feat: add background mail polling option for all workers

Check for new mail (recent, unseen, exists counts) with an external
command, or for imap with the STATUS command, at start or on
reconnection and every X time duration

IMAP:
The selected folder is skipped, per specification. Additional config
options are included for including/excluding folders explicitly.

Maildir/Notmuch:
An external command will be run in the background to check for new mail.
An optional timeout can be used with maildir/notmuch. Default is 10s

New account options:
check-mail
check-mail-cmd (maildir/notmuch only)
check-mail-timeout (maildir/notmuch only), default 10s
check-mail-include (IMAP only)
check-mail-exclude (IMAP only)

If unset, or set less than or equal to 0, check-mail will be ignored

Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>
Tested-by: Moritz Poldrack <moritz@poldrack.dev>
Acked-by: Robin Jarry <robin@jarry.cc>

2 files changed, 73 insertions, 28 deletions

diff --git a/widgets/account.go b/widgets/account.go
index b34396b..e913cb7 100644
--- a/widgets/account.go
+++ b/widgets/account.go
@@ -33,6 +33,7 @@ type AccountView struct {
 	msglist *MessageList
 	worker  *types.Worker
 	state   *statusline.State
+	newConn bool // True if this is a first run after a new connection/reconnection
 }
 
 func (acct *AccountView) UiConfig() config.UIConfig {
@@ -100,6 +101,9 @@ func NewAccountView(aerc *Aerc, conf *config.AercConfig, acct *config.AccountCon
 	worker.PostAction(&types.Configure{Config: acct}, nil)
 	worker.PostAction(&types.Connect{}, nil)
 	view.SetStatus(statusline.ConnectionActivity("Connecting..."))
+	if acct.CheckMail.Minutes() > 0 {
+		view.CheckMailTimer(acct.CheckMail)
+	}
 
 	return view, nil
 }
@@ -258,13 +262,14 @@ func (acct *AccountView) onMessage(msg types.WorkerMessage) {
 				}
 				acct.msglist.SetInitDone()
 				acct.logger.Println("Connected.")
-				acct.SetStatus(statusline.Connected(true))
+				acct.SetStatus(statusline.SetConnected(true))
+				acct.newConn = true
 			})
 		case *types.Disconnect:
 			acct.dirlist.UpdateList(nil)
 			acct.msglist.SetStore(nil)
 			acct.logger.Println("Disconnected.")
-			acct.SetStatus(statusline.Connected(false))
+			acct.SetStatus(statusline.SetConnected(false))
 		case *types.OpenDirectory:
 			if store, ok := acct.dirlist.SelectedMsgStore(); ok {
 				// If we've opened this dir before, we can re-render it from
@@ -279,6 +284,11 @@ func (acct *AccountView) onMessage(msg types.WorkerMessage) {
 			acct.dirlist.UpdateList(nil)
 		case *types.RemoveDirectory:
 			acct.dirlist.UpdateList(nil)
+		case *types.FetchMessageHeaders:
+			if acct.newConn && acct.AccountConfig().CheckMail.Minutes() > 0 {
+				acct.newConn = false
+				acct.CheckMail()
+			}
 		}
 	case *types.DirectoryInfo:
 		if store, ok := acct.dirlist.MsgStore(msg.Info.Name); ok {
@@ -327,7 +337,7 @@ func (acct *AccountView) onMessage(msg types.WorkerMessage) {
 		acct.labels = msg.Labels
 	case *types.ConnError:
 		acct.logger.Printf("connection error: [%s] %v", acct.acct.Name, msg.Error)
-		acct.SetStatus(statusline.Connected(false))
+		acct.SetStatus(statusline.SetConnected(false))
 		acct.PushError(msg.Error)
 		acct.msglist.SetStore(nil)
 		acct.worker.PostAction(&types.Reconnect{}, nil)
@@ -349,3 +359,33 @@ func (acct *AccountView) GetSortCriteria() []*types.SortCriterion {
 	}
 	return criteria
 }
+
+func (acct *AccountView) CheckMail() {
+	// Exclude selected mailbox, per IMAP specification
+	exclude := append(acct.AccountConfig().CheckMailExclude, acct.dirlist.Selected())
+	dirs := acct.dirlist.List()
+	dirs = acct.dirlist.FilterDirs(dirs, acct.AccountConfig().CheckMailInclude, false)
+	dirs = acct.dirlist.FilterDirs(dirs, exclude, true)
+	acct.logger.Printf("Checking for new mail on account %s", acct.Name())
+	acct.SetStatus(statusline.ConnectionActivity("Checking for new mail..."))
+	msg := &types.CheckMail{
+		Directories: dirs,
+		Command:     acct.acct.CheckMailCmd,
+		Timeout:     acct.acct.CheckMailTimeout,
+	}
+	acct.worker.PostAction(msg, func(_ types.WorkerMessage) {
+		acct.SetStatus(statusline.ConnectionActivity(""))
+	})
+}
+
+func (acct *AccountView) CheckMailTimer(d time.Duration) {
+	ticker := time.NewTicker(d)
+	go func() {
+		for range ticker.C {
+			if !acct.state.Connected() {
+				continue
+			}
+			acct.CheckMail()
+		}
+	}()
+}
diff --git a/widgets/dirlist.go b/widgets/dirlist.go
index 412ed06..ca0f6c1 100644
--- a/widgets/dirlist.go
+++ b/widgets/dirlist.go
@@ -40,6 +40,8 @@ type DirectoryLister interface {
 	SelectedMsgStore() (*lib.MessageStore, bool)
 	MsgStore(string) (*lib.MessageStore, bool)
 	SetMsgStore(string, *lib.MessageStore)
+
+	FilterDirs([]string, []string, bool) []string
 }
 
