package cmd

import (
	"errors"
	"fmt"
	"net/http"
	_ "net/http/pprof" // pprof handler
	"os"
	"os/signal"
	"strings"
	"sync"
	"syscall"
	"time"

	"github.com/evcc-io/evcc/core"
	"github.com/evcc-io/evcc/push"
	"github.com/evcc-io/evcc/server"
	"github.com/evcc-io/evcc/server/modbus"
	"github.com/evcc-io/evcc/server/updater"
	"github.com/evcc-io/evcc/util"
	"github.com/evcc-io/evcc/util/pipe"
	"github.com/evcc-io/evcc/util/sponsor"
	"github.com/evcc-io/evcc/util/telemetry"

	_ "github.com/joho/godotenv/autoload"
	"github.com/prometheus/client_golang/prometheus/promhttp"
	"github.com/spf13/cobra"
	"github.com/spf13/viper"
)

const rebootDelay = 5 * time.Minute // delayed reboot on error

var (
	log     = util.NewLogger("main")
	cfgFile string

	ignoreErrors = []string{"warn", "error"}        // don't add to cache
	ignoreMqtt   = []string{"auth", "releaseNotes"} // excessive size may crash certain brokers
)

// rootCmd represents the base command when called without any subcommands
var rootCmd = &cobra.Command{
	Use:     "evcc",
	Short:   "EV Charge Controller",
	Version: server.FormattedVersion(),
	Run:     runRoot,
}

func init() {
	cobra.OnInitialize(initConfig)

	// global options
	rootCmd.PersistentFlags().StringVarP(&cfgFile, "config", "c", "", "Config file (default \"~/evcc.yaml\" or \"/etc/evcc.yaml\")")

	rootCmd.PersistentFlags().BoolP("help", "h", false, "Help")

	rootCmd.PersistentFlags().Bool(flagHeaders, false, flagHeadersDescription)

	// config file options
	rootCmd.PersistentFlags().String(flagSqlite, conf.Database.Dsn, flagSqliteDescription)
	bindP(rootCmd, "database.dsn", flagSqlite)

	rootCmd.PersistentFlags().StringP("log", "l", "info", "Log level (fatal, error, warn, info, debug, trace)")
	bindP(rootCmd, "log")

	rootCmd.Flags().Bool("metrics", false, "Expose metrics")
	bind(rootCmd, "metrics")

	rootCmd.Flags().Bool("profile", false, "Expose pprof profiles")
	bind(rootCmd, "profile")
}

// initConfig reads in config file and ENV variables if set
func initConfig() {
	if cfgFile != "" {
		// Use config file from the flag
		viper.SetConfigFile(cfgFile)
	} else {
		// Search for config in home directory if available
		if home, err := os.UserHomeDir(); err == nil {
			viper.AddConfigPath(home)
		}

		// Search config in home directory with name "mbmd" (without extension).
		viper.AddConfigPath(".")    // optionally look for config in the working directory
		viper.AddConfigPath("/etc") // path to look for the config file in

		viper.SetConfigName("evcc")
	}

	viper.SetEnvPrefix("evcc")
	viper.AutomaticEnv() // read in environment variables that match

	// print version
	util.LogLevel("info", nil)
	log.INFO.Printf("evcc %s", server.FormattedVersion())
}

// Execute adds all child commands to the root command and sets flags appropriately.
func Execute() {
	if err := rootCmd.Execute(); err != nil {
		fmt.Println(err)
		os.Exit(1)
	}
}

func runRoot(cmd *cobra.Command, args []string) {
	// load config and re-configure logging after reading config file
	var err error
	if cfgErr := loadConfigFile(&conf); errors.As(cfgErr, &viper.ConfigFileNotFoundError{}) {
		log.INFO.Println("missing config file - switching into demo mode")
		if err := demoConfig(&conf); err != nil {
			log.FATAL.Fatal(err)
		}
	} else {
		err = cfgErr
	}

	// network config
	if viper.GetString("uri") != "" {
		log.WARN.Println("`uri` is deprecated and will be ignored. Use `network` instead.")
	}

	log.INFO.Printf("starting ui and api at :%d", conf.Network.Port)

	// start broadcasting values
	tee := new(util.Tee)

	// value cache
	cache := util.NewCache()
	go cache.Run(pipe.NewDropper(ignoreErrors...).Pipe(tee.Attach()))

