/*
 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

     https://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 ctl

import (
	"bytes"
	"encoding/base64"
	"encoding/json"
	"errors"
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"

	"github.com/google/uuid"
	"opendev.org/airship/airshipctl/pkg/config"
	"opendev.org/airship/airshipctl/pkg/document"
	"opendev.org/airship/airshipctl/pkg/document/pull"
	"opendev.org/airship/airshipctl/pkg/phase"
	"opendev.org/airship/airshipctl/pkg/phase/ifc"
	"opendev.org/airship/airshipui/pkg/configs"
)

var (
	fileIndex map[string]string
	docIndex  map[string]document.Document
)

// HandleDocumentRequest will flop between requests so we don't have to have them all mapped as function calls
func HandleDocumentRequest(user *string, request configs.WsMessage) configs.WsMessage {
	response := configs.WsMessage{
		Type:         configs.CTL,
		Component:    configs.Document,
		SubComponent: request.SubComponent,
	}

	var err error
	var message *string
	var id string

	client, err := NewClient(AirshipConfigPath, KubeConfigPath, request)
	if err != nil {
		e := err.Error()
		response.Error = &e
		return response
	}

	switch request.SubComponent {
	case configs.Pull:
		message, err = client.docPull()
	case configs.Plugin:
		err = fmt.Errorf("Subcomponent %s not implemented", request.SubComponent)
	case configs.YamlWrite:
		id = request.ID
		response.Name, response.YAML, err = client.writeYamlFile(id, request.YAML)
		s := fmt.Sprintf("File '%s' saved successfully", response.Name)
		message = &s
	case configs.GetYaml:
		id = request.ID
		message = request.Message
		response.Name, response.YAML, err = client.getYaml(id, *message)
	case configs.GetPhaseTree:
		response.Data, err = client.GetPhaseTree()
	case configs.GetPhase:
		id = request.ID
		s := "rendered"
		message = &s
		response.Name, response.Details, response.YAML, err = client.GetPhase(id)
	case configs.GetDocumentsBySelector:
		id = request.ID
		response.Data, err = GetDocumentsBySelector(request.ID, *request.Message)
	case configs.GetTarget:
		message = client.getTarget()
	case configs.GetExecutorDoc:
		id = request.ID
		s := "rendered"
		message = &s
		response.Name, response.YAML, err = client.GetExecutorDoc(id)
	default:
		err = fmt.Errorf("Subcomponent %s not found", request.SubComponent)
	}

	if err != nil {
		e := err.Error()
		response.Error = &e
	} else {
		response.Message = message
		response.ID = id
	}

	return response
}

// GetExecutorDoc returns the title and YAML of the executor document for the specified phase
func (c *Client) GetExecutorDoc(id string) (string, string, error) {
	helper, err := getHelper()
	if err != nil {
		return "", "", err
	}

	phaseID := ifc.ID{}

	err = json.Unmarshal([]byte(id), &phaseID)
	if err != nil {
		return "", "", err
	}

	ed, err := helper.ExecutorDoc(phaseID)
	if err != nil {
		return "", "", err
	}

	title := ed.GetName()
	bytes, err := ed.AsYAML()
	if err != nil {
		return "", "", err
	}

	return title, base64.StdEncoding.EncodeToString(bytes), nil
}

func (c *Client) getTarget() *string {
	var s string
	m, err := c.Config.CurrentContextManifest()
	if err != nil {
		s = "unknown"
		return &s
	}

	s = filepath.Join(m.TargetPath, m.SubPath)
	return &s
}

func (c *Client) getPhaseDetails(id ifc.ID) (string, error) {
	helper, err := getHelper()
	if err != nil {
		return "", err
	}

	pClient := phase.NewClient(helper)

	phaseIfc, err := pClient.PhaseByID(id)
	if err != nil {
		return "", err
	}

	return phaseIfc.Details()
}

func (c *Client) getYaml(id, message string) (string, string, error) {
	switch message {
	case "source":
		name, yaml, err := c.getFileYaml(id)
		return name, yaml, err
	case "rendered":
		name, yaml, err := c.getDocumentYaml(id)
		return name, yaml, err
	default:
		return "", "", fmt.Errorf("'%s' unrecognized document type", message)
	}
}

func (c *Client) getDocumentYaml(id string) (string, string, error) {
	doc, ok := docIndex[id]
	if !ok {
		return "", "", fmt.Errorf("document with ID '%s' not found", id)
	}
	title := doc.GetName()
	bytes, err := doc.AsYAML()
	if err != nil {
		return "", "", err
	}

	return title, base64.StdEncoding.EncodeToString(bytes), nil
}

func (c *Client) getFileYaml(id string) (string, string, error) {
	path, ok := fileIndex[id]
	if !ok {
		return "", "", fmt.Errorf("file with ID '%s' not found", id)
	}

	ccm, err := c.Config.CurrentContextManifest()
	if err != nil {
		return "", "", err
	}

	// this is making the assumption that the site definition
	// will always found at: targetPath/subPath
	sitePath := filepath.Join(ccm.TargetPath, ccm.SubPath)

	// TODO(mfuller): will this be true in treasuremap or
	// other external repos?
	manifestsDir := filepath.Join(sitePath, "..", "..")

