feat(profiling): Add CPU and MEM profiling

internal/qol/stats/runtime.go

@@ -0,0 +1,94 @@
+package stats
+
+import (
+	"encoding/csv"
+	"fmt"
+	"os"
+	"runtime"
+	"time"
+)
+
+type RuntimeStats struct {
+	TotalAlloc   uint64
+	Mallocs      uint64
+	NumGC        uint32
+	AllocDelta   uint64
+	MallocsDelta uint64
+	GCDelta      uint32
+}
+
+type RuntimeCollector struct {
+	startStats runtime.MemStats
+	memPath    string
+}
+
+func NewRuntimeCollector(memPath string) *RuntimeCollector {
+	var stats runtime.MemStats
+	runtime.ReadMemStats(&stats)
+
+	return &RuntimeCollector{
+		startStats: stats,
+		memPath:    memPath,
+	}
+}
+
+func (rc *RuntimeCollector) Collect() RuntimeStats {
+	var current runtime.MemStats
+	runtime.ReadMemStats(&current)
+
+	return RuntimeStats{
+		TotalAlloc:   current.TotalAlloc,
+		Mallocs:      current.Mallocs,
+		NumGC:        current.NumGC,
+		AllocDelta:   current.TotalAlloc - rc.startStats.TotalAlloc,
+		MallocsDelta: current.Mallocs - rc.startStats.Mallocs,
+		GCDelta:      current.NumGC - rc.startStats.NumGC,
+	}
+}
+
+func (rc *RuntimeCollector) WriteStats() error {
+	stats := rc.Collect()
+	timestamp := time.Now().Format(time.RFC3339Nano)
+
+	// Check if file exists
+	fileExists := false
+	if _, err := os.Stat(rc.memPath); err == nil {
+		fileExists = true
+	}
+
+	// Open in append mode
+	file, err := os.OpenFile(rc.memPath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+	if err != nil {
+		return fmt.Errorf("failed to open mem.csv: %w", err)
+	}
+	defer file.Close()
+
+	writer := csv.NewWriter(file)
+
+	// Write header if new file
+	if !fileExists {
+		header := []string{
+			"timestamp", "total_alloc_bytes", "mallocs", "gc_cycles",
+			"alloc_delta", "mallocs_delta", "gc_delta",
+		}
+		if err := writer.Write(header); err != nil {
+			return fmt.Errorf("failed to write mem.csv header: %w", err)
+		}
+	}
+
+	row := []string{
+		timestamp,
+		fmt.Sprintf("%d", stats.TotalAlloc),
+		fmt.Sprintf("%d", stats.Mallocs),
+		fmt.Sprintf("%d", stats.NumGC),
+		fmt.Sprintf("%d", stats.AllocDelta),
+		fmt.Sprintf("%d", stats.MallocsDelta),
+		fmt.Sprintf("%d", stats.GCDelta),
+	}
+	if err := writer.Write(row); err != nil {
+		return fmt.Errorf("failed to write mem.csv row: %w", err)
+	}
+
+	writer.Flush()
+	return writer.Error()
+}