From db383445ffdab046bb35099b914030ad84796f9f Mon Sep 17 00:00:00 2001
From: Jake <jake@moletastic.xyz>
Date: Thu, 19 Dec 2024 17:05:20 -0300
Subject: [PATCH] feat: add pgulid migration

---
 db/migrations/20241024151641_pgulid.sql | 85 +++++++++++++++++++++++++
 1 file changed, 85 insertions(+)
 create mode 100644 db/migrations/20241024151641_pgulid.sql

diff --git a/db/migrations/20241024151641_pgulid.sql b/db/migrations/20241024151641_pgulid.sql
new file mode 100644
index 0000000..0cc3a92
--- /dev/null
+++ b/db/migrations/20241024151641_pgulid.sql
@@ -0,0 +1,85 @@
+-- migrate:up
+
+-- pgulid is based on OK Log's Go implementation of the ULID spec
+--
+-- https://github.com/oklog/ulid
+-- https://github.com/ulid/spec
+--
+-- Copyright 2016 The Oklog Authors
+-- Licensed under the Apache License, Version 2.0 (the "License");
+-- you may not use this file except in compliance with the License.
+-- You may obtain a copy of the License at
+--
+-- http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS,
+-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+-- See the License for the specific language governing permissions and
+-- limitations under the License.
+
+CREATE EXTENSION IF NOT EXISTS pgcrypto;
+
+CREATE FUNCTION generate_ulid()
+RETURNS TEXT
+AS $$
+DECLARE
+  -- Crockford's Base32
+  encoding   BYTEA = '0123456789ABCDEFGHJKMNPQRSTVWXYZ';
+  timestamp  BYTEA = E'\\000\\000\\000\\000\\000\\000';
+  output     TEXT = '';
+
+  unix_time  BIGINT;
+  ulid       BYTEA;
+BEGIN
+  -- 6 timestamp bytes
+  unix_time = (EXTRACT(EPOCH FROM CLOCK_TIMESTAMP()) * 1000)::BIGINT;
+  timestamp = SET_BYTE(timestamp, 0, (unix_time >> 40)::BIT(8)::INTEGER);
+  timestamp = SET_BYTE(timestamp, 1, (unix_time >> 32)::BIT(8)::INTEGER);
+  timestamp = SET_BYTE(timestamp, 2, (unix_time >> 24)::BIT(8)::INTEGER);
+  timestamp = SET_BYTE(timestamp, 3, (unix_time >> 16)::BIT(8)::INTEGER);
+  timestamp = SET_BYTE(timestamp, 4, (unix_time >> 8)::BIT(8)::INTEGER);
+  timestamp = SET_BYTE(timestamp, 5, unix_time::BIT(8)::INTEGER);
+
+  -- 10 entropy bytes
+  ulid = timestamp || gen_random_bytes(10);
+
+  -- Encode the timestamp
+  output = output || CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 0) & 224) >> 5));
+  output = output || CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 0) & 31)));
+  output = output || CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 1) & 248) >> 3));
+  output = output || CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 1) & 7) << 2) | ((GET_BYTE(ulid, 2) & 192) >> 6)));
+  output = output || CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 2) & 62) >> 1));
+  output = output || CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 2) & 1) << 4) | ((GET_BYTE(ulid, 3) & 240) >> 4)));
+  output = output || CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 3) & 15) << 1) | ((GET_BYTE(ulid, 4) & 128) >> 7)));
+  output = output || CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 4) & 124) >> 2));
+  output = output || CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 4) & 3) << 3) | ((GET_BYTE(ulid, 5) & 224) >> 5)));
+  output = output || CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 5) & 31)));
+
+  -- Encode the entropy
+  output = output || CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 6) & 248) >> 3));
+  output = output || CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 6) & 7) << 2) | ((GET_BYTE(ulid, 7) & 192) >> 6)));
+  output = output || CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 7) & 62) >> 1));
+  output = output || CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 7) & 1) << 4) | ((GET_BYTE(ulid, 8) & 240) >> 4)));
+  output = output || CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 8) & 15) << 1) | ((GET_BYTE(ulid, 9) & 128) >> 7)));
+  output = output || CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 9) & 124) >> 2));
+  output = output || CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 9) & 3) << 3) | ((GET_BYTE(ulid, 10) & 224) >> 5)));
+  output = output || CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 10) & 31)));
+  output = output || CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 11) & 248) >> 3));
+  output = output || CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 11) & 7) << 2) | ((GET_BYTE(ulid, 12) & 192) >> 6)));
+  output = output || CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 12) & 62) >> 1));
+  output = output || CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 12) & 1) << 4) | ((GET_BYTE(ulid, 13) & 240) >> 4)));
+  output = output || CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 13) & 15) << 1) | ((GET_BYTE(ulid, 14) & 128) >> 7)));
+  output = output || CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 14) & 124) >> 2));
+  output = output || CHR(GET_BYTE(encoding, ((GET_BYTE(ulid, 14) & 3) << 3) | ((GET_BYTE(ulid, 15) & 224) >> 5)));
+  output = output || CHR(GET_BYTE(encoding, (GET_BYTE(ulid, 15) & 31)));
+
+  RETURN output;
+END
+$$
+LANGUAGE plpgsql
+VOLATILE;
+
+-- migrate:down
+
+DROP FUNCTION generate_ulid;