Merge pull request #82 from fac30/spotify

Spotify interface integration

src/controllers/spotify/index.ts

@@ -1,67 +1,263 @@
-import { SpotifyApi } from "@spotify/web-api-ts-sdk";
+import SpotifyWebApi from "spotify-web-api-node";
 import * as dotenv from "dotenv";
 import { spotifyResponse, track } from "../../types/spotifyResponse.js";
 import { spotifyQuery, spotifyFeatures } from "../../types/spotifyQuery.js";
 
 dotenv.config();
 
-// Access the client ID and secret from the .env file
-const clientId = process.env.SPOTIFY_CLIENT_ID;
-const clientSecret = process.env.SPOTIFY_CLIENT_SECRET;
+/*General explanation
+  This script builds upon the original index.ts that searches for tracks based on genre.
+  The original script effectively establishes the foundation for making API calls and processing responses.
+  Here, we are adding to that foundation by a date range (by year) search criteria and making a subsequent
+  API call to retrieve audio features, then filtering them and sorting them based on the intended audio
+  feature results we have targeted. We are making 6 API calls of 50 (API limit) to get a pool of 300 tracks
+  to filer and sort for audio filters in order to get tracks that more or less meet our criteria. We are
+  prioritising valence and energy audio features and then danceability, tempo and acousticness (in that order).
+  The playlist being output produced duplicate songs or many songs by the same artists so we are
+  also filtering the results so we only keep the highest scoring song by a certain artist.
+*/
 
-// Initialize the Spotify SDK using client credentials
-const sdk = SpotifyApi.withClientCredentials(clientId, clientSecret);
+/*spotify-web-api-node module instead of @spotify/web-api-ts-sdk - why?
+  In order to perform more custom queries, we can use spotify-web-api-node module which allows us to build
+  a custom query string (find the searchQuery string variable to see how this is built) and use it to search the
+  API using the spotifyApi.searchTracks function.
+*/
 
