package monitor

import (
	"runtime"
	"sync/atomic"
	"time"
)

var startedAt = time.Now()

var totalRequests uint64
var totalErrors uint64

type Snapshot struct {
	UptimeSeconds int64   `json:"uptime_seconds"`
	Goroutines    int     `json:"goroutines"`
	MemoryAllocMB float64 `json:"memory_alloc_mb"`
	MemorySysMB   float64 `json:"memory_sys_mb"`
	CPUCores      int     `json:"cpu_cores"`
	DiskTotalGB   float64 `json:"disk_total_gb"`
	DiskFreeGB    float64 `json:"disk_free_gb"`
	RequestsTotal uint64  `json:"requests_total"`
	ErrorsTotal   uint64  `json:"errors_total"`
}

func IncrementRequestCount() {
	atomic.AddUint64(&totalRequests, 1)
}

func IncrementErrorCount() {
	atomic.AddUint64(&totalErrors, 1)
}

func GetSnapshot() Snapshot {
	var mem runtime.MemStats
	runtime.ReadMemStats(&mem)

	diskTotal, diskFree := getDiskSpaceGB()

	return Snapshot{
		UptimeSeconds: int64(time.Since(startedAt).Seconds()),
		Goroutines:    runtime.NumGoroutine(),
		MemoryAllocMB: bytesToMB(mem.Alloc),
		MemorySysMB:   bytesToMB(mem.Sys),
		CPUCores:      runtime.NumCPU(),
		DiskTotalGB:   diskTotal,
		DiskFreeGB:    diskFree,
		RequestsTotal: atomic.LoadUint64(&totalRequests),
		ErrorsTotal:   atomic.LoadUint64(&totalErrors),
	}
}

func bytesToMB(v uint64) float64 {
	return float64(v) / 1024.0 / 1024.0
}