	title, err := filepath.Rel(manifestsDir, path)
	if err != nil {
		return "", "", err
	}

	file, err := os.Open(path)
	if err != nil {
		return "", "", err
	}

	defer file.Close()

	bytes, err := ioutil.ReadAll(file)
	if err != nil {
		return "", "", err
	}

	return title, base64.StdEncoding.EncodeToString(bytes), nil
}

func (c *Client) writeYamlFile(id, yaml64 string) (string, string, error) {
	path, ok := fileIndex[id]
	if !ok {
		return "", "", fmt.Errorf("ID %s not found", id)
	}

	yaml, err := base64.StdEncoding.DecodeString(yaml64)
	if err != nil {
		return "", "", err
	}

	err = ioutil.WriteFile(path, yaml, 0600)
	if err != nil {
		return "", "", err
	}

	return c.getFileYaml(id)
}

func getPhaseBundle(id ifc.ID) (document.Bundle, error) {
	helper, err := getHelper()
	if err != nil {
		return nil, err
	}

	pClient := phase.NewClient(helper)

	phaseIfc, err := pClient.PhaseByID(id)
	if err != nil {
		return nil, err
	}

	docRoot, err := phaseIfc.DocumentRoot()
	if err != nil {
		// if phase has no doc entrypoint defined, just
		// return nothing; otherwise, return the error
		if errors.As(err, &phase.ErrDocumentEntrypointNotDefined{}) {
			return nil, nil
		}
		return nil, err
	}

	b, err := document.NewBundleByPath(docRoot)
	if err != nil {
		return nil, err
	}
	return b, nil
}

// GetPhase returns the name, description, and doc bundle for specified phase
func (c *Client) GetPhase(id string) (string, string, string, error) {
	phaseID := ifc.ID{}

	err := json.Unmarshal([]byte(id), &phaseID)
	if err != nil {
		return "", "", "", err
	}

	title := phaseID.Name

	details, err := c.getPhaseDetails(phaseID)
	if err != nil {
		return "", "", "", err
	}

	bundle, err := getPhaseBundle(phaseID)
	if err != nil {
		return "", "", "", err
	}

	// only return title if phase has no bundle
	if bundle == nil {
		return title, details, "", nil
	}

	var buf bytes.Buffer
	err = bundle.Write(&buf)
	if err != nil {
		return "", "", "", err
	}

	return title, details, base64.StdEncoding.EncodeToString(buf.Bytes()), nil
}

func (c *Client) docPull() (*string, error) {
	var message *string
	cfgFactory := config.CreateFactory(AirshipConfigPath, KubeConfigPath)
	// 2nd arg is noCheckout, I assume we want to checkout the repo,
	// so setting to false
	err := pull.Pull(cfgFactory, false)
	if err == nil {
		s := fmt.Sprintf("Success")
		message = &s
	}

	return message, err
}

// SelectorParams structure to hold data for constructing a document Selector
type SelectorParams struct {
	Name       string `json:"name,omitempty"`
	Namespace  string `json:"namespace,omitempty"`
	GVK        GVK    `json:"gvk,omitempty"`
	Kind       string `json:"kind,omitempty"`
	Label      string `json:"label,omitempty"`
	Annotation string `json:"annotation,omitempty"`
}

// GVK small structure to hold group, version, kind for building a Selector
type GVK struct {
	Group   string `json:"group"`
	Version string `json:"version"`
	Kind    string `json:"kind"`
}

// GetDocumentsBySelector returns a slice of KustomNodes representing all phase
// documents returned by applying the provided Selector
func GetDocumentsBySelector(id string, data string) ([]KustomNode, error) {
	docIndex = map[string]document.Document{}

	selector, err := getSelector(data)
	if err != nil {
		return nil, err
	}

	phaseID := ifc.ID{}
	err = json.Unmarshal([]byte(id), &phaseID)
	if err != nil {
		return nil, err
	}

	helper, err := getHelper()
	if err != nil {
		return nil, err
	}

	pClient := phase.NewClient(helper)

	phaseIfc, err := pClient.PhaseByID(phaseID)
	if err != nil {
		return nil, err
	}

	docRoot, err := phaseIfc.DocumentRoot()
	if err != nil {
		return nil, err
	}

	bundle, err := document.NewBundleByPath(docRoot)
	if err != nil {
		return nil, err
	}

	docs, err := bundle.Select(selector)
	if err != nil {
		return nil, err
	}

	results := []KustomNode{}

	for _, doc := range docs {
		// this is a workaround for a kustomize issue where cluster-scoped objects
		// are included in matching results when a namespace selector is specified
		// (https://github.com/kubernetes-sigs/kustomize/issues/2248)
		if selector.Namespace != "" && selector.Namespace != doc.GetNamespace() {
			continue
		}

		id := uuid.New().String()
		docIndex[id] = doc

		name := doc.GetNamespace()
		if name == "" {
			name = "[none]"
		}

		results = append(results, KustomNode{
			ID: id,
			Name: fmt.Sprintf("%s/%s/%s",
				name,
				doc.GetKind(),
				doc.GetName(),
			)},
		)
	}

	return results, nil
}

func getSelector(data string) (document.Selector, error) {
	params := SelectorParams{}
	err := json.Unmarshal([]byte(data), &params)
	if err != nil {
		return document.Selector{}, err
	}

	s := document.NewSelector()

	// build selector based on what we were given
	if params.Name != "" {
		s = s.ByName(params.Name)
	}
	if params.Namespace != "" {
		s = s.ByNamespace(params.Namespace)
	}
	if (GVK{}) != params.GVK {
		s = s.ByGvk(
			params.GVK.Group,
			params.GVK.Version,
			params.GVK.Kind,
		)
	}
	if params.Kind != "" {
		s = s.ByKind(params.Kind)
	}
	if params.Label != "" {
		s = s.ByLabel(params.Label)
	}
	if params.Annotation != "" {
		s = s.ByAnnotation(params.Annotation)
	}
	return s, nil
}