	// create web server
	socketHub := server.NewSocketHub()
	httpd := server.NewHTTPd(fmt.Sprintf(":%d", conf.Network.Port), socketHub)

	// metrics
	if viper.GetBool("metrics") {
		httpd.Router().Handle("/metrics", promhttp.Handler())
	}

	// pprof
	if viper.GetBool("profile") {
		httpd.Router().PathPrefix("/debug/").Handler(http.DefaultServeMux)
	}

	// publish to UI
	go socketHub.Run(tee.Attach(), cache)

	// setup values channel
	valueChan := make(chan util.Param)
	go tee.Run(valueChan)

	// capture log messages for UI
	util.CaptureLogs(valueChan)

	// setup environment
	if err == nil {
		err = configureEnvironment(cmd, conf)
	}

	// setup telemetry
	if err == nil {
		telemetry.Create(conf.Plant)
		if conf.Telemetry {
			err = telemetry.Enable(true)
		}
	}

	// setup modbus proxy
	if err == nil {
		for _, cfg := range conf.ModbusProxy {
			if err = modbus.StartProxy(cfg.Port, cfg.Settings, cfg.ReadOnly); err != nil {
				break
			}
		}
	}

	// setup site and loadpoints
	var site *core.Site
	if err == nil {
		cp.TrackVisitors() // track duplicate usage
		site, err = configureSiteAndLoadpoints(conf)
	}

	// setup database
	if err == nil && conf.Influx.URL != "" {
		configureInflux(conf.Influx, site, tee.Attach())
	}

	// setup mqtt publisher
	if err == nil && conf.Mqtt.Broker != "" {
		publisher := server.NewMQTT(strings.Trim(conf.Mqtt.Topic, "/"))
		go publisher.Run(site, pipe.NewDropper(ignoreMqtt...).Pipe(tee.Attach()))
	}

	// announce on mDNS
	if err == nil && strings.HasSuffix(conf.Network.Host, ".local") {
		err = configureMDNS(conf.Network)
	}

	// start HEMS server
	if err == nil && conf.HEMS.Type != "" {
		err = configureHEMS(conf.HEMS, site, httpd)
	}

	// setup messaging
	var pushChan chan push.Event
	if err == nil {
		pushChan, err = configureMessengers(conf.Messaging, cache)
	}

	// run shutdown functions on stop
	var once sync.Once
	stopC := make(chan struct{})

	// catch signals
	go func() {
		signalC := make(chan os.Signal, 1)
		signal.Notify(signalC, os.Interrupt, syscall.SIGTERM)

		<-signalC                        // wait for signal
		once.Do(func() { close(stopC) }) // signal loop to end
	}()

	// wait for shutdown
	go func() {
		<-stopC

		select {
		case <-shutdownDoneC(): // wait for shutdown
		case <-time.After(conf.Interval):
		}

		if err != nil {
			os.Exit(1)
		}

		os.Exit(0)
	}()

	// show main ui
	if err == nil {
		httpd.RegisterSiteHandlers(site, cache)

		// set channels
		site.DumpConfig()
		site.Prepare(valueChan, pushChan)

		// show and check version
		valueChan <- util.Param{Key: "version", Val: server.FormattedVersion()}
		go updater.Run(log, httpd, valueChan)

		// expose sponsor to UI
		if sponsor.Subject != "" {
			valueChan <- util.Param{Key: "sponsor", Val: sponsor.Subject}
		}

		// allow web access for vehicles
		cp.webControl(conf.Network, httpd.Router(), valueChan)

		go func() {
			site.Run(stopC, conf.Interval)
		}()
	} else {
		httpd.RegisterShutdownHandler(func() {
			log.FATAL.Println("evcc was stopped. OS should restart the service. Or restart manually.")
			once.Do(func() { close(stopC) }) // signal loop to end
		})

		// improve error message
		err = wrapErrors(err)

		publishErrorInfo(valueChan, cfgFile, err)

		log.FATAL.Println(err)
		log.FATAL.Printf("will attempt restart in: %v", rebootDelay)

		go func() {
			<-time.After(rebootDelay)
			once.Do(func() { close(stopC) }) // signal loop to end
		}()
	}

	// uds health check listener
	go server.HealthListener(site)

	log.FATAL.Println(wrapErrors(httpd.ListenAndServe()))
}