/*
Copyright 2015 The Kubernetes Authors All rights reserved.

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 main

import (
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"net"
	"net/http"
	"net/url"
	"os"
	"strings"

	"github.com/ghodss/yaml"
	"github.com/gorilla/mux"
	"github.com/kubernetes/helm/cmd/manager/manager"
	"github.com/kubernetes/helm/cmd/manager/repository"
	"github.com/kubernetes/helm/cmd/manager/repository/persistent"
	"github.com/kubernetes/helm/cmd/manager/repository/transient"
	"github.com/kubernetes/helm/cmd/manager/router"
	"github.com/kubernetes/helm/pkg/common"
	"github.com/kubernetes/helm/pkg/httputil"
	"github.com/kubernetes/helm/pkg/repo"
	"github.com/kubernetes/helm/pkg/util"
)

// Deprecated. Use Context.Manager instead.
var backend manager.Manager

// Route defines a routing table entry to be registered with gorilla/mux.
//
// Route is deprecated. Use router.Routes instead.
type Route struct {
	Name        string
	Path        string
	Methods     string
	HandlerFunc http.HandlerFunc
	Type        string
}

func registerDeploymentRoutes(c *router.Context, h *router.Handler) {
	h.Add("GET /healthz", healthz)
	h.Add("GET /deployments", listDeploymentsHandlerFunc)
	h.Add("GET /deployments/*", getDeploymentHandlerFunc)
	h.Add("POST /deployments", createDeploymentHandlerFunc)
	h.Add("DELETE /deployments/*", deleteDeploymentHandlerFunc)
	h.Add("PUT /deployments/*", putDeploymentHandlerFunc)
	h.Add("GET /deployments/*/manifests", listManifestsHandlerFunc)
	h.Add("GET /deployments/*/manifests/*", getManifestHandlerFunc)
	h.Add("POST /expand", expandHandlerFunc)
	h.Add("GET /charts", listChartsHandlerFunc)
	h.Add("GET /charts/*/instances", listChartInstancesHandlerFunc)
	h.Add("GET /charts/*/repository", getRepoForChartHandlerFunc)
	h.Add("GET /charts/*/metadata", getMetadataForChartHandlerFunc)
	h.Add("GET /charts/*", getChartHandlerFunc)
	h.Add("POST /credentials/*", createCredentialHandlerFunc)
	h.Add("GET /credentials/*", getCredentialHandlerFunc)
}

func healthz(w http.ResponseWriter, r *http.Request, c *router.Context) error {
	log.Println("manager: healthz checkpoint")
	// TODO: This should check the availability of the repository, and fail if it
	// cannot connect.
	fmt.Fprintln(w, "OK")
	return nil
}

func setupDependencies(c *router.Context) error {
	var credentialProvider repo.ICredentialProvider
	if c.Config.CredentialFile != "" {
		if c.Config.CredentialSecrets {
			return errors.New("Both credentialFile and credentialSecrets are set")
		}
		var err error
		credentialProvider, err = repo.NewFilebasedCredentialProvider(c.Config.CredentialFile)
		if err != nil {
			return fmt.Errorf("cannot create credential provider %s: %s", c.Config.CredentialFile, err)
		}
	} else if *credentialSecrets {
		credentialProvider = repo.NewSecretsCredentialProvider()
	} else {
		credentialProvider = repo.NewInmemCredentialProvider()
	}
	c.CredentialProvider = credentialProvider
	c.Manager = newManager(c)

	return nil
}

const expanderPort = "8080"
const deployerPort = "8080"

func newManager(c *router.Context) manager.Manager {
	cfg := c.Config
	service := repo.NewInmemRepoService()
	cp := c.CredentialProvider
	rp := repo.NewRepoProvider(service, repo.NewGCSRepoProvider(cp), cp)
	expander := manager.NewExpander(getServiceURL(cfg.ExpanderURL, cfg.ExpanderName, expanderPort), rp)
	deployer := manager.NewDeployer(getServiceURL(cfg.DeployerURL, cfg.DeployerName, deployerPort))
	address := strings.TrimPrefix(getServiceURL(cfg.MongoAddress, cfg.MongoName, cfg.MongoPort), "http://")
	repository := createRepository(address)
	return manager.NewManager(expander, deployer, repository, rp, service, c.CredentialProvider)
}

