<?php
declare(strict_types=1);

class TaskMonitoringRepository
{
    public function listCycleKeysForTask(int $taskId, int $limit = 24): array
    {
        $limit = max(1, min(200, $limit));

        return TaskCertDb::fetchAll(
            'SELECT
                a.cycle_key,
                MIN(a.cycle_start_at) AS cycle_start_at,
                MAX(a.cycle_end_at) AS cycle_end_at,
                COUNT(*) AS assignment_count
             FROM task_assignment a
             WHERE a.task_id = ?
               AND a.cycle_key <> ""
             GROUP BY a.cycle_key
             ORDER BY COALESCE(MAX(a.cycle_start_at), MAX(a.assigned_at)) DESC, a.cycle_key DESC
             LIMIT ' . $limit,
            'i',
            [$taskId]
        );
    }

    public function findCycleKeyForTask(int $taskId, string $cycleKey): ?array
    {
        $cycleKey = trim($cycleKey);
        if ($taskId <= 0 || $cycleKey === '') {
            return null;
        }

        return TaskCertDb::fetchOne(
            'SELECT
                a.cycle_key,
                MIN(a.cycle_start_at) AS cycle_start_at,
                MAX(a.cycle_end_at) AS cycle_end_at,
                COUNT(*) AS assignment_count
             FROM task_assignment a
             WHERE a.task_id = ?
               AND a.cycle_key = ?
             GROUP BY a.cycle_key
             LIMIT 1',
            'is',
            [$taskId, $cycleKey]
        );
    }

    public function getKpisForTaskLatest(int $taskId): array
    {
        $statusRows = TaskCertDb::fetchAll(
            'SELECT a.status, COUNT(*) AS cnt
             FROM task_assignment a
             INNER JOIN (
                SELECT main_contact_id, MAX(id) AS latest_id
                FROM task_assignment
                WHERE task_id = ?
                GROUP BY main_contact_id
             ) latest ON latest.latest_id = a.id
             GROUP BY a.status',
            'i',
            [$taskId]
        );

        $statusCounts = [
            'open' => 0,
            'in_progress' => 0,
            'approval_pending' => 0,
            'overdue' => 0,
            'completed' => 0,
            'expired' => 0,
            'rejected' => 0,
        ];

        foreach ($statusRows as $row) {
            $status = (string) ($row['status'] ?? '');
            if (!array_key_exists($status, $statusCounts)) {
                continue;
            }

            $statusCounts[$status] = (int) ($row['cnt'] ?? 0);
        }

        $totalAssigned = array_sum($statusCounts);
        $completedCount = (int) $statusCounts['completed'];
        $todoCount = $totalAssigned - $completedCount;

        $awaitingApprovalCount = (int) TaskCertDb::scalar(
            'SELECT COUNT(*)
             FROM task_submission s
             INNER JOIN (
                SELECT main_contact_id, MAX(id) AS latest_id
                FROM task_assignment
                WHERE task_id = ?
                GROUP BY main_contact_id
             ) latest ON latest.latest_id = s.assignment_id
             WHERE s.status = "awaiting_approval"',
            'i',
            [$taskId]
        );

        $escalatedCount = (int) TaskCertDb::scalar(
            'SELECT COUNT(*)
             FROM task_assignment a
             INNER JOIN (
                SELECT main_contact_id, MAX(id) AS latest_id
                FROM task_assignment
                WHERE task_id = ?
                GROUP BY main_contact_id
             ) latest ON latest.latest_id = a.id
             WHERE a.escalation_level > 0',
            'i',
            [$taskId]
        );

        $withSubmissionCount = (int) TaskCertDb::scalar(
            'SELECT COUNT(DISTINCT s.assignment_id)
             FROM task_submission s
             INNER JOIN (
                SELECT main_contact_id, MAX(id) AS latest_id
                FROM task_assignment
                WHERE task_id = ?
                GROUP BY main_contact_id
             ) latest ON latest.latest_id = s.assignment_id',
            'i',
            [$taskId]
        );

