// Copyright © 2017-2018 Mikael Berthe <mikael@lilotux.net>

//

// Licensed under the MIT license.

// Please see the LICENSE file is this directory.

package cmd

import (

	"io"

	"os"

	"strings"

	"github.com/pkg/errors"

	"github.com/spf13/cobra"

	"github.com/McKael/madon"

)

var streamOpts struct {

	command           string

	notificationsOnly bool

	notificationTypes string

}

// Maximum number of websockets (1 hashtag <=> 1 ws)

const maximumHashtagStreamWS = 4

// streamCmd represents the stream command

var streamCmd = &cobra.Command{

	Use:   "stream [user|local|public|!LIST|:HASHTAG]",

	Short: "Listen to an event stream",

	Long: `Listen to an event stream

The stream command stays connected to the server and listen to a stream of

events (user, local or federated).

A list-based stream can be displayed by prefixing the list ID with a '!'.

It can also get a hashtag-based stream if the keyword is prefixed with

':' or '#'.`,

	Example: `  madonctl stream           # User timeline stream

  madonctl stream local     # Local timeline stream

  madonctl stream public    # Public timeline stream

  madonctl stream '!42'     # List (ID 42)

  madonctl stream :mastodon # Hashtag

  madonctl stream #madonctl

  madonctl stream --notifications-only

  madonctl stream --notifications-only --notification-types mentions,follows

Several (up to 4) hashtags can be given.

Note: madonctl will use 1 websocket per hashtag stream.

  madonctl stream #madonctl,#mastodon,#golang

  madonctl stream :madonctl,mastodon,api

`,

	RunE:       streamRunE,

	ValidArgs:  []string{"user", "public"},

	ArgAliases: []string{"home"},

}

func init() {

	RootCmd.AddCommand(streamCmd)

	streamCmd.Flags().StringVar(&streamOpts.command, "command", "", "Execute external command")

	streamCmd.Flags().BoolVar(&streamOpts.notificationsOnly, "notifications-only", false, "Display only notifications (user stream)")

	streamCmd.Flags().StringVar(&streamOpts.notificationTypes, "notification-types", "", "Filter notifications (mentions, favourites, reblogs, follows)")

}

func streamRunE(cmd *cobra.Command, args []string) error {

	streamName := "user"

	var param string

	var hashTagList []string

	if len(args) > 0 {

		if len(args) != 1 {

			return errors.New("too many parameters")

		}

		arg := args[0]

		switch arg {

		case "", "user":

		case "public":

			streamName = arg

		case "local":

			streamName = "public:local"

		default:

			if arg[0] == '!' {

				// List-based stream

				streamName = "list"

				param = arg[1:]

				if len(param) == 0 {

					return errors.New("empty list ID")

				}

				break

			}

			if arg[0] != ':' && arg[0] != '#' {

				return errors.New("invalid argument")

			}

			streamName = "hashtag"

			param = arg[1:]

			if len(param) == 0 {

				return errors.New("empty hashtag")

			}

			hashTagList = strings.Split(param, ",")

			for i, h := range hashTagList {

				if h[0] == ':' || h[0] == '#' {

					hashTagList[i] = h[1:]

				}

				if h == "" {

					return errors.New("empty hashtag")

				}

			}

			if len(hashTagList) > maximumHashtagStreamWS {

				return errors.Errorf("too many hashtags, maximum is %d", maximumHashtagStreamWS)

			}

		}

	}

	if err := madonInit(true); err != nil {

		return err

	}

	var filterMap *map[string]bool

	if streamOpts.notificationTypes != "" {

		var err error

		filterMap, err = buildFilterMap(streamOpts.notificationTypes)

		if err != nil {

			return err

		}

	}

	evChan := make(chan madon.StreamEvent, 10)

	stop := make(chan bool)

	done := make(chan bool)

	var err error

	if streamName != "hashtag" || len(hashTagList) <= 1 { // Usual case: Only 1 stream

		err = gClient.StreamListener(streamName, param, evChan, stop, done)

	} else { // Several streams

		n := len(hashTagList)

		tagEvCh := make([]chan madon.StreamEvent, n)

		tagDoneCh := make([]chan bool, n)

		for i, t := range hashTagList {

			if verbose {

				errPrint("Launching listener for tag '%s'", t)

			}

			tagEvCh[i] = make(chan madon.StreamEvent)

			tagDoneCh[i] = make(chan bool)

			e := gClient.StreamListener(streamName, t, tagEvCh[i], stop, tagDoneCh[i])

			if e != nil {

				if i > 0 { // Close previous connections

					close(stop)

				}

				err = e

				break

			}

			// Forward events to main ev channel

			go func(i int) {

				for {

					select {

					case _, ok := <-tagDoneCh[i]:

						if !ok { // end of streaming for this tag

							done <- true

							return

						}

					case ev := <-tagEvCh[i]:

						evChan <- ev

					}

				}

			}(i)

		}

	}

	if err != nil {

		errPrint("Error: %s", err.Error())

		os.Exit(1)

	}

	p, err := getPrinter()

	if err != nil {

		close(stop)

		<-done

		close(evChan)

		errPrint("Error: %s", err.Error())

		os.Exit(1)

	}

	// Set up external command

	p.setCommand(streamOpts.command)

LISTEN:

	for {

		select {

		case v, ok := <-done:

			if !ok || v == true { // done is closed, end of streaming

				break LISTEN

			}

		case ev := <-evChan:

			switch ev.Event {

			case "error":

				if ev.Error != nil {

					if ev.Error == io.ErrUnexpectedEOF {

						errPrint("The stream connection was unexpectedly closed")

						continue

					}

					errPrint("Error event: [%s] %s", ev.Event, ev.Error)

					continue

				}

				errPrint("Event: [%s]", ev.Event)

			case "update":

				if streamOpts.notificationsOnly {

					continue

				}

				s := ev.Data.(madon.Status)

				if err = p.printObj(&s); err != nil {

					break LISTEN

				}

				continue

			case "notification":

				n := ev.Data.(madon.Notification)

				if filterMap != nil && !(*filterMap)[n.Type] {

					continue

				}

				if p.printObj(&n); err != nil {

					break LISTEN

				}

				continue

			case "delete":

				if streamOpts.notificationsOnly {

					continue

				}

				// TODO PrintObj ?

				errPrint("Event: [%s] Status %s was deleted", ev.Event, ev.Data.(string))

			default:

				errPrint("Unhandled event: [%s] %T", ev.Event, ev.Data)

			}

		}

	}

	close(stop)

	close(evChan)

	if err != nil {

		errPrint("Error: %s", err.Error())

		os.Exit(1)

	}

	return nil

}