Add version command and improve flag descriptions

Makefile

@@ -4,13 +4,15 @@ BATS := $(BATS_DIR)/bin/bats
 BINARY := pomodoro
 
 GO_SOURCES := $(shell find . -name '*.go' -not -path './vendor/*')
+VERSION := $(shell git describe --tags --exact-match 2>/dev/null || git rev-parse --short HEAD 2>/dev/null || echo "dev")
+LDFLAGS := -X main.Version=$(VERSION)
 
 .PHONY: test
 test: $(BINARY) $(BATS)
 	$(BATS) test/
 
 $(BINARY): $(GO_SOURCES) go.mod go.sum
-	go build -o $(BINARY) .
+	go build -ldflags "$(LDFLAGS)" -o $(BINARY) .
 
 $(BATS):
 	@mkdir -p $(BATS_DIR)

cmd/root.go

@@ -66,6 +66,14 @@ func initConfig() {
 // Execute adds all child commands to the root command sets flags appropriately.
 // This is called by main.main(). It only needs to happen once to the rootCmd.
 func Execute() {
+	// Customize built-in flag descriptions once at startup
+	if helpFlag := RootCmd.Flags().Lookup("help"); helpFlag != nil {
+		helpFlag.Usage = "Show help"
+	}
+	if versionFlag := RootCmd.Flags().Lookup("version"); versionFlag != nil {
+		versionFlag.Usage = "Show version info"
+	}
+
 	if err := RootCmd.Execute(); err != nil {
 		fmt.Println(err)
 		os.Exit(-1)

cmd/version.go

@@ -0,0 +1,19 @@
+package cmd
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+)
+
+var versionCmd = &cobra.Command{
+	Use:   "version",
+	Short: "Print version information",
+	Run: func(cmd *cobra.Command, args []string) {
+		fmt.Printf("pomodoro version %s\n", RootCmd.Version)
+	},
+}
+
+func init() {
+	RootCmd.AddCommand(versionCmd)
+}

test/version.bats

@@ -0,0 +1,21 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+@test "version flag shows version" {
+    run pomodoro --version
+    [ "$status" -eq 0 ]
+    [[ "$output" =~ "pomodoro version" ]]
+}
+
+@test "version subcommand shows detailed version info" {
+    run pomodoro version
+    [ "$status" -eq 0 ]
+    [[ "$output" =~ "pomodoro version" ]]
+}
+
+@test "version subcommand appears in help" {
+    run pomodoro --help
+    [ "$status" -eq 0 ]
+    [[ "$output" =~ "version     Print version information" ]]
+}