package service

import (
	"net/http"
	"net/http/httptest"
	"net/url"
	"strconv"
	"testing"

	"github.com/gin-gonic/gin"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/client/fake"
)

func TestHandleComponentPodMetrics_UnknownComponent(t *testing.T) {
	svc := &AgentService{}
	gin.SetMode(gin.TestMode)
	router := gin.New()
	router.GET("/clusters/:cluster_id/components/:component_type/:pod_name/metrics",
		svc.HandleComponentPodMetrics)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/clusters/123/components/pd/db-pd-0/metrics", http.NoBody)
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusNotImplemented, w.Code)
	assert.Contains(t, w.Body.String(), "metrics proxy not implemented for component: pd")
}

func TestHandleTiKVPodMetrics_NilClient(t *testing.T) {
	svc := &AgentService{tikvHTTPClient: nil}
	gin.SetMode(gin.TestMode)
	router := gin.New()
	router.GET("/clusters/:cluster_id/components/:component_type/:pod_name/metrics",
		svc.HandleComponentPodMetrics)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/clusters/123/components/tikv/db-tikv-0/metrics", http.NoBody)
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusServiceUnavailable, w.Code)
	assert.Contains(t, w.Body.String(), "TiKV TLS client unavailable")
}

func TestHandleTiKVPodMetrics_PodNotFound(t *testing.T) {
	scheme := runtime.NewScheme()
	require.NoError(t, corev1.AddToScheme(scheme))
	cli := fake.NewClientBuilder().WithScheme(scheme).Build()

	svc := &AgentService{
		dataplaneCli:   cli,
		tikvHTTPClient: &http.Client{},
	}
	gin.SetMode(gin.TestMode)
	router := gin.New()
	router.GET("/clusters/:cluster_id/components/:component_type/:pod_name/metrics",
		svc.HandleComponentPodMetrics)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/clusters/123/components/tikv/db-tikv-0/metrics", http.NoBody)
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusNotFound, w.Code)
	assert.Contains(t, w.Body.String(), "pod not found")
}

func TestHandleTiKVPodMetrics_WrongComponent(t *testing.T) {
	scheme := runtime.NewScheme()
	require.NoError(t, corev1.AddToScheme(scheme))

	pod := &corev1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name:      "db-tikv-0",
			Namespace: "tidb123",
			Labels: map[string]string{
				K8sComponentLabelKey: "pd",
			},
		},
		Status: corev1.PodStatus{Phase: corev1.PodRunning},
	}
	cli := fake.NewClientBuilder().WithScheme(scheme).WithObjects(pod).Build()

	svc := &AgentService{
		dataplaneCli:   cli,
		tikvHTTPClient: &http.Client{},
	}
	gin.SetMode(gin.TestMode)
	router := gin.New()
	router.GET("/clusters/:cluster_id/components/:component_type/:pod_name/metrics",
		svc.HandleComponentPodMetrics)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/clusters/123/components/tikv/db-tikv-0/metrics", http.NoBody)
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusBadRequest, w.Code)
	assert.Contains(t, w.Body.String(), "pod is not a tikv component")
}

func TestHandleTiKVPodMetrics_PodNotRunning(t *testing.T) {
	scheme := runtime.NewScheme()
	require.NoError(t, corev1.AddToScheme(scheme))

	pod := &corev1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name:      "db-tikv-0",
			Namespace: "tidb123",
			Labels: map[string]string{
				K8sComponentLabelKey: TiKVComponentType,
			},
		},
		Status: corev1.PodStatus{Phase: corev1.PodPending},
	}
	cli := fake.NewClientBuilder().WithScheme(scheme).WithObjects(pod).Build()

	svc := &AgentService{
		dataplaneCli:   cli,
		tikvHTTPClient: &http.Client{},
	}
	gin.SetMode(gin.TestMode)
	router := gin.New()
	router.GET("/clusters/:cluster_id/components/:component_type/:pod_name/metrics",
		svc.HandleComponentPodMetrics)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/clusters/123/components/tikv/db-tikv-0/metrics", http.NoBody)
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusServiceUnavailable, w.Code)
	assert.Contains(t, w.Body.String(), "pod is not running")
}