        $completionRate = $totalAssigned > 0
            ? round(($completedCount / $totalAssigned) * 100, 1)
            : 0.0;

        return [
            'total_assigned' => $totalAssigned,
            'completed_count' => $completedCount,
            'todo_count' => $todoCount,
            'overdue_count' => (int) $statusCounts['overdue'],
            'awaiting_approval_count' => $awaitingApprovalCount,
            'escalated_count' => $escalatedCount,
            'with_submission_count' => $withSubmissionCount,
            'completion_rate' => $completionRate,
            'status_counts' => $statusCounts,
        ];
    }

    public function listTodoAssignmentsLatest(int $taskId, array $filters = [], int $limit = 100): array
    {
        $limit = max(1, min(500, $limit));
        $where = [
            'a.status <> "completed"',
        ];
        $types = 'i';
        $params = [$taskId];

        $status = (string) ($filters['status'] ?? '');
        if ($status !== '') {
            $where[] = 'a.status = ?';
            $types .= 's';
            $params[] = $status;
        }

        $query = trim((string) ($filters['q'] ?? ''));
        if ($query !== '') {
            $like = '%' . $query . '%';
            $where[] = '(c.name LIKE ? OR c.email LIKE ?)';
            $types .= 'ss';
            $params[] = $like;
            $params[] = $like;
        }

        $sql = 'SELECT
            a.*,
            c.name AS contact_name,
            c.email AS contact_email,
            ls.last_submitted_at
        FROM task_assignment a
        INNER JOIN (
            SELECT main_contact_id, MAX(id) AS latest_id
            FROM task_assignment
            WHERE task_id = ?
            GROUP BY main_contact_id
        ) latest ON latest.latest_id = a.id
        LEFT JOIN main_contact c ON c.id = a.main_contact_id
        LEFT JOIN (
            SELECT assignment_id, MAX(submitted_at) AS last_submitted_at
            FROM task_submission
            GROUP BY assignment_id
        ) ls ON ls.assignment_id = a.id
        WHERE ' . implode(' AND ', $where) . '
        ORDER BY
            CASE a.status
                WHEN "overdue" THEN 1
                WHEN "approval_pending" THEN 2
                WHEN "open" THEN 3
                WHEN "in_progress" THEN 4
                WHEN "rejected" THEN 5
                WHEN "expired" THEN 6
                ELSE 7
            END,
            a.due_at IS NULL,
            a.due_at ASC,
            a.id DESC
        LIMIT ' . $limit;

        return TaskCertDb::fetchAll($sql, $types, $params);
    }

    public function listCompletedAssignmentsLatest(int $taskId, array $filters = [], int $limit = 100): array
    {
        $limit = max(1, min(500, $limit));

        $status = (string) ($filters['status'] ?? '');
        if ($status !== '' && $status !== 'completed') {
            return [];
        }

        $where = [
            'a.status = "completed"',
        ];
        $types = 'i';
        $params = [$taskId];

        $query = trim((string) ($filters['q'] ?? ''));
        if ($query !== '') {
            $like = '%' . $query . '%';
            $where[] = '(c.name LIKE ? OR c.email LIKE ?)';
            $types .= 'ss';
            $params[] = $like;
            $params[] = $like;
        }

