1 files changed, 86 insertions, 0 deletions
diff --git a/lib/msgstore.go b/lib/msgstore.go
new file mode 100644
index 00000000..79e19770
--- /dev/null
+++ b/lib/msgstore.go
@@ -0,0 +1,86 @@
+package lib
+
+import (
+	"github.com/emersion/go-imap"
+
+	"git.sr.ht/~sircmpwn/aerc2/worker/types"
+)
+
+type MessageStore struct {
+	DirInfo  types.DirectoryInfo
+	Messages map[uint32]*types.MessageInfo
+	// Ordered list of known UIDs
+	Uids []uint32
+	// Map of uids we've asked the worker to fetch
+	onUpdate       func(store *MessageStore)
+	pendingBodies  map[uint32]interface{}
+	pendingHeaders map[uint32]interface{}
+	worker         *types.Worker
+}
+
+func NewMessageStore(worker *types.Worker,
+	dirInfo *types.DirectoryInfo) *MessageStore {
+
+	return &MessageStore{
+		DirInfo: *dirInfo,
+
+		pendingBodies:  make(map[uint32]interface{}),
+		pendingHeaders: make(map[uint32]interface{}),
+		worker:         worker,
+	}
+}
+
+func (store *MessageStore) FetchHeaders(uids []uint32) {
+	// TODO: this could be optimized by pre-allocating toFetch and trimming it
+	// at the end. In practice we expect to get most messages back in one frame.
+	var toFetch imap.SeqSet
+	for _, uid := range uids {
+		if _, ok := store.pendingHeaders[uid]; !ok {
+			toFetch.AddNum(uint32(uid))
+			store.pendingHeaders[uid] = nil
+		}
+	}
+	if !toFetch.Empty() {
+		store.worker.PostAction(&types.FetchMessageHeaders{
+			Uids: toFetch,
+		}, nil)
+	}
+}
+
+func (store *MessageStore) Update(msg types.WorkerMessage) {
+	update := false
+	switch msg := msg.(type) {
+	case *types.DirectoryInfo:
+		store.DirInfo = *msg
+		update = true
+		break
+	case *types.DirectoryContents:
+		newMap := make(map[uint32]*types.MessageInfo)
+		for _, uid := range msg.Uids {
+			if msg, ok := store.Messages[uid]; ok {
+				newMap[uid] = msg
+			} else {
+				newMap[uid] = nil
+			}
+		}
+		store.Messages = newMap
+		store.Uids = msg.Uids
+		update = true
+		break
+	case *types.MessageInfo:
+		// TODO: merge message info into existing record, if applicable
+		store.Messages[msg.Uid] = msg
+		if _, ok := store.pendingHeaders[msg.Uid]; msg.Envelope != nil && ok {
+			delete(store.pendingHeaders, msg.Uid)
+		}
+		update = true
+		break
+	}
+	if update && store.onUpdate != nil {
+		store.onUpdate(store)
+	}
+}
+
+func (store *MessageStore) OnUpdate(fn func(store *MessageStore)) {
+	store.onUpdate = fn
+}