feat: 增加账单

src/service/models/bill.ts

@@ -0,0 +1,29 @@
+import { Schema, model, models } from 'mongoose';
+
+const BillSchema = new Schema({
+  userId: {
+    type: Schema.Types.ObjectId,
+    ref: 'user',
+    required: true
+  },
+  chatId: {
+    type: Schema.Types.ObjectId,
+    ref: 'chat',
+    required: true
+  },
+  time: {
+    type: Number,
+    default: () => Date.now()
+  },
+  textLen: {
+    // 提示词+响应的总字数
+    type: Number,
+    required: true
+  },
+  price: {
+    type: Number,
+    required: true
+  }
+});
+
+export const Bill = models['bill'] || model('bill', BillSchema);