        $sql = 'SELECT
            a.*,
            c.name AS contact_name,
            c.email AS contact_email,
            tc.id AS certificate_id,
            tc.status AS certificate_status,
            tc.valid_from AS certificate_valid_from,
            tc.valid_until AS certificate_valid_until,
            tc.certificate_code
        FROM task_assignment a
        INNER JOIN (
            SELECT main_contact_id, MAX(id) AS latest_id
            FROM task_assignment
            WHERE task_id = ?
            GROUP BY main_contact_id
        ) latest ON latest.latest_id = a.id
        LEFT JOIN main_contact c ON c.id = a.main_contact_id
        LEFT JOIN task_certificate tc ON tc.assignment_id = a.id
        WHERE ' . implode(' AND ', $where) . '
        ORDER BY a.completed_at DESC, a.id DESC
        LIMIT ' . $limit;

        return TaskCertDb::fetchAll($sql, $types, $params);
    }

    public function listApprovalAndOverdueLatest(int $taskId, array $filters = [], int $limit = 100): array
    {
        $limit = max(1, min(500, $limit));

        $query = trim((string) ($filters['q'] ?? ''));
        $methodType = trim((string) ($filters['method_type'] ?? ''));
        $submissionStatus = trim((string) ($filters['submission_status'] ?? ''));
        $status = trim((string) ($filters['status'] ?? ''));

        $approvalWhere = [
            's.status = "awaiting_approval"',
        ];
        $approvalTypes = 'i';
        $approvalParams = [$taskId];

        if ($methodType !== '') {
            $approvalWhere[] = 'm.method_type = ?';
            $approvalTypes .= 's';
            $approvalParams[] = $methodType;
        }

        if ($submissionStatus !== '') {
            $approvalWhere[] = 's.status = ?';
            $approvalTypes .= 's';
            $approvalParams[] = $submissionStatus;
        }

        if ($status !== '') {
            $approvalWhere[] = 'a.status = ?';
            $approvalTypes .= 's';
            $approvalParams[] = $status;
        }

        if ($query !== '') {
            $like = '%' . $query . '%';
            $approvalWhere[] = '(c.name LIKE ? OR c.email LIKE ?)';
            $approvalTypes .= 'ss';
            $approvalParams[] = $like;
            $approvalParams[] = $like;
        }

        $approvalSql = 'SELECT
            s.*,
            a.status AS assignment_status,
            a.escalation_level,
            a.due_at,
            a.overdue_at,
            a.cycle_key,
            c.name AS contact_name,
            c.email AS contact_email,
            m.method_type
        FROM task_submission s
        INNER JOIN task_assignment a ON a.id = s.assignment_id
        INNER JOIN (
            SELECT main_contact_id, MAX(id) AS latest_id
            FROM task_assignment
            WHERE task_id = ?
            GROUP BY main_contact_id
        ) latest ON latest.latest_id = a.id
        INNER JOIN task_method m ON m.id = s.method_id
        LEFT JOIN main_contact c ON c.id = a.main_contact_id
        WHERE ' . implode(' AND ', $approvalWhere) . '
        ORDER BY s.submitted_at ASC, s.id ASC
        LIMIT ' . $limit;

        $overdueWhere = [
            'a.status <> "completed"',
            '(a.status = "overdue" OR a.escalation_level > 0)',
        ];
        $overdueTypes = 'i';
        $overdueParams = [$taskId];

        if ($status !== '') {
            $overdueWhere[] = 'a.status = ?';
            $overdueTypes .= 's';
            $overdueParams[] = $status;
        }

        if ($query !== '') {
            $like = '%' . $query . '%';
            $overdueWhere[] = '(c.name LIKE ? OR c.email LIKE ?)';
            $overdueTypes .= 'ss';
            $overdueParams[] = $like;
            $overdueParams[] = $like;
        }

        $overdueSql = 'SELECT
            a.*,
            c.name AS contact_name,
            c.email AS contact_email,
            ls.last_submitted_at
        FROM task_assignment a
        INNER JOIN (
            SELECT main_contact_id, MAX(id) AS latest_id
            FROM task_assignment
            WHERE task_id = ?
            GROUP BY main_contact_id
        ) latest ON latest.latest_id = a.id
        LEFT JOIN main_contact c ON c.id = a.main_contact_id
        LEFT JOIN (
            SELECT assignment_id, MAX(submitted_at) AS last_submitted_at
            FROM task_submission
            GROUP BY assignment_id
        ) ls ON ls.assignment_id = a.id
        WHERE ' . implode(' AND ', $overdueWhere) . '
        ORDER BY a.escalation_level DESC, a.due_at ASC, a.id DESC
        LIMIT ' . $limit;