 type DirectoryList struct {
@@ -441,38 +443,41 @@ func (dirlist *DirectoryList) sortDirsByFoldersSortConfig() {
 // dirstore, based on AccountConfig.Folders (inclusion) and
 // AccountConfig.FoldersExclude (exclusion), in that order.
 func (dirlist *DirectoryList) filterDirsByFoldersConfig() {
-	filterDirs := func(orig, filters []string, exclude bool) []string {
-		if len(filters) == 0 {
-			return orig
-		}
-		var dest []string
-		for _, folder := range orig {
-			// When excluding, include things by default, and vice-versa
-			include := exclude
-			for _, f := range filters {
-				if folderMatches(folder, f) {
-					// If matched an exclusion, don't include
-					// If matched an inclusion, do include
-					include = !exclude
-					break
-				}
-			}
-			if include {
-				dest = append(dest, folder)
-			}
-		}
-		return dest
-	}
-
 	dirlist.dirs = dirlist.store.List()
 
 	// 'folders' (if available) is used to make the initial list and
 	// 'folders-exclude' removes from that list.
 	configFolders := dirlist.acctConf.Folders
-	dirlist.dirs = filterDirs(dirlist.dirs, configFolders, false)
+	dirlist.dirs = dirlist.FilterDirs(dirlist.dirs, configFolders, false)
 
 	configFoldersExclude := dirlist.acctConf.FoldersExclude
-	dirlist.dirs = filterDirs(dirlist.dirs, configFoldersExclude, true)
+	dirlist.dirs = dirlist.FilterDirs(dirlist.dirs, configFoldersExclude, true)
+}
+
+// FilterDirs filters directories by the supplied filter. If exclude is false,
+// the filter will only include directories from orig which exist in filters.
+// If exclude is true, the directories in filters are removed from orig
+func (dirlist *DirectoryList) FilterDirs(orig, filters []string, exclude bool) []string {
+	if len(filters) == 0 {
+		return orig
+	}
+	var dest []string
+	for _, folder := range orig {
+		// When excluding, include things by default, and vice-versa
+		include := exclude
+		for _, f := range filters {
+			if folderMatches(folder, f) {
+				// If matched an exclusion, don't include
+				// If matched an inclusion, do include
+				include = !exclude
+				break
+			}
+		}
+		if include {
+			dest = append(dest, folder)
+		}
+	}
+	return dest
 }
 
 func (dirlist *DirectoryList) SelectedMsgStore() (*lib.MessageStore, bool) {