1 files changed, 53 insertions, 0 deletions
diff --git a/src/background/usecases/TabSelectUseCase.ts b/src/background/usecases/TabSelectUseCase.ts
new file mode 100644
index 0000000..a0b52f0
--- /dev/null
+++ b/src/background/usecases/TabSelectUseCase.ts
@@ -0,0 +1,53 @@
+import TabPresenter from '../presenters/TabPresenter';
+
+export default class TabSelectUseCase {
+  private tabPresenter: TabPresenter;
+
+  constructor() {
+    this.tabPresenter = new TabPresenter();
+  }
+
+  async selectPrev(count: number): Promise<any> {
+    let tabs = await this.tabPresenter.getAll();
+    if (tabs.length < 2) {
+      return;
+    }
+    let tab = tabs.find(t => t.active);
+    if (!tab) {
+      return;
+    }
+    let select = (tab.index - count + tabs.length) % tabs.length;
+    return this.tabPresenter.select(tabs[select].id as number);
+  }
+
+  async selectNext(count: number): Promise<any> {
+    let tabs = await this.tabPresenter.getAll();
+    if (tabs.length < 2) {
+      return;
+    }
+    let tab = tabs.find(t => t.active);
+    if (!tab) {
+      return;
+    }
+    let select = (tab.index + count) % tabs.length;
+    return this.tabPresenter.select(tabs[select].id as number);
+  }
+
+  async selectFirst(): Promise<any> {
+    let tabs = await this.tabPresenter.getAll();
+    return this.tabPresenter.select(tabs[0].id as number);
+  }
+
+  async selectLast(): Promise<any> {
+    let tabs = await this.tabPresenter.getAll();
+    return this.tabPresenter.select(tabs[tabs.length - 1].id as number);
+  }
+
+  async selectPrevSelected(): Promise<any> {
+    let tabId = await this.tabPresenter.getLastSelectedId();
+    if (tabId === null || typeof tabId === 'undefined') {
+      return Promise.resolve();
+    }
+    return this.tabPresenter.select(tabId);
+  }
+}