package srv

import (
	"context"
	"errors"
	"math/rand"
	"net/http"
	"sync"
	"time"
)

func handleHealthCheckFunc(_ context.Context) func(w http.ResponseWriter, r *http.Request) {
	// Return http handle func
	return func(w http.ResponseWriter, r *http.Request) {
		var err error
		var healthChecksFailed bool

		// TODO: Insert useful health checks here
		// For multiple checks, perform concurrently
		// Consider using errors.Join() for multiple checks
		var hcWg sync.WaitGroup
		for range 5 {
			hcWg.Add(1)
			go func() {
				defer hcWg.Done()
				err = errors.Join(err, dummyHealthCheck(r.Context()))
			}()
		}
		hcWg.Wait()
		if err != nil {
			healthChecksFailed = true
		}

		// TODO: Friendly reminder...
		err = errors.New("WARNING: Unimplemented health-check")

		if healthChecksFailed {
			w.WriteHeader(http.StatusInternalServerError)
		}

		if err != nil {
			w.Write([]byte(err.Error()))
		} else {
			w.Write([]byte("ok"))
		}
	}
}

func dummyHealthCheck(ctx context.Context) error {
	workFor := rand.Intn(750)
	ticker := time.NewTicker(time.Duration(time.Duration(workFor) * time.Millisecond))

	select {
	case <-ticker.C:
		return nil
	case <-ctx.Done():
		return ctx.Err()
	}
}