        return [
            'approvals' => TaskCertDb::fetchAll($approvalSql, $approvalTypes, $approvalParams),
            'overdue' => TaskCertDb::fetchAll($overdueSql, $overdueTypes, $overdueParams),
        ];
    }

    public function listSubmissionAuditLatest(int $taskId, array $filters = [], int $limit = 100): array
    {
        $limit = max(1, min(500, $limit));
        $where = [];
        $types = 'i';
        $params = [$taskId];

        $query = trim((string) ($filters['q'] ?? ''));
        if ($query !== '') {
            $like = '%' . $query . '%';
            $where[] = '(c.name LIKE ? OR c.email LIKE ?)';
            $types .= 'ss';
            $params[] = $like;
            $params[] = $like;
        }

        $methodType = trim((string) ($filters['method_type'] ?? ''));
        if ($methodType !== '') {
            $where[] = 'm.method_type = ?';
            $types .= 's';
            $params[] = $methodType;
        }

        $submissionStatus = trim((string) ($filters['submission_status'] ?? ''));
        if ($submissionStatus !== '') {
            $where[] = 's.status = ?';
            $types .= 's';
            $params[] = $submissionStatus;
        }

        $status = trim((string) ($filters['status'] ?? ''));
        if ($status !== '') {
            $where[] = 'a.status = ?';
            $types .= 's';
            $params[] = $status;
        }

        $whereClause = $where === [] ? '' : (' AND ' . implode(' AND ', $where));

        $sql = 'SELECT
            s.*,
            a.status AS assignment_status,
            a.cycle_key,
            a.due_at,
            a.overdue_at,
            a.completed_at,
            a.escalation_level,
            c.name AS contact_name,
            c.email AS contact_email,
            m.id AS method_id,
            m.method_type
        FROM task_submission s
        INNER JOIN task_assignment a ON a.id = s.assignment_id
        INNER JOIN (
            SELECT main_contact_id, MAX(id) AS latest_id
            FROM task_assignment
            WHERE task_id = ?
            GROUP BY main_contact_id
        ) latest ON latest.latest_id = a.id
        INNER JOIN task_method m ON m.id = s.method_id
        LEFT JOIN main_contact c ON c.id = a.main_contact_id
        WHERE 1=1' . $whereClause . '
        ORDER BY s.submitted_at DESC, s.id DESC
        LIMIT ' . $limit;

        return TaskCertDb::fetchAll($sql, $types, $params);
    }

    public function listSubmissionAuditLatestForExport(int $taskId): array
    {
        return TaskCertDb::fetchAll(
            'SELECT
                s.*,
                a.status AS assignment_status,
                a.cycle_key,
                a.due_at,
                a.overdue_at,
                a.completed_at,
                a.escalation_level,
                c.name AS contact_name,
                c.email AS contact_email,
                m.id AS method_id,
                m.method_type
             FROM task_submission s
             INNER JOIN task_assignment a ON a.id = s.assignment_id
             INNER JOIN (
                SELECT main_contact_id, MAX(id) AS latest_id
                FROM task_assignment
                WHERE task_id = ?
                GROUP BY main_contact_id
             ) latest ON latest.latest_id = a.id
             INNER JOIN task_method m ON m.id = s.method_id
             LEFT JOIN main_contact c ON c.id = a.main_contact_id
             ORDER BY s.submitted_at DESC, s.id DESC',
            'i',
            [$taskId]
        );
    }

    public function listMethodCompletionStatsLatest(int $taskId, array $filters = [], int $limit = 100): array
    {
        $limit = max(1, min(200, $limit));