func TestHandleTiKVPodMetrics_ProxySuccess(t *testing.T) {
	fakeMetricsBody := "# HELP tikv_store_size_bytes Size of storage.\ntikv_store_size_bytes 100\n"
	fakeTiKV := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		assert.Equal(t, "/metrics", r.URL.Path)
		w.Header().Set("Content-Type", "text/plain; version=0.0.4; charset=utf-8")
		w.WriteHeader(http.StatusOK)
		_, _ = w.Write([]byte(fakeMetricsBody))
	}))
	defer fakeTiKV.Close()

	scheme := runtime.NewScheme()
	require.NoError(t, corev1.AddToScheme(scheme))

	pod := &corev1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name:      "db-tikv-0",
			Namespace: "tidb123",
			Labels: map[string]string{
				K8sComponentLabelKey: TiKVComponentType,
			},
		},
		Status: corev1.PodStatus{Phase: corev1.PodRunning},
	}
	cli := fake.NewClientBuilder().WithScheme(scheme).WithObjects(pod).Build()

	svc := &AgentService{
		dataplaneCli:   cli,
		tikvHTTPClient: fakeTiKV.Client(),
	}

	gin.SetMode(gin.TestMode)
	router := gin.New()
	router.GET("/clusters/:cluster_id/components/:component_type/:pod_name/metrics",
		func(c *gin.Context) {
			clusterID := c.Param("cluster_id")
			podName := c.Param("pod_name")
			svc.handleTiKVPodMetricsWithURL(c, clusterID, podName, fakeTiKV.URL+"/metrics")
		})

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/clusters/123/components/tikv/db-tikv-0/metrics", http.NoBody)
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusOK, w.Code)
	assert.Equal(t, "text/plain; version=0.0.4; charset=utf-8", w.Header().Get("Content-Type"))
	assert.Equal(t, fakeMetricsBody, w.Body.String())
}

func TestHandleTiKVPodMetrics_TiKVUnreachable(t *testing.T) {
	scheme := runtime.NewScheme()
	require.NoError(t, corev1.AddToScheme(scheme))

	pod := &corev1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name:      "db-tikv-0",
			Namespace: "tidb123",
			Labels: map[string]string{
				K8sComponentLabelKey: TiKVComponentType,
			},
		},
		Status: corev1.PodStatus{Phase: corev1.PodRunning},
	}
	cli := fake.NewClientBuilder().WithScheme(scheme).WithObjects(pod).Build()

	svc := &AgentService{
		dataplaneCli:   cli,
		tikvHTTPClient: &http.Client{},
	}
	gin.SetMode(gin.TestMode)
	router := gin.New()
	router.GET("/clusters/:cluster_id/components/:component_type/:pod_name/metrics",
		func(c *gin.Context) {
			clusterID := c.Param("cluster_id")
			podName := c.Param("pod_name")
			svc.handleTiKVPodMetricsWithURL(c, clusterID, podName,
				"https://127.0.0.1:1/metrics")
		})

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/clusters/123/components/tikv/db-tikv-0/metrics", http.NoBody)
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusBadGateway, w.Code)
	assert.Contains(t, w.Body.String(), "failed to reach tikv metrics endpoint")
}

func newNodeMetricsRouter(svc *AgentService) *gin.Engine {
	gin.SetMode(gin.TestMode)
	r := gin.New()
	r.GET("/clusters/:cluster_id/components/:component_type/:pod_name/node-metrics",
		svc.HandleComponentPodNodeMetrics)
	return r
}

func buildFakeClientWithNodeIndex(scheme *runtime.Scheme, objs ...runtime.Object) *fake.ClientBuilder {
	return fake.NewClientBuilder().
		WithScheme(scheme).
		WithRuntimeObjects(objs...).
		WithIndex(&corev1.Pod{}, "spec.nodeName", func(o client.Object) []string {
			pod, ok := o.(*corev1.Pod)
			if !ok {
				return nil
			}
			return []string{pod.Spec.NodeName}
		})
}

func fakeNodeExporterPort(serverURL string) int {
	u, err := url.Parse(serverURL)
	if err != nil {
		return 0
	}
	p, err := strconv.Atoi(u.Port())
	if err != nil {
		return 0
	}
	return p
}

func TestHandleComponentPodNodeMetrics_UnknownComponent(t *testing.T) {
	svc := &AgentService{nodeExporterHTTPClient: &http.Client{}}
	router := newNodeMetricsRouter(svc)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/clusters/123/components/pd/db-pd-0/node-metrics", http.NoBody)
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusNotImplemented, w.Code)
	assert.Contains(t, w.Body.String(), "node metrics proxy not implemented for component: pd")
}

