add `git-leaderboard`

1 files changed, 128 insertions, 0 deletions

diff --git a/cmd/git-leaderboard/main.go b/cmd/git-leaderboard/main.go
new file mode 100644
index 0000000..7c846a5
--- /dev/null
+++ b/cmd/git-leaderboard/main.go
@@ -0,0 +1,128 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"os/exec"
+	"sort"
+	"strings"
+)
+
+type Author struct {
+	Name  string
+	Count int
+}
+
+func main() {
+	lineFlag := flag.Bool("line", false, "Count lines changed instead of commits")
+	flag.Parse()
+
+	if !isGitRepository() {
+		fmt.Println("Error: Not in a git repository")
+		os.Exit(1)
+	}
+
+	authors, err := getAuthors(*lineFlag)
+	if err != nil {
+		fmt.Printf("Error getting authors: %v\n", err)
+		os.Exit(1)
+	}
+
+	if len(authors) == 0 {
+		fmt.Println("No authors found. The repository might be empty or have no commits.")
+		os.Exit(0)
+	}
+
+	sort.Slice(authors, func(i, j int) bool {
+		return authors[i].Count > authors[j].Count
+	})
+
+	maxCount := authors[0].Count
+
+	fmt.Printf("%-30s %-10s %s\n", "Author", "Count", "Contribution")
+	fmt.Println(strings.Repeat("-", 80))
+
+	for _, author := range authors {
+		bar := generateBar(author.Count, maxCount)
+		fmt.Printf("%-30s %-10d %s\n", author.Name, author.Count, bar)
+	}
+}
+
+func isGitRepository() bool {
+	cmd := exec.Command("git", "rev-parse", "--is-inside-work-tree")
+	err := cmd.Run()
+	return err == nil
+}
+
+func getAuthors(countLines bool) ([]Author, error) {
+	var cmd *exec.Cmd
+
+	if countLines {
+		cmd = exec.Command("git", "log", "--pretty=format:%aN", "--numstat")
+	} else {
+		cmd = exec.Command("git", "shortlog", "-sn", "--no-merges", "HEAD")
+	}
+
+	output, err := cmd.Output()
+	if err != nil {
+		if exitErr, ok := err.(*exec.ExitError); ok {
+			return nil, fmt.Errorf("git command failed: %s. Error output: %s", err, exitErr.Stderr)
+		}
+		return nil, fmt.Errorf("error executing git command: %v", err)
+	}
+
+	lines := strings.Split(string(output), "\n")
+	authors := make(map[string]int)
+
+	if countLines {
+		currentAuthor := ""
+		for _, line := range lines {
+			if line == "" {
+				currentAuthor = ""
+				continue
+			}
+			if currentAuthor == "" {
+				currentAuthor = line
+				continue
+			} else {
+				fields := strings.Fields(line)
+				if len(fields) >= 2 {
+					added, _ := parseInt(fields[0])
+					deleted, _ := parseInt(fields[1])
+					authors[currentAuthor] += added + deleted
+				}
+			}
+		}
+	} else {
+		for _, line := range lines {
+			fields := strings.Fields(line)
+			if len(fields) >= 2 {
+				count, _ := parseInt(fields[0])
+				name := strings.Join(fields[1:], " ")
+				authors[name] = count
+			}
+		}
+	}
+
+	var result []Author
+	for name, count := range authors {
+		result = append(result, Author{Name: name, Count: count})
+	}
+	return result, nil
+}
+
+func parseInt(s string) (int, error) {
+	if s == "-" {
+		return 0, nil
+	}
+	var result int
+	_, err := fmt.Sscanf(s, "%d", &result)
+	return result, err
+}
+
+func generateBar(count, maxCount int) string {
+	maxWidth := 38
+	width := int(float64(count) / float64(maxCount) * float64(maxWidth))
+	return strings.Repeat("▆", width)
+}