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>

4 files changed, 56 insertions, 2 deletions

diff --git a/go.mod b/go.mod
index aeb7f8c..52a0309 100644
--- a/go.mod
+++ b/go.mod
@@ -9,9 +9,10 @@ require (
 	github.com/ddevault/go-libvterm v0.0.0-20190526194226-b7d861da3810
 	github.com/emersion/go-imap v1.0.0
 	github.com/emersion/go-imap-idle v0.0.0-20190519112320-2704abd7050e
+	github.com/emersion/go-imap-sortthread v1.0.1-0.20191002194849-97d602f80823
 	github.com/emersion/go-maildir v0.0.0-20190727102040-941194b0ac70
 	github.com/emersion/go-message v0.10.7
-	github.com/emersion/go-sasl v0.0.0-20190704090222-36b50694675c
+	github.com/emersion/go-sasl v0.0.0-20190817083125-240c8404624e
 	github.com/emersion/go-smtp v0.11.2
 	github.com/fsnotify/fsnotify v1.4.7
 	github.com/gdamore/tcell v1.1.5-0.20190724020331-84b54971b46c
diff --git a/go.sum b/go.sum
index 2749ac5..8f08a7a 100644
--- a/go.sum
+++ b/go.sum
@@ -19,6 +19,8 @@ github.com/emersion/go-imap v1.0.0 h1:/7HHNiSOk13DErenBZaQfTBmUy+quc6X7s3RNnuVtU
 github.com/emersion/go-imap v1.0.0/go.mod h1:MEiDDwwQFcZ+L45Pa68jNGv0qU9kbW+SJzwDpvSfX1s=
 github.com/emersion/go-imap-idle v0.0.0-20190519112320-2704abd7050e h1:L7bswVJZcf2YHofgom49oFRwVqmBj/qZqDy9/SJpZMY=
 github.com/emersion/go-imap-idle v0.0.0-20190519112320-2704abd7050e/go.mod h1:o14zPKCmEH5WC1vU5SdPoZGgNvQx7zzKSnxPQlobo78=
+github.com/emersion/go-imap-sortthread v1.0.1-0.20191002194849-97d602f80823 h1:E0Uc67DpLgG/nt8NhEqQ77TNGq3zDH1uvi4obW3SAyU=
+github.com/emersion/go-imap-sortthread v1.0.1-0.20191002194849-97d602f80823/go.mod h1:opHOzblOHZKQM1JEy+GPk1217giNLa7kleyWTN06qnc=
 github.com/emersion/go-maildir v0.0.0-20190727102040-941194b0ac70 h1:aUiPu6/iCjcsnNe/WkhsnMOq7vPmkYo9kFaMX5FiNZU=
 github.com/emersion/go-maildir v0.0.0-20190727102040-941194b0ac70/go.mod h1:I2j27lND/SRLgxROe50Vam81MSaqPFvJ0OHNnDZ7n84=
 github.com/emersion/go-message v0.10.4-0.20190609165112-592ace5bc1ca/go.mod h1:3h+HsGTCFHmk4ngJ2IV/YPhdlaOcR6hcgqM3yca9v7c=
@@ -28,6 +30,8 @@ github.com/emersion/go-sasl v0.0.0-20190520160400-47d427600317 h1:tYZxAY8nu3JJQK
 github.com/emersion/go-sasl v0.0.0-20190520160400-47d427600317/go.mod h1:G/dpzLu16WtQpBfQ/z3LYiYJn3ZhKSGWn83fyoyQe/k=
 github.com/emersion/go-sasl v0.0.0-20190704090222-36b50694675c h1:Spm8jy+jWYG/Dn6ygbq/LBW/6M27kg59GK+FkKjexuw=
 github.com/emersion/go-sasl v0.0.0-20190704090222-36b50694675c/go.mod h1:G/dpzLu16WtQpBfQ/z3LYiYJn3ZhKSGWn83fyoyQe/k=
+github.com/emersion/go-sasl v0.0.0-20190817083125-240c8404624e h1:ba7YsgX5OV8FjGi5ZWml8Jng6oBrJAb3ahqWMJ5Ce8Q=
+github.com/emersion/go-sasl v0.0.0-20190817083125-240c8404624e/go.mod h1:G/dpzLu16WtQpBfQ/z3LYiYJn3ZhKSGWn83fyoyQe/k=
 github.com/emersion/go-smtp v0.11.2 h1:5PO2Kwsx+HXuytntCfMvcworC/iq45TPGkwjnaBZFSg=
 github.com/emersion/go-smtp v0.11.2/go.mod h1:byi9Y32SuKwjTJt9DO2tTWYjtF3lEh154tE1AcaJQSY=
 github.com/emersion/go-textwrapper v0.0.0-20160606182133-d0e65e56babe h1:40SWqY0zE3qCi6ZrtTf5OUdNm5lDnGnjRSq9GgmeTrg=
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: