<?php
header('Content-Type: application/json');
session_start();
require_once 'db/config.php';

// Ensure admin is logged in
if (!isset($_SESSION['user_id']) || !in_array('Admin', $_SESSION['user_roles'])) {
    echo json_encode(['error' => 'Unauthorized']);
    exit;
}

$action = $_GET['action'] ?? '';

switch ($action) {
    case 'submissions_per_survey':
        $stmt = db()->query("SELECT s.title, COUNT(fs.id) as submission_count FROM surveys s LEFT JOIN feedback_submissions fs ON s.id = fs.survey_id GROUP BY s.id");
        $results = $stmt->fetchAll(PDO::FETCH_ASSOC);
        $labels = array_column($results, 'title');
        $values = array_column($results, 'submission_count');
        echo json_encode(['labels' => $labels, 'values' => $values]);
        break;

    case 'survey_question_analytics':
        $surveys_stmt = db()->query("SELECT id, title FROM surveys");
        $surveys = $surveys_stmt->fetchAll(PDO::FETCH_KEY_PAIR);

        $questions_stmt = db()->query("SELECT survey_id, id, question_text, question_type FROM survey_questions WHERE question_type = 'rating' OR question_type = 'multiple-choice'");
        $questions = $questions_stmt->fetchAll(PDO::FETCH_GROUP|PDO::FETCH_ASSOC);

        $answers_stmt = db()->query("SELECT q.id as question_id, a.answer_text FROM survey_answers a JOIN survey_questions q ON a.question_id = q.id WHERE q.question_type = 'rating' OR q.question_type = 'multiple-choice'");
        $answers_by_question = $answers_stmt->fetchAll(PDO::FETCH_GROUP|PDO::FETCH_COLUMN);

        $response = [];
        foreach ($surveys as $survey_id => $survey_title) {
            $survey_data = [
                'id' => $survey_id,
                'title' => $survey_title,
                'questions' => []
            ];

            if (isset($questions[$survey_id])) {
                foreach ($questions[$survey_id] as $question) {
                    $question_id = $question['id'];
                    $question_data = [
                        'id' => $question_id,
                        'question_text' => $question['question_text'],
                        'type' => $question['question_type'],
                    ];

                    $answers = $answers_by_question[$question_id] ?? [];

                    if ($question['question_type'] == 'multiple-choice') {
                        $answer_counts = [];
                        foreach ($answers as $answer_row) {
                            $options = preg_split('/,\s*/', $answer_row);
                            foreach ($options as $option) {
                                $trimmed_option = trim($option);
                                if (!empty($trimmed_option)) {
                                    if (!isset($answer_counts[$trimmed_option])) {
                                        $answer_counts[$trimmed_option] = 0;
                                    }
                                    $answer_counts[$trimmed_option]++;
                                }
                            }
                        }
                        $question_data['answers'] = [
                            'labels' => array_keys($answer_counts),
                            'values' => array_values($answer_counts)
                        ];
                    } else { // rating
                        $answer_counts = array_count_values($answers);
                        $question_data['answers'] = [
                            'labels' => array_keys($answer_counts),
                            'values' => array_values($answer_counts)
                        ];
                    }
                    $survey_data['questions'][] = $question_data;
                }
            }
            $response[] = $survey_data;
        }
        echo json_encode($response);
        break;

    default:
        echo json_encode(['error' => 'Invalid action']);
        break;
}