// Copyright (C) 2019 Storj Labs, Inc.
// See LICENSE for copying information.

package consoleweb

import (
	"context"
	"encoding/json"
	"net"
	"net/http"
	"path/filepath"
	"strconv"
	"strings"

	"github.com/graphql-go/graphql"
	"github.com/zeebo/errs"
	"go.uber.org/zap"
	"golang.org/x/sync/errgroup"

	"storj.io/storj/pkg/auth"
	"storj.io/storj/satellite/console"
	"storj.io/storj/satellite/console/consoleweb/consoleql"
	"storj.io/storj/satellite/mailservice"
)

const (
	authorization = "Authorization"
	contentType   = "Content-Type"

	authorizationBearer = "Bearer "

	applicationJSON    = "application/json"
	applicationGraphql = "application/graphql"
)

// Error is satellite console error type
var Error = errs.Class("satellite console error")

// Config contains configuration for console web server
type Config struct {
	Address         string `help:"server address of the graphql api gateway and frontend app" default:"127.0.0.1:8081"`
	StaticDir       string `help:"path to static resources" default:""`
	ExternalAddress string `help:"external endpoint of the satellite if hosted" default:""`

	// TODO: remove after Vanguard release
	AuthToken string `help:"auth token needed for access to registration token creation endpoint" default:""`

	PasswordCost int `internal:"true" help:"password hashing cost (0=automatic)" default:"0"`
}

// Server represents console web server
type Server struct {
	log *zap.Logger

	config      Config
	service     *console.Service
	mailService *mailservice.Service

	listener net.Listener
	server   http.Server

	schema graphql.Schema
}

// NewServer creates new instance of console server
func NewServer(logger *zap.Logger, config Config, service *console.Service, mailService *mailservice.Service, listener net.Listener) *Server {
	server := Server{
		log:         logger,
		config:      config,
		listener:    listener,
		service:     service,
		mailService: mailService,
	}

	logger.Debug("Starting Satellite UI...")

	if server.config.ExternalAddress != "" {
		if !strings.HasSuffix(server.config.ExternalAddress, "/") {
			server.config.ExternalAddress = server.config.ExternalAddress + "/"
		}
	} else {
		server.config.ExternalAddress = "http://" + server.listener.Addr().String() + "/"
	}

	mux := http.NewServeMux()
	fs := http.FileServer(http.Dir(server.config.StaticDir))

	mux.Handle("/api/graphql/v0", http.HandlerFunc(server.grapqlHandler))

	if server.config.StaticDir != "" {
		mux.Handle("/activation/", http.HandlerFunc(server.accountActivationHandler))
		mux.Handle("/registrationToken/", http.HandlerFunc(server.createRegistrationTokenHandler))
		mux.Handle("/static/", http.StripPrefix("/static", fs))
		mux.Handle("/", http.HandlerFunc(server.appHandler))
	}

	server.server = http.Server{
		Handler: mux,
	}

	return &server
}

// appHandler is web app http handler function
func (s *Server) appHandler(w http.ResponseWriter, req *http.Request) {
	http.ServeFile(w, req, filepath.Join(s.config.StaticDir, "dist", "public", "index.html"))
}

// accountActivationHandler is web app http handler function
func (s *Server) createRegistrationTokenHandler(w http.ResponseWriter, req *http.Request) {
	w.Header().Set(contentType, applicationJSON)

	var response struct {
		Secret string `json:"secret"`
		Error  string `json:"error,omitempty"`
	}

	defer func() {
		err := json.NewEncoder(w).Encode(&response)
		if err != nil {
			s.log.Error(err.Error())
		}
	}()

	authToken := req.Header.Get("Authorization")
	if authToken != s.config.AuthToken {
		w.WriteHeader(401)
		response.Error = "unauthorized"
		return
	}

	projectsLimitInput := req.URL.Query().Get("projectsLimit")

	projectsLimit, err := strconv.Atoi(projectsLimitInput)
	if err != nil {
		response.Error = err.Error()
		return
	}

	token, err := s.service.CreateRegToken(context.Background(), projectsLimit)
	if err != nil {
		response.Error = err.Error()
		return
	}

	response.Secret = token.Secret.String()
}

// accountActivationHandler is web app http handler function
func (s *Server) accountActivationHandler(w http.ResponseWriter, req *http.Request) {
	activationToken := req.URL.Query().Get("token")

	err := s.service.ActivateAccount(context.Background(), activationToken)
	if err != nil {
		s.log.Error("activation: failed to activate account",
			zap.String("token", activationToken),
			zap.Error(err))

		http.ServeFile(w, req, filepath.Join(s.config.StaticDir, "static", "errors", "404.html"))
		return
	}

	http.ServeFile(w, req, filepath.Join(s.config.StaticDir, "static", "activation", "success.html"))
}

// grapqlHandler is graphql endpoint http handler function
func (s *Server) grapqlHandler(w http.ResponseWriter, req *http.Request) {
	w.Header().Set(contentType, applicationJSON)

	token := getToken(req)
	query, err := getQuery(req)
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	ctx := auth.WithAPIKey(context.Background(), []byte(token))
	auth, err := s.service.Authorize(ctx)
	if err != nil {
		ctx = console.WithAuthFailure(ctx, err)
	} else {
		ctx = console.WithAuth(ctx, auth)
	}

	rootObject := make(map[string]interface{})

	rootObject["origin"] = s.config.ExternalAddress
	rootObject[consoleql.ActivationPath] = "activation/?token="
	rootObject[consoleql.SignInPath] = "login"

	result := graphql.Do(graphql.Params{
		Schema:         s.schema,
		Context:        ctx,
		RequestString:  query.Query,
		VariableValues: query.Variables,
		OperationName:  query.OperationName,
		RootObject:     rootObject,
	})

	err = json.NewEncoder(w).Encode(result)
	if err != nil {
		s.log.Error(err.Error())
		return
	}

	sugar := s.log.Sugar()
	sugar.Debug(result)
}

// Run starts the server that host webapp and api endpoint
func (s *Server) Run(ctx context.Context) error {
	var err error

	s.schema, err = consoleql.CreateSchema(s.log, s.service, s.mailService)
	if err != nil {
		return Error.Wrap(err)
	}

	ctx, cancel := context.WithCancel(ctx)
	var group errgroup.Group
	group.Go(func() error {
		<-ctx.Done()
		return s.server.Shutdown(nil)
	})
	group.Go(func() error {
		defer cancel()
		return s.server.Serve(s.listener)
	})

	return group.Wait()
}

// Close closes server and underlying listener
func (s *Server) Close() error {
	return s.server.Close()
}