1 files changed, 242 insertions, 0 deletions
diff --git a/lib/threadbuilder.go b/lib/threadbuilder.go
new file mode 100644
index 00000000..c87d0bfb
--- /dev/null
+++ b/lib/threadbuilder.go
@@ -0,0 +1,242 @@
+package lib
+
+import (
+	"log"
+	"time"
+
+	"git.sr.ht/~rjarry/aerc/models"
+	"git.sr.ht/~rjarry/aerc/worker/types"
+	"github.com/gatherstars-com/jwz"
+)
+
+type UidStorer interface {
+	Uids() []uint32
+}
+
+type ThreadBuilder struct {
+	threadBlocks   map[uint32]jwz.Threadable
+	messageidToUid map[string]uint32
+	seen           map[uint32]bool
+	store          UidStorer
+	logger         *log.Logger
+}
+
+func NewThreadBuilder(store UidStorer, logger *log.Logger) *ThreadBuilder {
+	tb := &ThreadBuilder{
+		threadBlocks:   make(map[uint32]jwz.Threadable),
+		messageidToUid: make(map[string]uint32),
+		seen:           make(map[uint32]bool),
+		store:          store,
+		logger:         logger,
+	}
+	return tb
+}
+
+func (builder *ThreadBuilder) Update(msg *models.MessageInfo) {
+	if msg != nil {
+		if threadable := newThreadable(msg); threadable != nil {
+			builder.messageidToUid[threadable.MessageThreadID()] = msg.Uid
+			builder.threadBlocks[msg.Uid] = threadable
+		}
+	}
+}
+
+func (builder *ThreadBuilder) Threads() []*types.Thread {
+	start := time.Now()
+
+	threads := builder.buildAercThreads(builder.generateStructure())
+
+	elapsed := time.Since(start)
+	builder.logger.Println("ThreadBuilder:", len(threads), "threads created in", elapsed)
+
+	return threads
+}
+
+func (builder *ThreadBuilder) generateStructure() jwz.Threadable {
+	jwzThreads := make([]jwz.Threadable, 0, len(builder.threadBlocks))
+	for _, uid := range builder.store.Uids() {
+		if thr, ok := builder.threadBlocks[uid]; ok {
+			jwzThreads = append(jwzThreads, thr)
+		}
+	}
+
+	threader := jwz.NewThreader()
+	threadStructure, err := threader.ThreadSlice(jwzThreads)
+	if err != nil {
+		builder.logger.Printf("ThreadBuilder: threading operation return error: %#v", err)
+	}
+	return threadStructure
+}
+
+func (builder *ThreadBuilder) buildAercThreads(structure jwz.Threadable) []*types.Thread {
+	threads := make([]*types.Thread, 0, len(builder.threadBlocks))
+	if structure == nil {
+		for _, uid := range builder.store.Uids() {
+			threads = append(threads, &types.Thread{Uid: uid})
+		}
+	} else {
+		// fill threads with nil messages
+		for _, uid := range builder.store.Uids() {
+			if _, ok := builder.threadBlocks[uid]; !ok {
+				threads = append(threads, &types.Thread{Uid: uid})
+			}
+		}
+		// append the on-the-fly created aerc threads
+		root := &types.Thread{Uid: 0}
+		builder.seen = make(map[uint32]bool)
+		builder.buildTree(structure, root)
+		for iter := root.FirstChild; iter != nil; iter = iter.NextSibling {
+			iter.Parent = nil
+			threads = append(threads, iter)
+		}
+	}
+	return threads
+}
+
+// buildTree recursively translates the jwz threads structure into aerc threads
+// builder.seen is used to avoid potential double-counting and should be empty
+// on first call of this function
+func (builder *ThreadBuilder) buildTree(treeNode jwz.Threadable, target *types.Thread) {
