feat: comprehensive UTC package enhancements

.gitignore

@@ -20,6 +20,7 @@
 # Coverage file
 coverage.txt
 coverage.out
+coverage.html
 
 # Go workspace file
 go.work

README.md

@@ -19,8 +19,8 @@ The `utc` package provides an enhanced alias of Go's `time.Time` that ensures yo
 ## Features
 
 - Guaranteed UTC time handling
-- JSON marshaling/unmarshaling support
-- SQL database compatibility
+- JSON marshaling/unmarshaling support with flexible parsing
+- SQL database compatibility with enhanced type support
 - Automatic timezone handling (PST/PDT, EST/EDT, etc.)
 - Extensive formatting options:
   - US date formats (MM/DD/YYYY)
@@ -29,6 +29,10 @@ The `utc` package provides an enhanced alias of Go's `time.Time` that ensures yo
   - Common components (weekday, month, etc.)
 - Timezone conversion methods with fallback support
 - Full compatibility with Go's standard `time.Time` methods
+- Nil-safe operations that return errors instead of panicking
+- Debug mode with detailed logging for development
+- Text encoding support for broader codec compatibility
+- Unix timestamp helpers and day boundary utilities
 
 ## Installation
 
@@ -38,6 +42,8 @@ To install the `utc` package, use the following command:
 go get github.com/agentstation/utc
 ```
 
+**Requirements**: Go 1.18 or later (uses `any` type and other modern Go features)
+
 ## Usage
 
 1. Import the package:
@@ -109,6 +115,45 @@ type Record struct {
 }
 ```
 
+## Debug Mode
+
+The package includes a debug mode that helps identify potential bugs during development:
+
+```sh
+# Build with debug mode enabled
+go build -tags debug
+
+# Run tests with debug mode
+go test -tags debug ./...
+```
+
+When debug mode is enabled, the package logs warnings when methods are called on nil receivers:
+
+```
+[UTC DEBUG] 2024/01/02 15:04:05 debug.go:26: String() called on nil *Time receiver
+[UTC DEBUG] 2024/01/02 15:04:05 debug.go:26: Value() called on nil *Time receiver
+```
+
+## Additional Utilities
+
+The package includes several convenience methods:
+
+```go
+// Unix timestamp conversions
+t1 := utc.FromUnix(1704199445)           // From Unix seconds
+t2 := utc.FromUnixMilli(1704199445000)   // From Unix milliseconds
+seconds := t.Unix()                       // To Unix seconds
+millis := t.UnixMilli()                   // To Unix milliseconds
+
+// Day boundaries
+start := t.StartOfDay()  // 2024-01-02 00:00:00.000000000 UTC
+end := t.EndOfDay()      // 2024-01-02 23:59:59.999999999 UTC
+
+// Generic timezone conversion
+eastern, err := t.In("America/New_York")
+tokyo, err := t.In("Asia/Tokyo")
+```
+
 <!-- gomarkdoc:embed:start -->
 
 <!-- Code generated by gomarkdoc. DO NOT EDIT -->

debug.go

@@ -0,0 +1,27 @@
+//go:build debug
+// +build debug
+
+package utc
+
+import (
+	"log"
+	"os"
+	"sync"
+)
+
+// debugLogger is only available in debug builds
+var (
+	debugLogger *log.Logger
+	debugOnce   sync.Once
+)
+
+func initDebugLogger() {
+	debugOnce.Do(func() {
+		debugLogger = log.New(os.Stderr, "[UTC DEBUG] ", log.Ldate|log.Ltime|log.Lshortfile)
+	})
+}
+
+func debugLog(format string, v ...any) {
+	initDebugLogger()
+	debugLogger.Printf(format, v...)
+}

debug_test.go

@@ -0,0 +1,69 @@
+//go:build debug
+// +build debug
+
+package utc
+
+import (
+	"bytes"
+	"os"
+	"strings"
+	"testing"
+)
+
+// TestDebugLogging verifies that debug logging works when enabled
+func TestDebugLogging(t *testing.T) {
+	// Capture stderr
+	old := os.Stderr
+	r, w, _ := os.Pipe()
+	os.Stderr = w
+
+	// Test nil receiver calls
+	var nilTime *Time
+
+	// These should log to stderr in debug mode
+	_ = nilTime.String()
+	_, _ = nilTime.Value()
+	_, _ = nilTime.MarshalJSON()
+
+	// Restore stderr and read output
+	w.Close()
+	os.Stderr = old
+
+	var buf bytes.Buffer
+	buf.ReadFrom(r)
+	output := buf.String()
+
+	// Verify debug logs were written
+	expectedLogs := []string{
+		"String() called on nil *Time receiver",
+		"Value() called on nil *Time receiver",
+		"MarshalJSON() called on nil *Time receiver",
+	}
+
+	for _, expected := range expectedLogs {
+		if !strings.Contains(output, expected) {
+			t.Errorf("Expected debug log containing %q, but got: %s", expected, output)
+		}
+	}
+
+	// Verify the format includes timestamp and file info
+	if !strings.Contains(output, "[UTC DEBUG]") {
+		t.Error("Debug logs should include [UTC DEBUG] prefix")
+	}
+}
+
+// TestDebugLogDirect tests the debugLog function directly
+func TestDebugLogDirect(t *testing.T) {
+	// This test just verifies debugLog doesn't panic and initializes correctly
+	// The actual output verification is done in TestDebugLogging which captures
+	// output in a more controlled way by testing real usage patterns
+
+	// This should not panic
+	debugLog("test message: %s", "hello")
+	debugLog("another test")
+
+	// Verify debugLogger is initialized (it should be after first call)
+	if debugLogger == nil {
+		t.Error("debugLogger should be initialized after debugLog calls")
+	}
+}

go.mod

@@ -1,3 +1,3 @@
 module github.com/agentstation/utc
 
-go 1.22.5
+go 1.18

nodebug.go

@@ -0,0 +1,9 @@
+//go:build !debug
+// +build !debug
+
+package utc
+
+// debugLog is a no-op in non-debug builds
+func debugLog(format string, v ...any) {
+	// No-op in production builds
+}