From 3653f3db9974bb85c1dbc925d1ca48185c324c1a Mon Sep 17 00:00:00 2001
From: Jesse McDonald <nybble41@gmail.com>
Date: Mon, 27 Apr 2020 17:55:28 -0500
Subject: [PATCH] add a REST API to submit new game data via POST

---
 index.js | 172 +++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 162 insertions(+), 10 deletions(-)

diff --git a/index.js b/index.js
index 6a34739..0d71dea 100644
--- a/index.js
+++ b/index.js
@@ -461,25 +461,177 @@ async function getMetaHandler(req, res, next) {
   }
 }
 
+const updateTemplate = {
+  lightName(x) { return typeof x === 'string'; },
+  darkName(x) { return typeof x === 'string'; },
+  moves(x) { return Number.isInteger(x); },
+  status(x) { return typeof x === 'string'; },
+  timestamp(x) { return Number.isInteger(x); },
+  board(x) { return true; },
+  modified(x) { return Number.isInteger(x); },
+};
+
+function validateUpdate(body) {
+  try {
+    if (typeof body !== 'object' || 'modified' in body === false) {
+      console.log('invalid type or missing modified property');
+      return null;
+    }
+
+    for (const key in body) {
+      if (key in updateTemplate === false) {
+        console.log('extra key', key);
+        return null;
+      }
+      if (updateTemplate[key](body[key]) === false) {
+        console.log('invalid value', body[key], 'for key', key);
+        return null;
+      }
+    }
+  } catch(err) {
+    console.log('exception', err);
+    return null;
+  }
+
+  return body;
+}
+
+async function postGameHandler(req, res, next) {
+  res.set('Cache-Control', 'no-store');
+  try {
+    const time = +new Date();
+    const gameId = req.params.gameId;
+    const body = validateUpdate(req.body);
+
+    console.log('update for', gameId, 'at time', time, req.body, !body);
+
+    if (!gameId.match(/^[0-9a-f]{16}$/)) {
+      res.status(400).json({ message: 'malformed game ID' });
+      return;
+    }
+
+    if (!body) {
+      res.status(400).json({ message: 'invalid request' });
+      return;
+    }
+
+    const params = {
+      $gameId: gameId,
+      $lightName: '',
+      $darkName: '',
+      $moves: 0,
+      $status: '',
+      $timestamp: 0,
+      $board: '',
+      $modified: body.modified,
+      $time: time,
+    };
+
+    if (params.$modified >= params.$time) {
+      res.status(400).json({ message: 'invalid modification time' });
+      return;
+    }
+
+    let setClause = '';
+    let whereClause = '';
+    let hasBoard = false;
+    let hasMeta = false;
+
+    for (const key in body) {
+      if (key !== 'modified') {
+        if (key in updateTemplate === false) {
+          throw { message: 'internal error' };
+        }
+        if (key === 'board') {
+          params['$' + key] = JSON.stringify(body[key]);
+          hasBoard = true;
+        } else {
+          params['$' + key] = body[key];
+          hasMeta = true;
+        }
+        if (setClause !== '') {
+          setClause += ', ';
+          whereClause += ' OR ';
+        }
+        setClause += key + ' = $' + key;
+        whereClause += key + ' <> $' + key;
+      }
+    }
+
+    if (setClause === '') {
+      res.status(400).json({ message: 'empty update' });
+      return;
+    }
+
+    const db = await dbInit;
+
+    const insertSql = `
+      INSERT INTO games (gameId, lightName, darkName, moves, status, timestamp, board, added, modified)
+        VALUES ($gameId, $lightName, $darkName, $moves, $status, $timestamp, $board, $time, $time)
+      ON CONFLICT (gameId) DO UPDATE SET ${setClause}, modified = $time
+        WHERE (${whereClause}) AND modified = $modified
+    `;
+    const selectSql = `SELECT * FROM games WHERE gameId = $gameId`
+    let beginP, insertP, selectP, commitP;
+    db.serialize(() => {
+      /* Important: We need to start all these queries without waiting in between. */
+      /* Otherwise db.serialize() will not have the desired effect. */
+      beginP = db.execAsync(`BEGIN TRANSACTION`);
+      insertP = db.runAsync(insertSql, params);
+      selectP = db.getAsync(selectSql, { $gameId: gameId });
+      commitP = db.execAsync(`COMMIT TRANSACTION`);
+    });
+    /* Now wait for all the queries to finish. */
+    await Promise.all([beginP, insertP, commitP]);
+    const result = await selectP;
+
+    if (!result || result.modified !== params.$time) {
+      res.status(409).json({ message: 'update failed', modified: (result || {}).modified });
+      return;
+    }
+
+    signalGameUpdate(gameId);
+
+    res.json({ success: true, modified: result.modified });
+
+    (async () => {
+      if (hasBoard) {
+        gun.get(PacoSakoUUID + '/game/' + gameId).get('board').put(result.board);
+      }
+
+      if (hasMeta) {
+        const meta = {
+          lightName: result.lightName,
+          darkName: result.darkName,
+          moves: result.moves,
+          timestamp: result.timestamp,
+          status: (result.status === '') ? null : result.status,
+        };
+
+        const metaRef = gun.get(PacoSakoUUID + '/meta/' + gameId).put(meta);
+
+        if (meta.lightName !== '' || meta.darkName !== '' || meta.moves !== 0) {
+          gun.get(PacoSakoUUID + '/meta').get(gameId).put(metaRef);
+        } else {
+          gun.get(PacoSakoUUID + '/meta').get(gameId).put(null);
+        }
+      }
+    })().catch(console.error);
+  } catch (err) {
+    internalErrorJson(err, res);
+  }
+}
+
 app.get('/pacosako/api/games/poll/:afterTime', getGameListHandler);
 app.get('/pacosako/api/games', getGameListHandler);
 
 app.get('/pacosako/api/game/:gameId/poll/:afterTime', getGameHandler);
 app.get('/pacosako/api/game/:gameId', getGameHandler);
+app.post('/pacosako/api/game/:gameId', express.json(), postGameHandler);
 
 app.get('/pacosako/api/meta/:gameId/poll/:afterTime', getMetaHandler);
 app.get('/pacosako/api/meta/:gameId', getMetaHandler);
 
-/* TODO: Add APIs for posting updates. */
-app.use('/pacosako/api/posttest', express.json());
-app.post('/pacosako/api/posttest', async function(req, res, next) {
-  try {
-    res.json(req.body);
-  } catch (err) {
-    internalErrorJson(err, res);
-  }
-});
-
 app.use('/pacosako/api', express.static('public'));
 
 app.use('/gun', Gun.serve(__dirname));