package query

import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"net/http"
	"net/http/httptest"
	"sync"
	"testing"
	"time"

	"github.com/grafana/grafana-plugin-sdk-go/backend"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"github.com/grafana/grafana/pkg/api/dtos"
	"github.com/grafana/grafana/pkg/components/simplejson"
	"github.com/grafana/grafana/pkg/expr"
	"github.com/grafana/grafana/pkg/infra/db"
	"github.com/grafana/grafana/pkg/infra/localcache"
	"github.com/grafana/grafana/pkg/infra/log"
	"github.com/grafana/grafana/pkg/infra/tracing"
	"github.com/grafana/grafana/pkg/models/roletype"
	"github.com/grafana/grafana/pkg/plugins"
	pluginFakes "github.com/grafana/grafana/pkg/plugins/manager/fakes"
	"github.com/grafana/grafana/pkg/services/contexthandler"
	"github.com/grafana/grafana/pkg/services/contexthandler/ctxkey"
	contextmodel "github.com/grafana/grafana/pkg/services/contexthandler/model"
	"github.com/grafana/grafana/pkg/services/datasources"
	fakeDatasources "github.com/grafana/grafana/pkg/services/datasources/fakes"
	"github.com/grafana/grafana/pkg/services/featuremgmt"
	"github.com/grafana/grafana/pkg/services/pluginsintegration/plugincontext"
	pluginSettings "github.com/grafana/grafana/pkg/services/pluginsintegration/pluginsettings/service"
	"github.com/grafana/grafana/pkg/services/secrets/fakes"
	secretskvs "github.com/grafana/grafana/pkg/services/secrets/kvstore"
	secretsmng "github.com/grafana/grafana/pkg/services/secrets/manager"
	"github.com/grafana/grafana/pkg/services/user"
	"github.com/grafana/grafana/pkg/setting"
	"github.com/grafana/grafana/pkg/web"
)

func TestParseMetricRequest(t *testing.T) {
	t.Run("Test a simple single datasource query", func(t *testing.T) {
		tc := setup(t)
		mr := metricRequestWithQueries(t, `{
			"refId": "A",
			"datasource": {
				"uid": "gIEkMvIVz",
				"type": "postgres"
			}
		}`, `{
			"refId": "B",
			"datasource": {
				"uid": "gIEkMvIVz",
				"type": "postgres"
			}
		}`)
		parsedReq, err := tc.queryService.parseMetricRequest(context.Background(), tc.signedInUser, true, mr)
		require.NoError(t, err)
		require.NotNil(t, parsedReq)
		assert.False(t, parsedReq.hasExpression)
		assert.Len(t, parsedReq.parsedQueries, 1)
		assert.Contains(t, parsedReq.parsedQueries, "gIEkMvIVz")
		assert.Len(t, parsedReq.getFlattenedQueries(), 2)
	})

	t.Run("Test a single datasource query with expressions", func(t *testing.T) {
		tc := setup(t)
		mr := metricRequestWithQueries(t, `{
			"refId": "A",
			"datasource": {
				"uid": "gIEkMvIVz",
				"type": "postgres"
			}
		}`, `{
			"refId": "B",
			"datasource": {
				"type": "__expr__",
				"uid": "__expr__",
				"name": "Expression"
			},
			"type": "math",
			"expression": "$A - 50"
		}`)
		parsedReq, err := tc.queryService.parseMetricRequest(context.Background(), tc.signedInUser, true, mr)
		require.NoError(t, err)
		require.NotNil(t, parsedReq)
		require.True(t, parsedReq.hasExpression)
		require.Len(t, parsedReq.parsedQueries, 2)
		require.Contains(t, parsedReq.parsedQueries, "gIEkMvIVz")
		require.Len(t, parsedReq.getFlattenedQueries(), 2)
		// Make sure we end up with something valid
		_, err = tc.queryService.handleExpressions(context.Background(), tc.signedInUser, parsedReq)
		require.NoError(t, err)