-// Define an async function to search tracks based on genre
-async function searchGenre(query: spotifyQuery) {
+/*Typescript
+  We also utilize TypeScript's typing system to define clear interfaces for our data structures.
+*/
+
+// Accessing the client ID and secret from the .env file
+const clientId = process.env.SPOTIFY_CLIENT_ID!;
+const clientSecret = process.env.SPOTIFY_CLIENT_SECRET!;
+
+// Initializing the Spotify API client with your credentials
+const spotifyApi = new SpotifyWebApi({
+  clientId: clientId,
+  clientSecret: clientSecret,
+});
+
+// Function to obtain and set an access token
+async function getAccessToken() {
+  const data = await spotifyApi.clientCredentialsGrant(); // Getting an access token using client credentials
+  spotifyApi.setAccessToken(data.body["access_token"]); // Setting the access token for future API requests
+}
+
+// Helper function to calculate the absolute difference between two numbers
+function calculateFeatureDifference(a: number, b: number) {
+  return Math.abs(a - b);
+}
+
+// Helper function to fetch audio features for tracks in batches - this is effectively a subsequent API call to retrieve
+// the audio feature settings of each song we collected from the previous 6 API calls
+async function getAudioFeaturesInBatches(
+  trackIds: string[],
+  spotifyApi: SpotifyWebApi,
+): Promise<SpotifyApi.AudioFeaturesObject[]> {
+  const audioFeatures: SpotifyApi.AudioFeaturesObject[] = [];
+  const batchSize = 100; // Spotify API allows up to 100 track IDs per request
+
+  // Looping through the track IDs in batches to comply with API limitations
+  for (let i = 0; i < trackIds.length; i += batchSize) {
+    const batch = trackIds.slice(i, i + batchSize); // Creating a batch of track IDs
+    const response = await spotifyApi.getAudioFeaturesForTracks(batch); // Fetching audio features for the batch
+    if (response.body.audio_features) {
+      audioFeatures.push(...response.body.audio_features); // Accumulating the audio features
+    }
+  }
+
+  return audioFeatures; // Returning all collected audio features
+}
+
+// Main function to search tracks based on genre, date range, and audio features
+async function generatePlaylist(query: spotifyQuery) {
   try {
-    const playlist: spotifyResponse = [];
-    const genre = query.genre;
-    console.log(`Searching for tracks in the genre: ${genre}`);
-
-    // Search for tracks by genre
-    const searchResults = await sdk.search(`genre:${genre}`, ["track"]);
-
-    // Check if any tracks are found
-    if (searchResults.tracks && searchResults.tracks.items.length > 0) {
-      searchResults.tracks.items.forEach((track, index) => {
-        const song: track = {
-          title: track.name,
-          artist: track.artists[0].name,
-          album: track.album.name,
-          releaseDate: new Date(track.album.release_date),
-          duration: track.duration_ms,
-        };
-
-        playlist.push(song);
-        console.log(track);
-        console.log(`${index + 1}. ${track.name} by ${track.artists[0].name}`);
+    await getAccessToken(); // Ensuring we have a valid access token before making API calls
+
+    const { genre, date, spotifyFeatures } = query; // Destructuring the query object
+
+    // Calculating the start and end dates for the 12-month range prior to the given date
+    const endDate = new Date(date);
+    const startDate = new Date(date);
+    startDate.setFullYear(startDate.getFullYear() - 1); // Subtracting one year to get the start date
+
+    const startYear = startDate.getFullYear();
+    const endYear = endDate.getFullYear();
+
+    // Creating the search query string to include genre and year range
+    const searchQuery = `genre:${genre} year:${startYear}-${endYear}`;
+
+    let allTracks: SpotifyApi.TrackObjectFull[] = [];
+
+    // Making multiple API calls to gather a larger set of tracks
+    // This expands on the original script's effective method of fetching tracks by genre
+    for (let i = 0; i < 6; i++) {
+      // Making 6 API calls to get 300 tracks in total
+      const searchResults = await spotifyApi.searchTracks(searchQuery, {
+        limit: 50,
+        offset: i * 50, // Using offset to fetch different sets of tracks
+      });
+      const tracks = searchResults.body.tracks?.items;
+      if (tracks && tracks.length > 0) {
+        allTracks = allTracks.concat(tracks); // Accumulating all tracks into one array
+      }
+    }
+
+    if (allTracks.length > 0) {
+      console.log(
+        `Found ${allTracks.length} tracks in the genre '${genre}' between ${startYear} and ${endYear}:`,
+      );
+
+      const trackIds = allTracks.map((track) => track.id); // Extracting track IDs for audio feature requests
+
+      // Fetching audio features for all tracks in batches
+      const audioFeatures = await getAudioFeaturesInBatches(
+        trackIds,
+        spotifyApi,
+      );
+
+      // Sorting tracks based on how closely they match the desired audio features
+      const sortedTracks = audioFeatures
+        ?.filter((feature) => feature) // Filtering out any undefined features
+        .map((feature) => {
+          if (!feature) return null;
+
+          // Calculating differences between each track's features and the target features
+          return {
+            feature,
+            differences: {
