feat(logger): add PICOCLAW_LOG_FILE env var for file-only logging

pkg/logger/logger.go

@@ -2,6 +2,7 @@ package logger
 
 import (
 	"fmt"
+	"io"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -100,6 +101,12 @@ func SetConsoleLevel(level LogLevel) {
 	logger = logger.Level(level)
 }
 
+func DisableConsole() {
+	mu.Lock()
+	defer mu.Unlock()
+	logger = zerolog.New(io.Discard).With().Timestamp().Caller().Logger()
+}
+
 func GetLevel() LogLevel {
 	mu.RLock()
 	defer mu.RUnlock()
@@ -170,6 +177,22 @@ func DisableFileLogging() {
 	fileLogger = zerolog.Logger{}
 }
 
+func ConfigureFromEnv() {
+	if logFile := os.Getenv("PICOCLAW_LOG_FILE"); logFile != "" {
+		if strings.HasPrefix(logFile, "~/") {
+			if home := os.Getenv("HOME"); home != "" {
+				logFile = filepath.Join(home, logFile[2:])
+			}
+		}
+
+		if err := EnableFileLogging(logFile); err != nil {
+			fmt.Fprintf(os.Stderr, "failed to enable file logging: %v\n", err)
+		} else {
+			DisableConsole()
+		}
+	}
+}
+
 func getCallerSkip() int {
 	for i := 2; i < 15; i++ {
 		pc, file, _, ok := runtime.Caller(i)

pkg/logger/logger_test.go

@@ -4,7 +4,11 @@ import (
 	"bytes"
 	"encoding/json"
 	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
 	"testing"
+	"time"
 
 	"github.com/rs/zerolog"
 )
@@ -365,3 +369,40 @@ func TestAppendFields_ErrorUsesErrorString(t *testing.T) {
 		t.Fatalf("error field = %#v, want %q", got["error"], "transcription request failed")
 	}
 }
+
+func TestDisableConsole(t *testing.T) {
+	DisableConsole()
+	Info("this should go to nowhere")
+}
+
+func TestConfigureFromEnv(t *testing.T) {
+	home := os.Getenv("HOME")
+	if home == "" {
+		t.Skip("HOME not set")
+	}
+
+	tmpFile := "/tmp/picoclaw_test_log_" + fmt.Sprintf("%d", time.Now().UnixNano())
+	defer os.Remove(tmpFile)
+
+	os.Setenv("PICOCLAW_LOG_FILE", tmpFile)
+	defer os.Unsetenv("PICOCLAW_LOG_FILE")
+
+	ConfigureFromEnv()
+
+	if logFile == nil {
+		t.Error("expected log file to be set")
+	}
+
+	Info("test message")
+
+	os.Setenv("PICOCLAW_LOG_FILE", "~/test_log")
+	ConfigureFromEnv()
+
+	expanded := filepath.Join(home, "test_log")
+	defer os.Remove(expanded)
+}
+
+func TestConfigureFromEnvNoEnv(t *testing.T) {
+	os.Unsetenv("PICOCLAW_LOG_FILE")
+	ConfigureFromEnv()
+}