WP-Database-Helper/Migration.php

<?php
namespace DatabaseHelper;

use DatabaseHelper\enums\Propagation;
use DatabaseHelper\enums\Type;
use InvalidArgumentException;

class Migration
{
    protected Schema $table;
    protected array $columnsToAdd = [];
    protected array $columnsToModify = [];
    protected array $columnsToDrop = [];
    protected array $primaryKey = null;
    protected array $foreignKeysToAdd = [];
    protected array $foreignKeysToDrop = [];

    public function __construct(Schema $table) {
        $this->table = $table->copy();
    }

    public function addColumn(string $name, Type $type, mixed $default = null, bool $isNullable = false, bool $isUnique = false): Migration {
        $this->table->columns[$name] = [
            'name' => $name,
            'type' => $type,
            'default' => $default,
            'isNullable' => $isNullable,
            'isUnique' => $isUnique
        ];
        $this->columnsToAdd[] = $name;
        return $this;
    }

    public function modifyColumn(string $name, Type $type, mixed $default = null, bool $isNullable = false, bool $isUnique = false): Migration {
        if (!isset($this->table->columns[$name])) {
            throw new InvalidArgumentException("Column $name does not exist.");
        }
        $this->table->columns[$name] = [
            'name' => $name,
            'type' => $type,
            'default' => $default,
            'isNullable' => $isNullable,
            'isUnique' => $isUnique
        ];
        $this->columnsToModify[] = $name;
        return $this;
    }

    public function dropColumn(string $name): Migration {
        if (!isset($this->table->columns[$name])) {
            throw new InvalidArgumentException("Column $name does not exist.");
        }
        unset($this->table->columns[$name]);
        $this->columnsToDrop[] = $name;
        return $this;
    }

    public function changePrimaryKey(string $name, bool $autoInc = false): Migration {
        if (!isset($this->table->columns[$name])) {
            throw new InvalidArgumentException("Column $name does not exist.");
        }
        $this->table->primaryKey = [
            'name' => $name,
            'autoInc' => $autoInc
        ];
        $this->primaryKey = $name;
        return $this;
    }

    public function addForeignKey(string $column, string $referencedTable, string $referencedColumn, Propagation $onDelete, Propagation $onUpdate): Migration {
        if (!isset($this->table->columns[$column])) {
            throw new InvalidArgumentException("Column $column does not exist.");
        }
        $this->table->foreignKeys[$column] = [
            'referencedTable' => $referencedTable,
            'referencedColumn' => $referencedColumn,
            'onDelete' => $onDelete,
            'onUpdate' => $onUpdate
        ];
        $this->foreignKeysToAdd[] = $column;
        return $this;
    }

    public function dropForeignKey(string $name): Migration {
        if (!isset($this->table->foreignKeys[$name])) {
            throw new InvalidArgumentException("Foreign key $name does not exist.");
        }
        unset($this->table->foreignKeys[$name]);
        $this->foreignKeysToDrop[] = $name;
        return $this;
    }

    public function toSql(): string {
        $sql = "ALTER TABLE `{$this->table->name}` ";
        $statements = [];

        foreach ($this->columnsToAdd as $name) {
            $col = $this->table->columns[$name];
            $statements[] = "ADD COLUMN `{$col['name']}` {$col['type']->toString()}" .
                ($col['isNullable'] ? "" : " NOT NULL") .
                ($col['isUnique'] ? " UNIQUE" : "") .
                ($col['default'] !== null ? " DEFAULT " . (is_string($col['default']) ? "'{$col['default']}'" : $col['default']) : "");
        }

        foreach ($this->columnsToModify as $name) {
            $col = $this->table->columns[$name];
            $statements[] = "MODIFY COLUMN `{$col['name']}` {$col['type']->toString()}" .
                ($col['isNullable'] ? "" : " NOT NULL") .
                ($col['isUnique'] ? " UNIQUE" : "") .
                ($col['default'] !== null ? " DEFAULT " . (is_string($col['default']) ? "'{$col['default']}'" : $col['default']) : "");
        }

        foreach ($this->columnsToDrop as $name) {
            $statements[] = "DROP COLUMN `$name`";
        }

        foreach ($this->foreignKeysToDrop as $name) {
            $statements[] = "DROP FOREIGN KEY `$name`";
        }

        foreach ($this->foreignKeysToAdd as $column) {
            $fk = $this->table->foreignKeys[$column];
            $statements[] = "ADD CONSTRAINT `fk_{$column}` FOREIGN KEY (`$column`) REFERENCES `{$fk['referencedTable']}` (`{$fk['referencedColumn']}`) ON DELETE {$fk['onDelete']->toString()} ON UPDATE {$fk['onUpdate']->toString()}";
        }

        return $sql . implode(", ", $statements) . ";";
    }

    public function drop(): null {

    }

    public function migrate(): Schema {
        global $wpdb;
        $sql = $this->toSql();
        $wpdb->query($sql);
        return $this->table;
    }
}