package httpx

import (
	"context"
	"net/http"
	"net/http/httptest"
	"sync/atomic"
	"testing"
	"time"
)

func noSleep(context.Context, time.Duration) error { return nil }

func TestRetrierRetriesOn5xxAnd429(t *testing.T) {
	var calls int32
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		switch atomic.AddInt32(&calls, 1) {
		case 1:
			w.WriteHeader(http.StatusTooManyRequests)
		case 2:
			w.WriteHeader(http.StatusBadGateway)
		default:
			w.WriteHeader(http.StatusOK)
		}
	}))
	defer srv.Close()
	r := Retrier{MaxAttempts: 4, BaseDelay: time.Millisecond, Sleep: noSleep}
	resp, err := r.Do(context.Background(), srv.Client(), func() (*http.Request, error) {
		return http.NewRequest(http.MethodGet, srv.URL, nil)
	})
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()
	if resp.StatusCode != 200 || calls != 3 {
		t.Fatalf("status=%d calls=%d", resp.StatusCode, calls)
	}
}

func TestRetrierNoRetryOn4xx(t *testing.T) {
	var calls int32
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		atomic.AddInt32(&calls, 1)
		w.WriteHeader(http.StatusNotFound)
	}))
	defer srv.Close()
	r := Retrier{MaxAttempts: 4, BaseDelay: time.Millisecond, Sleep: noSleep}
	resp, err := r.Do(context.Background(), srv.Client(), func() (*http.Request, error) {
		return http.NewRequest(http.MethodGet, srv.URL, nil)
	})
	if err != nil {
		t.Fatal(err)
	}
	resp.Body.Close()
	if calls != 1 || resp.StatusCode != 404 {
		t.Fatalf("calls=%d status=%d", calls, resp.StatusCode)
	}
}

func TestRetrierExhaustedReturnsLastResponse(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusServiceUnavailable)
	}))
	defer srv.Close()
	r := Retrier{MaxAttempts: 2, BaseDelay: time.Millisecond, Sleep: noSleep}
	resp, err := r.Do(context.Background(), srv.Client(), func() (*http.Request, error) {
		return http.NewRequest(http.MethodGet, srv.URL, nil)
	})
	if err != nil {
		t.Fatal(err)
	}
	resp.Body.Close()
	if resp.StatusCode != 503 {
		t.Fatalf("status=%d", resp.StatusCode)
	}
}

func TestRetrierNetworkError(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {}))
	url := srv.URL
	srv.Close()
	r := Retrier{MaxAttempts: 3, BaseDelay: time.Millisecond, Sleep: noSleep}
	_, err := r.Do(context.Background(), http.DefaultClient, func() (*http.Request, error) {
		return http.NewRequest(http.MethodGet, url, nil)
	})
	if err == nil {
		t.Fatal("ожидалась ошибка")
	}
}

func TestBackoffCapped(t *testing.T) {
	r := Retrier{BaseDelay: time.Second, MaxDelay: 5 * time.Second}
	if got := r.backoff(1); got != time.Second {
		t.Errorf("attempt1 = %v", got)
	}
	if got := r.backoff(10); got != 5*time.Second {
		t.Errorf("attempt10 = %v", got)
	}
}