package metricquery

import (
	"context"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"

	"github.com/itworx/pulse/internal/auth"
	"github.com/itworx/pulse/internal/metriccatalog"
	"github.com/itworx/pulse/internal/prometheus"
	"github.com/itworx/pulse/internal/queryplan"
)

func handlerService(t *testing.T) *Service {
	return testService(t, &fakeSource{result: prometheus.QueryResult{Status: "success", Data: []byte(`{"resultType":"matrix","result":[]}`)}}, NewCache(8, 1<<20))
}
func authenticatedRequest(method, path, body string) *http.Request {
	request := httptest.NewRequest(method, path, strings.NewReader(body))
	return request.WithContext(auth.WithPrincipal(context.Background(), auth.Principal{Subject: "viewer", Role: auth.RoleViewer}))
}
func operatorRequest(method, path, body string) *http.Request {
	request := httptest.NewRequest(method, path, strings.NewReader(body))
	return request.WithContext(auth.WithPrincipal(context.Background(), auth.Principal{Subject: "operator", Role: auth.RoleOperator}))
}

func TestHandlerRequiresAuthAndMapsUnavailableService(t *testing.T) {
	response := httptest.NewRecorder()
	Handler{Service: handlerService(t)}.ServeHTTP(response, httptest.NewRequest(http.MethodPost, "/api/v1/metrics/query-range", strings.NewReader(`{}`)))
	if response.Code != http.StatusUnauthorized {
		t.Fatalf("status=%d", response.Code)
	}
	response = httptest.NewRecorder()
	Handler{}.ServeHTTP(response, authenticatedRequest(http.MethodPost, "/api/v1/metrics/query-range", `{}`))
	if response.Code != http.StatusServiceUnavailable {
		t.Fatalf("status=%d", response.Code)
	}
}
func TestHandlerRejectsMalformedAndOversizedBodies(t *testing.T) {
	service := handlerService(t)
	response := httptest.NewRecorder()
	Handler{Service: service}.ServeHTTP(response, authenticatedRequest(http.MethodPost, "/api/v1/metrics/query-range", `{"metric":`))
	if response.Code != http.StatusBadRequest {
		t.Fatalf("malformed=%d", response.Code)
	}
	response = httptest.NewRecorder()
	oversized := `{"padding":"` + strings.Repeat("x", maxRequestBody) + `"}`
	Handler{Service: service}.ServeHTTP(response, authenticatedRequest(http.MethodPost, "/api/v1/metrics/query-range", oversized))
	if response.Code != http.StatusRequestEntityTooLarge {
		t.Fatalf("oversized=%d", response.Code)
	}
}
func TestHandlerPermissionedInspector(t *testing.T) {
	service := handlerService(t)
	payload, _ := json.Marshal(testRequest())
	response := httptest.NewRecorder()
	Handler{Service: service}.ServeHTTP(response, authenticatedRequest(http.MethodPost, "/api/v1/metrics/inspect", string(payload)))
	if response.Code != http.StatusForbidden {
		t.Fatalf("viewer status=%d body=%s", response.Code, response.Body.String())
	}
	response = httptest.NewRecorder()
	Handler{Service: service}.ServeHTTP(response, operatorRequest(http.MethodPost, "/api/v1/metrics/inspect", string(payload)))
	if response.Code != http.StatusOK {
		t.Fatalf("operator status=%d body=%s", response.Code, response.Body.String())
	}
	var decoded struct {
		Inspector Inspector `json:"inspector"`
	}
	if err := json.Unmarshal(response.Body.Bytes(), &decoded); err != nil {
		t.Fatal(err)
	}
	if decoded.Inspector.GeneratedQuery == "" || decoded.Inspector.Cost.Series < 1 || decoded.Inspector.Limits.MaxPoints < 1 {
		t.Fatalf("inspector=%+v", decoded.Inspector)
	}
}

func TestHandlerReturnsBoundedQueryResponse(t *testing.T) {
	service := handlerService(t)
	request := testRequest()
	payload, _ := json.Marshal(request)
	response := httptest.NewRecorder()
	Handler{Service: service}.ServeHTTP(response, authenticatedRequest(http.MethodPost, "/api/v1/metrics/query-range", string(payload)))
	if response.Code != http.StatusOK {
		t.Fatalf("status=%d body=%s", response.Code, response.Body.String())
	}
	var decoded Response
	if err := json.Unmarshal(response.Body.Bytes(), &decoded); err != nil {
		t.Fatal(err)
	}
	if decoded.Provenance.Source != "prometheus" || decoded.Freshness != "fresh" {
		t.Fatalf("response=%+v", decoded)
	}
}
func TestHandlerMapsSourceErrorsWithoutLeakingDetails(t *testing.T) {
	service := testService(t, &fakeSource{err: context.DeadlineExceeded}, nil)
	payload, _ := json.Marshal(testRequest())
	response := httptest.NewRecorder()
	Handler{Service: service}.ServeHTTP(response, authenticatedRequest(http.MethodPost, "/api/v1/metrics/query-range", string(payload)))
	if response.Code != http.StatusServiceUnavailable || strings.Contains(response.Body.String(), "DeadlineExceeded") {
		t.Fatalf("status=%d body=%s", response.Code, response.Body.String())
	}
}
func TestHandlerInstantRoute(t *testing.T) {
	registry, err := metriccatalog.DefaultRegistry()
	if err != nil {
		t.Fatal(err)
	}
	source := &fakeSource{result: prometheus.QueryResult{Status: "success", Data: []byte(`{}`)}}
	service := NewService(queryplan.NewPlanner(registry, queryplan.Limits{}), source, nil)
	payload := `{"metric":"host.cpu.utilization","scope":{"serverId":"server-1"},"at":"` + time.Date(2026, 8, 1, 12, 0, 0, 0, time.UTC).Format(time.RFC3339) + `"}`
	response := httptest.NewRecorder()
	Handler{Service: service}.ServeHTTP(response, authenticatedRequest(http.MethodPost, "/api/v1/metrics/query", payload))
	if response.Code != http.StatusOK || source.instantCalls != 1 {
		t.Fatalf("status=%d calls=%d body=%s", response.Code, source.instantCalls, response.Body.String())
	}
}