refactor: better project structure (#35)

This project is starting to grow, and I've seen flaws in the initial
project structure design
I think I'll restructure the entire project directory for better
scalability and also cleaner

internal/logger/logger_test.go

@@ -0,0 +1,89 @@
+package logger
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestLogger(t *testing.T) {
+	tempDir, err := os.MkdirTemp("", "iris-log-test-*")
+	if err != nil {
+		t.Fatalf("failed to create temp dir: %v", err)
+	}
+	defer os.RemoveAll(tempDir)
+
+	logFilePath := filepath.Join(tempDir, "test.log")
+
+	// test 1: default init sets level to info
+	Init(logFilePath, false)
+	Debugf("this debug msg should not be logged")
+	Infof("this info msg should be logged")
+	Close()
+
+	data, err := os.ReadFile(logFilePath)
+	if err != nil {
+		t.Fatalf("failed to read log file: %v", err)
+	}
+
+	content := string(data)
+	if strings.Contains(content, "this debug msg should not be logged") {
+		t.Errorf("expected debug log to be skipped, got: %s", content)
+	}
+	if !strings.Contains(content, "this info msg should be logged") {
+		t.Errorf("expected info log to be recorded, got: %s", content)
+	}
+	if !strings.Contains(content, "[INFO]") {
+		t.Errorf("expected log to contain INFO tag, got: %s", content)
+	}
+	if !strings.Contains(content, "logger_test.go:") {
+		t.Errorf("expected log to contain caller trace info, got: %s", content)
+	}
+
+	// test 2: override init with debug = true
+	_ = os.Remove(logFilePath)
+	Init(logFilePath, true)
+	Debugf("this debug msg should now be logged")
+	Close()
+
+	data, err = os.ReadFile(logFilePath)
+	if err != nil {
+		t.Fatalf("failed to read log file: %v", err)
+	}
+
+	content = string(data)
+	if !strings.Contains(content, "this debug msg should now be logged") {
+		t.Errorf("expected debug log to be recorded, got: %s", content)
+	}
+	if !strings.Contains(content, "[DEBUG]") {
+		t.Errorf("expected log to contain DEBUG tag, got: %s", content)
+	}
+
+	// test 3: test log rotation to .old
+	// create a large file
+	largeData := make([]byte, 6*1024*1024)
+	err = os.WriteFile(logFilePath, largeData, 0644)
+	if err != nil {
+		t.Fatalf("failed to write large file: %v", err)
+	}
+
+	Init(logFilePath, false)
+	Infof("new log after rotation")
+	Close()
+
+	// check if old file exists and is rotated
+	oldPath := logFilePath + ".old"
+	if _, err = os.Stat(oldPath); os.IsNotExist(err) {
+		t.Errorf("expected rotated log file to exist at %s", oldPath)
+	}
+
+	data, err = os.ReadFile(logFilePath)
+	if err != nil {
+		t.Fatalf("failed to read log file: %v", err)
+	}
+	content = string(data)
+	if !strings.Contains(content, "new log after rotation") {
+		t.Errorf("expected new log to exist in the fresh log file, got: %s", content)
+	}
+}