package handlers

import (
	"context"
	"fmt"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"

	"sneak.berlin/go/pixa/internal/httpfetcher"
	"sneak.berlin/go/pixa/internal/imageprocessor"
	"sneak.berlin/go/pixa/internal/imgcache"
)

// TestServerBusyAnswers503 checks that both image routes answer 503 with
// a clear error when the image service gives up waiting for a free upstream
// connection or processing slot, wrapped as the service wraps them.
func TestServerBusyAnswers503(t *testing.T) {
	t.Parallel()

	h := &Handlers{log: slog.New(slog.DiscardHandler)}
	req := &imgcache.ImageRequest{SourceHost: "img.example.com", SourcePath: "/a.jpg"}

	for _, err := range []error{
		fmt.Errorf("upstream fetch failed: %w", httpfetcher.ErrTooManyConnections),
		fmt.Errorf("image processing failed: %w", imageprocessor.ErrTooManyImages),
	} {
		plain := httptest.NewRecorder()
		h.respondImageError(plain, req, err)

		encrypted := httptest.NewRecorder()
		h.handleImageError(encrypted, err)

		for route, rec := range map[string]*httptest.ResponseRecorder{
			"/v1/image/": plain, "/v1/e/": encrypted,
		} {
			if rec.Code != http.StatusServiceUnavailable {
				t.Errorf("%s for %v: status = %d, want %d",
					route, err, rec.Code, http.StatusServiceUnavailable)
			}

			if !strings.Contains(rec.Body.String(), "server busy, try again later") {
				t.Errorf("%s for %v: body = %q, want the server busy error",
					route, err, rec.Body.String())
			}
		}
	}
}

// TestProcessingTimedOutAnswers503 checks that respondImageError and
// handleImageError, which answer the errors of the two image routes, answer
// 503 with the server busy error when the image service reports that
// processing stopped at the deadline of the request doing it, wrapped as the
// service wraps it. A request that waited for that processing gets this error
// while its own deadline may have time left. The request's source only goes
// into a log line, so it is left empty.
func TestProcessingTimedOutAnswers503(t *testing.T) {
	t.Parallel()

	h := &Handlers{log: slog.New(slog.DiscardHandler)}
	err := fmt.Errorf("%w: failed to encode: %w",
		imgcache.ErrProcessingTimedOut, context.DeadlineExceeded)

	plain := httptest.NewRecorder()
	h.respondImageError(plain, &imgcache.ImageRequest{}, err)

	encrypted := httptest.NewRecorder()
	h.handleImageError(encrypted, err)

	for name, rec := range map[string]*httptest.ResponseRecorder{
		"respondImageError": plain, "handleImageError": encrypted,
	} {
		t.Logf("%s: status = %d, body = %q", name, rec.Code, rec.Body.String())

		if rec.Code != http.StatusServiceUnavailable {
			t.Errorf("%s: status = %d, want %d",
				name, rec.Code, http.StatusServiceUnavailable)
		}

		if !strings.Contains(rec.Body.String(), "server busy, try again later") {
			t.Errorf("%s: body = %q, want the server busy error",
				name, rec.Body.String())
		}
	}
}