header-selector"`
 	Scope  CommitMessageScopeConfig             `yaml:"scope"`
 	Footer map[string]CommitMessageFooterConfig `yaml:"footer"`
 	Issue  CommitMessageIssueConfig             `yaml:"issue"`
diff --git a/sv/message.go b/sv/message.go
index 57d1dad..1c96e52 100644
--- a/sv/message.go
+++ b/sv/message.go
@@ -11,7 +11,7 @@ const (
 	breakingChangeFooterKey   = "BREAKING CHANGE"
 	breakingChangeMetadataKey = "breaking-change"
 	issueMetadataKey          = "issue"
-	messageRegexGroupName     = "message"
+	messageRegexGroupName     = "header"
 )
 
 // CommitMessage is a message using conventional commits.
@@ -203,16 +203,13 @@ func (p MessageProcessorImpl) Format(msg CommitMessage) (string, string, string)
 
 // Parse a commit message.
 func (p MessageProcessorImpl) Parse(subject, body string) CommitMessage {
-	filteredSubject := subject
-	if p.messageCfg.MessageSelector != "" {
-		subjectRegex := regexp.MustCompile(p.messageCfg.MessageSelector)
-		subjectMessageIndex := subjectRegex.SubexpIndex(messageRegexGroupName)
-		subjectMatch := subjectRegex.FindStringSubmatch(subject)
-		
-		filteredSubject = subjectMatch[subjectMessageIndex]
+	preparedSubject, prepError := p.prepareHeader(subject)
+
+	if prepError != nil {
+	    fmt.Println(prepError)
 	}
 	
-	commitType, scope, description, hasBreakingChange := parseSubjectMessage(filteredSubject)
+	commitType, scope, description, hasBreakingChange := parseSubjectMessage(preparedSubject)
 
 	metadata := make(map[string]string)
 	for key, mdCfg := range p.messageCfg.Footer {
@@ -241,6 +238,30 @@ func (p MessageProcessorImpl) Parse(subject, body string) CommitMessage {
 	}
 }
 
+func (p MessageProcessorImpl) prepareHeader(header string) (string, error) {
+	if p.messageCfg.HeaderSelector == "" {
+		return header, nil
+	}
+
+	regex, err := regexp.Compile(p.messageCfg.HeaderSelector)
+	if err != nil {
+		return "", fmt.Errorf("invalid regex on header-selector %s, error: %s", p.messageCfg.HeaderSelector, err.Error())
+	}
+
+	index := regex.SubexpIndex(messageRegexGroupName)
+	if index < 0 {
+		return "", fmt.Errorf("could not find %s regex group on header-selector regex", messageRegexGroupName)
+	}
+
+	match := regex.FindStringSubmatch(header)
+
+	if match == nil || len(match) < index {
+		return "", fmt.Errorf("could not find %s regex group in match result for '%s'", messageRegexGroupName, header)
+	}
+
+	return match[index], nil
+}
+
 func parseSubjectMessage(message string) (string, string, string, bool) {
 	regex := regexp.MustCompile(`([a-z]+)(\((.*)\))?(!)?: (.*)`)
 	result := regex.FindStringSubmatch(message)