// Package cmd provides the ntfy CLI application
package cmd

import (
	"errors"
	"fmt"
	"github.com/urfave/cli/v2"
	"github.com/urfave/cli/v2/altsrc"
	"heckel.io/ntfy/config"
	"heckel.io/ntfy/server"
	"heckel.io/ntfy/util"
	"log"
	"os"
	"time"
)

// New creates a new CLI application
func New() *cli.App {
	flags := []cli.Flag{
		&cli.StringFlag{Name: "config", Aliases: []string{"c"}, EnvVars: []string{"NTFY_CONFIG_FILE"}, Value: "/etc/ntfy/config.yml", DefaultText: "/etc/ntfy/config.yml", Usage: "config file"},
		altsrc.NewStringFlag(&cli.StringFlag{Name: "listen-http", Aliases: []string{"l"}, EnvVars: []string{"NTFY_LISTEN_HTTP"}, Value: config.DefaultListenHTTP, Usage: "ip:port used to as HTTP listen address"}),
		altsrc.NewStringFlag(&cli.StringFlag{Name: "listen-https", Aliases: []string{"L"}, EnvVars: []string{"NTFY_LISTEN_HTTPS"}, Usage: "ip:port used to as HTTPS listen address"}),
		altsrc.NewStringFlag(&cli.StringFlag{Name: "key-file", Aliases: []string{"K"}, EnvVars: []string{"NTFY_KEY_FILE"}, Usage: "private key file, if listen-https is set"}),
		altsrc.NewStringFlag(&cli.StringFlag{Name: "cert-file", Aliases: []string{"E"}, EnvVars: []string{"NTFY_CERT_FILE"}, Usage: "certificate file, if listen-https is set"}),
		altsrc.NewStringFlag(&cli.StringFlag{Name: "firebase-key-file", Aliases: []string{"F"}, EnvVars: []string{"NTFY_FIREBASE_KEY_FILE"}, Usage: "Firebase credentials file; if set additionally publish to FCM topic"}),
		altsrc.NewStringFlag(&cli.StringFlag{Name: "cache-file", Aliases: []string{"C"}, EnvVars: []string{"NTFY_CACHE_FILE"}, Usage: "cache file used for message caching"}),
		altsrc.NewDurationFlag(&cli.DurationFlag{Name: "cache-duration", Aliases: []string{"b"}, EnvVars: []string{"NTFY_CACHE_DURATION"}, Value: config.DefaultCacheDuration, Usage: "buffer messages for this time to allow `since` requests"}),
		altsrc.NewDurationFlag(&cli.DurationFlag{Name: "keepalive-interval", Aliases: []string{"k"}, EnvVars: []string{"NTFY_KEEPALIVE_INTERVAL"}, Value: config.DefaultKeepaliveInterval, Usage: "interval of keepalive messages"}),
		altsrc.NewDurationFlag(&cli.DurationFlag{Name: "manager-interval", Aliases: []string{"m"}, EnvVars: []string{"NTFY_MANAGER_INTERVAL"}, Value: config.DefaultManagerInterval, Usage: "interval of for message pruning and stats printing"}),
		altsrc.NewIntFlag(&cli.IntFlag{Name: "global-topic-limit", Aliases: []string{"T"}, EnvVars: []string{"NTFY_GLOBAL_TOPIC_LIMIT"}, Value: config.DefaultGlobalTopicLimit, Usage: "total number of topics allowed"}),
		altsrc.NewIntFlag(&cli.IntFlag{Name: "visitor-subscription-limit", Aliases: []string{"V"}, EnvVars: []string{"NTFY_VISITOR_SUBSCRIPTION_LIMIT"}, Value: config.DefaultVisitorSubscriptionLimit, Usage: "number of subscriptions per visitor"}),
		altsrc.NewIntFlag(&cli.IntFlag{Name: "visitor-request-limit-burst", Aliases: []string{"B"}, EnvVars: []string{"NTFY_VISITOR_REQUEST_LIMIT_BURST"}, Value: config.DefaultVisitorRequestLimitBurst, Usage: "initial limit of requests per visitor"}),
		altsrc.NewDurationFlag(&cli.DurationFlag{Name: "visitor-request-limit-replenish", Aliases: []string{"R"}, EnvVars: []string{"NTFY_VISITOR_REQUEST_LIMIT_REPLENISH"}, Value: config.DefaultVisitorRequestLimitReplenish, Usage: "interval at which burst limit is replenished (one per x)"}),
		altsrc.NewBoolFlag(&cli.BoolFlag{Name: "behind-proxy", Aliases: []string{"P"}, EnvVars: []string{"NTFY_BEHIND_PROXY"}, Value: false, Usage: "if set, use X-Forwarded-For header to determine visitor IP address (for rate limiting)"}),
	}
	return &cli.App{
		Name:                   "ntfy",
		Usage:                  "Simple pub-sub notification service",
		UsageText:              "ntfy [OPTION..]",
		HideHelp:               true,
		HideVersion:            true,
		EnableBashCompletion:   true,
		UseShortOptionHandling: true,
		Reader:                 os.Stdin,
		Writer:                 os.Stdout,
		ErrWriter:              os.Stderr,
		Action:                 execRun,
		Before:                 initConfigFileInputSource("config", flags),
		Flags:                  flags,
	}
}

