messages: Implements /messages API

model/message.go

@@ -0,0 +1,18 @@
+package model
+
+import "time"
+
+type Message struct {
+	Text   string    `json:"text"`
+	Guid   string    `json:"guid"`
+	Sender *string   `json:"sender"` // Optional: nil means from "me"
+	Date   time.Time `json:"date"`
+
+	// Map of attachment GUID to attachment metadata
+	Attachments *map[string]AttributionInfo `json:"attachmentMetadata"` // Optional
+}
+
+type AttributionInfo struct {
+	ThumbnailWidth  int `json:"pgensw"`
+	ThumbnailHeight int `json:"pgensh"`
+}