From b33aa78976f177dea693905eaf401dfc56b2d0fb Mon Sep 17 00:00:00 2001
From: Matthew Bucci <buccim2@gene.com>
Date: Thu, 22 Feb 2024 19:11:41 -0800
Subject: [PATCH] add support for REPLACE INTO rewriting

---
 pg4wp/driver_pgsql_rewrite.php             |   2 +-
 pg4wp/rewriters/ReplaceIntoSQLRewriter.php | 107 +++++++++++++++++++++
 tests/rewriteTest.php                      |  12 +++
 3 files changed, 120 insertions(+), 1 deletion(-)
 create mode 100644 pg4wp/rewriters/ReplaceIntoSQLRewriter.php

diff --git a/pg4wp/driver_pgsql_rewrite.php b/pg4wp/driver_pgsql_rewrite.php
index 0292cd0..4b16556 100644
--- a/pg4wp/driver_pgsql_rewrite.php
+++ b/pg4wp/driver_pgsql_rewrite.php
@@ -12,7 +12,7 @@ spl_autoload_register(function ($className) {
 function createSQLRewriter(string $sql): AbstractSQLRewriter
 {
     $sql = trim($sql);
-    if (preg_match('/^(SELECT|INSERT|UPDATE|DELETE|DESCRIBE|ALTER TABLE|CREATE TABLE|DROP TABLE|SHOW INDEX|SHOW VARIABLES|SHOW TABLES|OPTIMIZE TABLE|SET NAMES|SHOW FULL COLUMNS)\b/i', $sql, $matches)) {
+    if (preg_match('/^(SELECT|INSERT|REPLACE INTO|UPDATE|DELETE|DESCRIBE|ALTER TABLE|CREATE TABLE|DROP TABLE|SHOW INDEX|SHOW VARIABLES|SHOW TABLES|OPTIMIZE TABLE|SET NAMES|SHOW FULL COLUMNS)\b/i', $sql, $matches)) {
         // Convert to a format suitable for class names (e.g., "SHOW TABLES" becomes "ShowTables")
         $type = str_replace(' ', '', ucwords(str_replace('_', ' ', strtolower($matches[1]))));
         $className = $type . 'SQLRewriter';
diff --git a/pg4wp/rewriters/ReplaceIntoSQLRewriter.php b/pg4wp/rewriters/ReplaceIntoSQLRewriter.php
new file mode 100644
index 0000000..a47aab5
--- /dev/null
+++ b/pg4wp/rewriters/ReplaceIntoSQLRewriter.php
@@ -0,0 +1,107 @@
+<?php
+
+class ReplaceIntoSQLRewriter extends AbstractSQLRewriter
+{
+    public function rewrite(): string
+    {
+        global $wpdb;
+
+        $sql = $this->original();
+
+        $splitStatements = function (string $sql): array {
+            $statements = [];
+            $buffer = '';
+            $quote = null;
+
+            for ($i = 0, $len = strlen($sql); $i < $len; $i++) {
+                $char = $sql[$i];
+
+                if ($quote) {
+                    if ($char === $quote && $sql[$i - 1] !== '\\') {
+                        $quote = null;
+                    }
+                } elseif ($char === '"' || $char === "'") {
+                    $quote = $char;
+                } elseif ($char === ';') {
+                    $statements[] = $buffer . ';';
+                    $buffer = '';
+                    continue;
+                }
+
+                $buffer .= $char;
+            }
+
+            if (!empty($buffer)) {
+                $statements[] = $buffer;
+            }
+
+            return $statements;
+        };
+
+        $statements = $splitStatements($sql);
+
+        foreach ($statements as $statement) {
+            $statement = trim($statement);
+
+            // Skip empty statements
+            if (empty($statement)) {
+                continue;
+            }
+
+            // Replace backticks with double quotes for PostgreSQL compatibility
+            $statement = str_replace('`', '"', $statement);
+
+            // Find index positions for the SQL components
+            $insertIndex = strpos($statement, 'REPLACE INTO');
+            $columnsStartIndex = strpos($statement, "(");
+            $columnsEndIndex = strpos($statement, ")");
+            $valuesIndex = strpos($statement, 'VALUES');
+            $onDuplicateKeyIndex = strpos($statement, 'ON DUPLICATE KEY UPDATE');
+
+            // Extract SQL components
+            $tableSection = trim(substr($statement, $insertIndex, $columnsStartIndex - $insertIndex));
+            $valuesSection = trim(substr($statement, $valuesIndex, strlen($statement) - $valuesIndex));
+            $columnsSection = trim(substr($statement, $columnsStartIndex, $columnsEndIndex - $columnsStartIndex + 1)); 
+
+            // Extract and clean up column names from the update section
+            $updateCols = explode(',', substr($columnsSection, 1, strlen($columnsSection) - 2));
+            $updateCols = array_map(function ($col) {
+                return  trim($col); 
+            }, $updateCols);
+
+            // Choose a primary key for ON CONFLICT
+            $primaryKey = 'option_name';
+            if (!in_array($primaryKey, $updateCols)) {
+                $primaryKey = 'meta_name';
+                if (!in_array($primaryKey, $updateCols)) {
+                    $primaryKey = $updateCols[0] ?? '';
+                }
+            }
+
+            // SWAP REPLACE INTO for INSERT INTO
+            $tableSection = str_replace("REPLACE INTO", "INSERT INTO", $tableSection);
+
+            // Construct the PostgreSQL ON CONFLICT DO UPDATE section
+            $updateSection = "";
+            foreach($updateCols as $col) {
+                if ($col !== $primaryKey) {
+                    $updateSection .= ", ";
+                    $updateSection .= "$col = EXCLUDED.$col";
+                }
+            }
+
+            // trim any preceding commas
+            $updateSection = ltrim($updateSection,", ");
+
+            // Construct the PostgreSQL query
+            $postgresSQL = sprintf('%s %s %s ON CONFLICT (%s) DO UPDATE SET %s', $tableSection, $columnsSection, $valuesSection, $primaryKey, $updateSection);
+
+            // Append to the converted statements list
+            $convertedStatements[] = $postgresSQL;
+        }
+
+        $sql = implode('; ', $convertedStatements);
+
+        return $sql;
+    }
+}
diff --git a/tests/rewriteTest.php b/tests/rewriteTest.php
index 786c3a3..bd50816 100644
--- a/tests/rewriteTest.php
+++ b/tests/rewriteTest.php
@@ -383,6 +383,18 @@ final class rewriteTest extends TestCase
     }
 
 
+    public function test_it_can_handle_replacement_sql()
+    {
+        $sql = "REPLACE INTO test2 (column1, column2, column3) VALUES (1, 'Old', '2014-08-20 18:47:00')";
+        $expected = "INSERT INTO test2 (column1, column2, column3) VALUES (1, 'Old', '2014-08-20 18:47:00') ON CONFLICT (column1) DO UPDATE SET column2 = EXCLUDED.column2, column3 = EXCLUDED.column3";
+
+        $postgresql = pg4wp_rewrite($sql);
+        $this->assertSame(trim($expected), trim($postgresql));
+    }
+
+
+
+
 
     protected function setUp(): void
     {