From f168248be70c48b4f41ec75a5dc16c516993aa3a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maciej=20P=C4=99dzich?= <dnalop.me@gmail.com>
Date: Mon, 12 Sep 2022 20:58:06 +0200
Subject: [PATCH] Implement proper pull request event handling

---
 index.ts | 126 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 123 insertions(+), 3 deletions(-)

diff --git a/index.ts b/index.ts
index f6fcc1e..727eeae 100644
--- a/index.ts
+++ b/index.ts
@@ -1,9 +1,129 @@
 import { ApplicationFunction } from 'probot';
 
 const appFn: ApplicationFunction = (app) => {
-  app.onAny((context) => {
-    console.log(JSON.stringify(context.payload, null, 2));
-  });
+  app.on(
+    ['pull_request.opened', 'pull_request.synchronize'],
+    async (context) => {
+      const registryDirectoryPath = 'playlists/registry/';
+      const siQueryStart = '?si=';
+      const pull_number = context.payload.number;
+      const repo = {
+        owner: 'mackorone',
+        repo: 'spotify-playlist-archive'
+      };
+
+      const removePathFromFilename = (filename: string) =>
+        filename.replace(registryDirectoryPath, '');
+
+      const upsertReview = async (body: string, review_id: number) => {
+        if (review_id) {
+          await context.octokit.pulls.updateReview({
+            ...repo,
+            pull_number,
+            review_id,
+            body
+          });
+        } else {
+          await context.octokit.pulls.createReview({
+            ...repo,
+            pull_number,
+            event: 'REQUEST_CHANGES',
+            body
+          });
+        }
+      };
+
+      try {
+        const { data: prFiles } = await context.octokit.pulls.listFiles({
+          ...repo,
+          pull_number
+        });
+
+        const filesToVerify = prFiles.filter(
+          ({ status, filename }) =>
+            status === 'added' && filename.startsWith(registryDirectoryPath)
+        );
+
+        const filesWithSiQuery = filesToVerify.filter(({ filename }) =>
+          filename.includes(siQueryStart)
+        );
+
+        const playlistLookupResults = await Promise.all(
+          filesToVerify.map(async ({ filename }) => {
+            const filenameWithoutPath = removePathFromFilename(filename);
+            const spotifyResponse = await fetch(
+              `https://open.spotify.com/playlist/${filenameWithoutPath}`
+            );
+
+            return {
+              filename: removePathFromFilename(filename),
+              found: spotifyResponse.status === 200
+            };
+          })
+        );
+
+        const notFoundPlaylists = playlistLookupResults.filter(
+          ({ found }) => !found
+        );
+
+        const { data: priorReviews } = await context.octokit.pulls.listReviews({
+          ...repo,
+          pull_number
+        });
+
+        const [existingReview] = priorReviews;
+
+        if (notFoundPlaylists.length > 0) {
+          const renameList = notFoundPlaylists
+            .map(({ filename }) => `- ${filename}`)
+            .join('\n');
+
+          const body = `It looks like the following playlists don't exist: ${renameList}`;
+
+          await upsertReview(body, existingReview?.id);
+        } else {
+          if (filesWithSiQuery.length > 0) {
+            const renameList = filesWithSiQuery
+              .map(({ filename }) => {
+                const filenameWithoutPath = removePathFromFilename(filename);
+                const [targetFilename] =
+                  filenameWithoutPath.split(siQueryStart);
+
+                return `- Rename ${filenameWithoutPath} to **${targetFilename}**`;
+              })
+              .join('\n');
+
+            const body = `In order for me to accept changes, you have to: ${renameList}`;
+
+            await upsertReview(body, existingReview?.id);
+          } else {
+            if (existingReview) {
+              await context.octokit.pulls.dismissReview({
+                ...repo,
+                pull_number,
+                review_id: existingReview.id,
+                message: 'Changes can now be accepted!'
+              });
+            }
+
+            await context.octokit.pulls.merge({
+              ...repo,
+              pull_number
+            });
+          }
+        }
+      } catch (error) {
+        console.error(error);
+
+        await context.octokit.pulls.createReview({
+          ...repo,
+          pull_number,
+          event: 'COMMENT',
+          body: 'Something went wrong while performing automatic verification! @mackorone should handle it manually.'
+        });
+      }
+    }
+  );
 };
 
 export = appFn;