/*
Copyright 2016 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 fission_cli

import (
	"context"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"os"
	"regexp"
	"strings"

	"github.com/dchest/uniuri"
	"github.com/urfave/cli"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"

	fv1 "github.com/fission/fission/pkg/apis/fission.io/v1"
	"github.com/fission/fission/pkg/fission-cli/log"
	"github.com/fission/fission/pkg/fission-cli/util"
	v1 "github.com/fission/fission/pkg/v1"
)

type (
	V1FissionState struct {
		Functions    []v1.Function            `json:"functions"`
		Environments []v1.Environment         `json:"environments"`
		HTTPTriggers []v1.HTTPTrigger         `json:"httptriggers"`
		Mqtriggers   []v1.MessageQueueTrigger `json:"mqtriggers"`
		TimeTriggers []v1.TimeTrigger         `json:"timetriggers"`
		Watches      []v1.Watch               `json:"watches"`
		NameChanges  map[string]string        `json:"namechanges"`
	}
	nameRemapper struct {
		oldToNew map[string]string
		newNames map[string]bool
	}
)

func getV1URL(serverUrl string) string {
	if len(serverUrl) == 0 {
		log.Fatal("Need --server or FISSION_URL set to your fission server.")
	}
	isHTTPS := strings.Index(serverUrl, "https://") == 0
	isHTTP := strings.Index(serverUrl, "http://") == 0
	if !(isHTTP || isHTTPS) {
		serverUrl = "http://" + serverUrl
	}
	v1url := strings.TrimSuffix(serverUrl, "/") + "/v1"
	return v1url
}

func get(url string) []byte {
	resp, err := http.Get(url)
	util.CheckErr(err, "get fission v0.1 state")
	defer resp.Body.Close()

	body, err := ioutil.ReadAll(resp.Body)
	util.CheckErr(err, "reading server response")

	if resp.StatusCode != 200 {
		log.Fatal(fmt.Sprintf("Failed to fetch fission v0.1 state: %v", string(body)))
	}
	return body
}

// track a name in the remapper, creating a new name if needed
func (nr *nameRemapper) trackName(old string) {
	// all kubernetes names must match this regex
	kubeNameRegex := "^[a-z0-9]([-a-z0-9]*[a-z0-9])?$"
	maxLen := 63

	ok, err := regexp.MatchString(kubeNameRegex, old)
	util.CheckErr(err, "match name regexp")
	if ok && len(old) < maxLen {
		// no rename
		nr.oldToNew[old] = old
		nr.newNames[old] = true
		return
	}

	newName := strings.ToLower(old)

	// remove disallowed
	inv, err := regexp.Compile("[^-a-z0-9]")
	util.CheckErr(err, "compile regexp")
	newName = string(inv.ReplaceAll([]byte(newName), []byte("-")))

	// trim leading non-alphabetic
	leadingnonalpha, err := regexp.Compile("^[^a-z]+")
	util.CheckErr(err, "compile regexp")
	newName = string(leadingnonalpha.ReplaceAll([]byte(newName), []byte{}))

	// trim trailing
	trailing, err := regexp.Compile("[^a-z0-9]+$")
	util.CheckErr(err, "compile regexp")
	newName = string(trailing.ReplaceAll([]byte(newName), []byte{}))

	// truncate to length
	if len(newName) > maxLen-4 {
		newName = newName[0:(maxLen - 4)]
	}

	// uniqueness
	n := newName
	i := 0
	for {
		_, exists := nr.newNames[n]
		if !exists {
			break
		} else {
			i++
			n = fmt.Sprintf("%v-%v", newName, i)
		}
	}
	newName = n

	// track
	nr.oldToNew[old] = newName
	nr.newNames[newName] = true
}

func upgradeDumpV1State(v1url string, filename string) {
	var v1state V1FissionState

	fmt.Println("Getting environments")
	resp := get(v1url + "/environments")
	err := json.Unmarshal(resp, &v1state.Environments)
	util.CheckErr(err, "parse server response")

	fmt.Println("Getting watches")
	resp = get(v1url + "/watches")
	err = json.Unmarshal(resp, &v1state.Watches)
	util.CheckErr(err, "parse server response")

	fmt.Println("Getting routes")
	resp = get(v1url + "/triggers/http")
	err = json.Unmarshal(resp, &v1state.HTTPTriggers)
	util.CheckErr(err, "parse server response")

	fmt.Println("Getting message queue triggers")
	resp = get(v1url + "/triggers/messagequeue")
	err = json.Unmarshal(resp, &v1state.Mqtriggers)
	util.CheckErr(err, "parse server response")

	fmt.Println("Getting time triggers")
	resp = get(v1url + "/triggers/time")
	err = json.Unmarshal(resp, &v1state.TimeTriggers)
	util.CheckErr(err, "parse server response")

	fmt.Println("Getting function list")
	resp = get(v1url + "/functions")
	err = json.Unmarshal(resp, &v1state.Functions)
	util.CheckErr(err, "parse server response")

