/*
   Copyright 2021 The Kubernetes Authors.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

package handler3

import (
	"bytes"
	"fmt"
	"io"
	"mime"
	"net/http"
	"net/http/httptest"
	"reflect"
	"strconv"
	"testing"
	"time"

	"encoding/json"

	"k8s.io/kube-openapi/pkg/spec3"
)

var returnedOpenAPI = []byte(`{
  "openapi": "3.0",
  "info": {
   "title": "Kubernetes",
   "version": "v1.23.0"
  },
  "paths": {}}`)

func TestRegisterOpenAPIVersionedService(t *testing.T) {
	var s *spec3.OpenAPI
	buffer := new(bytes.Buffer)
	if err := json.Compact(buffer, returnedOpenAPI); err != nil {
		t.Errorf("%v", err)
	}
	compactOpenAPI := buffer.Bytes()
	var hash = computeETag(compactOpenAPI)

	var returnedGroupVersionListJSON = []byte(`{"paths":{"apis/apps/v1":{"serverRelativeURL":"/openapi/v3/apis/apps/v1?hash=` + hash + `"}}}`)

	json.Unmarshal(compactOpenAPI, &s)

	returnedJSON, err := json.Marshal(s)
	if err != nil {
		t.Fatalf("Unexpected error in preparing returnedJSON: %v", err)
	}

	returnedPb, err := ToV3ProtoBinary(compactOpenAPI)

	if err != nil {
		t.Fatalf("Unexpected error in preparing returnedPb: %v", err)
	}

	mux := http.NewServeMux()
	o := NewOpenAPIService()
	if err != nil {
		t.Fatal(err)
	}

	mux.Handle("/openapi/v3", http.HandlerFunc(o.HandleDiscovery))
	mux.Handle("/openapi/v3/apis/apps/v1", http.HandlerFunc(o.HandleGroupVersion))

	o.UpdateGroupVersion("apis/apps/v1", s)

	server := httptest.NewServer(mux)
	defer server.Close()
	client := server.Client()