		t.Run("Should forward user and org ID to QueryData from expression request", func(t *testing.T) {
			require.NotNil(t, tc.pluginContext.req)
			require.NotNil(t, tc.pluginContext.req.PluginContext.User)
			require.Equal(t, tc.signedInUser.Login, tc.pluginContext.req.PluginContext.User.Login)
			require.Equal(t, tc.signedInUser.Name, tc.pluginContext.req.PluginContext.User.Name)
			require.Equal(t, tc.signedInUser.Email, tc.pluginContext.req.PluginContext.User.Email)
			require.Equal(t, string(tc.signedInUser.OrgRole), tc.pluginContext.req.PluginContext.User.Role)
			require.Equal(t, tc.signedInUser.OrgID, tc.pluginContext.req.PluginContext.OrgID)
		})
	})

	t.Run("Test a simple mixed datasource query", func(t *testing.T) {
		tc := setup(t)
		mr := metricRequestWithQueries(t, `{
			"refId": "A",
			"datasource": {
				"uid": "gIEkMvIVz",
				"type": "postgres"
			}
		}`, `{
			"refId": "B",
			"datasource": {
				"uid": "sEx6ZvSVk",
				"type": "testdata"
			}
		}`, `{
			"refId": "C",
			"datasource": {
				"uid": "sEx6ZvSVk",
				"type": "testdata"
			}
		}`)
		parsedReq, err := tc.queryService.parseMetricRequest(context.Background(), tc.signedInUser, true, mr)
		require.NoError(t, err)
		require.NotNil(t, parsedReq)
		assert.False(t, parsedReq.hasExpression)
		assert.Len(t, parsedReq.parsedQueries, 2)
		assert.Contains(t, parsedReq.parsedQueries, "gIEkMvIVz")
		assert.Len(t, parsedReq.parsedQueries["gIEkMvIVz"], 1)
		assert.Contains(t, parsedReq.parsedQueries, "sEx6ZvSVk")
		assert.Len(t, parsedReq.parsedQueries["sEx6ZvSVk"], 2)
		assert.Len(t, parsedReq.getFlattenedQueries(), 3)
	})

	t.Run("Test a mixed datasource query with expressions", func(t *testing.T) {
		tc := setup(t)
		mr := metricRequestWithQueries(t, `{
			"refId": "A",
			"datasource": {
				"uid": "gIEkMvIVz",
				"type": "postgres"
			}
		}`, `{
			"refId": "B",
			"datasource": {
				"uid": "sEx6ZvSVk",
				"type": "testdata"
			}
		}`, `{
			"refId": "A_resample",
			"datasource": {
				"type": "__expr__",
				"uid": "__expr__",
				"name": "Expression"
			},
			"expression": "A",
			"type": "resample",
			"downsampler": "mean",
			"upsampler": "fillna",
			"window": "10s"
		}`, `{
			"refId": "B_resample",
			"datasource": {
				"type": "__expr__",
				"uid": "__expr__",
				"name": "Expression"
			},
			"expression": "B",
			"type": "resample",
			"downsampler": "mean",
			"upsampler": "fillna",
			"window": "10s"
		}`, `{
			"refId": "C",
			"datasource": {
				"type": "__expr__",
				"uid": "__expr__",
				"name": "Expression"
			},
			"type": "math",
			"expression": "$A_resample + $B_resample"
		}`)
		parsedReq, err := tc.queryService.parseMetricRequest(context.Background(), tc.signedInUser, true, mr)
		require.NoError(t, err)
		require.NotNil(t, parsedReq)
		assert.True(t, parsedReq.hasExpression)
		assert.Len(t, parsedReq.parsedQueries, 3)
		assert.Contains(t, parsedReq.parsedQueries, "gIEkMvIVz")
		assert.Contains(t, parsedReq.parsedQueries, "sEx6ZvSVk")
		assert.Len(t, parsedReq.getFlattenedQueries(), 5)
		// Make sure we end up with something valid
		_, err = tc.queryService.handleExpressions(context.Background(), tc.signedInUser, parsedReq)
		assert.NoError(t, err)
	})

