package server

import (
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"strconv"
	"testing"

	"sneak.berlin/go/pixa/internal/healthcheck"
)

// unsignedImagePath is an image URL that carries no signature.
const unsignedImagePath = "/v1/image/cdn.example.com/cat.jpg/100x100.jpeg"

// TestMaintenanceModeRefusesImageRequests verifies that while maintenance
// mode is on, both image routes answer 503 Service Unavailable with a
// Retry-After header and the JSON error body the image handlers send.
func TestMaintenanceModeRefusesImageRequests(t *testing.T) {
	t.Parallel()

	s := newTestServer(t)
	s.config.MaintenanceMode = true

	requests := []struct {
		method string
		path   string
	}{
		{http.MethodGet, unsignedImagePath},
		{http.MethodHead, unsignedImagePath},
		{http.MethodGet, "/v1/e/token/cat.jpg"},
	}

	for _, tc := range requests {
		t.Run(tc.method+" "+tc.path, func(t *testing.T) {
			t.Parallel()

			rec := httptest.NewRecorder()
			s.ServeHTTP(rec, httptest.NewRequestWithContext(
				t.Context(), tc.method, tc.path, nil))
			t.Logf("status %d, body %s", rec.Code, rec.Body.String())

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

			retryAfter := rec.Header().Get("Retry-After")

			seconds, err := strconv.Atoi(retryAfter)
			if err != nil || seconds <= 0 {
				t.Errorf("Retry-After = %q, want a positive number of seconds",
					retryAfter)
			}

			// A HEAD response carries no body.
			if tc.method == http.MethodHead {
				return
			}

			var body struct {
				Error     string `json:"error"`
				Status    int    `json:"status"`
				Timestamp string `json:"timestamp"`
			}

			err = json.NewDecoder(rec.Body).Decode(&body)
			if err != nil {
				t.Fatalf("body is not JSON: %v", err)
			}

			if body.Error == "" || body.Status != http.StatusServiceUnavailable ||
				body.Timestamp == "" {
				t.Errorf("body = %+v, want an error, status %d and a timestamp",
					body, http.StatusServiceUnavailable)
			}
		})
	}
}

// TestImageRequestsServedWithoutMaintenanceMode verifies that while
// maintenance mode is off, image requests reach the image handlers instead
// of the 503. The handlers refuse an unsigned image URL with 401 and a token
// they cannot decrypt with 400, so either status shows a request got through.
func TestImageRequestsServedWithoutMaintenanceMode(t *testing.T) {
	t.Parallel()

	s := newTestServer(t)
	s.config.MaintenanceMode = false

	requests := []struct {
		method string
		path   string
		want   int
	}{
		{http.MethodGet, unsignedImagePath, http.StatusUnauthorized},
		{http.MethodHead, unsignedImagePath, http.StatusUnauthorized},
		{http.MethodGet, "/v1/e/token/cat.jpg", http.StatusBadRequest},
	}

	for _, tc := range requests {
		t.Run(tc.method+" "+tc.path, func(t *testing.T) {
			t.Parallel()

			rec := httptest.NewRecorder()
			s.ServeHTTP(rec, httptest.NewRequestWithContext(
				t.Context(), tc.method, tc.path, nil))
			t.Logf("status %d, body %s", rec.Code, rec.Body.String())

			if rec.Code != tc.want {
				t.Errorf("status = %d, want %d from the image handler",
					rec.Code, tc.want)
			}
		})
	}
}

// TestMaintenanceModeKeepsOtherRoutes verifies that while maintenance mode
// is on, the health check still answers 200 and reports it, and the login
// page and /metrics still answer 200. The image's Docker HEALTHCHECK
// requests the health check: a 503 there would make the container
// unhealthy, and upaas marks a deploy failed when its container is
// unhealthy.
func TestMaintenanceModeKeepsOtherRoutes(t *testing.T) {
	t.Parallel()

	s := newTestServer(t)
	s.config.MaintenanceMode = true

	// /metrics is routed only when its username is set.
	s.config.MetricsUsername = "metrics"
	s.config.MetricsPassword = "metrics-password"
	s.SetupRoutes()

	rec := httptest.NewRecorder()
	s.ServeHTTP(rec, httptest.NewRequestWithContext(t.Context(),
		http.MethodGet, "/.well-known/healthcheck.json", nil))
	t.Logf("health check status %d, body %s", rec.Code, rec.Body.String())

	if rec.Code != http.StatusOK {
		t.Fatalf("health check status = %d, want %d", rec.Code, http.StatusOK)
	}

	var health healthcheck.Response

	err := json.NewDecoder(rec.Body).Decode(&health)
	if err != nil || !health.Maintenance {
		t.Errorf("health check maintenance_mode = %v (error %v), want true",
			health.Maintenance, err)
	}

	rec = httptest.NewRecorder()
	s.ServeHTTP(rec, clientRequest(t, http.MethodGet, nil, firstClient, ""))

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

	req := httptest.NewRequestWithContext(t.Context(),
		http.MethodGet, "/metrics", nil)
	req.SetBasicAuth(s.config.MetricsUsername, s.config.MetricsPassword)

	rec = httptest.NewRecorder()
	s.ServeHTTP(rec, req)

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