REFACTOR: channel retention reminder text (#20310)

- Moves logic into one specialised component
- Adds more tests
- Removes duplicate key
- Uses pluralization
- Handles 0 case properly

Co-authored-by: Gerhard Schlager <mail@gerhard-schlager.at>

plugins/chat/test/javascripts/components/chat-retention-reminder-text-test.js

@@ -0,0 +1,54 @@
+import ChatChannel from "discourse/plugins/chat/discourse/models/chat-channel";
+import { setupRenderingTest } from "discourse/tests/helpers/component-test";
+import hbs from "htmlbars-inline-precompile";
+import I18n from "I18n";
+import { module, test } from "qunit";
+import { render } from "@ember/test-helpers";
+
+module(
+  "Discourse Chat | Component | chat-retention-reminder-text",
+  function (hooks) {
+    setupRenderingTest(hooks);
+
+    test("when setting is set on 0", async function (assert) {
+      this.channel = ChatChannel.create({ chatable_type: "Category" });
+      this.siteSettings.chat_channel_retention_days = 0;
+
+      await render(
+        hbs`<ChatRetentionReminderText @channel={{this.channel}} />`
+      );
+
+      assert
+        .dom(".chat-retention-reminder-text")
+        .includesText(I18n.t("chat.retention_reminders.public_none"));
+    });
+
+    test("when channel is a public channel", async function (assert) {
+      const count = 10;
+      this.channel = ChatChannel.create({ chatable_type: "Category" });
+      this.siteSettings.chat_channel_retention_days = count;
+
+      await render(
+        hbs`<ChatRetentionReminderText @channel={{this.channel}} />`
+      );
+
+      assert
+        .dom(".chat-retention-reminder-text")
+        .includesText(I18n.t("chat.retention_reminders.public", { count }));
+    });
+
+    test("when channel is a DM channel", async function (assert) {
+      const count = 10;
+      this.channel = ChatChannel.create({ chatable_type: "DirectMessage" });
+      this.siteSettings.chat_dm_retention_days = count;
+
+      await render(
+        hbs`<ChatRetentionReminderText @channel={{this.channel}} />`
+      );
+
+      assert
+        .dom(".chat-retention-reminder-text")
+        .includesText(I18n.t("chat.retention_reminders.dm", { count }));
+    });
+  }
+);