From 19467de809301ddecbc414676e9c5bbfe29b2977 Mon Sep 17 00:00:00 2001
From: junderw <jonathan.underwood4649@gmail.com>
Date: Sun, 18 Sep 2022 22:30:09 +0900
Subject: [PATCH] Backend: Add block height from timestamp endpoint

---
 backend/src/api/mining/mining-routes.ts      | 20 +++++++++++++
 backend/src/repositories/BlocksRepository.ts | 30 ++++++++++++++++++++
 2 files changed, 50 insertions(+)

diff --git a/backend/src/api/mining/mining-routes.ts b/backend/src/api/mining/mining-routes.ts
index f52d42d1f..c9ace12e5 100644
--- a/backend/src/api/mining/mining-routes.ts
+++ b/backend/src/api/mining/mining-routes.ts
@@ -27,6 +27,7 @@ class MiningRoutes {
       .get(config.MEMPOOL.API_URL_PREFIX + 'mining/difficulty-adjustments/:interval', this.$getDifficultyAdjustments)
       .get(config.MEMPOOL.API_URL_PREFIX + 'mining/blocks/predictions/:interval', this.$getHistoricalBlockPrediction)
       .get(config.MEMPOOL.API_URL_PREFIX + 'mining/blocks/audit/:hash', this.$getBlockAudit)
+      .get(config.MEMPOOL.API_URL_PREFIX + 'mining/blocks/timestamp/:timestamp', this.$getHeightFromTimestamp)
     ;
   }
 
@@ -246,6 +247,25 @@ class MiningRoutes {
       res.status(500).send(e instanceof Error ? e.message : e);
     }
   }
+
+  private async $getHeightFromTimestamp(req: Request, res: Response) {
+    try {
+      const timestamp = parseInt(req.params.timestamp, 10);
+      // Prevent non-integers that are not seconds
+      if (!/^[1-9][0-9]*$/.test(req.params.timestamp) || timestamp >= 2 ** 32) {
+        throw new Error(`Invalid timestamp, value must be Unix seconds`);
+      }
+      const result = await BlocksRepository.$getBlockHeightFromTimestamp(
+        timestamp,
+      );
+      res.header('Pragma', 'public');
+      res.header('Cache-control', 'public');
+      res.setHeader('Expires', new Date(Date.now() + 1000 * 300).toUTCString());
+      res.json(result);
+    } catch (e) {
+      res.status(500).send(e instanceof Error ? e.message : e);
+    }
+  }
 }
 
 export default new MiningRoutes();
diff --git a/backend/src/repositories/BlocksRepository.ts b/backend/src/repositories/BlocksRepository.ts
index 40f670833..c5a1a2ae4 100644
--- a/backend/src/repositories/BlocksRepository.ts
+++ b/backend/src/repositories/BlocksRepository.ts
@@ -392,6 +392,36 @@ class BlocksRepository {
     }
   }
 
+  /**
+   * Get the first block at or directly after a given timestamp
+   * @param timestamp number unix time in seconds
+   * @returns The height and timestamp of a block (timestamp might vary from given timestamp)
+   */
+  public async $getBlockHeightFromTimestamp(
+    timestamp: number,
+  ): Promise<{ height: number; timestamp: number }> {
+    try {
+      // Get first block at or after the given timestamp
+      const query = `SELECT height, blockTimestamp as timestamp FROM blocks
+        WHERE blockTimestamp >= FROM_UNIXTIME(?)
+        ORDER BY blockTimestamp ASC
+        LIMIT 1`;
+      const params = [timestamp];
+      const [rows]: any[][] = await DB.query(query, params);
+      if (rows.length === 0) {
+        throw new Error(`No block was found after timestamp ${timestamp}`);
+      }
+
+      return rows[0];
+    } catch (e) {
+      logger.err(
+        'Cannot get block height from timestamp from the db. Reason: ' +
+          (e instanceof Error ? e.message : e),
+      );
+      throw e;
+    }
+  }
+
   /**
    * Return blocks height
    */