support znc.in/playback

irc/znc.go

@@ -0,0 +1,96 @@
+// Copyright (c) 2019 Shivaram Lingamneni <slingamn@cs.stanford.edu>
+// released under the MIT license
+
+package irc
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+)
+
+type zncCommandHandler func(client *Client, command string, params []string, rb *ResponseBuffer)
+
+var zncHandlers = map[string]zncCommandHandler{
+	"*playback": zncPlaybackHandler,
+}
+
+func zncPrivmsgHandler(client *Client, command string, privmsg string, rb *ResponseBuffer) {
+	zncModuleHandler(client, command, strings.Fields(privmsg), rb)
+}
+
+func zncModuleHandler(client *Client, command string, params []string, rb *ResponseBuffer) {
+	command = strings.ToLower(command)
+	if subHandler, ok := zncHandlers[command]; ok {
+		subHandler(client, command, params, rb)
+	} else {
+		rb.Add(nil, "*status!znc@znc.in", "NOTICE", rb.target.Nick(), fmt.Sprintf(client.t("No such module [%s]"), command))
+	}
+}
+
+// "number of seconds (floating point for millisecond precision) elapsed since January 1, 1970"
+func zncWireTimeToTime(str string) (result time.Time) {
+	var secondsPortion, fracPortion string
+	dot := strings.IndexByte(str, '.')
+	if dot == -1 {
+		secondsPortion = str
+	} else {
+		secondsPortion = str[:dot]
+		fracPortion = str[dot:]
+	}
+	seconds, _ := strconv.ParseInt(secondsPortion, 10, 64)
+	fraction, _ := strconv.ParseFloat(fracPortion, 64)
+	return time.Unix(seconds, int64(fraction*1000000000))
+}
+
+type zncPlaybackTimes struct {
+	after   time.Time
+	before  time.Time
+	targets map[string]bool // nil for "*" (everything), otherwise the channel names
+}
+
+// https://wiki.znc.in/Playback
+// PRIVMSG *playback :play <target> [lower_bound] [upper_bound]
+// e.g., PRIVMSG *playback :play * 1558374442
+func zncPlaybackHandler(client *Client, command string, params []string, rb *ResponseBuffer) {
+	if len(params) < 2 {
+		return
+	} else if strings.ToLower(params[0]) != "play" {
+		return
+	}
+	targetString := params[1]
+
+	var after, before time.Time
+	if 2 < len(params) {
+		after = zncWireTimeToTime(params[2])
+	}
+	if 3 < len(params) {
+		before = zncWireTimeToTime(params[3])
+	}
+
+	var targets map[string]bool
+
+	// OK: the user's PMs get played back immediately on receiving this,
+	// then we save the timestamps in the session to handle replay on future channel joins
+	config := client.server.Config()
+	if params[1] == "*" {
+		items, _ := client.history.Between(after, before, false, config.History.ChathistoryMax)
+		client.replayPrivmsgHistory(rb, items, true)
+	} else {
+		for _, targetName := range strings.Split(targetString, ",") {
+			if cfTarget, err := CasefoldChannel(targetName); err == nil {
+				if targets == nil {
+					targets = make(map[string]bool)
+				}
+				targets[cfTarget] = true
+			}
+		}
+	}
+
+	rb.session.zncPlaybackTimes = &zncPlaybackTimes{
+		after:   after,
+		before:  before,
+		targets: targets,
+	}
+}