Try to select sticky mail if in list

Fix the sticky mail selection behavior so that if we are on the list, it
will visually show that mail being selected. If not, don't try to go to
that list.

Fixes #7585

src/mail-app/mail/view/MailViewModel.ts

@@ -155,12 +155,22 @@ export class MailViewModel {
 
 		// This should be very quick as we only wait for the cache,
 		await this.loadExplicitMailTarget(listId, elementId, onMissingExplicitMailTarget)
+	}
 
-		if (!isSameId(this.stickyMailId, fullMailId)) return
+	private async resetOrInitializeList(stickyMailId: IdTuple) {
+		if (this._folder != null) {
+			// If we already have a folder, deselect.
+			this.listModel?.selectNone()
+		} else {
+			// Otherwise, load the inbox so that it won't be empty on mobile when you try to go back.
+			const userInbox = await this.getFolderForUserInbox()
 
-		// Make sure that we display *something* in the list, otherwise it'll be empty on mobile
-		// We could try to open the location of the mail, but it might have been moved around soon after
-		this.setListId(await this.getFolderForUserInbox())
+			if (this.didStickyMailChange(stickyMailId, "after loading user inbox ID")) {
+				return
+			}
+
+			this.setListId(userInbox)
+		}
 	}
 
 	private async showMail(folder?: MailFolder | null, mailId?: Id) {
@@ -230,16 +240,26 @@ export class MailViewModel {
 	}
 
 	private async loadExplicitMailTarget(listId: Id, mailId: Id, onMissingTargetEmail: () => unknown) {
+		const expectedStickyMailId: IdTuple = [listId, mailId]
+
+		// shouldStop returning true guarantees we won't load anything if the mail is not in the list already, so
+		// this will be synchronous
+		const listMail = await this.listModel?.loadAndSelect(mailId, () => true)
+		if (listMail) {
+			console.log(TAG, "opening mail from list", mailId)
+			return
+		}
+
 		const cached = await this.cacheStorage.get(MailTypeRef, listId, mailId)
 		if (cached) {
 			console.log(TAG, "opening cached mail", mailId)
+			await this.resetOrInitializeList([listId, mailId])
 			this.createConversationViewModel({ mail: cached, showFolder: false })
-			this.listModel?.selectNone()
 			this.updateUi()
+			return
 		}
 
-		if (!isSameId(this.stickyMailId, [listId, mailId])) {
-			console.log(TAG, "target mail id changed 1", mailId, this.stickyMailId)
+		if (this.didStickyMailChange(expectedStickyMailId, "after loading cached")) {
 			return
 		}
 
@@ -256,14 +276,13 @@ export class MailViewModel {
 			}
 		}
 
-		if (!isSameId(this.stickyMailId, [listId, mailId])) {
-			console.log(TAG, "target mail id changed 2", mailId, this.stickyMailId)
+		if (this.didStickyMailChange(expectedStickyMailId, "after loading from entity client")) {
 			return
 		}
 
 		if (mail) {
+			await this.resetOrInitializeList(expectedStickyMailId)
 			this.createConversationViewModel({ mail, showFolder: false })
-			this.listModel?.selectNone()
 			this.updateUi()
 		} else {
 			console.log(TAG, "Explicit mail target is not found", listId, mailId)
@@ -274,6 +293,14 @@ export class MailViewModel {
 		}
 	}
 
+	private didStickyMailChange(expectedId: IdTuple, message: string): boolean {
+		const changed = !isSameId(this.stickyMailId, expectedId)
+		if (changed) {
+			console.log(TAG, "target mail id changed", message, expectedId, this.stickyMailId)
+		}
+		return changed
+	}
+
 	private async loadAndSelectMail(folder: MailFolder, mailId: Id) {
 		const foundMail = await this.listModel?.loadAndSelect(
 			mailId,