package handlers

import (
	"encoding/json"
	"fmt"
	"net/http"
	"runtime"
	"time"

	"github.com/rs/zerolog/hlog"
)

const (
	jsonContentType = "application/json;charset=utf-8"
)

type Timing struct {
	TimeMillis time.Duration `json:"timeMillis"`
	Source     string        `json:"source"`
}

type HealthCheckResult struct {
	Success  bool                `json:"success"`
	Messages []string            `json:"messages"`
	Time     time.Time           `json:"time"`
	Timing   []Timing            `json:"timing"`
	Response HealthCheckResponse `json:"response"`
}

type HealthCheckResponse struct {
	IpAddress string `json:"ipAddress"`
	MemUsage  string `json:"memUsage"`
}

func (app *Application) HealthCheck(w http.ResponseWriter, r *http.Request) {
	l := hlog.FromRequest(r)
	l.Info().Msg("HealthCheck")
	start := time.Now()

	t, _ := json.Marshal(HealthCheckResult{
		Success:  true,
		Messages: []string{},
		Time:     time.Now().UTC(),
		Timing: []Timing{
			{
				Source:     "HealthCheck",
				TimeMillis: time.Since(start),
			},
		},
		Response: HealthCheckResponse{
			IpAddress: getIP(r),
			MemUsage:  memUsage(),
		},
	})

	w.Header().Set("content-type", jsonContentType)
	_, _ = fmt.Fprint(w, string(t))
}

func getIP(r *http.Request) string {
	// forwarded := r.Header.Get("X-FORWARDED-FOR")
	// if forwarded != "" {
	// 	return forwarded
	// }
	return r.RemoteAddr
}

func memUsage() string {
	var m runtime.MemStats
	runtime.ReadMemStats(&m)
	result := fmt.Sprintf("memoryusage::Alloc = %v MB::TotalAlloc = %v MB::Sys = %v MB::tNumGC = %v", bToMb(m.Alloc), bToMb(m.TotalAlloc), bToMb(m.Sys), m.NumGC)
	return result
}

func bToMb(b uint64) uint64 {
	return b / 1024 / 1024
}