feat(manga): best guess estimation

1 files changed, 80 insertions, 0 deletions

diff --git a/src/lib/AniList/media.ts b/src/lib/AniList/media.ts
index 341e09a4..6187094d 100644
--- a/src/lib/AniList/media.ts
+++ b/src/lib/AniList/media.ts
@@ -170,3 +170,83 @@ export const publicMediaListCollection = async (userId: number, type: Type): Pro
 
 	return flattenLists(userIdResponse['data']['MediaListCollection']['lists']);
 };
+
+export const recentMediaActivities = async (
+	userIdentity: UserIdentity,
+	media: Media
+): Promise<number | null> => {
+	const activities = await (
+		await fetch('https://graphql.anilist.co', {
+			method: 'POST',
+			headers: {
+				'Content-Type': 'application/json',
+				Accept: 'application/json'
+			},
+			body: JSON.stringify({
+				query: `{
+					Page(page: 1) {
+						activities(mediaId: ${media.id}, sort: ID_DESC) {
+							... on ListActivity { progress }
+						}
+					}
+
+					MediaList(userId: ${userIdentity.id}, mediaId: ${media.id}) { progress }
+				}`
+			})
+		})
+	).json();
+	// Essentially, just Automail estimation. All credit to hoh and the Automail contributors.
+	let guesses: number[] = [];
+
+	activities['data']['Page']['activities'].forEach((activity: { progress: string }) => {
+		if (activity.progress !== null) {
+			const progress = Number((activity.progress.match(/\d+$/) || [0])[0]);
+
+			if (progress !== 65535) {
+				guesses.push(progress);
+			}
+		}
+	});
+	guesses.sort((a, b) => b - a);
+
+	if (guesses.length) {
+		let bestGuess = guesses[0];
+
+		if (guesses.length > 2) {
+			if (guesses.filter((val) => val < 7000).length) {
+				guesses = guesses.filter((val) => val < 7000);
+			}
+
+			const difference = guesses[0] - guesses[1];
+			const inverseDifference = 1 + Math.ceil(25 / (difference + 1));
+
+			if (guesses.length >= inverseDifference) {
+				if (
+					guesses[1] === guesses[inverseDifference] ||
+					guesses[0] - guesses[1] > 500 ||
+					(guesses[0] - guesses[1] > 100 && guesses[1] >= guesses[inverseDifference] - 1)
+				) {
+					bestGuess = guesses[1];
+
+					if (
+						guesses.length > 15 &&
+						guesses[1] - guesses[2] > 50 &&
+						guesses[2] === guesses[guesses.length - 1]
+					) {
+						bestGuess = guesses[2];
+					}
+				}
+			}
+		}
+
+		if (activities['data']['MediaList']['progress'] !== null) {
+			if (activities['data']['MediaList']['progress'] > bestGuess) {
+				bestGuess = activities['data']['MediaList']['progress'];
+			}
+		}
+
+		return bestGuess;
+	}
+
+	return null;
+};