	tcs := []struct {
		acceptHeader              string
		respStatus                int
		urlPath                   string
		respBody                  []byte
		expectedETag              string
		sendETag                  bool
		responseContentTypeHeader string
	}{
		{
			acceptHeader:              "",
			respStatus:                200,
			urlPath:                   "openapi/v3",
			respBody:                  returnedGroupVersionListJSON,
			expectedETag:              computeETag(returnedGroupVersionListJSON),
			responseContentTypeHeader: "application/json",
		}, {
			acceptHeader: "",
			respStatus:   304,
			urlPath:      "openapi/v3",
			respBody:     returnedGroupVersionListJSON,
			expectedETag: computeETag(returnedGroupVersionListJSON),
			sendETag:     true,
		}, {
			acceptHeader:              "",
			respStatus:                200,
			urlPath:                   "openapi/v3/apis/apps/v1",
			respBody:                  returnedJSON,
			expectedETag:              computeETag(returnedJSON),
			responseContentTypeHeader: "application/json",
		}, {
			acceptHeader: "",
			respStatus:   304,
			urlPath:      "openapi/v3/apis/apps/v1",
			respBody:     returnedJSON,
			expectedETag: computeETag(returnedJSON),
			sendETag:     true,
		}, {
			acceptHeader:              "*/*",
			respStatus:                200,
			urlPath:                   "openapi/v3/apis/apps/v1",
			respBody:                  returnedJSON,
			expectedETag:              computeETag(returnedJSON),
			responseContentTypeHeader: "application/json",
		}, {
			acceptHeader:              "application/json",
			respStatus:                200,
			urlPath:                   "openapi/v3/apis/apps/v1",
			respBody:                  returnedJSON,
			expectedETag:              computeETag(returnedJSON),
			responseContentTypeHeader: "application/json",
		}, {
			acceptHeader:              "application/*",
			respStatus:                200,
			urlPath:                   "openapi/v3/apis/apps/v1",
			respBody:                  returnedJSON,
			expectedETag:              computeETag(returnedJSON),
			responseContentTypeHeader: "application/json",
		}, {
			acceptHeader: "test/test",
			respStatus:   406,
			urlPath:      "openapi/v3/apis/apps/v1",
			respBody:     []byte{},
		}, {
			acceptHeader: "application/test",
			respStatus:   406,
			urlPath:      "openapi/v3/apis/apps/v1",
			respBody:     []byte{},
		}, {
			acceptHeader:              "application/test,  */*",
			respStatus:                200,
			urlPath:                   "openapi/v3/apis/apps/v1",
			respBody:                  returnedJSON,
			expectedETag:              computeETag(returnedJSON),
			responseContentTypeHeader: "application/json",
		}, {
			acceptHeader:              "application/com.github.proto-openapi.spec.v3.v1.0+protobuf",
			respStatus:                200,
			urlPath:                   "openapi/v3/apis/apps/v1",
			respBody:                  returnedPb,
			expectedETag:              computeETag(returnedJSON),
			responseContentTypeHeader: "application/com.github.proto-openapi.spec.v3.v1.0+protobuf",
		}, {
			acceptHeader: "application/com.github.proto-openapi.spec.v3.v1.0+protobuf",
			respStatus:   304,
			urlPath:      "openapi/v3/apis/apps/v1",
			respBody:     returnedPb,
			expectedETag: computeETag(returnedJSON),
			sendETag:     true,
		}, {
			acceptHeader:              "application/json, application/com.github.proto-openapi.spec.v2.v1.0+protobuf",
			respStatus:                200,
			urlPath:                   "openapi/v3/apis/apps/v1",
			respBody:                  returnedJSON,
			expectedETag:              computeETag(returnedJSON),
			responseContentTypeHeader: "application/json",
		}, {
			acceptHeader:              "application/com.github.proto-openapi.spec.v3.v1.0+protobuf, application/json",
			respStatus:                200,
			urlPath:                   "openapi/v3/apis/apps/v1",
			respBody:                  returnedPb,
			expectedETag:              computeETag(returnedJSON),
			responseContentTypeHeader: "application/com.github.proto-openapi.spec.v3.v1.0+protobuf",
		}, {
			acceptHeader: "application/com.github.proto-openapi.spec.v3.v1.0+protobuf, application/json",
			respStatus:   304,
			urlPath:      "openapi/v3/apis/apps/v1",
			respBody:     returnedPb,
			expectedETag: computeETag(returnedJSON),
			sendETag:     true,
		}, {
			acceptHeader:              "application/com.github.proto-openapi.spec.v3.v1.0+protobuf; q=0.5, application/json",
			respStatus:                200,
			urlPath:                   "openapi/v3/apis/apps/v1",
			respBody:                  returnedJSON,
			expectedETag:              computeETag(returnedJSON),
			responseContentTypeHeader: "application/json",
		}, {
			acceptHeader:              "application/com.github.proto-openapi.spec.v3@v1.0+protobuf",
			respStatus:                200,
			urlPath:                   "openapi/v3/apis/apps/v1",
			respBody:                  returnedPb,
			expectedETag:              computeETag(returnedJSON),
			responseContentTypeHeader: "application/com.github.proto-openapi.spec.v3.v1.0+protobuf",
		}, {
			acceptHeader: "application/com.github.proto-openapi.spec.v3@v1.0+protobuf",
			respStatus:   304,
			urlPath:      "openapi/v3/apis/apps/v1",
			respBody:     returnedPb,
			expectedETag: computeETag(returnedJSON),
			sendETag:     true,
		}, {
			acceptHeader:              "application/com.github.proto-openapi.spec.v3@v1.0+protobuf, application/json",
			respStatus:                200,
			urlPath:                   "openapi/v3/apis/apps/v1",
			respBody:                  returnedPb,
			expectedETag:              computeETag(returnedJSON),
			responseContentTypeHeader: "application/com.github.proto-openapi.spec.v3.v1.0+protobuf",
		}, {
			acceptHeader:              "application/com.github.proto-openapi.spec.v3@v1.0+protobuf; q=0.5, application/json",
			respStatus:                200,
			urlPath:                   "openapi/v3/apis/apps/v1",
			respBody:                  returnedJSON,
			expectedETag:              computeETag(returnedJSON),
			responseContentTypeHeader: "application/json",
		},
	}

