add functions and routes for ai: including new function for getting r…

…eviews rather than just modifying function in course

server/src/ai/ai.functions.ts

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+import dotenv from 'dotenv';
+import OpenAI from "openai";
+import { Reviews } from "../../db/schema";
+import { findCourseById } from '../course/course.data-access';
+import { CourseIdRequestType } from '../course/course.type';
+import { findReviewCrossListOR } from '../utils';
+
+dotenv.config();
+const openai = new OpenAI({
+  apiKey: process.env.OPENAI_API_KEY,
+});
+
+/** Docstring for makeSummary. Takes in all reviews from a course as text and 
+ * creates a 50 word summary of those reviews.
+ * @params all reviews from a course
+ * @returns summary of reviews
+ */
+async function makeSummary(text: string) {
+  const completion = await openai.chat.completions.create({
+    model: "gpt-3.5-turbo",
+    messages: [
+      { role: "system", content: "You are creating a 50 word summary based on the collection of course reviews provided." },
+      { role: "user", content: text }
+    ],
+  });
+  return completion.choices[0].message.content;
+}
+
+/** Docstring for getCoursesWithMinReviews. We only want to create summaries for
+ * courses that have at least a certain number of reviews, so takes in that number
+ * and returns the courses that have at least that number of reviews.
+ * @params min reviews summary should be created for
+ * @returns courses ids with at least min reviews
+ */
+async function getCoursesWithMinReviews(minimum) {
+  const courses = await Reviews.aggregate([
+    {
+      $group: {
+        _id: "$class",
+        reviewCount: { $sum: 1 }
+      }
+    },
+    { $match: { reviewCount: { $gte: minimum } } },
+    {
+      $project: {
+        _id: 0,
+        classId: "$_id"
+      }
+    }
+  ]);
+
+  const courseIds = courses.map(course => course.classId);
+  return courseIds;
+}
+
+/**
+ * DocString for getReviewsForSummary. Gets all reviews from a course that will be used 
+ * to generate the summary for a course
+ * @param params takes in the courseID of a course that we need to generate a summary for
+ * @returns all reviews for that course concatenated into a single string
+ */
+async function getReviewsForSummary(params: CourseIdRequestType) {
+  const { courseId } = params;
+
+  // Validate the course ID format
+  const regex = new RegExp(/^(?=.*[A-Z0-9])/i);
+  if (!regex.test(courseId)) {
+    return null; // Return null for invalid course ID
+  }
+
+  // Fetch the course by ID
+  const course = await findCourseById(courseId);
+  if (!course) return null; // Return null if no course is found
+
+  // Fetch reviews for the course, including cross-listed courses
+  const crossListOR = getCrossListOR(course);
+  if (!crossListOR) return null; // Return null if no cross-listing data is available
+
+  const reviews = await findReviewCrossListOR(crossListOR);
+  if (reviews.length === 0) return null; // Return null if no reviews are found
+
+  // Create a single string of all review texts separated by '/'
+  const reviewTexts = reviews.map(review => review.text || "No review text").join(' / ');
+
+  return reviewTexts;
+}
+
+
+/**
+ * Helper function to get crosslist OR search criteria from a course.
+ * @param course The course object to extract crosslist data.
+ * @returns The formatted search criteria for crosslist.
+ */
+const getCrossListOR = (course) => {
+  if (!course || !course.crossList || course.crossList.length === 0) {
+    return null;
+  }
+  return [...course.crossList.map(cID => ({ class: cID })), { class: course._id }];
+};
+
+export { makeSummary, getCoursesWithMinReviews, getReviewsForSummary } 

server/src/ai/ai.router.ts

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+import express from 'express';
+import { makeSummary, getCoursesWithMinReviews } from './ai.functions';
+
+const aiRouter = express.Router();
+
+aiRouter.use(express.json());
+
+/** Reachable at POST /api/summarizeReviews
+ * @body a block of text containing all reviews from a course
+ * returns a summary created by OpenAI
+*/
+aiRouter.post('/summarizeReviews', async (req, res) => {
+  try {
+    if (!req.body.text) {
+      return res.status(400).json({ error: 'No text provided' });
+    }
+    const summary = await makeSummary(req.body.text);
+    res.status(200).json({ summary });
+  } catch (err) {
+    console.error(err);
+    res.status(500).json({ error: 'Internal Server Error' });
+  }
+});
+
+/** Reachable at POST /api/getCourseIdsForSummary
+ * @body minimum number of reviews needed to create a summary
+ * returns all course ids that have at least that number of reviews
+*/
+aiRouter.post('/getCourseIdsForSummary', async (req, res) => {
+  try {
+    const min = req.body.min;
+    const ids = await getCoursesWithMinReviews(min);
+    if (ids === null) {
+      return res.status(400).json({
+        error: `No courses found with given minimum number of reviews`,
+      });
+    }
+
+    return res.status(200).json({
+      message: 'Retrieved all courses',
+      ids: ids,
+    });
+  } catch (err) {
+    return res.status(500).json({ error: `Internal Server Error: ${err}` });
+  }
+});
+
+export default aiRouter;