/*
Copyright 2017 The Fission 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 buildermgr

import (
	"fmt"
	"log"
	"net/http"
	"strings"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"

	"github.com/dchest/uniuri"
	"github.com/fission/fission"
	"github.com/fission/fission/builder"
	builderClient "github.com/fission/fission/builder/client"
	"github.com/fission/fission/crd"
	"github.com/fission/fission/environments/fetcher"
	fetcherClient "github.com/fission/fission/environments/fetcher/client"
)

// buildPackage helps to build source package into deployment package.
// Following is steps buildPackage takes to complete the build process.
// 1. Check package status
// 2. Update package status to running state
// 3. Send fetch request to fetcher to fetch source package.
// 4. Send build request to builder to start a build.
// 5. Send upload request to fetcher to upload deployment package.
// 6. Update package status to succeed state
// 7. Update package resource in package ref of functions that share the same package
// *. Update package status to failed state,if any one of steps above failed
func buildPackage(fissionClient *crd.FissionClient, builderNamespace string,
	storageSvcUrl string, pkg *crd.Package) (buildLogs string, err error) {

	// Only do build for pending packages
	if pkg.Status.BuildStatus != fission.BuildStatusPending {
		e := "package is not in pending state"
		log.Println(e)
		return e, fission.MakeError(http.StatusBadRequest, e)
	}

	// update package status to running state, so that
	// we can know what status a package is through cli.
	newPkgRV, err := updatePackage(fissionClient, pkg, fission.BuildStatusRunning, "", nil)

	// Kubernetes checks resource version before applying
	// new resource config. The update operation will be
	// rejected if the resource version in metadata is lower
	// than the latest version. Set resource version with
	// latest return from updatePackage.
	pkg.Metadata.ResourceVersion = newPkgRV
	if err != nil {
		e := fmt.Sprintf("Error setting package pending state: %v", err)
		log.Println(e)
		updatePackage(fissionClient, pkg, fission.BuildStatusFailed, e, nil)
		return e, fission.MakeError(http.StatusInternalServerError, e)
	}

	env, err := fissionClient.Environments(metav1.NamespaceDefault).Get(pkg.Spec.Environment.Name)
	if err != nil {
		e := fmt.Sprintf("Error getting environment CRD info: %v", err)
		log.Println(e)
		updatePackage(fissionClient, pkg, fission.BuildStatusFailed, e, nil)
		return e, fission.MakeError(http.StatusInternalServerError, e)
	}

	svcName := fmt.Sprintf("%v-%v.%v", env.Metadata.Name, env.Metadata.ResourceVersion, builderNamespace)
	srcPkgFilename := fmt.Sprintf("%v-%v", pkg.Metadata.Name, strings.ToLower(uniuri.NewLen(6)))
	fetcherC := fetcherClient.MakeClient(fmt.Sprintf("http://%v:8000", svcName))
	builderC := builderClient.MakeClient(fmt.Sprintf("http://%v:8001", svcName))

	fetchReq := &fetcher.FetchRequest{
		FetchType: fetcher.FETCH_SOURCE,
		Package:   pkg.Metadata,
		Filename:  srcPkgFilename,
	}

	// send fetch request to fetcher
	err = fetcherC.Fetch(fetchReq)
	if err != nil {
		e := fmt.Sprintf("Error fetching source package: %v", err)
		log.Println(e)
		updatePackage(fissionClient, pkg, fission.BuildStatusFailed, e, nil)
		return e, fission.MakeError(http.StatusInternalServerError, e)
	}

	buildCmd := pkg.Spec.BuildCommand
	if len(buildCmd) == 0 {
		buildCmd = env.Spec.Builder.Command
	}

	pkgBuildReq := &builder.PackageBuildRequest{
		SrcPkgFilename: srcPkgFilename,
		BuildCommand:   buildCmd,
	}

	log.Printf("Start building with source package: %v", srcPkgFilename)
	// send build request to builder
	buildResp, err := builderC.Build(pkgBuildReq)
	if err != nil {
		e := fmt.Sprintf("Error building deployment package: %v", err)
		log.Println(e)
		var buildLogs string
		if buildResp != nil {
			buildLogs = buildResp.BuildLogs
		}
		buildLogs += fmt.Sprintf("%v\n", e)
		updatePackage(fissionClient, pkg, fission.BuildStatusFailed, buildLogs, nil)
		return e, fission.MakeError(http.StatusInternalServerError, e)
	}