	t.Run("Header validation", func(t *testing.T) {
		tc := setup(t)
		mr := metricRequestWithQueries(t, `{
			"refId": "A",
			"datasource": {
				"uid": "gIEkMvIVz",
				"type": "postgres"
			}
		}`, `{
			"refId": "B",
			"datasource": {
				"uid": "sEx6ZvSVk",
				"type": "testdata"
			}
		}`)
		httpreq, err := http.NewRequest(http.MethodPost, "http://localhost/", bytes.NewReader([]byte{}))
		require.NoError(t, err)

		reqCtx := &contextmodel.ReqContext{
			Context: &web.Context{},
		}
		ctx := ctxkey.Set(context.Background(), reqCtx)

		*httpreq = *httpreq.WithContext(ctx)
		reqCtx.Req = httpreq

		httpreq.Header.Add("X-Datasource-Uid", "gIEkMvIVz")
		_, err = tc.queryService.parseMetricRequest(httpreq.Context(), tc.signedInUser, true, mr)
		require.NoError(t, err)

		// With the second value it is OK
		httpreq.Header.Add("X-Datasource-Uid", "sEx6ZvSVk")
		_, err = tc.queryService.parseMetricRequest(httpreq.Context(), tc.signedInUser, true, mr)
		require.NoError(t, err)

		// Single header with comma syntax
		httpreq, _ = http.NewRequest(http.MethodPost, "http://localhost/", bytes.NewReader([]byte{}))
		httpreq.Header.Set("X-Datasource-Uid", "gIEkMvIVz, sEx6ZvSVk")
		_, err = tc.queryService.parseMetricRequest(httpreq.Context(), tc.signedInUser, true, mr)
		require.NoError(t, err)
	})

	t.Run("Test a duplicated refId", func(t *testing.T) {
		tc := setup(t)
		mr := metricRequestWithQueries(t, `{
			"refId": "A",
			"datasource": {
				"uid": "gIEkMvIVz",
				"type": "postgres"
			}
		}`, `{
			"refId": "A",
			"datasource": {
				"uid": "gIEkMvIVz",
				"type": "postgres"
			}
		}`)
		_, err := tc.queryService.parseMetricRequest(context.Background(), tc.signedInUser, true, mr)
		require.Error(t, err)
	})
}

func TestQueryDataMultipleSources(t *testing.T) {
	t.Run("can query multiple datasources", func(t *testing.T) {
		tc := setup(t)
		query1, err := simplejson.NewJson([]byte(`
			{
				"datasource": {
					"type": "mysql",
					"uid": "ds1"
				},
				"refId": "A"
			}
		`))
		require.NoError(t, err)
		query2, err := simplejson.NewJson([]byte(`
			{
				"datasource": {
					"type": "mysql",
					"uid": "ds2"
				},
				"refId": "B"
			}
		`))
		require.NoError(t, err)
		queries := []*simplejson.Json{query1, query2}
		reqDTO := dtos.MetricRequest{
			From:    "2022-01-01",
			To:      "2022-01-02",
			Queries: queries,
			Debug:   false,
		}

		req, err := http.NewRequest("POST", "http://localhost:3000", nil)
		require.NoError(t, err)
		reqCtx := &contextmodel.ReqContext{
			SkipQueryCache: false,
			Context: &web.Context{
				Resp: web.NewResponseWriter(http.MethodGet, httptest.NewRecorder()),
				Req:  req,
			},
		}
		ctx := ctxkey.Set(context.Background(), reqCtx)

		_, err = tc.queryService.QueryData(ctx, tc.signedInUser, true, reqDTO)
		require.NoError(t, err)

		// response headers should be merged
		header := contexthandler.FromContext(ctx).Resp.Header()
		assert.Len(t, header.Values("test"), 2)
	})

	t.Run("can query multiple datasources with an expression present", func(t *testing.T) {
		tc := setup(t)
		query1, err := simplejson.NewJson([]byte(`
			{
				"datasource": {
					"type": "mysql",
					"uid": "ds1"
				},
				"refId": "A"
			}
		`))
		require.NoError(t, err)
		query2, err := simplejson.NewJson([]byte(`
			{
				"datasource": {
					"type": "mysql",
					"uid": "ds2"
				},
				"refId": "B"
			}
		`))
		require.NoError(t, err)
		query3, err := simplejson.NewJson([]byte(`
			{
				"datasource": {
					"name": "Expression",
					"type": "__expr__",
					"uid": "__expr__"
				},
				"expression": "$A + 1",
				"hide": false,
				"refId": "EXPRESSION",
				"type": "math"
			}
		`))
		require.NoError(t, err)
		queries := []*simplejson.Json{query1, query2, query3}
		reqDTO := dtos.MetricRequest{
			From:    "2022-01-01",
			To:      "2022-01-02",
			Queries: queries,
			Debug:   false,
		}

		// without query parameter
		_, err = tc.queryService.QueryData(context.Background(), tc.signedInUser, true, reqDTO)
		require.NoError(t, err)

		httpreq, err := http.NewRequest(http.MethodPost, "http://localhost/ds/query?expression=true", bytes.NewReader([]byte{}))
		require.NoError(t, err)

		reqCtx := &contextmodel.ReqContext{
			Context: &web.Context{},
		}
		ctx := ctxkey.Set(context.Background(), reqCtx)

		*httpreq = *httpreq.WithContext(ctx)
		reqCtx.Req = httpreq

		httpreq.Header.Add("X-Datasource-Uid", "gIEkMvIVz")

		// with query parameter
		_, err = tc.queryService.QueryData(httpreq.Context(), tc.signedInUser, true, reqDTO)
		require.NoError(t, err)
	})

	t.Run("error is returned in query when one of the queries fails", func(t *testing.T) {
		tc := setup(t)

		query1, _ := simplejson.NewJson([]byte(`
			{
				"datasource": {
					"type": "mysql",
					"uid": "ds1"
				},
				"refId": "A"
			}
		`))
		query2, _ := simplejson.NewJson([]byte(`
			{
				"datasource": {
					"type": "prometheus",
					"uid": "ds2"
				},
				"refId": "B",
				"queryType": "FAIL"
			}
		`))

		queries := []*simplejson.Json{query1, query2}

		reqDTO := dtos.MetricRequest{
			From:    "2022-01-01",
			To:      "2022-01-02",
			Queries: queries,
			Debug:   false,
		}

		res, err := tc.queryService.QueryData(context.Background(), tc.signedInUser, true, reqDTO)

		require.NoError(t, err)
		require.Error(t, res.Responses["B"].Error)
		// Responses aren't mocked, so a "healthy" query will just return an empty response
		require.NotContains(t, res.Responses, "A")
	})

	t.Run("ignores a deprecated datasourceID", func(t *testing.T) {
		tc := setup(t)
		query1, err := simplejson.NewJson([]byte(`
			{
				"datasource": {
					"type": "mysql",
					"uid": "ds1"
				},
				"datasourceId": 1,
				"refId": "A"
			}
		`))
		require.NoError(t, err)
		queries := []*simplejson.Json{query1}
		reqDTO := dtos.MetricRequest{
			From:    "2022-01-01",
			To:      "2022-01-02",
			Queries: queries,
			Debug:   false,
		}

		_, err = tc.queryService.QueryData(context.Background(), tc.signedInUser, true, reqDTO)

		require.NoError(t, err)
	})
}

func setup(t *testing.T) *testContext {
	dss := []*datasources.DataSource{
		{UID: "gIEkMvIVz", Type: "postgres"},
		{UID: "sEx6ZvSVk", Type: "testdata"},
		{UID: "ds1", Type: "mysql"},
		{UID: "ds2", Type: "mysql"},
	}

	t.Helper()
	pc := &fakePluginClient{}
	dc := &fakeDataSourceCache{cache: dss}
	rv := &fakePluginRequestValidator{}