+              valence: calculateFeatureDifference(
+                feature.valence,
+                spotifyFeatures.valence,
+              ),
+              energy: calculateFeatureDifference(
+                feature.energy,
+                spotifyFeatures.energy,
+              ),
+              danceability: calculateFeatureDifference(
+                feature.danceability,
+                spotifyFeatures.danceability,
+              ),
+              tempo: calculateFeatureDifference(
+                feature.tempo,
+                spotifyFeatures.tempo,
+              ),
+              acousticness: calculateFeatureDifference(
+                feature.acousticness,
+                spotifyFeatures.acousticness,
+              ),
+            },
+          };
+        })
+        .filter(
+          (
+            item,
+          ): item is {
+            feature: SpotifyApi.AudioFeaturesObject;
+            differences: spotifyFeatures;
+          } => item !== null,
+        )
+        .sort((a, b) => {
+          // Prioritizing valence and energy equally, then danceability, tempo, and acousticness
+          const valenceEnergyDifference =
+            a.differences.valence +
+            a.differences.energy -
+            (b.differences.valence + b.differences.energy);
+          if (valenceEnergyDifference !== 0) return valenceEnergyDifference;
+          return (
+            a.differences.danceability - b.differences.danceability ||
+            a.differences.tempo - b.differences.tempo ||
+            a.differences.acousticness - b.differences.acousticness
+          );
+        });
+
+      // Removing duplicate artists to ensure diversity in the playlist
+      const uniqueArtistTracks = sortedTracks.filter((item, index, self) => {
+        const track = allTracks.find((t) => t.id === item.feature.id);
+        if (!track) return false;
+        const artistName = track.artists[0].name;
+        // Keeping only the first occurrence of each artist
+        return (
+          index ===
+          self.findIndex((t) => {
+            const otherTrack = allTracks.find((t2) => t2.id === t.feature.id);
+            return otherTrack?.artists[0].name === artistName;
+          })
+        );
       });
-      console.log(Object.keys(searchResults.tracks.items[0].album));
+
+      // Selecting the top 10 tracks that best match the criteria
+      const topTracks = uniqueArtistTracks.slice(0, 10);
+      const playlist: spotifyResponse = [];
+
+      if (topTracks.length > 0) {
+        console.log(
+          `Returning ${topTracks.length} tracks matching audio feature criteria:`,
+        );
+
+        // Displaying detailed information about each selected track
+        topTracks.forEach((item, index) => {
+          const track = allTracks.find((t) => t.id === item.feature.id);
+          if (track) {
+            const releaseDate = track.album.release_date;
+            console.log(
+              `${index + 1}. ${track.name} by ${track.artists[0].name}, Release Date: ${releaseDate}`,
+            );
+            console.log(
+              `   Valence: ${item.feature.valence.toFixed(2)} (Target: ${spotifyFeatures.valence})`,
+            );
+            console.log(
+              `   Energy: ${item.feature.energy.toFixed(2)} (Target: ${spotifyFeatures.energy})`,
+            );
+            console.log(
+              `   Danceability: ${item.feature.danceability.toFixed(2)} (Target: ${spotifyFeatures.danceability})`,
+            );
+            console.log(
+              `   Acousticness: ${item.feature.acousticness.toFixed(2)} (Target: ${spotifyFeatures.acousticness})`,
+            );
+            console.log(
+              `   Tempo: ${item.feature.tempo.toFixed(2)} BPM (Target: ${spotifyFeatures.tempo})`,
+            );
+          }
+          const song: track = {
+            title: track.name,
+            artist: track.artists[0].name,
+            album: track.album.name,
+            releaseDate: new Date(track.album.release_date),
+            duration: track.duration_ms,
+          };
+          playlist.push(song);
+        });
+
+      } else {
+        console.log("No tracks found matching the audio feature criteria.");
+      }
       console.log(playlist);
+      return playlist; // Returning the top tracks
     } else {
-      console.log(`No tracks found for the genre: ${genre}`);
+      console.log(
+        `No tracks found in the genre '${genre}' between ${startYear} and ${endYear}`,
+      );
     }
-
-    return searchResults.tracks?.items;
   } catch (error) {
-    console.error("Error fetching tracks by genre:", error);
+    console.error("Error searching for tracks:", error);
   }
 }
-//dummy Object
 
+// Example usage:
+// Creating a query object with desired genre, date, and audio features
 const query: spotifyQuery = {
-  mood: "sad",
   genre: "jazz",
-  date: new Date("2024-09-23T19:00:00.000z"),
+  mood: "jazzy",
+  date: new Date("2024-09-23T19:00:00.000Z"),
   spotifyFeatures: {
-    valence: 0.9,
-    energy: 0.8,
-    danceability: 0.8,
-    acousticness: 0.1,
+    valence: 0.8,
+    energy: 0.7,
+    danceability: 0.6,
+    acousticness: 0.2,
     tempo: 120,
   },
 };
 
-// Call the function with a specific genre (e.g., jazz)
-searchGenre(query);
+// Calling the function with the query object
+generatePlaylist(query);