        $where = [
            'm.task_id = ?',
            'm.active = 1',
        ];
        $whereTypes = 'i';
        $whereParams = [$taskId];

        $methodType = trim((string) ($filters['method_type'] ?? ''));
        if ($methodType !== '') {
            $where[] = 'm.method_type = ?';
            $whereTypes .= 's';
            $whereParams[] = $methodType;
        }

        $joinTypes = '';
        $joinParams = [];
        $query = trim((string) ($filters['q'] ?? ''));
        $assignmentContactFilter = '';
        if ($query !== '') {
            $like = '%' . $query . '%';
            $assignmentContactFilter = ' AND EXISTS (
                SELECT 1
                FROM main_contact c
                WHERE c.id = a.main_contact_id
                  AND (c.name LIKE ? OR c.email LIKE ?)
            )';
            $joinTypes .= 'ss';
            $joinParams[] = $like;
            $joinParams[] = $like;
        }

        $sql = 'SELECT
            m.id AS method_id,
            m.method_type,
            m.is_required,
            m.sort_order,
            COUNT(DISTINCT a.id) AS assignment_count,
            SUM(
                CASE
                    WHEN a.id IS NULL THEN 0
                    WHEN EXISTS (
                        SELECT 1
                        FROM task_submission s2
                        WHERE s2.assignment_id = a.id
                          AND s2.method_id = m.id
                          AND s2.status IN ("auto_passed", "approved")
                    ) THEN 1
                    ELSE 0
                END
            ) AS fulfilled_count
        FROM task_method m
        LEFT JOIN (
            SELECT a1.*
            FROM task_assignment a1
            INNER JOIN (
                SELECT main_contact_id, MAX(id) AS latest_id
                FROM task_assignment
                WHERE task_id = ?
                GROUP BY main_contact_id
            ) latest ON latest.latest_id = a1.id
        ) a ON a.task_id = m.task_id' . $assignmentContactFilter . '
        WHERE ' . implode(' AND ', $where) . '
        GROUP BY m.id, m.method_type, m.is_required, m.sort_order
        ORDER BY m.sort_order ASC, m.id ASC
        LIMIT ' . $limit;

        // Placeholder order: derived latest task_id, JOIN filters, WHERE filters.
        $types = 'i' . $joinTypes . $whereTypes;
        $params = array_merge([$taskId], $joinParams, $whereParams);

        return TaskCertDb::fetchAll($sql, $types, $params);
    }

    public function getKpisForTaskCycle(int $taskId, string $cycleKey): array
    {
        $statusRows = TaskCertDb::fetchAll(
            'SELECT a.status, COUNT(*) AS cnt
             FROM task_assignment a
             WHERE a.task_id = ?
               AND a.cycle_key = ?
             GROUP BY a.status',
            'is',
            [$taskId, $cycleKey]
        );

        $statusCounts = [
            'open' => 0,
            'in_progress' => 0,
            'approval_pending' => 0,
            'overdue' => 0,
            'completed' => 0,
            'expired' => 0,
            'rejected' => 0,
        ];

        foreach ($statusRows as $row) {
            $status = (string) ($row['status'] ?? '');
            if (!array_key_exists($status, $statusCounts)) {
                continue;
            }

            $statusCounts[$status] = (int) ($row['cnt'] ?? 0);
        }

        $totalAssigned = array_sum($statusCounts);
        $completedCount = (int) $statusCounts['completed'];
        $todoCount = $totalAssigned - $completedCount;

        $awaitingApprovalCount = (int) TaskCertDb::scalar(
            'SELECT COUNT(*)
             FROM task_submission s
             INNER JOIN task_assignment a ON a.id = s.assignment_id
             WHERE a.task_id = ?
               AND a.cycle_key = ?
               AND s.status = "awaiting_approval"',
            'is',
            [$taskId, $cycleKey]
        );

