Expose license-location-threshold as config item

.licenserc.yaml

@@ -76,6 +76,10 @@ header: # `header` section is configurations for source codes license header.
 
   comment: on-failure # on what condition license-eye will comment on the pull request, `on-failure`, `always`, `never`.
 
+  # license-location-threshold specifies the index threshold where the license header can be located,
+  # after all, a "header" cannot be TOO far from the file start.
+  license-location-threshold: 80
+
 dependency:
   files:
     - go.mod

pkg/header/check.go

@@ -31,12 +31,6 @@ import (
 	"github.com/bmatcuk/doublestar/v2"
 )
 
-var (
-	// LicenseLocationThreshold specifies the index threshold where the license header can be located,
-	// after all, a "header" cannot be TOO far from the file start.
-	LicenseLocationThreshold = 80
-)
-
 // Check checks the license headers of the specified paths/globs.
 func Check(config *ConfigHeader, result *Result) error {
 	for _, pattern := range config.Paths {
@@ -129,7 +123,7 @@ func CheckFile(file string, config *ConfigHeader, result *Result) error {
 	content := lcs.NormalizeHeader(string(bs))
 	expected, pattern := config.NormalizedLicense(), config.NormalizedPattern()
 
-	if satisfy(content, expected, pattern) {
+	if satisfy(content, config, expected, pattern) {
 		result.Succeed(file)
 	} else {
 		logger.Log.Debugln("Content is:", content)
@@ -140,15 +134,15 @@ func CheckFile(file string, config *ConfigHeader, result *Result) error {
 	return nil
 }
 
-func satisfy(content, license string, pattern *regexp.Regexp) bool {
+func satisfy(content string, config *ConfigHeader, license string, pattern *regexp.Regexp) bool {
 	if index := strings.Index(content, license); strings.TrimSpace(license) != "" && index >= 0 {
-		return index < LicenseLocationThreshold
+		return index < config.LicenseLocationThreshold
 	}
 
 	if pattern == nil {
 		return false
 	}
 	index := pattern.FindStringIndex(content)
 
-	return len(index) == 2 && index[0] < LicenseLocationThreshold
+	return len(index) == 2 && index[0] < config.LicenseLocationThreshold
 }

pkg/header/config.go

@@ -56,6 +56,10 @@ type ConfigHeader struct {
 	Paths       []string      `yaml:"paths"`
 	PathsIgnore []string      `yaml:"paths-ignore"`
 	Comment     CommentOption `yaml:"comment"`
+
+	// LicenseLocationThreshold specifies the index threshold where the license header can be located,
+	// after all, a "header" cannot be TOO far from the file start.
+	LicenseLocationThreshold int `yaml:"license-location-threshold"`
 }
 
 // NormalizedLicense returns the normalized string of the license content,
@@ -120,6 +124,10 @@ func (config *ConfigHeader) Finalize() error {
 		logger.Log.Debugln("Pattern is:", p)
 	}
 
+	if config.LicenseLocationThreshold <= 0 {
+		config.LicenseLocationThreshold = 80
+	}
+
 	return nil
 }