<?php

namespace flight\database;

use PDO;
use PDOStatement;

class PdoWrapper extends PDO
{
    /**
     * How you create the connection for the database
     *
     * @param string $dsn - Ex: 'mysql:host=localhost;port=3306;dbname=testdb;charset=utf8mb4'
     * @param string $username - Ex: 'root'
     * @param string $password - Ex: 'password'
     * @param array<int,mixed> $options - PDO options you can pass in
     */
    public function __construct(string $dsn, ?string $username = null, ?string $password = null, array $options = [])
    {
        parent::__construct($dsn, $username, $password, $options);
    }

    /**
     * Use this for INSERTS, UPDATES, or if you plan on using a SELECT in a while loop
     *
     * Ex: $statement = $db->runQuery("SELECT * FROM table WHERE something = ?", [ $something ]);
     *      while($row = $statement->fetch()) {
     *          // ...
     *      }
     *
     *  $db->runQuery("INSERT INTO table (name) VALUES (?)", [ $name ]);
     *  $db->runQuery("UPDATE table SET name = ? WHERE id = ?", [ $name, $id ]);
     *
     * @param string $sql       - Ex: "SELECT * FROM table WHERE something = ?"
     * @param array<int|string,mixed> $params   - Ex: [ $something ]
     * @return PDOStatement
     */
    public function runQuery(string $sql, array $params = []): PDOStatement
    {
        $processed_sql_data = $this->processInStatementSql($sql, $params);
        $sql = $processed_sql_data['sql'];
        $params = $processed_sql_data['params'];
        $statement = $this->prepare($sql);
        $statement->execute($params);
        return $statement;
    }

    /**
     * Pulls one field from the query
     *
     * Ex: $id = $db->fetchField("SELECT id FROM table WHERE something = ?", [ $something ]);
     *
     * @param string $sql   - Ex: "SELECT id FROM table WHERE something = ?"
     * @param array<int|string,mixed> $params - Ex: [ $something ]
     * @return mixed
     */
    public function fetchField(string $sql, array $params = [])
    {
        $data = $this->fetchRow($sql, $params);
        return reset($data);
    }

    /**
     * Pulls one row from the query
     *
     * Ex: $row = $db->fetchRow("SELECT * FROM table WHERE something = ?", [ $something ]);
     *
     * @param string $sql   - Ex: "SELECT * FROM table WHERE something = ?"
     * @param array<int|string,mixed> $params - Ex: [ $something ]
     * @return array<string,mixed>
     */
    public function fetchRow(string $sql, array $params = []): array
    {
        $sql .= stripos($sql, 'LIMIT') === false ? ' LIMIT 1' : '';
        $result = $this->fetchAll($sql, $params);
        return count($result) > 0 ? $result[0] : [];
    }

    /**
     * Pulls all rows from the query
     *
     * Ex: $rows = $db->fetchAll("SELECT * FROM table WHERE something = ?", [ $something ]);
     * foreach($rows as $row) {
     *      // ...
     * }
     *
     * @param string $sql   - Ex: "SELECT * FROM table WHERE something = ?"
     * @param array<int|string,mixed> $params   - Ex: [ $something ]
     * @return array<int,array<string,mixed>>
     */
    public function fetchAll(string $sql, array $params = []): array
    {
        $processed_sql_data = $this->processInStatementSql($sql, $params);
        $sql = $processed_sql_data['sql'];
        $params = $processed_sql_data['params'];
        $statement = $this->prepare($sql);
        $statement->execute($params);
        $result = $statement->fetchAll();
        return is_array($result) ? $result : [];
    }

    /**
     * Don't worry about this guy. Converts stuff for IN statements
     *
     * Ex: $row = $db->fetchAll("SELECT * FROM table WHERE id = ? AND something IN(?), [ $id, [1,2,3] ]);
     *      Converts this to "SELECT * FROM table WHERE id = ? AND something IN(?,?,?)"
     *
     * @param string $sql    the sql statement
     * @param array<int|string,mixed>  $params the params for the sql statement
     * @return array<string,string|array<int|string,mixed>>
     */
    protected function processInStatementSql(string $sql, array $params = []): array
    {

        // Handle "IN(?)". This is to be used with a comma delimited string, but can also be used with an array.
        // Remove the spaces in variations of "IN ( ? )" where the space after IN is optional, and any number of spaces before and after the question mark is optional.
        // Then loop through each "IN(?)" in the query and replace the single question mark with the correct number of question marks.
        $sql = preg_replace('/IN\s*\(\s*\?\s*\)/i', 'IN(?)', $sql);
        $current_index = 0;
        while (($current_index = strpos($sql, 'IN(?)', $current_index)) !== false) {
            $preceeding_count = substr_count($sql, '?', 0, $current_index - 1);

            $param = $params[$preceeding_count];
            $question_marks = '?';

            // If param is a string, explode it and replace the question mark with the correct number of question marks
            if (is_string($param) || is_array($param)) {
                $params_to_use = $param;
                if (is_string($param)) {
                    $params_to_use = explode(',', $param);
                }

                foreach ($params_to_use as $key => $value) {
                    if (is_string($value)) {
                        $params_to_use[$key] = trim($value);
                    }
                }

                // Replace the single question mark with the appropriate number of question marks.
                $question_marks = join(',', array_fill(0, count($params_to_use), '?'));
                $sql = substr_replace($sql, $question_marks, $current_index + 3, 1);

                // Insert the new params into the params array.
                array_splice($params, $preceeding_count, 1, $params_to_use);
            }

            // Increment by the length of the question marks and accounting for the length of "IN()"
            $current_index += strlen($question_marks) + 4;
        }

        return [ 'sql' => $sql, 'params' => $params ];
    }
}