package handler

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"github.com/fastenhealth/fasten-onprem/backend/pkg"
	"github.com/fastenhealth/fasten-onprem/backend/pkg/database"
	"github.com/fastenhealth/fasten-onprem/backend/pkg/event_bus"
	"github.com/fastenhealth/fasten-onprem/backend/pkg/jwk"
	"github.com/fastenhealth/fasten-onprem/backend/pkg/models"
	"github.com/fastenhealth/fasten-sources/clients/factory"
	sourceModels "github.com/fastenhealth/fasten-sources/clients/models"
	sourcePkg "github.com/fastenhealth/fasten-sources/pkg"
	"github.com/gin-gonic/gin"
	"github.com/sirupsen/logrus"
	"io"
	"io/ioutil"
	"net/http"
)

func CreateSource(c *gin.Context) {
	logger := c.MustGet(pkg.ContextKeyTypeLogger).(*logrus.Entry)
	databaseRepo := c.MustGet(pkg.ContextKeyTypeDatabase).(database.DatabaseRepository)

	sourceCred := models.SourceCredential{}
	if err := c.ShouldBindJSON(&sourceCred); err != nil {
		logger.Errorln("An error occurred while parsing posted source credential", err)
		c.JSON(http.StatusBadRequest, gin.H{"success": false})
		return
	}

	logger.Infof("Parsed Create SourceCredential Credentials Payload: %v", sourceCred)

	if sourceCred.DynamicClientRegistrationMode == "user-authenticated" {
		logger.Warnf("This client requires a dynamice client registration, starting registration process")

		if len(sourceCred.RegistrationEndpoint) == 0 {
			logger.Errorln("Empty registration endpoint, cannot be used with dynamic-client registration mode:", sourceCred.DynamicClientRegistrationMode)
			c.JSON(http.StatusBadRequest, gin.H{"success": false})
			return
		}
		//this source requires dynamic client registration
		// see https://fhir.epic.com/Documentation?docId=Oauth2&section=Standalone-Oauth2-OfflineAccess-0

		// Generate a public-private key pair
		// Must be 2048 bits (larger keys will silently fail when used with Epic, untested on other providers)
		sourceSpecificClientKeyPair, err := jwk.JWKGenerate()
		if err != nil {
			logger.Errorln("An error occurred while generating device-specific keypair for dynamic client", err)
			c.JSON(http.StatusBadRequest, gin.H{"success": false})
			return
		}
		//store in sourceCredential
		serializedKeypair, err := jwk.JWKSerialize(sourceSpecificClientKeyPair)
		if err != nil {
			logger.Errorln("An error occurred while serializing keypair for dynamic client", err)
			c.JSON(http.StatusBadRequest, gin.H{"success": false})
			return
		}
		sourceCred.DynamicClientJWKS = []map[string]string{
			serializedKeypair,
		}

		//generate dynamic client registration request
		payload := models.ClientRegistrationRequest{
			SoftwareId: sourceCred.ClientId,
			Jwks: models.ClientRegistrationRequestJwks{
				Keys: []models.ClientRegistrationRequestJwksKey{
					{
						KeyType:        "RSA",
						KeyId:          serializedKeypair["kid"],
						Modulus:        serializedKeypair["n"],
						PublicExponent: serializedKeypair["e"],
					},
				},
			},
		}
		payloadBytes, err := json.Marshal(payload)
		if err != nil {
			logger.Errorln("An error occurred while marshalling dynamic client registration request", err)
			c.JSON(http.StatusBadRequest, gin.H{"success": false})
			return
		}

		//http.Post("https://fhir.epic.com/interconnect-fhir-oauth/oauth2/token", "application/x-www-form-urlencoded", bytes.NewBuffer([]byte(fmt.Sprintf("grant_type=client_credentials&client_assertion_type=urn:ietf:params:oauth:client-assertion-type:jwt-bearer&client_assertion=%s&scope=system/Patient.read", sourceSpecificClientKeyPair))))
		req, err := http.NewRequest(http.MethodPost, sourceCred.RegistrationEndpoint, bytes.NewBuffer(payloadBytes))
		if err != nil {
			logger.Errorln("An error occurred while generating dynamic client registration request", err)
			c.JSON(http.StatusBadRequest, gin.H{"success": false})
			return
		}
		req.Header.Set("Content-Type", "application/json")
		req.Header.Set("Accept", "application/json")
		req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", sourceCred.AccessToken))

		registrationResponse, err := http.DefaultClient.Do(req)

		if err != nil {
			logger.Errorln("An error occurred while sending dynamic client registration request", err)
			c.JSON(http.StatusBadRequest, gin.H{"success": false})
			return
		}
		defer registrationResponse.Body.Close()
		if registrationResponse.StatusCode >= 300 || registrationResponse.StatusCode < 200 {
			logger.Errorln("An error occurred while reading dynamic client registration response, status code was not 200", registrationResponse.StatusCode)
			b, err := io.ReadAll(registrationResponse.Body)
			if err == nil {
				logger.Printf("Error Response body: %s", string(b))
			}

			c.JSON(http.StatusBadRequest, gin.H{"success": false})
			return
		}

		//read response
		var registrationResponseBytes models.ClientRegistrationResponse
		err = json.NewDecoder(registrationResponse.Body).Decode(&registrationResponseBytes)
		if err != nil {
			logger.Errorln("An error occurred while parsing dynamic client registration response", err)
			c.JSON(http.StatusBadRequest, gin.H{"success": false})
			return
		}

