worker/imap: Add threading extension

* Import the go-imap-sortthread library
* Add sortthread client to imapClient in worker
* Add handleDirectoryThreaded, which uses the go-imap-sortthread, and
  converts the results to the aerc thread type

Signed-off-by: Kevin Kuehler <keur@xcf.berkeley.edu>

2 files changed, 50 insertions, 1 deletions

diff --git a/worker/imap/open.go b/worker/imap/open.go
index 452c309..bdb794b 100644
--- a/worker/imap/open.go
+++ b/worker/imap/open.go
@@ -2,6 +2,7 @@ package imap
 
 import (
 	"github.com/emersion/go-imap"
+	sortthread "github.com/emersion/go-imap-sortthread"
 
 	"git.sr.ht/~sircmpwn/aerc/worker/types"
 )
@@ -48,3 +49,47 @@ func (imapw *IMAPWorker) handleFetchDirectoryContents(
 		imapw.worker.PostMessage(&types.Done{types.RespondTo(msg)}, nil)
 	}
 }
+
+func (imapw *IMAPWorker) handleDirectoryThreaded(
+	msg *types.FetchDirectoryThreaded) {
+	imapw.worker.Logger.Printf("Fetching threaded UID list")
+
+	seqSet := &imap.SeqSet{}
+	seqSet.AddRange(1, imapw.selected.Messages)
+	threads, err := imapw.client.tc.UidThread(sortthread.References,
+		&imap.SearchCriteria{SeqNum: seqSet})
+	if err != nil {
+		imapw.worker.PostMessage(&types.Error{
+			Message: types.RespondTo(msg),
+			Error:   err,
+		}, nil)
+	} else {
+		aercThreads, count := convertThreads(threads)
+		imapw.seqMap = make([]uint32, count)
+		imapw.worker.PostMessage(&types.DirectoryThreaded{
+			Message: types.RespondTo(msg),
+			Threads: aercThreads,
+		}, nil)
+		imapw.worker.PostMessage(&types.Done{types.RespondTo(msg)}, nil)
+	}
+}
+
+// This sucks... TODO: find a better way to do this.
+func convertThreads(threads []*sortthread.Thread) ([]*types.Thread, int) {
+	if threads == nil {
+		return nil, 0
+	}
+	conv := make([]*types.Thread, len(threads))
+	count := 0
+
+	for i := 0; i < len(threads); i++ {
+		t := threads[i]
+		children, childCount := convertThreads(t.Children)
+		conv[i] = &types.Thread{
+			Uid:      t.Id,
+			Children: children,
+		}
+		count += childCount + 1
+	}
+	return conv, count
+}
diff --git a/worker/imap/worker.go b/worker/imap/worker.go
index cd63c39..afc7289 100644
--- a/worker/imap/worker.go
+++ b/worker/imap/worker.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/emersion/go-imap"
 	idle "github.com/emersion/go-imap-idle"
+	sortthread "github.com/emersion/go-imap-sortthread"
 	"github.com/emersion/go-imap/client"
 	"golang.org/x/oauth2"
 
@@ -26,6 +27,7 @@ var errUnsupported = fmt.Errorf("unsupported command")
 
 type imapClient struct {
 	*client.Client
+	tc   *sortthread.ThreadClient
 	idle *idle.IdleClient
 }
 
@@ -152,7 +154,7 @@ func (w *IMAPWorker) handleMessage(msg types.WorkerMessage) error {
 		}
 
 		c.Updates = w.updates
-		w.client = &imapClient{c, idle.NewClient(c)}
+		w.client = &imapClient{c, sortthread.NewThreadClient(c), idle.NewClient(c)}
 		w.worker.PostMessage(&types.Done{types.RespondTo(msg)}, nil)
 	case *types.ListDirectories:
 		w.handleListDirectories(msg)
@@ -160,6 +162,8 @@ func (w *IMAPWorker) handleMessage(msg types.WorkerMessage) error {
 		w.handleOpenDirectory(msg)
 	case *types.FetchDirectoryContents:
 		w.handleFetchDirectoryContents(msg)
+	case *types.FetchDirectoryThreaded:
+		w.handleDirectoryThreaded(msg)
 	case *types.CreateDirectory:
 		w.handleCreateDirectory(msg)
 	case *types.FetchMessageHeaders: