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/imageproxy"
	"sneak.berlin/go/pixa/internal/imagerequest"
)

// TestServerBusyAnswers503 checks that respondImageError, which answers the
// errors of both image routes, answers 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 := &imagerequest.Request{
		Source: imagerequest.Source{Host: "img.example.com", Path: "/a.jpg"},
	}

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

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

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

// TestProcessingTimedOutAnswers503 checks that respondImageError, which
// answers the errors of both image routes, answers 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",
		imageproxy.ErrProcessingTimedOut, context.DeadlineExceeded)

	rec := httptest.NewRecorder()
	h.respondImageError(rec, &imagerequest.Request{}, err)
	t.Logf("status = %d, body = %q", rec.Code, rec.Body.String())

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

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