Create meaningful lines calculations.

internal/diff/analyzer.go

@@ -0,0 +1,137 @@
+package diff
+
+import (
+	"strings"
+)
+
+// IsCommentLine checks if a line is a code comment (should not count as meaningful contribution)
+func IsCommentLine(line string) bool {
+	trimmed := strings.TrimSpace(line)
+	if trimmed == "" {
+		return true // Empty lines don't count
+	}
+
+	// Common comment patterns across languages
+	commentPrefixes := []string{
+		"//",     // C, C++, Java, Go, JS, TS, Swift, Kotlin, etc.
+		"#",      // Python, Ruby, Shell, YAML, Perl, etc.
+		"/*",     // C-style block comment start
+		"*/",     // C-style block comment end
+		"*",      // C-style block comment continuation
+		"<!--",   // HTML/XML comment
+		"-->",    // HTML/XML comment end
+		"--",     // SQL, Lua, Haskell
+		";",      // Assembly, Lisp, INI files
+		"'",      // VB comment
+		"\"\"\"", // Python docstring
+		"'''",    // Python docstring
+	}
+
+	for _, prefix := range commentPrefixes {
+		if strings.HasPrefix(trimmed, prefix) {
+			return true
+		}
+	}
+
+	return false
+}
+
+// IsWhitespaceLine checks if a line contains only whitespace characters
+func IsWhitespaceLine(line string) bool {
+	return strings.TrimSpace(line) == ""
+}
+
+// IsDocumentationFile checks if a file is documentation-only
+func IsDocumentationFile(filename string) bool {
+	// Documentation file extensions and patterns
+	docPatterns := []string{
+		".md", ".markdown", ".rst", ".txt", ".adoc",
+		"README", "CHANGELOG", "LICENSE", "CONTRIBUTING",
+		"docs/", "documentation/", "/doc/",
+	}
+
+	lowerFilename := strings.ToLower(filename)
+	for _, pattern := range docPatterns {
+		if strings.Contains(lowerFilename, strings.ToLower(pattern)) {
+			return true
+		}
+	}
+	return false
+}
+
+// PatchStats holds the results of analyzing a diff patch
+type PatchStats struct {
+	TotalAdditions      int
+	TotalDeletions      int
+	MeaningfulAdditions int
+	MeaningfulDeletions int
+	CommentAdditions    int
+	CommentDeletions    int
+	WhitespaceAdditions int
+	WhitespaceDeletions int
+}
+
+// AnalyzePatch analyzes a unified diff patch and returns both raw and meaningful line counts.
+// It parses diff hunks and categorizes each changed line as meaningful, comment, or whitespace.
+func AnalyzePatch(patch string) PatchStats {
+	stats := PatchStats{}
+
+	lines := strings.Split(patch, "\n")
+	for _, line := range lines {
+		if len(line) == 0 {
+			continue
+		}
+
+		// Check if this is an addition or deletion line
+		isAddition := strings.HasPrefix(line, "+") && !strings.HasPrefix(line, "+++")
+		isDeletion := strings.HasPrefix(line, "-") && !strings.HasPrefix(line, "---")
+
+		if !isAddition && !isDeletion {
+			continue // Context line or header
+		}
+
+		// Remove the diff prefix to get actual content
+		content := line[1:]
+
+		// Categorize the line
+		if IsWhitespaceLine(content) {
+			if isAddition {
+				stats.TotalAdditions++
+				stats.WhitespaceAdditions++
+			} else {
+				stats.TotalDeletions++
+				stats.WhitespaceDeletions++
+			}
+		} else if IsCommentLine(content) {
+			if isAddition {
+				stats.TotalAdditions++
+				stats.CommentAdditions++
+			} else {
+				stats.TotalDeletions++
+				stats.CommentDeletions++
+			}
+		} else {
+			// Meaningful code line
+			if isAddition {
+				stats.TotalAdditions++
+				stats.MeaningfulAdditions++
+			} else {
+				stats.TotalDeletions++
+				stats.MeaningfulDeletions++
+			}
+		}
+	}
+
+	return stats
+}
+
+// AnalyzePatchSimple returns just the meaningful additions and deletions
+func AnalyzePatchSimple(patch string) (meaningfulAdds, meaningfulDels int) {
+	stats := AnalyzePatch(patch)
+	return stats.MeaningfulAdditions, stats.MeaningfulDeletions
+}
+
+// IsMeaningfulLine checks if a line of code is meaningful (not a comment or whitespace)
+func IsMeaningfulLine(line string) bool {
+	return !IsWhitespaceLine(line) && !IsCommentLine(line)
+}