ui: enable showing of thread-context

Add a UI config value to enable showing of "thread-context", similar
to `notmuch show --entire-thread=true`. Add an associated style called
"msglist_thread_context" which can be used to style such messages.

Currently this feature is only supported by notmuch. It would be
possible for maildir to implement as well, IMAP with gmail custom
extensions, and JMAP. This patch merely implements the notmuch version
and puts the groundwork in for handling these sorts of displays.

Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>
Tested-by: Inwit <inwit@sindominio.net>
Acked-by: Robin Jarry <robin@jarry.cc>

15 files changed, 64 insertions, 15 deletions

diff --git a/commands/commands_test.go b/commands/commands_test.go
index a1518aaa..7edd0228 100644
--- a/commands/commands_test.go
+++ b/commands/commands_test.go
@@ -77,6 +77,7 @@ func (d *dummyData) Header(string) string                      { return "" }
 func (d *dummyData) ThreadPrefix() string                      { return "└─>" }
 func (d *dummyData) ThreadCount() int                          { return 0 }
 func (d *dummyData) ThreadFolded() bool                        { return false }
+func (d *dummyData) ThreadContext() bool                       { return false }
 func (d *dummyData) Subject() string                           { return "Re: [PATCH] hey" }
 func (d *dummyData) SubjectBase() string                       { return "[PATCH] hey" }
 func (d *dummyData) Number() int                               { return 0 }
diff --git a/config/aerc.conf b/config/aerc.conf
index 00c8501f..4b4e7cb6 100644
--- a/config/aerc.conf
+++ b/config/aerc.conf
@@ -290,6 +290,14 @@
 # Default: false
 #force-client-threads=false
 
+# Show thread context enables messages which do not match the current query (or
+# belong to the current mailbox) to be shown for context. These messages can be
+# styled separately using "msglist_thread_context" in a styleset. This feature
+# is not supported by all backends
+#
+# Default: false
+#show-thread-context=false
+
 # Debounce client-side thread building
 #
 # Default: 50ms
diff --git a/config/style.go b/config/style.go
index 3f117fc0..8a88dcfc 100644
--- a/config/style.go
+++ b/config/style.go
@@ -41,6 +41,7 @@ const (
 	STYLE_MSGLIST_THREAD_FOLDED
 	STYLE_MSGLIST_GUTTER
 	STYLE_MSGLIST_PILL
+	STYLE_MSGLIST_THREAD_CONTEXT
 
 	STYLE_DIRLIST_DEFAULT
 	STYLE_DIRLIST_UNREAD
@@ -89,7 +90,8 @@ var StyleNames = map[string]StyleObject{
 	"msglist_gutter":   STYLE_MSGLIST_GUTTER,
 	"msglist_pill":     STYLE_MSGLIST_PILL,
 
-	"msglist_thread_folded": STYLE_MSGLIST_THREAD_FOLDED,
+	"msglist_thread_folded":  STYLE_MSGLIST_THREAD_FOLDED,
+	"msglist_thread_context": STYLE_MSGLIST_THREAD_CONTEXT,
 
