<?php
namespace Gateway;
use Gateway\Connection;
use PDO;

class QuestionGateway extends Gateway
{

    /**
     * Creates a new question entry in the database.
     *
     * This method inserts a new question into the `Question` table, including the question text,
     * multiple choice answers (A, B, C, D), and the correct answer.
     *
     * @param int $id_question The unique ID of the question.
     * @param string $question The question text.
     * @param string $answerA The first multiple choice answer.
     * @param string $answerB The second multiple choice answer.
     * @param string $answerC The third multiple choice answer.
     * @param string $answerD The fourth multiple choice answer.
     * @param string $cAnswer The correct answer among the options (A, B, C, D).
     *
     * @return bool Returns `true` if the question was successfully created, `false` otherwise.
     */
    public function create(int $id_question, string $question, string $answerA, string $answerB, string $answerC, string $answerD, string $cAnswer): bool
    {
        // SQL query to insert a new question with its answers and correct answer
        $query = "INSERT INTO Question 
            VALUES (:id_q, :question, :answerA, :answerB, :answerC, :answerD, :cAnswer)";

        // Execute the query, binding the parameters securely to prevent SQL injection
        return $this -> co -> executeQuery($query, [
            'id_q' => array($id_question, PDO::PARAM_INT),
            'question' => array($question, PDO::PARAM_STR),
            'answerA' => array($answerA, PDO::PARAM_STR),
            'answerB' => array($answerB, PDO::PARAM_STR),
            'answerC' => array($answerC, PDO::PARAM_STR),
            'answerD' => array($answerD, PDO::PARAM_STR),
            'cAnswer' => array($cAnswer, PDO::PARAM_STR),
        ]);
    }



    /**
     * Retrieves a question by its ID from the database.
     *
     * This method queries the `Question` table to find the question with the specified ID
     * and returns all its details, including the question text, possible answers, and the correct answer.
     *
     * @param int $id The unique ID of the question to be retrieved.
     *
     * @return array An associative array containing the details of the question (if found).
     *               The keys correspond to the column names in the `Question` table.
     *               Returns an empty array if the question is not found.
     */
    public function findById(int $id) : array
    {
        // SQL query to select the question with the specified ID
        $query = "SELECT * 
                  FROM Question 
                  WHERE id_question = :id_q";

        // Execute the query, binding the parameter securely to prevent SQL injection
        $this -> co -> executeQuery($query, ['id_q' => array($id, PDO::PARAM_INT)]);

        // Retrieve and return the results as an associative array
        return $this -> co -> getResults();
    }



    /**
    * Updates the text of a question in the database.
    *
    * This method modifies the `question` field of a specific question in the `Question` table,
    * identified by its unique ID.
    *
    * @param int $id_q The unique ID of the question to be updated.
    * @param string $newQuestion The new text to replace the current question text.
    *
    * @return bool Returns `true` if the query was successfully executed, or `false` otherwise.
    */
    public function updateText(int $id_q, string $newQuestion) : bool
    {
        // SQL query to update the question text for a specific ID
        $query = "UPDATE Question
            SET question = :question
            WHERE id_question = :id_q";

        // Execute the query with bound parameters
        return $this -> co -> executeQuery($query, [
            'id_q' => array($id_q, PDO::PARAM_INT),        // Bind the ID of the question
            'question' => array($newQuestion, PDO::PARAM_STR) // Bind the new question text
        ]);
    }



    /**
     * Updates the answers for a specific question in the database.
     *
     * This method modifies the answer options (`answerA`, `answerB`, `answerC`, `answerD`)
     * and the correct answer (`cAnswer`) of a specific question identified by its unique ID.
     *
     * @param int $id_q The unique ID of the question to be updated.
     * @param string $newA The new value for the first answer option (A).
     * @param string $newB The new value for the second answer option (B).
     * @param string $newC The new value for the third answer option (C).
     * @param string $newD The new value for the fourth answer option (D).
     * @param string $newCorrect The new correct answer.
     *
     * @return bool Returns `true` if the query was successfully executed, or `false` otherwise.
     */
    public function updateAnswers(int $id_q, string $newA, string $newB, string $newC, string $newD, string $newCorrect): bool
    {
        // SQL query to update the answers and the correct answer for a specific question
        $query = "UPDATE Question
            SET answerA = :answerA, answerB = :answerB, 
                answerC = :answerC, answerD = :answerD, cAnswer = :cAnswer
            WHERE id_question = :id_q";

        // Execute the query with bound parameters
        return $this -> co -> executeQuery($query, [
            'id_q' => array($id_q, PDO::PARAM_INT),        // Bind the ID of the question
            'answerA' => array($newA, PDO::PARAM_STR),     // Bind the new answer A
            'answerB' => array($newB, PDO::PARAM_STR),     // Bind the new answer B
            'answerC' => array($newC, PDO::PARAM_STR),     // Bind the new answer C
            'answerD' => array($newD, PDO::PARAM_STR),     // Bind the new answer D
            'cAnswer' => array($newCorrect, PDO::PARAM_STR) // Bind the new correct answer
        ]);
    }


    /**
     * Deletes a question from the database.
     *
     * This method removes a specific question from the `Question` table based on its unique ID.
     *
     * @param int $id The unique ID of the question to be deleted.
     *
     * @return bool Returns `true` if the query was successfully executed, or `false` otherwise.
     */
    public function delete(int $id) : bool
    {
        // SQL query to delete a question by its ID
        $query = "DELETE FROM Question 
                  WHERE id_question = :id_q";

        // Execute the query with the provided ID
        return $this -> co -> executeQuery($query, [
            'id_q' => array($id, PDO::PARAM_INT) // Bind the ID parameter to the query
        ]);
    }


    /**
     * Retrieves all questions from the database.
     *
     * This method fetches all records from the `Question` table, returning an array
     * of questions with their associated details.
     *
     * @return array Returns an array containing all the questions. Each question is represented
     *               as an associative array with keys corresponding to the table columns.
     */
    public function findAll() : array
    {
        // SQL query to select all questions
        $query = "SELECT * FROM Question";

        // Execute the query
        $this -> co -> executeQuery($query);

        // Return all results as an array
        return $this -> co -> getResults();
    }


    /**
     * Retrieves a random question from the database.
     *
     * This method selects one random record from the `Question` table.
     *
     * @return array Returns an array containing the details of a randomly selected question.
     *               The result is an associative array with keys corresponding to the table columns.
     */
    public function findRdmQuestion() : array
    {
        // SQL query to fetch a random question
        $query = "SELECT * 
                  FROM Question 
                  ORDER BY RANDOM() 
                  LIMIT 1";

        // Execute the query
        $this -> co -> executeQuery($query);

        // Return the randomly selected question
        return $this -> co -> getResults();
    }
}