<?php
namespace Hurrytimer;

class SQL_Builder
{
    public $table;
    public $charset_collate;
    public $sql_fields = [];
    const DELETE_CASCADE = 1;
    public function __construct($_table)
    {
        global $wpdb;
        $this->table = "{$wpdb->prefix}$_table";
        $this->charset_collate = $wpdb->get_charset_collate();
    }

    public function create()
    {
        $sql = "CREATE TABLE {$this->table} (";
        $this->sql_fields[] = $sql;
        return $this;
    }
    private function _field($name, $type, $length, $unsigned = false, $is_nullable = false)
    {
        $sql = $name . ' ' . strtoupper($type) . '(' . $length . ') ';
        $sql .= ($unsigned ? 'UNSIGNED ' : '');
        $sql .= ($is_nullable ? 'NULL' : 'NOT NULL');
        return $sql;
    }
    public function string($name, $length = 50, $is_nullable = false)
    {
        $sql = $this->_field($name, "VARCHAR", $length, false, $is_nullable);
        $this->sql_fields[] = $sql;
        return $this;
    }
    public function primary_key($name)
    {
        $sql = "PRIMARY KEY($name)";
        $this->sql_fields[] = $sql;
        return $this;
    }
    public function foreign_key($name, $reference, $delete)
    {
        global $wpdb;
        $sql = "FOREIGN KEY($name) REFERENCES {$wpdb->prefix}$reference ON DELETE ";
        switch ($delete) {
            case self::DELETE_CASCADE:
                $sql .= "CASCADE";
                break;
        }
        $this->sql_fields[] = $sql;
        return $this;
    }

    public function run()
    {
        require_once ABSPATH . 'wp-admin/includes/upgrade.php';
        dbDelta($this->build_query());
    }

    public function build_query()
    {
        $sql = array_shift($this->sql_fields);
        $sql .= implode(',', $this->sql_fields);
        $sql .= ')';
        if ($this->charset_collate) {
            $sql .= ' ' . $this->charset_collate . ';';
        }
        return $sql;
    }

    public function bigint($name, $length = 20, $unsigned = false, $is_nullable = false, $auto_increment = false)
    {
        $sql = $this->_field($name, 'BIGINT', $length, $unsigned, $is_nullable);
        $sql .= ($auto_increment ? ' AUTO_INCREMENT' : '');
        $this->sql_fields[] = $sql;
        return $this;
    }

    public function boolean($name)
    {
        $sql = $this->_field($name, 'TINYINT', 1, true, true);
        $this->sql_fields[] = $sql;
        return $this;
    }
    public function timestamp($name, $is_nullable = false)
    {
        $sql = $name . ' ' . 'TIMESTAMP ';
        $sql .= ($is_nullable ? 'NULL' : 'NOT NULL');
        $this->sql_fields[] = $sql;
        return $this;
    }

}