<?php

require_once __DIR__ . '/../lib/questionnaire_reachability.php';

$tokenRec = require_valid_token();

if ($method !== 'GET') {
    json_error('METHOD_NOT_ALLOWED', 'Method not allowed', 405);
}

$qnID = $_GET['questionnaireID'] ?? '';
if (!$qnID) {
    json_error('MISSING_PARAM', 'questionnaireID query param required', 400);
}

[$pdo, $tmpDb, $lockFp] = qdb_open(false);

$qn = $pdo->prepare("SELECT * FROM questionnaire WHERE questionnaireID = :id");
$qn->execute([':id' => $qnID]);
$questionnaire = $qn->fetch(PDO::FETCH_ASSOC);
if (!$questionnaire) {
    qdb_discard($tmpDb, $lockFp);
    json_error('NOT_FOUND', 'Questionnaire not found', 404);
}

$qStmt = $pdo->prepare("SELECT questionID, defaultText, orderIndex FROM question WHERE questionnaireID = :id ORDER BY orderIndex");
$qStmt->execute([':id' => $qnID]);
$questions = $qStmt->fetchAll(PDO::FETCH_ASSOC);
$questionIDs = array_column($questions, 'questionID');

$optionTextMap = [];
foreach ($questionIDs as $qid) {
    $aoStmt = $pdo->prepare("SELECT answerOptionID, defaultText FROM answer_option WHERE questionID = :qid");
    $aoStmt->execute([':qid' => $qid]);
    foreach ($aoStmt->fetchAll(PDO::FETCH_ASSOC) as $ao) {
        $optionTextMap[$ao['answerOptionID']] = $ao['defaultText'];
    }
}

[$rbacClause, $rbacParams] = rbac_client_filter($tokenRec, 'cl');

$sql = "
    SELECT cl.clientCode, cl.coachID,
           co.username AS coachUsername,
           sv.username AS supervisorUsername,
           cq.status, cq.sumPoints, cq.startedAt, cq.completedAt
    FROM client cl
    INNER JOIN completed_questionnaire cq ON cq.clientCode = cl.clientCode AND cq.questionnaireID = :qnid
    LEFT JOIN coach co ON co.coachID = cl.coachID
    LEFT JOIN supervisor sv ON sv.supervisorID = co.supervisorID
    WHERE $rbacClause
    ORDER BY cl.clientCode
";
$params = array_merge([':qnid' => $qnID], $rbacParams);
$cStmt = $pdo->prepare($sql);
$cStmt->execute($params);
$clients = $cStmt->fetchAll(PDO::FETCH_ASSOC);

$qPlaceholders = !empty($questionIDs) ? implode(',', array_fill(0, count($questionIDs), '?')) : "'__none__'";
$answerStmt = $pdo->prepare("
    SELECT questionID, answerOptionID, freeTextValue, numericValue
    FROM client_answer
    WHERE clientCode = ? AND questionID IN ($qPlaceholders)
");

$rows = [];
foreach ($clients as $c) {
    $row = [
        'clientCode'  => $c['clientCode'],
        'coach'       => $c['coachUsername'] ?? $c['coachID'],
        'supervisor'  => $c['supervisorUsername'] ?? '',
        'status'      => $c['status'],
        'sumPoints'   => $c['sumPoints'],
        'startedAt'   => $c['startedAt'] ? date('Y-m-d H:i', (int)$c['startedAt']) : '',
        'completedAt' => $c['completedAt'] ? date('Y-m-d H:i', (int)$c['completedAt']) : '',
    ];

    $bindParams = array_merge([$c['clientCode']], $questionIDs);
    $answerStmt->execute($bindParams);
    $answers = $answerStmt->fetchAll(PDO::FETCH_ASSOC);
    $answerMap = [];
    foreach ($answers as $a) $answerMap[$a['questionID']] = $a;

    $reachable = qrb_reachable_question_ids($pdo, $qnID, $answerMap, $optionTextMap);

    foreach ($questions as $q) {
        $qid = $q['questionID'];
        $header = $q['defaultText'];
        if (!isset($reachable[$qid])) {
            $row[$header] = '';
            continue;
        }
        if (isset($answerMap[$qid])) {
            $row[$header] = qrb_format_cell($answerMap[$qid], $optionTextMap);
        } else {
            $row[$header] = '';
        }
    }
    $rows[] = $row;
}

qdb_discard($tmpDb, $lockFp);

// CSV output (not JSON -- overrides the router's Content-Type)
$safeName = preg_replace('/[^a-zA-Z0-9_-]/', '_', $questionnaire['name']);
$filename = $safeName . '_v' . $questionnaire['version'] . '.csv';

header('Content-Type: text/csv; charset=UTF-8');
header('Content-Disposition: attachment; filename="' . $filename . '"');

$out = fopen('php://output', 'w');
fwrite($out, "\xEF\xBB\xBF");

if (!empty($rows)) {
    fputcsv($out, array_keys($rows[0]));
    foreach ($rows as $row) {
        fputcsv($out, array_values($row));
    }
} else {
    $header = ['clientCode', 'coachID', 'status', 'sumPoints', 'startedAt', 'completedAt'];
    foreach ($questions as $q) $header[] = $q['defaultText'];
    fputcsv($out, $header);
}
fclose($out);