implement CHANSERV AMODE

irc/channel.go

@@ -232,13 +232,7 @@ func (channel *Channel) ClientIsAtLeast(client *Client, permission modes.Mode) b
 
 	clientModes := channel.members[client]
 
-	// get voice, since it's not a part of ChannelPrivModes
-	if clientModes.HasMode(permission) {
-		return true
-	}
-
-	// check regular modes
-	for _, mode := range modes.ChannelPrivModes {
+	for _, mode := range modes.ChannelUserModes {
 		if clientModes.HasMode(mode) {
 			return true
 		}

irc/chanserv.go

@@ -5,6 +5,7 @@ package irc
 
 import (
 	"fmt"
+	"sort"
 	"strings"
 
 	"github.com/goshuirc/irc-go/ircfmt"
@@ -42,6 +43,18 @@ remembered.`,
 			helpShort:    `$bREGISTER$b lets you own a given channel.`,
 			authRequired: true,
 		},
+		"amode": {
+			handler: csAmodeHandler,
+			help: `Syntax: $bAMODE #channel [mode change] [account]$b
+
+AMODE lists or modifies persistent mode settings that affect channel members.
+For example, $bAMODE #channel +o dan$b grants the the holder of the "dan"
+account the +o operator mode every time they join #channel. To list current
+accounts and modes, use $bAMODE #channel$b. Note that users are always
+referenced by their registered account names, not their nicknames.`,
+			helpShort:    `$bAMODE$b modifies persistent mode settings for channel members.`,
+			authRequired: true,
+		},
 	}
 )
 
@@ -50,6 +63,71 @@ func csNotice(rb *ResponseBuffer, text string) {
 	rb.Add(nil, "ChanServ", "NOTICE", rb.target.Nick(), text)
 }
 
+func csAmodeHandler(server *Server, client *Client, command, params string, rb *ResponseBuffer) {
+	channelName, modeChange := utils.ExtractParam(params)
+
+	channel := server.channels.Get(channelName)
+	if channel == nil {
+		csNotice(rb, client.t("Channel does not exist"))
+		return
+	}
+
+	clientAccount := client.Account()
+	if clientAccount == "" || clientAccount != channel.Founder() {
+		csNotice(rb, client.t("You must be the channel founder to use AMODE"))
+		return
+	}
+
+	modeChanges, unknown := modes.ParseChannelModeChanges(strings.Fields(modeChange)...)
+
+	if len(modeChanges) > 1 || len(unknown) > 0 {
+		csNotice(rb, client.t("Invalid mode change"))
+		return
+	}
+
+	if len(modeChanges) == 0 || modeChanges[0].Op == modes.List {
+		persistentModes := channel.AccountToUmode()
+		// sort the persistent modes in descending order of priority, i.e.,
+		// ascending order of their index in the ChannelUserModes list
+		sort.Slice(persistentModes, func(i, j int) bool {
+			index := func(modeChange modes.ModeChange) int {
+				for idx, mode := range modes.ChannelUserModes {
+					if modeChange.Mode == mode {
+						return idx
+					}
+				}
+				return len(modes.ChannelUserModes)
+			}
+			return index(persistentModes[i]) < index(persistentModes[j])
+		})
+		csNotice(rb, fmt.Sprintf(client.t("Channel %s has %d persistent modes set"), channelName, len(persistentModes)))
+		for _, modeChange := range persistentModes {
+			csNotice(rb, fmt.Sprintf(client.t("Account %s receives mode +%s"), modeChange.Arg, string(modeChange.Mode)))
+		}
+		return
+	}
+
+	accountIsValid := false
+	change := modeChanges[0]
+	// Arg is the account name, casefold it here
+	change.Arg, _ = CasefoldName(change.Arg)
+	if change.Arg != "" {
+		_, err := server.accounts.LoadAccount(change.Arg)
+		accountIsValid = (err == nil)
+	}
+	if !accountIsValid {
+		csNotice(rb, client.t("Account does not exist"))
+		return
+	}
+	applied := channel.ApplyAccountToUmodeChange(change)
+	if applied {
+		csNotice(rb, fmt.Sprintf(client.t("Successfully set mode %s"), change.String()))
+		go server.channelRegistry.StoreChannel(channel, IncludeLists)
+	} else {
+		csNotice(rb, client.t("Change was a no-op"))
+	}
+}
+
 func csOpHandler(server *Server, client *Client, command, params string, rb *ResponseBuffer) {
 	channelName, clientToOp := utils.ExtractParam(params)
 