		//store the dynamic client id
		sourceCred.DynamicClientId = registrationResponseBytes.ClientId

		//generate a JWT token and then use it to get an access token for the dynamic client
		err = sourceCred.RefreshDynamicClientAccessToken()
		if err != nil {
			logger.Errorln("An error occurred while retrieving access token for dynamic client", err)
			c.JSON(http.StatusBadRequest, gin.H{"success": false})
			return
		}
	}

	err := databaseRepo.CreateSource(c, &sourceCred)
	if err != nil {
		logger.Errorln("An error occurred while storing source credential", err)
		c.JSON(http.StatusInternalServerError, gin.H{"success": false})
		return
	}

	// after creating the source, we should do a bulk import (in the background)

	summary, err := SyncSourceResources(GetBackgroundContext(c), logger, databaseRepo, &sourceCred)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"success": false})
		return
	}

	c.JSON(http.StatusOK, gin.H{"success": true, "source": sourceCred, "data": summary})
}

func SourceSync(c *gin.Context) {
	logger := c.MustGet(pkg.ContextKeyTypeLogger).(*logrus.Entry)
	databaseRepo := c.MustGet(pkg.ContextKeyTypeDatabase).(database.DatabaseRepository)
	eventBus := c.MustGet(pkg.ContextKeyTypeEventBusServer).(event_bus.Interface)

	logger.Infof("Get SourceCredential Credentials: %v", c.Param("sourceId"))

	sourceCred, err := databaseRepo.GetSource(c, c.Param("sourceId"))
	if err != nil {
		logger.Errorln("An error occurred while retrieving source credential", err)
		c.JSON(http.StatusInternalServerError, gin.H{"success": false})
		return
	}

	// after creating the source, we should do a bulk import (in the background)
	summary, err := SyncSourceResources(GetBackgroundContext(c), logger, databaseRepo, sourceCred)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"success": false})
		return
	}

	//publish event
	currentUser, _ := databaseRepo.GetCurrentUser(c)
	err = eventBus.PublishMessage(
		models.NewEventSourceComplete(
			currentUser.ID.String(),
			sourceCred.ID.String(),
		),
	)
	if err != nil {
		logger.Warnf("ignoring: an error occurred while publishing sync complete event: %v", err)
	}

	c.JSON(http.StatusOK, gin.H{"success": true, "source": sourceCred, "data": summary})
}

func CreateManualSource(c *gin.Context) {
	logger := c.MustGet(pkg.ContextKeyTypeLogger).(*logrus.Entry)
	databaseRepo := c.MustGet(pkg.ContextKeyTypeDatabase).(database.DatabaseRepository)
	eventBus := c.MustGet(pkg.ContextKeyTypeEventBusServer).(event_bus.Interface)

	// single file
	file, err := c.FormFile("file")
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"success": false, "error": "could not extract file from form"})
		return
	}
	fmt.Printf("Uploaded filename: %s", file.Filename)

	// create a temporary file to store this uploaded file
	bundleFile, err := ioutil.TempFile("", file.Filename)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"success": false, "error": "could not create temp file"})
		return
	}

	// Upload the file to specific bundleFile.
	err = c.SaveUploadedFile(file, bundleFile.Name())
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"success": false, "error": "could not save temp file"})
		return
	}

	// We cannot save the "SourceCredential" object yet, as we do not know the patientID

	// create a "manual" client, which we can use to parse the
	manualSourceCredential := models.SourceCredential{
		SourceType: sourcePkg.SourceTypeManual,
	}
	tempSourceClient, err := factory.GetSourceClient(sourcePkg.GetFastenLighthouseEnv(), sourcePkg.SourceTypeManual, c, logger, &manualSourceCredential)
	if err != nil {
		logger.Errorln("An error occurred while initializing hub client using manual source without credentials", err)
		c.JSON(http.StatusInternalServerError, gin.H{"success": false})
		return
	}

	patientId, bundleType, err := tempSourceClient.ExtractPatientId(bundleFile)
	if err != nil {
		logger.Errorln("An error occurred while extracting patient id", err)
		c.JSON(http.StatusInternalServerError, gin.H{"success": false, "error": err.Error()})
		return
	}
	manualSourceCredential.Patient = patientId