	// we have to change names that are disallowed in kubernetes
	nr := nameRemapper{
		oldToNew: make(map[string]string),
		newNames: make(map[string]bool),
	}

	// get all referenced function metadata
	funcMetaSet := make(map[v1.Metadata]bool)
	for _, f := range v1state.Functions {
		funcMetaSet[f.Metadata] = true
		nr.trackName(f.Metadata.Name)
	}
	for _, t := range v1state.HTTPTriggers {
		funcMetaSet[t.Function] = true
		nr.trackName(t.Metadata.Name)
	}
	for _, t := range v1state.Mqtriggers {
		funcMetaSet[t.Function] = true
		nr.trackName(t.Metadata.Name)
	}
	for _, t := range v1state.Watches {
		funcMetaSet[t.Function] = true
		nr.trackName(t.Metadata.Name)
	}
	for _, t := range v1state.TimeTriggers {
		funcMetaSet[t.Function] = true
		nr.trackName(t.Metadata.Name)
	}

	for _, e := range v1state.Environments {
		nr.trackName(e.Metadata.Name)
	}

	fmt.Println("Getting functions")
	// get each function
	funcs := make(map[v1.Metadata]v1.Function)
	for m := range funcMetaSet {
		if len(m.Uid) != 0 {
			resp = get(fmt.Sprintf("%v/functions/%v?uid=%v", v1url, m.Name, m.Uid))
		} else {
			resp = get(fmt.Sprintf("%v/functions/%v", v1url, m.Name))
		}

		var f v1.Function

		// unmarshal
		err = json.Unmarshal(resp, &f)
		util.CheckErr(err, "parse server response")

		// load into a map to remove duplicates
		funcs[f.Metadata] = f
	}

	// add list of unique functions to v1state from map
	v1state.Functions = make([]v1.Function, 0)
	for _, f := range funcs {
		v1state.Functions = append(v1state.Functions, f)
	}

	// dump name changes
	v1state.NameChanges = nr.oldToNew

	// serialize v1state
	out, err := json.MarshalIndent(v1state, "", "    ")
	util.CheckErr(err, "serialize v0.1 state")

	// dump to file fission-v01-state.json
	if len(filename) == 0 {
		filename = "fission-v01-state.json"
	}
	err = ioutil.WriteFile(filename, out, 0644)
	util.CheckErr(err, "write file")

	fmt.Printf("Done: Saved %v functions, %v HTTP triggers, %v watches, %v message queue triggers, %v time triggers.\n",
		len(v1state.Functions), len(v1state.HTTPTriggers), len(v1state.Watches), len(v1state.Mqtriggers), len(v1state.TimeTriggers))
}

func functionRefFromV1Metadata(m *v1.Metadata, nameRemap map[string]string) *fv1.FunctionReference {
	return &fv1.FunctionReference{
		Type: fv1.FunctionReferenceTypeFunctionName,
		Name: nameRemap[m.Name],
	}
}

func crdMetadataFromV1Metadata(m *v1.Metadata, nameRemap map[string]string) *metav1.ObjectMeta {
	return &metav1.ObjectMeta{
		Name:      nameRemap[m.Name],
		Namespace: metav1.NamespaceDefault,
	}
}

func upgradeDumpState(c *cli.Context) error {
	u := getV1URL(c.GlobalString("server"))
	filename := c.String("file")

	// check v1
	resp, err := http.Get(u + "/environments")
	util.CheckErr(err, "reach fission server")
	if resp.StatusCode == http.StatusNotFound {
		msg := fmt.Sprintf("Server %v isn't a v1 Fission server. Use --server to point at a pre-0.2.x Fission server.", u)
		log.Fatal(msg)
	}

	upgradeDumpV1State(u, filename)
	return nil
}

func upgradeRestoreState(c *cli.Context) error {
	filename := c.String("file")
	if len(filename) == 0 {
		filename = "fission-v01-state.json"
	}

	contents, err := ioutil.ReadFile(filename)
	util.CheckErr(err, fmt.Sprintf("open file %v", filename))

	var v1state V1FissionState
	err = json.Unmarshal(contents, &v1state)
	util.CheckErr(err, "parse dumped v1 state")

	// create a regular v2 client
	client := util.GetApiClient(c.GlobalString("server"))

	// create functions
	for _, f := range v1state.Functions {

		// get post-rename function name, derive pkg name from it
		fnName := v1state.NameChanges[f.Metadata.Name]
		pkgName := fmt.Sprintf("%v-%v", fnName, strings.ToLower(uniuri.NewLen(6)))