 	"dirlist_default": STYLE_DIRLIST_DEFAULT,
 	"dirlist_unread":  STYLE_DIRLIST_UNREAD,
diff --git a/config/templates.go b/config/templates.go
index 3f0249df..e2adeac2 100644
--- a/config/templates.go
+++ b/config/templates.go
@@ -78,6 +78,7 @@ func (d *dummyData) Header(string) string            { return "" }
 func (d *dummyData) ThreadPrefix() string            { return "└─>" }
 func (d *dummyData) ThreadCount() int                { return 0 }
 func (d *dummyData) ThreadFolded() bool              { return false }
+func (d *dummyData) ThreadContext() bool             { return true }
 func (d *dummyData) Subject() string                 { return "Re: [PATCH] hey" }
 func (d *dummyData) SubjectBase() string             { return "[PATCH] hey" }
 func (d *dummyData) Attach(string) string            { return "" }
diff --git a/config/ui.go b/config/ui.go
index 0479c13b..3b637278 100644
--- a/config/ui.go
+++ b/config/ui.go
@@ -41,6 +41,7 @@ type UIConfig struct {
 	ThreadingEnabled              bool          `ini:"threading-enabled"`
 	ForceClientThreads            bool          `ini:"force-client-threads"`
 	ClientThreadsDelay            time.Duration `ini:"client-threads-delay" default:"50ms"`
+	ThreadContext                 bool          `ini:"show-thread-context"`
 	FuzzyComplete                 bool          `ini:"fuzzy-complete"`
 	NewMessageBell                bool          `ini:"new-message-bell" default:"true"`
 	Spinner                       string        `ini:"spinner" default:"[..]    , [..]   ,  [..]  ,   [..] ,    [..],   [..] ,  [..]  , [..]   "`
diff --git a/doc/aerc-config.5.scd b/doc/aerc-config.5.scd
index cace2beb..b6855c7a 100644
--- a/doc/aerc-config.5.scd
+++ b/doc/aerc-config.5.scd
@@ -431,6 +431,12 @@ These options are configured in the *[ui]* section of _aerc.conf_.
 
 	Default: _50ms_
 
+*show-thread-context* = _true_|_false_
+	Enable showing of thread context. Note: this is not supported by all
+	backends.
+
+	Default: _false_
+
 ## CONTEXTUAL UI CONFIGURATION
 
 The UI configuration can be specialized for accounts, specific mail
diff --git a/lib/msgstore.go b/lib/msgstore.go
index 01b78289..6186b195 100644
--- a/lib/msgstore.go
+++ b/lib/msgstore.go
@@ -49,6 +49,7 @@ type MessageStore struct {
 
 	threadedView       bool
 	reverseThreadOrder bool
+	threadContext      bool
 	sortThreadSiblings bool
 	buildThreads       bool
 	builder            *ThreadBuilder
@@ -87,6 +88,7 @@ func NewMessageStore(worker *types.Worker,
 	reverseOrder bool, reverseThreadOrder bool, sortThreadSiblings bool,
 	triggerNewEmail func(*models.MessageInfo),
 	triggerDirectoryChange func(), onSelect func(*models.MessageInfo),
+	threadContext bool,
 ) *MessageStore {
 	if !worker.Backend.Capabilities().Thread {
 		clientThreads = true
@@ -104,6 +106,7 @@ func NewMessageStore(worker *types.Worker,
 
 		threadedView:       thread,
 		buildThreads:       clientThreads,
+		threadContext:      threadContext,
 		reverseThreadOrder: reverseThreadOrder,
 		sortThreadSiblings: sortThreadSiblings,
 
@@ -831,6 +834,7 @@ func (store *MessageStore) Sort(criteria []*types.SortCriterion, cb func(types.W
 			Context:        store.ctx,
 			SortCriteria:   criteria,
 			FilterCriteria: store.filter,
+			ThreadContext:  store.threadContext,
 		}, handle_return)
 	} else {
 		store.worker.PostAction(&types.FetchDirectoryContents{
diff --git a/lib/state/templates.go b/lib/state/templates.go
index fbe5aa4a..88c5eeae 100644
--- a/lib/state/templates.go
+++ b/lib/state/templates.go
@@ -20,7 +20,7 @@ type DataSetter interface {
 	Data() models.TemplateData
 	SetHeaders(*mail.Header, *models.OriginalMail)
 	SetInfo(*models.MessageInfo, int, bool)
-	SetThreading(string, bool, int, bool)
+	SetThreading(string, bool, int, bool, bool)
 	SetComposer(Composer)
 	SetAccount(*config.AccountConfig)
 	SetFolder(*models.Directory)
@@ -34,6 +34,7 @@ type ThreadInfo struct {
 	Prefix      string
 	Count       int
 	Folded      bool
+	Context     bool
 }
 
 type templateData struct {
@@ -86,12 +87,13 @@ func (d *templateData) SetInfo(info *models.MessageInfo, num int, marked bool,
 }
 
 func (d *templateData) SetThreading(prefix string, same bool, count int,
-	folded bool,
+	folded bool, context bool,
 ) {
 	d.threadInfo.Prefix = prefix
 	d.threadInfo.SameSubject = same
 	d.threadInfo.Count = count
 	d.threadInfo.Folded = folded
+	d.threadInfo.Context = context
 }
 
 func (d *templateData) SetAccount(acct *config.AccountConfig) {
@@ -300,6 +302,10 @@ func (d *templateData) ThreadFolded() bool {
 	return d.threadInfo.Folded
 }
 