func TestHandleComponentPodNodeMetrics_PodNotFound(t *testing.T) {
	scheme := runtime.NewScheme()
	require.NoError(t, corev1.AddToScheme(scheme))
	cli := fake.NewClientBuilder().WithScheme(scheme).Build()

	svc := &AgentService{dataplaneCli: cli, nodeExporterHTTPClient: &http.Client{}}
	router := newNodeMetricsRouter(svc)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/clusters/123/components/tikv/db-tikv-0/node-metrics", http.NoBody)
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusNotFound, w.Code)
	assert.Contains(t, w.Body.String(), "pod not found")
}

func TestHandleComponentPodNodeMetrics_WrongComponent(t *testing.T) {
	scheme := runtime.NewScheme()
	require.NoError(t, corev1.AddToScheme(scheme))
	pod := &corev1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name:      "db-tikv-0",
			Namespace: "tidb123",
			Labels:    map[string]string{K8sComponentLabelKey: "pd"},
		},
		Status: corev1.PodStatus{Phase: corev1.PodRunning},
	}
	cli := fake.NewClientBuilder().WithScheme(scheme).WithObjects(pod).Build()

	svc := &AgentService{dataplaneCli: cli, nodeExporterHTTPClient: &http.Client{}}
	router := newNodeMetricsRouter(svc)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/clusters/123/components/tikv/db-tikv-0/node-metrics", http.NoBody)
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusBadRequest, w.Code)
	assert.Contains(t, w.Body.String(), "pod is not a tikv component")
}

func TestHandleComponentPodNodeMetrics_PodNotRunning(t *testing.T) {
	scheme := runtime.NewScheme()
	require.NoError(t, corev1.AddToScheme(scheme))
	pod := &corev1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name:      "db-tikv-0",
			Namespace: "tidb123",
			Labels:    map[string]string{K8sComponentLabelKey: TiKVComponentType},
		},
		Status: corev1.PodStatus{Phase: corev1.PodPending},
	}
	cli := fake.NewClientBuilder().WithScheme(scheme).WithObjects(pod).Build()

	svc := &AgentService{dataplaneCli: cli, nodeExporterHTTPClient: &http.Client{}}
	router := newNodeMetricsRouter(svc)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/clusters/123/components/tikv/db-tikv-0/node-metrics", http.NoBody)
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusServiceUnavailable, w.Code)
	assert.Contains(t, w.Body.String(), "pod is not running")
}

func TestHandleComponentPodNodeMetrics_NoNodeExporterPod(t *testing.T) {
	scheme := runtime.NewScheme()
	require.NoError(t, corev1.AddToScheme(scheme))
	tikvPod := &corev1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name:      "db-tikv-0",
			Namespace: "tidb123",
			Labels:    map[string]string{K8sComponentLabelKey: TiKVComponentType},
		},
		Spec:   corev1.PodSpec{NodeName: "node-1"},
		Status: corev1.PodStatus{Phase: corev1.PodRunning, HostIP: "10.0.0.1"},
	}
	cli := buildFakeClientWithNodeIndex(scheme, tikvPod).Build()

	svc := &AgentService{dataplaneCli: cli, nodeExporterHTTPClient: &http.Client{}}
	router := newNodeMetricsRouter(svc)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/clusters/123/components/tikv/db-tikv-0/node-metrics", http.NoBody)
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusServiceUnavailable, w.Code)
	assert.Contains(t, w.Body.String(), "node-exporter unavailable")
}

func TestHandleComponentPodNodeMetrics_ProxySuccess(t *testing.T) {
	fakeBody := "node_disk_reads_completed_total{device=\"nvme0n1\"} 12345\n"
	fakeNodeExporter := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		assert.Equal(t, "/metrics", r.URL.Path)
		w.Header().Set("Content-Type", "text/plain; version=0.0.4")
		w.WriteHeader(http.StatusOK)
		_, _ = w.Write([]byte(fakeBody))
	}))
	defer fakeNodeExporter.Close()