irc/getters.go

@@ -303,3 +303,37 @@ func (channel *Channel) Founder() string {
 	defer channel.stateMutex.RUnlock()
 	return channel.registeredFounder
 }
+
+func (channel *Channel) AccountToUmode() (result []modes.ModeChange) {
+	channel.stateMutex.RLock()
+	defer channel.stateMutex.RUnlock()
+	for account, mode := range channel.accountToUMode {
+		result = append(result, modes.ModeChange{
+			Mode: mode,
+			Arg:  account,
+			Op:   modes.Add,
+		})
+	}
+
+	return
+}
+
+func (channel *Channel) ApplyAccountToUmodeChange(change modes.ModeChange) (applied bool) {
+	channel.stateMutex.Lock()
+	defer channel.stateMutex.Unlock()
+
+	current := channel.accountToUMode[change.Arg]
+	switch change.Op {
+	case modes.Add:
+		applied = (current != change.Mode)
+		if applied {
+			channel.accountToUMode[change.Arg] = change.Mode
+		}
+	case modes.Remove:
+		applied = (current == change.Mode)
+		if applied {
+			delete(channel.accountToUMode, change.Arg)
+		}
+	}
+	return
+}

irc/modes/modes.go

@@ -147,6 +147,12 @@ var (
 		ChannelFounder, ChannelAdmin, ChannelOperator, Halfop,
 	}
 
+	// ChannelUserModes holds the list of all modes that can be applied to a user in a channel,
+	// including Voice, in descending order of precedence
+	ChannelUserModes = Modes{
+		ChannelFounder, ChannelAdmin, ChannelOperator, Halfop, Voice,
+	}
+
 	ChannelModePrefixes = map[Mode]string{
 		ChannelFounder:  "~",
 		ChannelAdmin:    "&",
@@ -176,20 +182,13 @@ func SplitChannelMembershipPrefixes(target string) (prefixes string, name string
 }
 
 // GetLowestChannelModePrefix returns the lowest channel prefix mode out of the given prefixes.
-func GetLowestChannelModePrefix(prefixes string) *Mode {
-	var lowest *Mode
-
-	if strings.Contains(prefixes, "+") {
-		lowest = &Voice
-	} else {
-		for i, mode := range ChannelPrivModes {
+func GetLowestChannelModePrefix(prefixes string) (lowest *Mode) {
+	for i, mode := range ChannelUserModes {
 		if strings.Contains(prefixes, ChannelModePrefixes[mode]) {
 			lowest = &ChannelPrivModes[i]
 		}
 	}
-	}
-
-	return lowest
+	return
 }
 
 //
@@ -304,15 +303,12 @@ func ParseChannelModeChanges(params ...string) (ModeChanges, map[rune]bool) {
 					break
 				}
 			}
-			for _, supportedMode := range ChannelPrivModes {
+			for _, supportedMode := range ChannelUserModes {
 				if rune(supportedMode) == mode {
 					isKnown = true
 					break
 				}
 			}
-			if mode == rune(Voice) {
-				isKnown = true
-			}
 			if !isKnown {
 				unknown[mode] = true
 				continue
@@ -392,14 +388,11 @@ func (set *ModeSet) Prefixes(isMultiPrefix bool) (prefixes string) {
 	defer set.RUnlock()
 
 	// add prefixes in order from highest to lowest privs
-	for _, mode := range ChannelPrivModes {
+	for _, mode := range ChannelUserModes {
 		if set.modes[mode] {
 			prefixes += ChannelModePrefixes[mode]
 		}
 	}
-	if set.modes[Voice] {
-		prefixes += ChannelModePrefixes[Voice]
-	}
 
 	if !isMultiPrefix && len(prefixes) > 1 {
 		prefixes = string(prefixes[0])