        $escalatedCount = (int) TaskCertDb::scalar(
            'SELECT COUNT(*)
             FROM task_assignment a
             WHERE a.task_id = ?
               AND a.cycle_key = ?
               AND a.escalation_level > 0',
            'is',
            [$taskId, $cycleKey]
        );

        $withSubmissionCount = (int) TaskCertDb::scalar(
            'SELECT COUNT(DISTINCT s.assignment_id)
             FROM task_submission s
             INNER JOIN task_assignment a ON a.id = s.assignment_id
             WHERE a.task_id = ?
               AND a.cycle_key = ?',
            'is',
            [$taskId, $cycleKey]
        );

        $completionRate = $totalAssigned > 0
            ? round(($completedCount / $totalAssigned) * 100, 1)
            : 0.0;

        return [
            'total_assigned' => $totalAssigned,
            'completed_count' => $completedCount,
            'todo_count' => $todoCount,
            'overdue_count' => (int) $statusCounts['overdue'],
            'awaiting_approval_count' => $awaitingApprovalCount,
            'escalated_count' => $escalatedCount,
            'with_submission_count' => $withSubmissionCount,
            'completion_rate' => $completionRate,
            'status_counts' => $statusCounts,
        ];
    }

    public function listTodoAssignments(int $taskId, string $cycleKey, array $filters = [], int $limit = 100): array
    {
        $limit = max(1, min(500, $limit));
        $where = [
            'a.task_id = ?',
            'a.cycle_key = ?',
            'a.status <> "completed"',
        ];
        $types = 'is';
        $params = [$taskId, $cycleKey];

        $status = (string) ($filters['status'] ?? '');
        if ($status !== '') {
            $where[] = 'a.status = ?';
            $types .= 's';
            $params[] = $status;
        }

        $query = trim((string) ($filters['q'] ?? ''));
        if ($query !== '') {
            $like = '%' . $query . '%';
            $where[] = '(c.name LIKE ? OR c.email LIKE ?)';
            $types .= 'ss';
            $params[] = $like;
            $params[] = $like;
        }

        $sql = 'SELECT
            a.*,
            c.name AS contact_name,
            c.email AS contact_email,
            ls.last_submitted_at
        FROM task_assignment a
        LEFT JOIN main_contact c ON c.id = a.main_contact_id
        LEFT JOIN (
            SELECT assignment_id, MAX(submitted_at) AS last_submitted_at
            FROM task_submission
            GROUP BY assignment_id
        ) ls ON ls.assignment_id = a.id
        WHERE ' . implode(' AND ', $where) . '
        ORDER BY
            CASE a.status
                WHEN "overdue" THEN 1
                WHEN "approval_pending" THEN 2
                WHEN "open" THEN 3
                WHEN "in_progress" THEN 4
                WHEN "rejected" THEN 5
                WHEN "expired" THEN 6
                ELSE 7
            END,
            a.due_at IS NULL,
            a.due_at ASC,
            a.id DESC
        LIMIT ' . $limit;

        return TaskCertDb::fetchAll($sql, $types, $params);
    }

    public function listCompletedAssignments(int $taskId, string $cycleKey, array $filters = [], int $limit = 100): array
    {
        $limit = max(1, min(500, $limit));

        $status = (string) ($filters['status'] ?? '');
        if ($status !== '' && $status !== 'completed') {
            return [];
        }

        $where = [
            'a.task_id = ?',
            'a.cycle_key = ?',
            'a.status = "completed"',
        ];
        $types = 'is';
        $params = [$taskId, $cycleKey];

        $query = trim((string) ($filters['q'] ?? ''));
        if ($query !== '') {
            $like = '%' . $query . '%';
            $where[] = '(c.name LIKE ? OR c.email LIKE ?)';
            $types .= 'ss';
            $params[] = $like;
            $params[] = $like;
        }