+func (d *templateData) ThreadContext() bool {
+	return d.threadInfo.Context
+}
+
 func (d *templateData) Subject() string {
 	var subject string
 	switch {
diff --git a/models/templates.go b/models/templates.go
index 0c684e86..ac6d410a 100644
--- a/models/templates.go
+++ b/models/templates.go
@@ -22,6 +22,7 @@ type TemplateData interface {
 	ThreadPrefix() string
 	ThreadCount() int
 	ThreadFolded() bool
+	ThreadContext() bool
 	Subject() string
 	SubjectBase() string
 	Number() int
diff --git a/widgets/account.go b/widgets/account.go
index 982d75f8..7e380996 100644
--- a/widgets/account.go
+++ b/widgets/account.go
@@ -255,6 +255,7 @@ func (acct *AccountView) newStore(name string) *lib.MessageStore {
 			}
 		},
 		acct.updateSplitView,
+		acct.dirlist.UiConfig(name).ThreadContext,
 	)
 	store.SetMarker(marker.New(store))
 	return store
diff --git a/widgets/msglist.go b/widgets/msglist.go
index dcb4cd31..3187b5d5 100644
--- a/widgets/msglist.go
+++ b/widgets/msglist.go
@@ -209,8 +209,13 @@ func addMessage(
 	}
 	// folded thread
 	templateData, ok := data.(models.TemplateData)
-	if ok && templateData.ThreadFolded() {
-		params.styles = append(params.styles, config.STYLE_MSGLIST_THREAD_FOLDED)
+	if ok {
+		if templateData.ThreadFolded() {
+			params.styles = append(params.styles, config.STYLE_MSGLIST_THREAD_FOLDED)
+		}
+		if templateData.ThreadContext() {
+			params.styles = append(params.styles, config.STYLE_MSGLIST_THREAD_CONTEXT)
+		}
 	}
 	// marked message
 	marked := store.Marker().IsMarked(msg.Uid)
@@ -476,7 +481,7 @@ func newThreadView(store *lib.MessageStore) *threadView {
 }
 
 func (t *threadView) Update(data state.DataSetter, uid uint32) {
-	prefix, same, count, folded := "", false, 0, false
+	prefix, same, count, folded, context := "", false, 0, false, false
 	thread, err := t.store.Thread(uid)
 	if thread != nil && err == nil {
 		prefix = threadPrefix(thread, t.reverse, true)
@@ -486,6 +491,7 @@ func (t *threadView) Update(data state.DataSetter, uid uint32) {
 		t.prevSubj = subject
 		count = countThreads(thread)
 		folded = thread.FirstChild != nil && thread.FirstChild.Hidden
+		context = thread.Context
 	}
-	data.SetThreading(prefix, same, count, folded)
+	data.SetThreading(prefix, same, count, folded, context)
 }
diff --git a/worker/notmuch/lib/database.go b/worker/notmuch/lib/database.go
index 9a6689c4..e7914156 100644
--- a/worker/notmuch/lib/database.go
+++ b/worker/notmuch/lib/database.go
@@ -111,7 +111,7 @@ func (db *DB) MsgIDsFromQuery(ctx context.Context, q string) ([]string, error) {
 	return msgIDs, err
 }
 