	sqlStore := db.InitTestDB(t)
	secretsService := secretsmng.SetupTestService(t, fakes.NewFakeSecretsStore())
	ss := secretskvs.NewSQLSecretsKVStore(sqlStore, secretsService, log.New("test.logger"))
	fakeDatasourceService := &fakeDatasources.FakeDataSourceService{
		DataSources:           dss,
		SimulatePluginFailure: false,
	}

	pCtxProvider := plugincontext.ProvideService(
		localcache.ProvideService(), &pluginFakes.FakePluginStore{
			PluginList: []plugins.PluginDTO{
				{JSONData: plugins.JSONData{ID: "postgres"}},
				{JSONData: plugins.JSONData{ID: "testdata"}},
				{JSONData: plugins.JSONData{ID: "mysql"}},
			},
		}, fakeDatasourceService,
		pluginSettings.ProvideService(sqlStore, secretsService),
	)
	exprService := expr.ProvideService(&setting.Cfg{ExpressionsEnabled: true}, pc, pCtxProvider,
		&featuremgmt.FeatureManager{}, nil, tracing.InitializeTracerForTest())
	queryService := ProvideService(setting.NewCfg(), dc, exprService, rv, pc, pCtxProvider) // provider belonging to this package
	return &testContext{
		pluginContext:          pc,
		secretStore:            ss,
		pluginRequestValidator: rv,
		queryService:           queryService,
		signedInUser:           &user.SignedInUser{OrgID: 1, Login: "login", Name: "name", Email: "email", OrgRole: roletype.RoleAdmin},
	}
}

type testContext struct {
	pluginContext          *fakePluginClient
	secretStore            secretskvs.SecretsKVStore
	pluginRequestValidator *fakePluginRequestValidator
	queryService           *ServiceImpl // implementation belonging to this package
	signedInUser           *user.SignedInUser
}

func metricRequestWithQueries(t *testing.T, rawQueries ...string) dtos.MetricRequest {
	t.Helper()
	queries := make([]*simplejson.Json, 0)
	for _, q := range rawQueries {
		json, err := simplejson.NewJson([]byte(q))
		require.NoError(t, err)
		queries = append(queries, json)
	}
	return dtos.MetricRequest{
		From:    "now-1h",
		To:      "now",
		Queries: queries,
		Debug:   false,
	}
}

type fakePluginRequestValidator struct {
	err error
}

func (rv *fakePluginRequestValidator) Validate(dsURL string, req *http.Request) error {
	return rv.err
}

type fakeDataSourceCache struct {
	cache []*datasources.DataSource
}

func (c *fakeDataSourceCache) GetDatasource(ctx context.Context, datasourceID int64, user *user.SignedInUser, skipCache bool) (*datasources.DataSource, error) {
	// deprecated: fake an error to ensure we are using GetDatasourceByUID
	return nil, fmt.Errorf("not found")
}

func (c *fakeDataSourceCache) GetDatasourceByUID(ctx context.Context, datasourceUID string, user *user.SignedInUser, skipCache bool) (*datasources.DataSource, error) {
	for _, ds := range c.cache {
		if ds.UID == datasourceUID {
			return ds, nil
		}
	}

	return nil, fmt.Errorf("not found")
}

type fakePluginClient struct {
	plugins.Client
	req *backend.QueryDataRequest
	mu  sync.Mutex
}

func (c *fakePluginClient) QueryData(ctx context.Context, req *backend.QueryDataRequest) (*backend.QueryDataResponse, error) {
	c.mu.Lock()
	defer c.mu.Unlock()

	c.req = req

	// If an expression query ends up getting directly queried, we want it to return an error in our test.
	if req.PluginContext.PluginID == expr.DatasourceUID {
		return nil, errors.New("cant query an expression datasource")
	}

	if req.Queries[0].QueryType == "FAIL" {
		return nil, errors.New("plugin client failed")
	}

	if reqCtx := contexthandler.FromContext(ctx); reqCtx != nil && reqCtx.Resp != nil {
		reqCtx.Resp.Header().Add("test", fmt.Sprintf("header-%d", time.Now().Nanosecond()))
	}

	return &backend.QueryDataResponse{Responses: make(backend.Responses)}, nil
}