From acff469ba069b6f090adfd5ed91379c9f146aa77 Mon Sep 17 00:00:00 2001
From: Logan Hunt <loganhunt@simponic.xyz>
Date: Wed, 30 Mar 2022 15:18:16 -0600
Subject: Ability to add, remove, update radius and location of chatrooms with
 a leaflet

---
 .../1648669551959-AddDistanceFunction.ts           | 45 ++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 server/database/migrations/1648669551959-AddDistanceFunction.ts

(limited to 'server/database/migrations/1648669551959-AddDistanceFunction.ts')

diff --git a/server/database/migrations/1648669551959-AddDistanceFunction.ts b/server/database/migrations/1648669551959-AddDistanceFunction.ts
new file mode 100644
index 0000000..0890936
--- /dev/null
+++ b/server/database/migrations/1648669551959-AddDistanceFunction.ts
@@ -0,0 +1,45 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+
+export class AddDistanceFunction1648669551959 implements MigrationInterface {
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    // From https://stackoverflow.com/questions/61135374/postgresql-calculate-distance-between-two-points-without-using-postgis
+    await queryRunner.query(`
+CREATE OR REPLACE FUNCTION calculate_distance(lat1 float, lon1 float, lat2 float, lon2 float, units varchar)
+  RETURNS float AS $dist$
+      DECLARE
+          dist float = 0;
+          radlat1 float;
+          radlat2 float;
+          theta float;
+          radtheta float;
+      BEGIN
+          IF lat1 = lat2 OR lon1 = lon2
+              THEN RETURN dist;
+          ELSE
+              radlat1 = pi() * lat1 / 180;
+              radlat2 = pi() * lat2 / 180;
+              theta = lon1 - lon2;
+              radtheta = pi() * theta / 180;
+              dist = sin(radlat1) * sin(radlat2) + cos(radlat1) * cos(radlat2) * cos(radtheta);
+  
+              IF dist > 1 THEN dist = 1; END IF;
+  
+              dist = acos(dist);
+              dist = dist * 180 / pi();
+              dist = dist * 60 * 1.1515;
+  
+              IF units = 'K' THEN dist = dist * 1.609344; END IF;
+              IF units = 'N' THEN dist = dist * 0.8684; END IF;
+  
+              RETURN dist;
+          END IF;
+      END;
+  $dist$ LANGUAGE plpgsql;`);
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(
+      `DROP FUNCTION IF EXISTS calculate_distance(lat1 float, lon1 float, lat2 float, lon2 float, units varchar);`,
+    );
+  }
+}
-- 
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