func createRepository(address string) repository.Repository {
	r, err := persistent.NewRepository(address)
	if err != nil {
		r = transient.NewRepository()
	}

	return r
}

func getServiceURL(serviceURL, serviceName, servicePort string) string {
	if serviceURL == "" {
		serviceURL = makeEnvVariableURL(serviceName)
		if serviceURL == "" {
			addrs, err := net.LookupHost(serviceName)
			if err != nil || len(addrs) < 1 {
				log.Fatalf("cannot resolve service:%v. environment:%v\n", serviceName, os.Environ())
			}

			serviceURL = fmt.Sprintf("http://%s:%s", addrs[0], servicePort)
		}
	}

	return serviceURL
}

// makeEnvVariableURL takes a service name and returns the value of the
// environment variable that identifies its URL, if it exists, or the empty
// string, if it doesn't.
func makeEnvVariableURL(str string) string {
	prefix := makeEnvVariableName(str)
	url := os.Getenv(prefix + "_PORT")
	return strings.Replace(url, "tcp", "http", 1)
}

// makeEnvVariableName is copied from the Kubernetes source,
// which is referenced by the documentation for service environment variables.
func makeEnvVariableName(str string) string {
	// TODO: If we simplify to "all names are DNS1123Subdomains" this
	// will need two tweaks:
	//   1) Handle leading digits
	//   2) Handle dots
	return strings.ToUpper(strings.Replace(str, "-", "_", -1))
}

func listDeploymentsHandlerFunc(w http.ResponseWriter, r *http.Request, c *router.Context) error {
	handler := "manager: list deployments"
	util.LogHandlerEntry(handler, r)
	l, err := c.Manager.ListDeployments()
	if err != nil {
		util.LogAndReturnError(handler, http.StatusInternalServerError, err, w)
		return nil
	}
	var names []string
	for _, d := range l {
		names = append(names, d.Name)
	}

	util.LogHandlerExitWithJSON(handler, w, names, http.StatusOK)
	return nil
}

func getDeploymentHandlerFunc(w http.ResponseWriter, r *http.Request, c *router.Context) error {
	handler := "manager: get deployment"
	util.LogHandlerEntry(handler, r)
	name, err := pos(w, r, 2)
	if err != nil {
		return nil
	}

	d, err := c.Manager.GetDeployment(name)
	if err != nil {
		util.LogAndReturnError(handler, http.StatusBadRequest, err, w)
		return nil
	}

	util.LogHandlerExitWithJSON(handler, w, d, http.StatusOK)
	return nil
}

func createDeploymentHandlerFunc(w http.ResponseWriter, r *http.Request, c *router.Context) error {
	handler := "manager: create deployment"
	util.LogHandlerEntry(handler, r)
	defer r.Body.Close()
	depReq := getDeploymentRequest(w, r, handler)
	if depReq != nil {
		d, err := c.Manager.CreateDeployment(depReq)
		if err != nil {
			httputil.BadRequest(w, r, err)
			return nil
		}

		util.LogHandlerExitWithJSON(handler, w, d, http.StatusCreated)
	}

	return nil
}

func deleteDeploymentHandlerFunc(w http.ResponseWriter, r *http.Request, c *router.Context) error {
	handler := "manager: delete deployment"
	util.LogHandlerEntry(handler, r)
	defer r.Body.Close()
	name, err := pos(w, r, 2)
	if err != nil {
		return err
	}

	d, err := c.Manager.DeleteDeployment(name, true)
	if err != nil {
		return err
	}

	util.LogHandlerExitWithJSON(handler, w, d, http.StatusOK)
	return nil
}

func putDeploymentHandlerFunc(w http.ResponseWriter, r *http.Request, c *router.Context) error {
	handler := "manager: update deployment"
	util.LogHandlerEntry(handler, r)
	defer r.Body.Close()
	name, err := pos(w, r, 2)
	if err != nil {
		return err
	}

	depReq := getDeploymentRequest(w, r, handler)
	if depReq != nil {
		d, err := c.Manager.PutDeployment(name, depReq)
		if err != nil {
			httputil.BadRequest(w, r, err)
			return nil
		}

