/*
Copyright 2019 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 spec

import (
	"bytes"
	"context"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"github.com/hashicorp/go-multierror"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime/schema"

	fv1 "github.com/fission/fission/pkg/apis/core/v1"
	"github.com/fission/fission/pkg/fission-cli/cliwrapper/cli"
	"github.com/fission/fission/pkg/fission-cli/cmd"
	"github.com/fission/fission/pkg/fission-cli/console"
	flagkey "github.com/fission/fission/pkg/fission-cli/flag/key"
	"github.com/fission/fission/pkg/fission-cli/util"
	"github.com/fission/fission/pkg/utils"
	"github.com/fission/fission/pkg/utils/gitrepo"
)

type ValidateSubCommand struct {
	cmd.CommandActioner
}

// Validate parses a set of specs and checks for references to
// resources that don't exist.
func Validate(input cli.Input) error {
	return (&ValidateSubCommand{}).do(input)
}

func (opts *ValidateSubCommand) do(input cli.Input) error {
	return opts.run(input, nil)
}

func validateForApply(input cli.Input, fr *FissionResources) error {

	return (&ValidateSubCommand{}).doValidateForApply(input, fr)
}
func (opts *ValidateSubCommand) doValidateForApply(input cli.Input, fr *FissionResources) error {
	return opts.run(input, fr)
}

func (opts *ValidateSubCommand) run(input cli.Input, fr *FissionResources) (err error) {

	// this will error on parse errors and on duplicates
	specDir := util.GetSpecDir(input)
	specIgnore := util.GetSpecIgnore(input)

	// If the call for validate is from apply spec we already have a parsed fission resource
	if fr == nil {
		fr, err = ReadSpecs(specDir, specIgnore, false)
		if err != nil {
			return fmt.Errorf("error reading specs: %w", err)
		}
	}

	console.Infof("DeployUID: %v", fr.DeploymentConfig.UID)
	console.Infof("Resources:\n * %v Functions\n * %v Environments\n * %v Packages \n * %v Http Triggers \n * %v MessageQueue Triggers\n * %v Time Triggers\n * %v Kube Watchers\n * %v ArchiveUploadSpec\n",
		len(fr.Functions), len(fr.Environments), len(fr.Packages), len(fr.HttpTriggers), len(fr.MessageQueueTriggers), len(fr.TimeTriggers), len(fr.KubernetesWatchTriggers), len(fr.ArchiveUploadSpecs))

	var warnings []string
	// this does the rest of the checks, like dangling refs
	warnings, err = fr.Validate(input, opts.Client())
	if err != nil {
		return fmt.Errorf("error validating specs: %w", err)
	}

	err = resourceConflictCheck(input.Context(), opts.Client(), fr, input.Bool(flagkey.SpecAllowConflicts), "")
	if err != nil {
		return fmt.Errorf("name conflict error: %w", err)
	}

	for _, warning := range warnings {
		console.Warn(warning)
	}

	console.Info("Validation Successful")

	return nil
}

// resourceConflictCheck checks if any of the spec resources with
// the same name is already present in the same cluster namespace.
// If a same name resource exists in the same namespace, a name
// conflict error will be returned.
func resourceConflictCheck(ctx context.Context, c cmd.Client, fr *FissionResources, specAllowConflicts bool, namespace string) error {
	deployUID := fr.DeploymentConfig.UID
	result := utils.MultiErrorWithFormat()

	fnList, err := getAllFunctions(ctx, c, namespace)
	if err != nil {
		return fmt.Errorf("unable to get Functions %v", err.Error())
	}
	for _, sObj := range fr.Functions {
		for _, cObj := range fnList {
			if err := isResourceConflicts(deployUID, &sObj, &cObj, specAllowConflicts); err != nil {
				result = multierror.Append(result, err)
				break
			}
		}
	}

	envList, err := getAllEnvironments(ctx, c, namespace)
	if err != nil {
		return fmt.Errorf("unable to get Environments %v", err.Error())
	}
	for _, sObj := range fr.Environments {
		for _, cObj := range envList {
			if err := isResourceConflicts(deployUID, &sObj, &cObj, specAllowConflicts); err != nil {
				result = multierror.Append(result, err)
				break
			}
		}
	}

	pkgList, err := getAllPackages(ctx, c, namespace)
	if err != nil {
		return fmt.Errorf("unable to get Packages %v", err.Error())
	}
	for _, sObj := range fr.Packages {
		for _, cObj := range pkgList {
			if err := isResourceConflicts(deployUID, &sObj, &cObj, specAllowConflicts); err != nil {
				result = multierror.Append(result, err)
				break
			}
		}
	}

	httptriggerList, err := getAllHTTPTriggers(ctx, c, namespace)
	if err != nil {
		return fmt.Errorf("unable to get HTTPTrigger %v", err.Error())
	}
	for _, sObj := range fr.HttpTriggers {
		for _, cObj := range httptriggerList {
			if err := isResourceConflicts(deployUID, &sObj, &cObj, specAllowConflicts); err != nil {
				result = multierror.Append(result, err)
				break
			}
		}
	}