	//store the manualSourceCredential
	err = databaseRepo.CreateSource(c, &manualSourceCredential)
	if err != nil {
		logger.Errorln("An error occurred while creating manual source", err)
		c.JSON(http.StatusInternalServerError, gin.H{"success": false, "error": err.Error()})
		return
	}

	manualSourceClient, err := factory.GetSourceClient(sourcePkg.GetFastenLighthouseEnv(), sourcePkg.SourceTypeManual, c, logger, &manualSourceCredential)
	if err != nil {
		logger.Errorln("An error occurred while initializing hub client using manual source with credential", err)
		c.JSON(http.StatusInternalServerError, gin.H{"success": false})
		return
	}

	summary, err := manualSourceClient.SyncAllBundle(databaseRepo, bundleFile, bundleType)
	if err != nil {
		logger.Errorln("An error occurred while processing bundle", err)
		c.JSON(http.StatusInternalServerError, gin.H{"success": false, "error": err.Error()})
		return
	}

	//publish event
	currentUser, _ := databaseRepo.GetCurrentUser(c)

	err = eventBus.PublishMessage(
		models.NewEventSourceComplete(
			currentUser.ID.String(),
			manualSourceCredential.ID.String(),
		),
	)
	if err != nil {
		logger.Warnf("ignoring: an error occurred while publishing sync complete event: %v", err)
	}

	c.JSON(http.StatusOK, gin.H{"success": true, "data": summary, "source": manualSourceCredential})

}

func GetSource(c *gin.Context) {
	logger := c.MustGet(pkg.ContextKeyTypeLogger).(*logrus.Entry)
	databaseRepo := c.MustGet(pkg.ContextKeyTypeDatabase).(database.DatabaseRepository)

	sourceCred, err := databaseRepo.GetSource(c, c.Param("sourceId"))
	if err != nil {
		logger.Errorln("An error occurred while retrieving source credential", err)
		c.JSON(http.StatusInternalServerError, gin.H{"success": false})
		return
	}
	c.JSON(http.StatusOK, gin.H{"success": true, "data": sourceCred})
}

func GetSourceSummary(c *gin.Context) {
	logger := c.MustGet(pkg.ContextKeyTypeLogger).(*logrus.Entry)
	databaseRepo := c.MustGet(pkg.ContextKeyTypeDatabase).(database.DatabaseRepository)

	sourceSummary, err := databaseRepo.GetSourceSummary(c, c.Param("sourceId"))
	if err != nil {
		logger.Errorln("An error occurred while retrieving source summary", err)
		c.JSON(http.StatusInternalServerError, gin.H{"success": false})
		return
	}
	c.JSON(http.StatusOK, gin.H{"success": true, "data": sourceSummary})
}

func ListSource(c *gin.Context) {
	logger := c.MustGet(pkg.ContextKeyTypeLogger).(*logrus.Entry)
	databaseRepo := c.MustGet(pkg.ContextKeyTypeDatabase).(database.DatabaseRepository)

	sourceCreds, err := databaseRepo.GetSources(c)
	if err != nil {
		logger.Errorln("An error occurred while listing source credentials", err)
		c.JSON(http.StatusInternalServerError, gin.H{"success": false})
		return
	}
	c.JSON(http.StatusOK, gin.H{"success": true, "data": sourceCreds})
}

func SyncSourceResources(c context.Context, logger *logrus.Entry, databaseRepo database.DatabaseRepository, sourceCred *models.SourceCredential) (sourceModels.UpsertSummary, error) {
	// after creating the source, we should do a bulk import
	sourceClient, err := factory.GetSourceClient(sourcePkg.GetFastenLighthouseEnv(), sourceCred.SourceType, c, logger, sourceCred)
	if err != nil {
		logger.Errorln("An error occurred while initializing hub client using source credential", err)
		return sourceModels.UpsertSummary{}, err
	}

	summary, err := sourceClient.SyncAll(databaseRepo)
	if err != nil {
		logger.Errorln("An error occurred while bulk import of resources from source", err)
		return summary, err
	}

	//update source incase the access token/refresh token has been updated
	sourceCredential := sourceClient.GetSourceCredential()
	sourceCredentialConcrete, ok := sourceCredential.(*models.SourceCredential)
	if !ok {
		logger.Errorln("An error occurred while updating source credential, source credential is not of type *models.SourceCredential")
		return summary, fmt.Errorf("source credential is not of type *models.SourceCredential")
	}
	err = databaseRepo.UpdateSource(c, sourceCredentialConcrete)
	if err != nil {
		logger.Errorf("An error occurred while updating source credential: %v", err)
		return summary, err
	}

	return summary, nil
}

//

func GetBackgroundContext(ginContext *gin.Context) context.Context {
	//TODO: this should be a background context
	return context.WithValue(ginContext.Request.Context(), pkg.ContextKeyTypeAuthUsername, ginContext.Value(pkg.ContextKeyTypeAuthUsername).(string))
}