-func (db *DB) ThreadsFromQuery(ctx context.Context, q string) ([]*types.Thread, error) {
+func (db *DB) ThreadsFromQuery(ctx context.Context, q string, entireThread bool) ([]*types.Thread, error) {
 	query, err := db.newQuery(q)
 	if err != nil {
 		return nil, err
@@ -136,7 +136,7 @@ func (db *DB) ThreadsFromQuery(ctx context.Context, q string) ([]*types.Thread,
 		default:
 			thread := threads.Thread()
 			tlm := thread.TopLevelMessages()
-			root := db.makeThread(nil, &tlm)
+			root := db.makeThread(nil, &tlm, entireThread)
 			res = append(res, root)
 			tlm.Close()
 			thread.Close()
@@ -306,7 +306,7 @@ func (db *DB) KeyFromUid(uid uint32) (string, bool) {
 	return db.uidStore.GetKey(uid)
 }
 
-func (db *DB) makeThread(parent *types.Thread, msgs *notmuch.Messages) *types.Thread {
+func (db *DB) makeThread(parent *types.Thread, msgs *notmuch.Messages, threadContext bool) *types.Thread {
 	var lastSibling *types.Thread
 	for msgs.Next() {
 		msg := msgs.Message()
@@ -319,14 +319,19 @@ func (db *DB) makeThread(parent *types.Thread, msgs *notmuch.Messages) *types.Th
 		}
 		replies := msg.Replies()
 		defer replies.Close()
-		if !match {
-			parent = db.makeThread(parent, &replies)
+		if !match && !threadContext {
+			parent = db.makeThread(parent, &replies, threadContext)
 			continue
 		}
 		node := &types.Thread{
 			Uid:    db.uidStore.GetOrInsert(msgID),
 			Parent: parent,
-			Hidden: !match,
+		}
+		switch threadContext {
+		case true:
+			node.Context = !match
+		default:
+			node.Hidden = !match
 		}
 		if parent != nil && parent.FirstChild == nil {
 			parent.FirstChild = node
@@ -340,7 +345,7 @@ func (db *DB) makeThread(parent *types.Thread, msgs *notmuch.Messages) *types.Th
 			lastSibling.NextSibling = node
 		}
 		lastSibling = node
-		db.makeThread(node, &replies)
+		db.makeThread(node, &replies, threadContext)
 	}
 
 	// We want to return the root node
diff --git a/worker/notmuch/worker.go b/worker/notmuch/worker.go
index d1eb69d0..2f601528 100644
--- a/worker/notmuch/worker.go
+++ b/worker/notmuch/worker.go
@@ -635,6 +635,7 @@ func (w *worker) emitDirectoryContents(parent types.WorkerMessage) error {
 func (w *worker) emitDirectoryThreaded(parent types.WorkerMessage) error {
 	query := w.query
 	ctx := context.Background()
+	threadContext := false
 	if msg, ok := parent.(*types.FetchDirectoryThreaded); ok {
 		log.Debugf("filter input: '%v'", msg.FilterCriteria)
 		s, err := translate(msg.FilterCriteria)
@@ -646,8 +647,9 @@ func (w *worker) emitDirectoryThreaded(parent types.WorkerMessage) error {
 			log.Debugf("filter query: '%s'", query)
 		}
 		ctx = msg.Context
+		threadContext = msg.ThreadContext
 	}
-	threads, err := w.db.ThreadsFromQuery(ctx, query)
+	threads, err := w.db.ThreadsFromQuery(ctx, query, threadContext)
 	if err != nil {
 		return err
 	}
diff --git a/worker/types/messages.go b/worker/types/messages.go
index 26408684..7cab9a7a 100644
--- a/worker/types/messages.go
+++ b/worker/types/messages.go
@@ -115,6 +115,7 @@ type FetchDirectoryThreaded struct {
 	Context        context.Context
 	SortCriteria   []*SortCriterion
 	FilterCriteria []string
+	ThreadContext  bool
 }
 
 type SearchDirectory struct {
diff --git a/worker/types/thread.go b/worker/types/thread.go
index 2f739bc2..75651280 100644
--- a/worker/types/thread.go
+++ b/worker/types/thread.go
@@ -17,6 +17,10 @@ type Thread struct {
 
 	Hidden  bool // if this flag is set the message isn't rendered in the UI
 	Deleted bool // if this flag is set the message was deleted
+
+	// Context indicates the message doesn't match the mailbox / query but
+	// is displayed for context
+	Context bool
 }
 
 // AddChild appends the child node at the end of the existing children of t.