	mqtriggerList, err := getAllMessageQueueTriggers(ctx, c, "", namespace)
	if err != nil {
		return fmt.Errorf("unable to get Message Queue Trigger %v", err.Error())
	}
	for _, sObj := range fr.MessageQueueTriggers {
		for _, cObj := range mqtriggerList {
			if err := isResourceConflicts(deployUID, &sObj, &cObj, specAllowConflicts); err != nil {
				result = multierror.Append(result, err)
				break
			}
		}
	}

	timetriggerList, err := getAllTimeTriggers(ctx, c, namespace)
	if err != nil {
		return fmt.Errorf("unable to get Time Trigger %v", err.Error())
	}
	for _, sObj := range fr.TimeTriggers {
		for _, cObj := range timetriggerList {
			if err := isResourceConflicts(deployUID, &sObj, &cObj, specAllowConflicts); err != nil {
				result = multierror.Append(result, err)
				break
			}
		}
	}

	kubewatchtriggerList, err := getAllKubeWatchTriggers(ctx, c, namespace)
	if err != nil {
		return fmt.Errorf("unable to get Kubernetes Watch Trigger %v", err.Error())
	}
	for _, sObj := range fr.KubernetesWatchTriggers {
		for _, cObj := range kubewatchtriggerList {
			if err := isResourceConflicts(deployUID, &sObj, &cObj, specAllowConflicts); err != nil {
				result = multierror.Append(result, err)
				break
			}
		}
	}

	return result.ErrorOrNil()
}

type objectWithKind interface {
	schema.ObjectKind
	metav1.Object
}

func isResourceConflicts(deployUID string, specObj objectWithKind, clusterObj objectWithKind, specAllowConflicts bool) error {
	if specObj.GetName() == clusterObj.GetName() &&
		specObj.GetNamespace() == clusterObj.GetNamespace() &&
		deployUID != clusterObj.GetAnnotations()[FISSION_DEPLOYMENT_UID_KEY] {
		if specAllowConflicts {
			return nil
		}
		return fmt.Errorf("%s: '%s/%s' with different deploy uid already exists",
			clusterObj.GroupVersionKind().Kind, clusterObj.GetName(), clusterObj.GetNamespace())
	}
	return nil
}

// ReadSpecs reads all specs in the specified directory and returns a parsed set of
// fission resources.
func ReadSpecs(specDir, specIgnore string, applyCommitLabel bool) (*FissionResources, error) {

	// make sure spec directory exists before continue
	if _, err := os.Stat(specDir); os.IsNotExist(err) {
		return nil, fmt.Errorf("spec directory %v doesn't exist. "+
			"Please check directory path or run \"fission spec init\" to create it", specDir)
	}

	ignoreParser, err := util.GetSpecIgnoreParser(specDir, specIgnore)
	if err != nil {
		return nil, err
	}

	fr := FissionResources{
		Packages:                make([]fv1.Package, 0),
		Functions:               make([]fv1.Function, 0),
		Environments:            make([]fv1.Environment, 0),
		HttpTriggers:            make([]fv1.HTTPTrigger, 0),
		KubernetesWatchTriggers: make([]fv1.KubernetesWatchTrigger, 0),
		TimeTriggers:            make([]fv1.TimeTrigger, 0),
		MessageQueueTriggers:    make([]fv1.MessageQueueTrigger, 0),

		SourceMap: SourceMap{
			Locations: make(map[string](map[string](map[string]Location))),
		},
	}

	// get absolute path of specdir
	if !filepath.IsAbs(specDir) {
		cwd, err := filepath.Abs("./")
		if err != nil {
			return nil, err
		}
		specDir = filepath.Join(cwd, specDir)
	}

	var gr *gitrepo.GitRepo
	// check if applyCommitLabel flag is true
	if applyCommitLabel {
		gr = gitrepo.NewGitRepo(specDir)
	}

	var result *multierror.Error

	// Users can organize the specdir into subdirs if they want to.
	err = filepath.Walk(specDir, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}

		// For now just read YAML files. We'll add jsonnet at some point. Skip
		// unsupported files.
		if !(strings.HasSuffix(path, ".yaml") || strings.HasSuffix(path, ".yml")) {
			return nil
		}

		// check if file matches any path in .specignore file
		if ignoreParser.MatchesPath(path) {
			return nil
		}

		var fileCommitLabelVal string
		// check if applyCommitLabel is true and specdir is tracked by git repo
		if applyCommitLabel {
			fileCommitLabelVal, _ = gr.GetFileCommitLabel(path)
		}

		// read
		b, err := os.ReadFile(path)
		if err != nil {
			result = multierror.Append(result, err)
			return nil
		}

		// handle the case where there are multiple YAML docs per file. go-yaml
		// doesn't support this directly, yet.
		docs := bytes.Split(b, []byte("\n---"))
		lines := 1
		for _, doc := range docs {
			d := []byte(strings.TrimSpace(string(doc)))
			if len(d) != 0 {
				// parse this document and add whatever is in it to fr
				err = fr.ParseYaml(d, &Location{
					Path: path,
					Line: lines,
				}, fileCommitLabelVal)
				if err != nil {
					// collect all errors so user can fix them all
					result = multierror.Append(result, err)
				}
			}
			// the separator occupies one line, hence the +1
			lines += strings.Count(string(doc), "\n") + 1
		}
		return nil
	})

	if err != nil {
		return nil, err
	}
	if err = result.ErrorOrNil(); err != nil {
		return nil, err
	}

	return &fr, nil
}