	log.Printf("Build succeed, source package: %v, deployment package: %v", srcPkgFilename, buildResp.ArtifactFilename)

	uploadReq := &fetcher.UploadRequest{
		Filename:      buildResp.ArtifactFilename,
		StorageSvcUrl: storageSvcUrl,
	}

	log.Printf("Start uploading deployment package: %v", buildResp.ArtifactFilename)
	// ask fetcher to upload the deployment package
	uploadResp, err := fetcherC.Upload(uploadReq)
	if err != nil {
		e := fmt.Sprintf("Error uploading deployment package: %v", err)
		log.Println(e)
		buildResp.BuildLogs += fmt.Sprintf("%v\n", e)
		updatePackage(fissionClient, pkg, fission.BuildStatusFailed, buildResp.BuildLogs, nil)
		return e, fission.MakeError(http.StatusInternalServerError, e)
	}

	log.Printf("Start updating info of package: %v", pkg.Metadata.Name)
	// update package status and also build logs
	newPkgRV, err = updatePackage(fissionClient, pkg,
		fission.BuildStatusSucceeded, buildResp.BuildLogs, uploadResp)
	pkg.Metadata.ResourceVersion = newPkgRV
	if err != nil {
		e := fmt.Sprintf("Error creating deployment package CRD resource: %v", err)
		log.Println(e)
		buildResp.BuildLogs += fmt.Sprintf("%v\n", e)
		updatePackage(fissionClient, pkg, fission.BuildStatusFailed, buildResp.BuildLogs, nil)
		return e, fission.MakeError(http.StatusInternalServerError, e)
	}

	fnList, err := fissionClient.
		Functions(metav1.NamespaceDefault).List(metav1.ListOptions{})
	if err != nil {
		e := fmt.Sprintf("Error getting function list: %v", err)
		log.Println(e)
		buildResp.BuildLogs += fmt.Sprintf("%v\n", e)
		updatePackage(fissionClient, pkg, fission.BuildStatusFailed, buildResp.BuildLogs, nil)
		return e, fission.MakeError(http.StatusInternalServerError, e)
	}

	// A package may be used by multiple functions. Update
	// functions with old package resource version
	for _, fn := range fnList.Items {
		if fn.Spec.Package.PackageRef.Name == pkg.Metadata.Name &&
			fn.Spec.Package.PackageRef.Namespace == pkg.Metadata.Namespace &&
			fn.Spec.Package.PackageRef.ResourceVersion != pkg.Metadata.ResourceVersion {
			fn.Spec.Package.PackageRef.ResourceVersion = newPkgRV
			// update CRD
			_, err = fissionClient.Functions(fn.Metadata.Namespace).Update(&fn)
			if err != nil {
				e := fmt.Sprintf("Error updating function package resource version: %v", err)
				log.Println(e)
				buildResp.BuildLogs += fmt.Sprintf("%v\n", e)
				updatePackage(fissionClient, pkg, fission.BuildStatusFailed, buildResp.BuildLogs, nil)
				return e, fission.MakeError(http.StatusInternalServerError, e)
			}
		}
	}

	log.Printf("Completed build request for package: %v", pkg.Metadata.Name)

	return buildResp.BuildLogs, nil
}

func updatePackage(fissionClient *crd.FissionClient,
	pkg *crd.Package, status fission.BuildStatus, buildLogs string,
	uploadResp *fetcher.UploadResponse) (string, error) {

	pkg.Status = fission.PackageStatus{
		BuildStatus: status,
		BuildLog:    buildLogs,
	}

	if uploadResp != nil {
		pkg.Spec.Deployment = fission.Archive{
			Type:     fission.ArchiveTypeUrl,
			URL:      uploadResp.ArchiveDownloadUrl,
			Checksum: uploadResp.Checksum,
		}
	}

	// update package spec
	pkg, err := fissionClient.Packages(metav1.NamespaceDefault).Update(pkg)
	if err != nil {
		log.Printf("Error updating package: %v", err)
		return "", err
	}

	// return resource version for function to update function package ref
	return pkg.Metadata.ResourceVersion, nil
}