        $sql = 'SELECT
            a.*,
            c.name AS contact_name,
            c.email AS contact_email,
            tc.id AS certificate_id,
            tc.status AS certificate_status,
            tc.valid_from AS certificate_valid_from,
            tc.valid_until AS certificate_valid_until,
            tc.certificate_code
        FROM task_assignment a
        LEFT JOIN main_contact c ON c.id = a.main_contact_id
        LEFT JOIN task_certificate tc ON tc.assignment_id = a.id
        WHERE ' . implode(' AND ', $where) . '
        ORDER BY a.completed_at DESC, a.id DESC
        LIMIT ' . $limit;

        return TaskCertDb::fetchAll($sql, $types, $params);
    }

    public function listApprovalAndOverdue(int $taskId, string $cycleKey, array $filters = [], int $limit = 100): array
    {
        $limit = max(1, min(500, $limit));

        $query = trim((string) ($filters['q'] ?? ''));
        $methodType = trim((string) ($filters['method_type'] ?? ''));
        $submissionStatus = trim((string) ($filters['submission_status'] ?? ''));
        $status = trim((string) ($filters['status'] ?? ''));

        $approvalWhere = [
            'a.task_id = ?',
            'a.cycle_key = ?',
            's.status = "awaiting_approval"',
        ];
        $approvalTypes = 'is';
        $approvalParams = [$taskId, $cycleKey];

        if ($methodType !== '') {
            $approvalWhere[] = 'm.method_type = ?';
            $approvalTypes .= 's';
            $approvalParams[] = $methodType;
        }

        if ($submissionStatus !== '') {
            $approvalWhere[] = 's.status = ?';
            $approvalTypes .= 's';
            $approvalParams[] = $submissionStatus;
        }

        if ($status !== '') {
            $approvalWhere[] = 'a.status = ?';
            $approvalTypes .= 's';
            $approvalParams[] = $status;
        }

        if ($query !== '') {
            $like = '%' . $query . '%';
            $approvalWhere[] = '(c.name LIKE ? OR c.email LIKE ?)';
            $approvalTypes .= 'ss';
            $approvalParams[] = $like;
            $approvalParams[] = $like;
        }

        $approvalSql = 'SELECT
            s.*,
            a.status AS assignment_status,
            a.escalation_level,
            a.due_at,
            a.overdue_at,
            a.cycle_key,
            c.name AS contact_name,
            c.email AS contact_email,
            m.method_type
        FROM task_submission s
        INNER JOIN task_assignment a ON a.id = s.assignment_id
        INNER JOIN task_method m ON m.id = s.method_id
        LEFT JOIN main_contact c ON c.id = a.main_contact_id
        WHERE ' . implode(' AND ', $approvalWhere) . '
        ORDER BY s.submitted_at ASC, s.id ASC
        LIMIT ' . $limit;

        $overdueWhere = [
            'a.task_id = ?',
            'a.cycle_key = ?',
            'a.status <> "completed"',
            '(a.status = "overdue" OR a.escalation_level > 0)',
        ];
        $overdueTypes = 'is';
        $overdueParams = [$taskId, $cycleKey];

        if ($status !== '') {
            $overdueWhere[] = 'a.status = ?';
            $overdueTypes .= 's';
            $overdueParams[] = $status;
        }

        if ($query !== '') {
            $like = '%' . $query . '%';
            $overdueWhere[] = '(c.name LIKE ? OR c.email LIKE ?)';
            $overdueTypes .= 'ss';
            $overdueParams[] = $like;
            $overdueParams[] = $like;
        }