	for _, tc := range tcs {
		req, err := http.NewRequest("GET", server.URL+"/"+tc.urlPath, nil)
		if err != nil {
			t.Errorf("Accept: %v: Unexpected error in creating new request: %v", tc.acceptHeader, err)
		}

		req.Header.Add("Accept", tc.acceptHeader)
		if tc.sendETag {
			req.Header.Add("If-None-Match", strconv.Quote(tc.expectedETag))
		}
		resp, err := client.Do(req)
		if err != nil {
			t.Errorf("Accept: %v: Unexpected error in serving HTTP request: %v", tc.acceptHeader, err)
		}
		defer resp.Body.Close()

		if resp.StatusCode != tc.respStatus {
			t.Errorf("Accept: %v: Unexpected response status code, want: %v, got: %v", tc.acceptHeader, tc.respStatus, resp.StatusCode)
		}

		if tc.respStatus == 304 {
			body, err := io.ReadAll(resp.Body)
			if err != nil {
				t.Errorf("Accept: %v: Unexpected error in reading response body: %v", tc.acceptHeader, err)
			}
			if len(body) != 0 {
				t.Errorf("Response Body length must be 0 if 304 is returned.")
			}
		}
		if tc.respStatus != 200 {
			continue
		}

		responseContentType := resp.Header.Get("Content-Type")
		if responseContentType != tc.responseContentTypeHeader {
			t.Errorf("Accept: %v: Unexpected content type in response, want: %v, got: %v", tc.acceptHeader, tc.responseContentTypeHeader, responseContentType)
		}
		_, _, err = mime.ParseMediaType(responseContentType)
		if err != nil {
			t.Errorf("Unexpected error in parsing response content type: %v, err: %v", responseContentType, err)
		}

		gotETag := resp.Header.Get("ETag")
		if strconv.Quote(tc.expectedETag) != gotETag {
			t.Errorf("Expect ETag %s, got %s", strconv.Quote(tc.expectedETag), gotETag)
		}

		body, err := io.ReadAll(resp.Body)
		if err != nil {
			t.Errorf("Accept: %v: Unexpected error in reading response body: %v", tc.acceptHeader, err)
		}
		if !reflect.DeepEqual(body, tc.respBody) {
			t.Errorf("Accept: %v: Response body mismatches, \nwant: %s, \ngot:  %s", tc.acceptHeader, string(tc.respBody), string(body))
		}
	}
}

func TestCacheBusting(t *testing.T) {
	var s *spec3.OpenAPI
	buffer := new(bytes.Buffer)
	if err := json.Compact(buffer, returnedOpenAPI); err != nil {
		t.Errorf("%v", err)
	}
	compactOpenAPI := buffer.Bytes()
	var hash = computeETag(compactOpenAPI)

	json.Unmarshal(compactOpenAPI, &s)

	returnedJSON, err := json.Marshal(s)
	if err != nil {
		t.Fatalf("Unexpected error in preparing returnedJSON: %v", err)
	}

	returnedPb, err := ToV3ProtoBinary(compactOpenAPI)

	if err != nil {
		t.Fatalf("Unexpected error in preparing returnedPb: %v", err)
	}

	mux := http.NewServeMux()
	o := NewOpenAPIService()
	if err != nil {
		t.Fatal(err)
	}