		util.LogHandlerExitWithJSON(handler, w, d, http.StatusCreated)
	}

	return nil
}

// pos gets a path item by position.
//
// For example. the path "/foo/bar" has three positions: "" at 0, "foo" at
// 1, and "bar" at 2.
//
// For verb/path combos, position 0 will be the verb: "GET /foo/bar" will have
// "GET " at position 0.
func pos(w http.ResponseWriter, r *http.Request, i int) (string, error) {
	parts := strings.Split(r.URL.Path, "/")
	if len(parts) < i-1 {
		return "", fmt.Errorf("No index for %d", i)
	}
	return parts[i], nil
}

func getPathVariable(w http.ResponseWriter, r *http.Request, variable, handler string) (string, error) {
	vars := mux.Vars(r)
	escaped, ok := vars[variable]
	if !ok {
		e := fmt.Errorf("%s name not found in URL", variable)
		util.LogAndReturnError(handler, http.StatusBadRequest, e, w)
		return "", e
	}

	unescaped, err := url.QueryUnescape(escaped)
	if err != nil {
		e := fmt.Errorf("cannot decode name (%v)", variable)
		util.LogAndReturnError(handler, http.StatusBadRequest, e, w)
		return "", e
	}

	return unescaped, nil
}

func getDeploymentRequest(w http.ResponseWriter, r *http.Request, handler string) *common.DeploymentRequest {
	util.LogHandlerEntry(handler, r)
	depReq := &common.DeploymentRequest{}
	if err := httputil.Decode(w, r, depReq); err != nil {
		httputil.BadRequest(w, r, err)
		return nil
	}

	return depReq
}

func listManifestsHandlerFunc(w http.ResponseWriter, r *http.Request, c *router.Context) error {
	handler := "manager: list manifests"
	util.LogHandlerEntry(handler, r)
	deploymentName, err := pos(w, r, 2)
	if err != nil {
		return err
	}

	m, err := c.Manager.ListManifests(deploymentName)
	if err != nil {
		return err
	}

	var manifestNames []string
	for _, manifest := range m {
		manifestNames = append(manifestNames, manifest.Name)
	}

	util.LogHandlerExitWithJSON(handler, w, manifestNames, http.StatusOK)
	return nil
}

func getManifestHandlerFunc(w http.ResponseWriter, r *http.Request, c *router.Context) error {
	handler := "manager: get manifest"
	util.LogHandlerEntry(handler, r)
	deploymentName, err := pos(w, r, 2)
	if err != nil {
		return err
	}

	manifestName, err := pos(w, r, 4)
	if err != nil {
		return err
	}

	m, err := c.Manager.GetManifest(deploymentName, manifestName)
	if err != nil {
		httputil.BadRequest(w, r, err)
		return nil
	}

	util.LogHandlerExitWithJSON(handler, w, m, http.StatusOK)
	return nil
}

func expandHandlerFunc(w http.ResponseWriter, r *http.Request, c *router.Context) error {
	handler := "manager: expand config"
	util.LogHandlerEntry(handler, r)
	defer r.Body.Close()
	depReq := getDeploymentRequest(w, r, handler)
	if depReq != nil {
		c, err := c.Manager.Expand(depReq)
		if err != nil {
			httputil.BadRequest(w, r, err)
			return nil
		}

		util.LogHandlerExitWithJSON(handler, w, c, http.StatusCreated)
	}

	return nil
}

// Putting Type handlers here for now because deployments.go
// currently owns its own Manager backend and doesn't like to share.
func listChartsHandlerFunc(w http.ResponseWriter, r *http.Request, c *router.Context) error {
	handler := "manager: list charts"
	util.LogHandlerEntry(handler, r)
	types, err := c.Manager.ListCharts()
	if err != nil {
		httputil.BadRequest(w, r, err)
		return nil
	}

	util.LogHandlerExitWithJSON(handler, w, types, http.StatusOK)
	return nil
}

func listChartInstancesHandlerFunc(w http.ResponseWriter, r *http.Request, c *router.Context) error {
	handler := "manager: list chart instances"
	util.LogHandlerEntry(handler, r)
	chartName, err := pos(w, r, 2)
	if err != nil {
		return err
	}