func execRun(c *cli.Context) error {
	// Read all the options
	listenHTTP := c.String("listen-http")
	listenHTTPS := c.String("listen-https")
	keyFile := c.String("key-file")
	certFile := c.String("cert-file")
	firebaseKeyFile := c.String("firebase-key-file")
	cacheFile := c.String("cache-file")
	cacheDuration := c.Duration("cache-duration")
	keepaliveInterval := c.Duration("keepalive-interval")
	managerInterval := c.Duration("manager-interval")
	globalTopicLimit := c.Int("global-topic-limit")
	visitorSubscriptionLimit := c.Int("visitor-subscription-limit")
	visitorRequestLimitBurst := c.Int("visitor-request-limit-burst")
	visitorRequestLimitReplenish := c.Duration("visitor-request-limit-replenish")
	behindProxy := c.Bool("behind-proxy")

	// Check values
	if firebaseKeyFile != "" && !util.FileExists(firebaseKeyFile) {
		return errors.New("if set, FCM key file must exist")
	} else if keepaliveInterval < 5*time.Second {
		return errors.New("keepalive interval cannot be lower than five seconds")
	} else if managerInterval < 5*time.Second {
		return errors.New("manager interval cannot be lower than five seconds")
	} else if cacheDuration > 0 && cacheDuration < managerInterval {
		return errors.New("cache duration cannot be lower than manager interval")
	} else if keyFile != "" && !util.FileExists(keyFile) {
		return errors.New("if set, key file must exist")
	} else if certFile != "" && !util.FileExists(certFile) {
		return errors.New("if set, certificate file must exist")
	} else if listenHTTPS != "" && (keyFile == "" || certFile == "") {
		return errors.New("if listen-https is set, both key-file and cert-file must be set")
	}

	// Run server
	conf := config.New(listenHTTP)
	conf.ListenHTTPS = listenHTTPS
	conf.KeyFile = keyFile
	conf.CertFile = certFile
	conf.FirebaseKeyFile = firebaseKeyFile
	conf.CacheFile = cacheFile
	conf.CacheDuration = cacheDuration
	conf.KeepaliveInterval = keepaliveInterval
	conf.ManagerInterval = managerInterval
	conf.GlobalTopicLimit = globalTopicLimit
	conf.VisitorSubscriptionLimit = visitorSubscriptionLimit
	conf.VisitorRequestLimitBurst = visitorRequestLimitBurst
	conf.VisitorRequestLimitReplenish = visitorRequestLimitReplenish
	conf.BehindProxy = behindProxy
	s, err := server.New(conf)
	if err != nil {
		log.Fatalln(err)
	}
	if err := s.Run(); err != nil {
		log.Fatalln(err)
	}
	log.Printf("Exiting.")
	return nil
}

// initConfigFileInputSource is like altsrc.InitInputSourceWithContext and altsrc.NewYamlSourceFromFlagFunc, but checks
// if the config flag is exists and only loads it if it does. If the flag is set and the file exists, it fails.
func initConfigFileInputSource(configFlag string, flags []cli.Flag) cli.BeforeFunc {
	return func(context *cli.Context) error {
		configFile := context.String(configFlag)
		if context.IsSet(configFlag) && !util.FileExists(configFile) {
			return fmt.Errorf("config file %s does not exist", configFile)
		} else if !context.IsSet(configFlag) && !util.FileExists(configFile) {
			return nil
		}
		inputSource, err := altsrc.NewYamlSourceFromFile(configFile)
		if err != nil {
			return err
		}
		return altsrc.ApplyInputSourceValues(context, inputSource, flags)
	}
}