+	if treeNode == nil {
+		return
+	}
+
+	// deal with child
+	uid, ok := builder.messageidToUid[treeNode.MessageThreadID()]
+	if _, seen := builder.seen[uid]; ok && !seen {
+		builder.seen[uid] = true
+		childNode := &types.Thread{Uid: uid, Parent: target}
+		target.OrderedInsert(childNode)
+		builder.buildTree(treeNode.GetChild(), childNode)
+	} else {
+		builder.buildTree(treeNode.GetChild(), target)
+	}
+
+	// deal with siblings
+	for next := treeNode.GetNext(); next != nil; next = next.GetNext() {
+
+		uid, ok := builder.messageidToUid[next.MessageThreadID()]
+		if _, seen := builder.seen[uid]; ok && !seen {
+			builder.seen[uid] = true
+			nn := &types.Thread{Uid: uid, Parent: target}
+			target.OrderedInsert(nn)
+			builder.buildTree(next.GetChild(), nn)
+		} else {
+			builder.buildTree(next.GetChild(), target)
+		}
+	}
+}
+
+// threadable implements the jwz.threadable interface which is required for the
+// jwz threading algorithm
+type threadable struct {
+	MsgInfo   *models.MessageInfo
+	MessageId string
+	Next      jwz.Threadable
+	Parent    jwz.Threadable
+	Child     jwz.Threadable
+	Dummy     bool
+}
+
+func newThreadable(msg *models.MessageInfo) *threadable {
+	msgid, err := msg.MsgId()
+	if err != nil {
+		return nil
+	}
+	return &threadable{
+		MessageId: msgid,
+		MsgInfo:   msg,
+		Next:      nil,
+		Parent:    nil,
+		Child:     nil,
+		Dummy:     false,
+	}
+}
+
+func (t *threadable) MessageThreadID() string {
+	return t.MessageId
+}
+
+func (t *threadable) MessageThreadReferences() []string {
+	if t.IsDummy() || t.MsgInfo == nil {
+		return nil
+	}
+	refs, err := t.MsgInfo.References()
+	if err != nil || len(refs) == 0 {
+		inreplyto, err := t.MsgInfo.InReplyTo()
+		if err != nil {
+			return nil
+		}
+		refs = []string{inreplyto}
+	}
+	return refs
+}
+
+func (t *threadable) Subject() string {
+	// deactivate threading by subject for now
+	return ""
+
+	if t.IsDummy() || t.MsgInfo == nil || t.MsgInfo.Envelope == nil {
+		return ""
+	}
+	return t.MsgInfo.Envelope.Subject
+}
+
+func (t *threadable) SimplifiedSubject() string {
+	return ""
+}
+
+func (t *threadable) SubjectIsReply() bool {
+	return false
+}
+
+func (t *threadable) SetNext(next jwz.Threadable) {
+	t.Next = next
+}
+
+func (t *threadable) SetChild(kid jwz.Threadable) {
+	t.Child = kid
+	if kid != nil {
+		kid.SetParent(t)
+	}
+}
+
+func (t *threadable) SetParent(parent jwz.Threadable) {
+	t.Parent = parent
+}
+
+func (t *threadable) GetNext() jwz.Threadable {
+	return t.Next
+}
+
+func (t *threadable) GetChild() jwz.Threadable {
+	return t.Child
+}
+
+func (t *threadable) GetParent() jwz.Threadable {
+	return t.Parent
+}
+
+func (t *threadable) GetDate() time.Time {
+	if t.IsDummy() {
+		if t.GetChild() != nil {
+			return t.GetChild().GetDate()
+		}
+		return time.Unix(0, 0)
+	}
+	if t.MsgInfo == nil || t.MsgInfo.Envelope == nil {
+		return time.Unix(0, 0)
+	}
+	return t.MsgInfo.Envelope.Date
+}
+
+func (t *threadable) MakeDummy(forID string) jwz.Threadable {
+	return &threadable{
+		MessageId: forID,
+		Dummy:     true,
+	}
+}
+
+func (t *threadable) IsDummy() bool {
+	return t.Dummy
+}