	mux.Handle("/openapi/v3", http.HandlerFunc(o.HandleDiscovery))
	mux.Handle("/openapi/v3/apis/apps/v1", http.HandlerFunc(o.HandleGroupVersion))

	o.UpdateGroupVersion("apis/apps/v1", s)

	server := httptest.NewServer(mux)
	defer server.Close()
	client := server.Client()

	tcs := []struct {
		acceptHeader string
		respStatus   int
		urlPath      string
		respBody     []byte
		expectedHash string
		cacheControl string
	}{
		// Correct hash should yield the proper expiry and Cache Control headers
		{"application/json",
			200,
			"openapi/v3/apis/apps/v1?hash=" + hash,
			returnedJSON,
			hash,
			"public, immutable",
		},
		{"application/com.github.proto-openapi.spec.v3.v1.0+protobuf",
			200,
			"openapi/v3/apis/apps/v1?hash=" + hash,
			returnedPb,
			hash,
			"public, immutable",
		},
		// Incorrect hash should redirect to the page with the correct hash
		{"application/json",
			200,
			"openapi/v3/apis/apps/v1?hash=OUTDATEDHASH",
			returnedJSON,
			hash,
			"public, immutable",
		},
		{"application/com.github.proto-openapi.spec.v3.v1.0+protobuf",
			200,
			"openapi/v3/apis/apps/v1?hash=OUTDATEDHASH",
			returnedPb,
			hash,
			"public, immutable",
		},
		// No hash should not return Cache Control information
		{"application/json",
			200,
			"openapi/v3/apis/apps/v1",
			returnedJSON,
			"",
			"",
		},
		{"application/com.github.proto-openapi.spec.v3.v1.0+protobuf",
			200,
			"openapi/v3/apis/apps/v1",
			returnedPb,
			"",
			"",
		},
	}

	for _, tc := range tcs {
		req, err := http.NewRequest("GET", server.URL+"/"+tc.urlPath, nil)
		if err != nil {
			t.Errorf("Accept: %v: Unexpected error in creating new request: %v", tc.acceptHeader, err)
		}

		req.Header.Add("Accept", tc.acceptHeader)
		resp, err := client.Do(req)
		if err != nil {
			t.Errorf("Accept: %v: Unexpected error in serving HTTP request: %v", tc.acceptHeader, err)
		}

		if resp.StatusCode != 200 {
			t.Errorf("Accept: Unexpected response status code, want: %v, got: %v", 200, resp.StatusCode)
		}

		if cacheControl := resp.Header.Get("Cache-Control"); cacheControl != tc.cacheControl {
			t.Errorf("Expected Cache Control %v, got %v", tc.cacheControl, cacheControl)
		}

		if tc.expectedHash != "" {
			if hash := resp.Request.URL.Query().Get("hash"); hash != tc.expectedHash {
				t.Errorf("Expected Hash: %s, got %s", tc.expectedHash, hash)
			}

			expires := resp.Header.Get("Expires")
			parsedTime, err := time.Parse(time.RFC1123, expires)
			if err != nil {
				t.Errorf("Could not parse cache expiry %v", expires)
			}

			difference := parsedTime.Sub(time.Now()).Hours()
			if difference <= 0 {
				t.Errorf("Expected cache expiry to be in the future")
			}
		} else {
			hash := resp.Request.URL.Query()["hash"]
			if len(hash) != 0 {
				t.Errorf("Expect no redirect and empty hash if the hash is not provide")
			}
			expires := resp.Header.Get("Expires")
			if expires != "" {
				t.Errorf("Expected an empty Expiry if hash is not provided,  got %v", expires)
			}
		}

		defer resp.Body.Close()
		body, err := io.ReadAll(resp.Body)
		if err != nil {
			t.Errorf("Accept: %v: Unexpected error in reading response body: %v", tc.acceptHeader, err)
		}
		if !reflect.DeepEqual(body, tc.respBody) {
			t.Errorf("Accept: %v: Response body mismatches, \nwant: %s, \ngot:  %s", tc.acceptHeader, string(tc.respBody), string(body))
		}
	}
}