	instances, err := c.Manager.ListChartInstances(chartName)
	if err != nil {
		httputil.BadRequest(w, r, err)
		return nil
	}

	util.LogHandlerExitWithJSON(handler, w, instances, http.StatusOK)
	return nil
}

func getRepoForChartHandlerFunc(w http.ResponseWriter, r *http.Request, c *router.Context) error {
	handler := "manager: get repository for chart"
	util.LogHandlerEntry(handler, r)
	chartName, err := pos(w, r, 2)
	if err != nil {
		return err
	}

	repository, err := c.Manager.GetRepoForChart(chartName)
	if err != nil {
		httputil.BadRequest(w, r, err)
		return nil
	}

	util.LogHandlerExitWithJSON(handler, w, repository, http.StatusOK)
	return nil
}

func getMetadataForChartHandlerFunc(w http.ResponseWriter, r *http.Request, c *router.Context) error {
	handler := "manager: get chart metadata"
	util.LogHandlerEntry(handler, r)
	chartName, err := pos(w, r, 2)
	if err != nil {
		return err
	}

	metadata, err := c.Manager.GetMetadataForChart(chartName)
	if err != nil {
		httputil.BadRequest(w, r, err)
		return nil
	}

	util.LogHandlerExitWithJSON(handler, w, metadata, http.StatusOK)
	return nil
}

func getChartHandlerFunc(w http.ResponseWriter, r *http.Request, c *router.Context) error {
	handler := "manager: get chart"
	util.LogHandlerEntry(handler, r)
	chartName, err := pos(w, r, 2)
	if err != nil {
		return err
	}

	ch, err := c.Manager.GetChart(chartName)
	if err != nil {
		httputil.BadRequest(w, r, err)
		return nil
	}

	util.LogHandlerExitWithJSON(handler, w, ch, http.StatusOK)
	return nil
}

func getCredential(w http.ResponseWriter, r *http.Request, handler string) *repo.Credential {
	util.LogHandlerEntry(handler, r)
	t := &repo.Credential{}
	if err := httputil.Decode(w, r, t); err != nil {
		httputil.BadRequest(w, r, err)
		return nil
	}
	return t
}

func createCredentialHandlerFunc(w http.ResponseWriter, r *http.Request, c *router.Context) error {
	handler := "manager: create credential"
	util.LogHandlerEntry(handler, r)
	defer r.Body.Close()
	credentialName, err := pos(w, r, 2)
	if err != nil {
		return err
	}

	cr := getCredential(w, r, handler)
	if cr != nil {
		err = c.Manager.CreateCredential(credentialName, cr)
		if err != nil {
			httputil.BadRequest(w, r, err)
			return nil
		}
	}

	util.LogHandlerExitWithJSON(handler, w, c, http.StatusOK)
	return nil
}

func getCredentialHandlerFunc(w http.ResponseWriter, r *http.Request, c *router.Context) error {
	handler := "manager: get credential"
	util.LogHandlerEntry(handler, r)
	credentialName, err := pos(w, r, 2)
	if err != nil {
		return err
	}

	cr, err := c.Manager.GetCredential(credentialName)
	if err != nil {
		httputil.BadRequest(w, r, err)
		return nil
	}

	util.LogHandlerExitWithJSON(handler, w, cr, http.StatusOK)
	return nil
}

func getJSONFromRequest(w http.ResponseWriter, r *http.Request, handler string) ([]byte, error) {
	util.LogHandlerEntry(handler, r)
	b := io.LimitReader(r.Body, *maxLength*1024)
	y, err := ioutil.ReadAll(b)
	if err != nil {
		util.LogAndReturnError(handler, http.StatusBadRequest, err, w)
		return []byte{}, err
	}

	// Reject the input if it exceeded the length limit,
	// since we may not have read all of it into the buffer.
	if _, err = b.Read(make([]byte, 0, 1)); err != io.EOF {
		e := fmt.Errorf("template exceeds maximum length of %d KB", *maxLength)
		util.LogAndReturnError(handler, http.StatusBadRequest, e, w)
		return []byte{}, err
	}

	if err := r.Body.Close(); err != nil {
		util.LogAndReturnError(handler, http.StatusInternalServerError, err, w)
		return []byte{}, err
	}

	return yaml.YAMLToJSON(y)
}