	scheme := runtime.NewScheme()
	require.NoError(t, corev1.AddToScheme(scheme))
	tikvPod := &corev1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name:      "db-tikv-0",
			Namespace: "tidb123",
			Labels:    map[string]string{K8sComponentLabelKey: TiKVComponentType},
		},
		Spec:   corev1.PodSpec{NodeName: "node-1"},
		Status: corev1.PodStatus{Phase: corev1.PodRunning, HostIP: "127.0.0.1"},
	}
	nePod := &corev1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name:      "node-exporter-abc",
			Namespace: nodeExporterNamespace,
			Labels: map[string]string{
				nodeExporterInstanceKey: nodeExporterInstanceValue,
			},
		},
		Spec: corev1.PodSpec{
			NodeName: "node-1",
			Containers: []corev1.Container{{
				Ports: []corev1.ContainerPort{{
					Name:          nodeExporterPortName,
					ContainerPort: int32(fakeNodeExporterPort(fakeNodeExporter.URL)),
				}},
			}},
		},
		Status: corev1.PodStatus{Phase: corev1.PodRunning},
	}
	cli := buildFakeClientWithNodeIndex(scheme, tikvPod, nePod).Build()

	svc := &AgentService{dataplaneCli: cli, nodeExporterHTTPClient: fakeNodeExporter.Client()}
	router := newNodeMetricsRouter(svc)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/clusters/123/components/tikv/db-tikv-0/node-metrics", http.NoBody)
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusOK, w.Code)
	assert.Equal(t, "text/plain; version=0.0.4", w.Header().Get("Content-Type"))
	assert.Equal(t, fakeBody, w.Body.String())
}

func TestHandleComponentPodNodeMetrics_UpstreamError(t *testing.T) {
	scheme := runtime.NewScheme()
	require.NoError(t, corev1.AddToScheme(scheme))
	tikvPod := &corev1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name:      "db-tikv-0",
			Namespace: "tidb123",
			Labels:    map[string]string{K8sComponentLabelKey: TiKVComponentType},
		},
		Spec:   corev1.PodSpec{NodeName: "node-1"},
		Status: corev1.PodStatus{Phase: corev1.PodRunning, HostIP: "127.0.0.1"},
	}
	nePod := &corev1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name:      "node-exporter-abc",
			Namespace: nodeExporterNamespace,
			Labels: map[string]string{
				nodeExporterInstanceKey: nodeExporterInstanceValue,
			},
		},
		Spec: corev1.PodSpec{
			NodeName: "node-1",
			Containers: []corev1.Container{{
				Ports: []corev1.ContainerPort{{
					Name:          nodeExporterPortName,
					ContainerPort: 1,
				}},
			}},
		},
		Status: corev1.PodStatus{Phase: corev1.PodRunning},
	}
	cli := buildFakeClientWithNodeIndex(scheme, tikvPod, nePod).Build()

	svc := &AgentService{dataplaneCli: cli, nodeExporterHTTPClient: &http.Client{}}
	router := newNodeMetricsRouter(svc)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/clusters/123/components/tikv/db-tikv-0/node-metrics", http.NoBody)
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusBadGateway, w.Code)
	assert.Contains(t, w.Body.String(), "failed to reach node-exporter")
}

func TestHandleComponentPodNodeMetrics_NoNamedPort(t *testing.T) {
	scheme := runtime.NewScheme()
	require.NoError(t, corev1.AddToScheme(scheme))
	tikvPod := &corev1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name:      "db-tikv-0",
			Namespace: "tidb123",
			Labels:    map[string]string{K8sComponentLabelKey: TiKVComponentType},
		},
		Spec:   corev1.PodSpec{NodeName: "node-1"},
		Status: corev1.PodStatus{Phase: corev1.PodRunning, HostIP: "10.0.0.1"},
	}
	nePod := &corev1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name:      "node-exporter-abc",
			Namespace: nodeExporterNamespace,
			Labels: map[string]string{
				nodeExporterInstanceKey: nodeExporterInstanceValue,
			},
		},
		Spec: corev1.PodSpec{
			NodeName:   "node-1",
			Containers: []corev1.Container{{Ports: []corev1.ContainerPort{{Name: "other", ContainerPort: 9100}}}},
		},
		Status: corev1.PodStatus{Phase: corev1.PodRunning},
	}
	cli := buildFakeClientWithNodeIndex(scheme, tikvPod, nePod).Build()

	svc := &AgentService{dataplaneCli: cli, nodeExporterHTTPClient: &http.Client{}}
	router := newNodeMetricsRouter(svc)

	w := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet,
		"/clusters/123/components/tikv/db-tikv-0/node-metrics", http.NoBody)
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusServiceUnavailable, w.Code)
	assert.Contains(t, w.Body.String(), "node-exporter unavailable")
}