func openAPIOrDie(name string) *spec3.OpenAPI {
	openapi := fmt.Sprintf(`{
  "openapi": "3.0",
  "info": {
   "title": "%s",
   "version": "v1.23.0"
  },
  "paths": {}}`, name)
	spec := spec3.OpenAPI{}
	if err := json.Unmarshal([]byte(openapi), &spec); err != nil {
		panic(err)
	}
	return &spec
}

func getDiscovery(server *httptest.Server, path string) (*OpenAPIV3Discovery, string, error) {
	client := server.Client()
	req, err := http.NewRequest("GET", server.URL+"/"+path, nil)
	if err != nil {
		return nil, "", fmt.Errorf("error in creating new request: %v", err)
	}

	resp, err := client.Do(req)
	if err != nil {
		return nil, "", fmt.Errorf("error in serving HTTP request: %v", err)
	}
	if resp.StatusCode != 200 {
		return nil, "", fmt.Errorf("unexpected response status code, want: %v, got: %v", 200, resp.StatusCode)
	}
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, "", fmt.Errorf("Failed to read request body: %v", err)
	}

	discovery := &OpenAPIV3Discovery{}
	if err := json.Unmarshal(body, &discovery); err != nil {
		return nil, "", fmt.Errorf("failed to unmarshal discovery: %v", err)
	}
	return discovery, resp.Header.Get("etag"), nil
}

func TestUpdateGroupVersion(t *testing.T) {
	mux := http.NewServeMux()
	o := NewOpenAPIService()

	mux.Handle("/openapi/v3", http.HandlerFunc(o.HandleDiscovery))

	o.UpdateGroupVersion("apis/apps/v1", openAPIOrDie("apps-v1"))

	server := httptest.NewServer(mux)
	defer server.Close()

	discovery, discovery_etag, err := getDiscovery(server, "/openapi/v3")
	if err != nil {
		t.Fatalf("failed to get /openapi/v3: %v", err)
	}
	etag, ok := discovery.Paths["apis/apps/v1"]
	if !ok {
		t.Fatalf("missing apis/apps/v1")
	}

	// Update with the same thing, make sure we don't update anything.
	o.UpdateGroupVersion("apis/apps/v1", openAPIOrDie("apps-v1"))

	discovery, discovery_etag_updated, err := getDiscovery(server, "/openapi/v3")
	if err != nil {
		t.Fatalf("failed to get /openapi/v3: %v", err)
	}
	if len(discovery.Paths) != 1 {
		t.Fatalf("Invalid number of Paths, expected 1: %v", discovery.Paths)
	}
	etag_updated, ok := discovery.Paths["apis/apps/v1"]
	if !ok {
		t.Fatalf("missing apis/apps/v1")
	}

	if discovery_etag_updated != discovery_etag {
		t.Fatalf("No-op update shouldn't update OpenAPI Discovery etag")
	}

	if etag_updated != etag {
		t.Fatalf("No-op update shouldn't update OpenAPI etag")
	}

	// Add one more, make sure it's in the list
	o.UpdateGroupVersion("apis/something/v1", openAPIOrDie("something-v1"))
	discovery, _, err = getDiscovery(server, "/openapi/v3")
	if err != nil {
		t.Fatalf("failed to get /openapi/v3: %v", err)
	}
	if len(discovery.Paths) != 2 {
		t.Fatalf("Invalid number of Paths, expected 2: %v", discovery.Paths)
	}

	// And remove
	o.DeleteGroupVersion("apis/apps/v1")
	discovery, _, err = getDiscovery(server, "/openapi/v3")
	if err != nil {
		t.Fatalf("failed to get /openapi/v3: %v", err)
	}
	if len(discovery.Paths) != 1 {
		t.Fatalf("Invalid number of Paths, expected 2: %v", discovery.Paths)
	}
}