		// write function to file
		tmpfile, err := ioutil.TempFile("", pkgName)
		util.CheckErr(err, "create temporary file")
		code, err := base64.StdEncoding.DecodeString(f.Code)
		util.CheckErr(err, "decode base64 function contents")
		tmpfile.Write(code)
		tmpfile.Sync()
		tmpfile.Close()

		// upload
		ctx := context.Background()
		archive := uploadArchive(ctx, client, tmpfile.Name())
		os.Remove(tmpfile.Name())

		// create pkg
		pkgSpec := fv1.PackageSpec{
			Environment: fv1.EnvironmentReference{
				Name:      v1state.NameChanges[f.Environment.Name],
				Namespace: metav1.NamespaceDefault,
			},
			Deployment: *archive,
		}
		pkg, err := client.PackageCreate(&fv1.Package{
			Metadata: metav1.ObjectMeta{
				Name:      pkgName,
				Namespace: metav1.NamespaceDefault,
			},
			Spec: pkgSpec,
		})
		util.CheckErr(err, fmt.Sprintf("create package %v", pkgName))
		_, err = client.FunctionCreate(&fv1.Function{
			Metadata: *crdMetadataFromV1Metadata(&f.Metadata, v1state.NameChanges),
			Spec: fv1.FunctionSpec{
				Environment: pkgSpec.Environment,
				Package: fv1.FunctionPackageRef{
					PackageRef: fv1.PackageRef{
						Name:            pkg.Name,
						Namespace:       pkg.Namespace,
						ResourceVersion: pkg.ResourceVersion,
					},
				},
			},
		})
		util.CheckErr(err, fmt.Sprintf("create function %v", v1state.NameChanges[f.Metadata.Name]))

	}

	// create envs
	for _, e := range v1state.Environments {
		_, err = client.EnvironmentCreate(&fv1.Environment{
			Metadata: *crdMetadataFromV1Metadata(&e.Metadata, v1state.NameChanges),
			Spec: fv1.EnvironmentSpec{
				Version: 1,
				Runtime: fv1.Runtime{
					Image: e.RunContainerImageUrl,
				},
			},
		})
		util.CheckErr(err, fmt.Sprintf("create environment %v", e.Metadata.Name))
	}

	// create httptriggers
	for _, t := range v1state.HTTPTriggers {
		_, err = client.HTTPTriggerCreate(&fv1.HTTPTrigger{
			Metadata: *crdMetadataFromV1Metadata(&t.Metadata, v1state.NameChanges),
			Spec: fv1.HTTPTriggerSpec{
				RelativeURL:       t.UrlPattern,
				Method:            t.Method,
				FunctionReference: *functionRefFromV1Metadata(&t.Function, v1state.NameChanges),
			},
		})
		util.CheckErr(err, fmt.Sprintf("create http trigger %v", t.Metadata.Name))
	}

	// create mqtriggers
	for _, t := range v1state.Mqtriggers {
		_, err = client.MessageQueueTriggerCreate(&fv1.MessageQueueTrigger{
			Metadata: *crdMetadataFromV1Metadata(&t.Metadata, v1state.NameChanges),
			Spec: fv1.MessageQueueTriggerSpec{
				FunctionReference: *functionRefFromV1Metadata(&t.Function, v1state.NameChanges),
				MessageQueueType:  fv1.MessageQueueTypeNats, // only NATS is supported at that time (v1 types)
				Topic:             t.Topic,
				ResponseTopic:     t.ResponseTopic,
			},
		})
		util.CheckErr(err, fmt.Sprintf("create http trigger %v", t.Metadata.Name))
	}

	// create time triggers
	for _, t := range v1state.TimeTriggers {
		_, err = client.TimeTriggerCreate(&fv1.TimeTrigger{
			Metadata: *crdMetadataFromV1Metadata(&t.Metadata, v1state.NameChanges),
			Spec: fv1.TimeTriggerSpec{
				FunctionReference: *functionRefFromV1Metadata(&t.Function, v1state.NameChanges),
				Cron:              t.Cron,
			},
		})
		util.CheckErr(err, fmt.Sprintf("create time trigger %v", t.Metadata.Name))
	}

	// create watches
	for _, t := range v1state.Watches {
		_, err = client.WatchCreate(&fv1.KubernetesWatchTrigger{
			Metadata: *crdMetadataFromV1Metadata(&t.Metadata, v1state.NameChanges),
			Spec: fv1.KubernetesWatchTriggerSpec{
				Namespace:         t.Namespace,
				Type:              t.ObjType,
				FunctionReference: *functionRefFromV1Metadata(&t.Function, v1state.NameChanges),
			},
		})
		util.CheckErr(err, fmt.Sprintf("create kubernetes watch trigger %v", t.Metadata.Name))
	}

	return nil
}