<?php
/**
 * One-time migration to v4: submission history, uploadedAt, activity tables.
 */

function qdb_migrate_v4(PDO $pdo): void {
    $cols = $pdo->query("PRAGMA table_info(completed_questionnaire)")->fetchAll(PDO::FETCH_ASSOC);
    $hasUploaded = false;
    foreach ($cols as $c) {
        if (($c['name'] ?? '') === 'uploadedAt') {
            $hasUploaded = true;
            break;
        }
    }
    if (!$hasUploaded) {
        $pdo->exec('ALTER TABLE completed_questionnaire ADD COLUMN uploadedAt INTEGER');
    }

    $subCount = (int)$pdo->query('SELECT COUNT(*) FROM questionnaire_submission')->fetchColumn();
    if ($subCount > 0) {
        return;
    }

    $completions = $pdo->query('SELECT * FROM completed_questionnaire')->fetchAll(PDO::FETCH_ASSOC);
    if (empty($completions)) {
        return;
    }

    $insertSub = $pdo->prepare("
        INSERT INTO questionnaire_submission (
            submissionID, clientCode, questionnaireID, assignedByCoach, status,
            startedAt, completedAt, uploadedAt, sumPoints, submissionVersion,
            submittedByUserID, submittedByRole
        ) VALUES (
            :sid, :cc, :qn, :abc, :st, :sa, :ca, :ua, :sp, 1, NULL, NULL
        )
    ");
    $insertAns = $pdo->prepare("
        INSERT INTO submission_answer (submissionID, questionID, answerOptionID, freeTextValue, numericValue, answeredAt)
        VALUES (:sid, :qid, :aoid, :ftv, :nv, :at)
    ");
    $updateCq = $pdo->prepare('UPDATE completed_questionnaire SET uploadedAt = :ua WHERE clientCode = :cc AND questionnaireID = :qn');

    foreach ($completions as $cq) {
        $cc = $cq['clientCode'];
        $qn = $cq['questionnaireID'];
        $uploadedAt = $cq['completedAt'] !== null ? (int)$cq['completedAt'] : (int)(microtime(true) * 1000);
        $submissionID = 'mig_' . bin2hex(random_bytes(12));

        $insertSub->execute([
            ':sid' => $submissionID,
            ':cc'  => $cc,
            ':qn'  => $qn,
            ':abc' => $cq['assignedByCoach'] ?? null,
            ':st'  => $cq['status'] ?: 'completed',
            ':sa'  => $cq['startedAt'],
            ':ca'  => $cq['completedAt'],
            ':ua'  => $uploadedAt,
            ':sp'  => $cq['sumPoints'],
        ]);

        $ansStmt = $pdo->prepare("
            SELECT questionID, answerOptionID, freeTextValue, numericValue, answeredAt
            FROM client_answer WHERE clientCode = :cc
            AND questionID IN (SELECT questionID FROM question WHERE questionnaireID = :qn)
        ");
        $ansStmt->execute([':cc' => $cc, ':qn' => $qn]);
        foreach ($ansStmt->fetchAll(PDO::FETCH_ASSOC) as $a) {
            $insertAns->execute([
                ':sid'  => $submissionID,
                ':qid'  => $a['questionID'],
                ':aoid' => $a['answerOptionID'],
                ':ftv'  => $a['freeTextValue'],
                ':nv'   => $a['numericValue'],
                ':at'   => $a['answeredAt'],
            ]);
        }

        $updateCq->execute([':ua' => $uploadedAt, ':cc' => $cc, ':qn' => $qn]);
    }
}