        $overdueSql = 'SELECT
            a.*,
            c.name AS contact_name,
            c.email AS contact_email,
            ls.last_submitted_at
        FROM task_assignment a
        LEFT JOIN main_contact c ON c.id = a.main_contact_id
        LEFT JOIN (
            SELECT assignment_id, MAX(submitted_at) AS last_submitted_at
            FROM task_submission
            GROUP BY assignment_id
        ) ls ON ls.assignment_id = a.id
        WHERE ' . implode(' AND ', $overdueWhere) . '
        ORDER BY a.escalation_level DESC, a.due_at ASC, a.id DESC
        LIMIT ' . $limit;

        return [
            'approvals' => TaskCertDb::fetchAll($approvalSql, $approvalTypes, $approvalParams),
            'overdue' => TaskCertDb::fetchAll($overdueSql, $overdueTypes, $overdueParams),
        ];
    }

    public function listSubmissionAudit(int $taskId, string $cycleKey, array $filters = [], int $limit = 100): array
    {
        $limit = max(1, min(500, $limit));
        $where = [
            'a.task_id = ?',
            'a.cycle_key = ?',
        ];
        $types = 'is';
        $params = [$taskId, $cycleKey];

        $query = trim((string) ($filters['q'] ?? ''));
        if ($query !== '') {
            $like = '%' . $query . '%';
            $where[] = '(c.name LIKE ? OR c.email LIKE ?)';
            $types .= 'ss';
            $params[] = $like;
            $params[] = $like;
        }

        $methodType = trim((string) ($filters['method_type'] ?? ''));
        if ($methodType !== '') {
            $where[] = 'm.method_type = ?';
            $types .= 's';
            $params[] = $methodType;
        }

        $submissionStatus = trim((string) ($filters['submission_status'] ?? ''));
        if ($submissionStatus !== '') {
            $where[] = 's.status = ?';
            $types .= 's';
            $params[] = $submissionStatus;
        }

        $status = trim((string) ($filters['status'] ?? ''));
        if ($status !== '') {
            $where[] = 'a.status = ?';
            $types .= 's';
            $params[] = $status;
        }

        $sql = 'SELECT
            s.*,
            a.status AS assignment_status,
            a.cycle_key,
            a.due_at,
            a.overdue_at,
            a.completed_at,
            a.escalation_level,
            c.name AS contact_name,
            c.email AS contact_email,
            m.id AS method_id,
            m.method_type
        FROM task_submission s
        INNER JOIN task_assignment a ON a.id = s.assignment_id
        INNER JOIN task_method m ON m.id = s.method_id
        LEFT JOIN main_contact c ON c.id = a.main_contact_id
        WHERE ' . implode(' AND ', $where) . '
        ORDER BY s.submitted_at DESC, s.id DESC
        LIMIT ' . $limit;

        return TaskCertDb::fetchAll($sql, $types, $params);
    }

    public function listSubmissionAuditForCycleExport(int $taskId, string $cycleKey): array
    {
        return TaskCertDb::fetchAll(
            'SELECT
                s.*,
                a.status AS assignment_status,
                a.cycle_key,
                a.due_at,
                a.overdue_at,
                a.completed_at,
                a.escalation_level,
                c.name AS contact_name,
                c.email AS contact_email,
                m.id AS method_id,
                m.method_type
             FROM task_submission s
             INNER JOIN task_assignment a ON a.id = s.assignment_id
             INNER JOIN task_method m ON m.id = s.method_id
             LEFT JOIN main_contact c ON c.id = a.main_contact_id
             WHERE a.task_id = ?
               AND a.cycle_key = ?
             ORDER BY s.submitted_at DESC, s.id DESC',
            'is',
            [$taskId, $cycleKey]
        );
    }

    public function listMethodCompletionStats(int $taskId, string $cycleKey, array $filters = [], int $limit = 100): array
    {
        $limit = max(1, min(200, $limit));

        $where = [
            'm.task_id = ?',
            'm.active = 1',
        ];
        $whereTypes = 'i';
        $whereParams = [$taskId];

        $methodType = trim((string) ($filters['method_type'] ?? ''));
        if ($methodType !== '') {
            $where[] = 'm.method_type = ?';
            $whereTypes .= 's';
            $whereParams[] = $methodType;
        }

        $joinTypes = '';
        $joinParams = [];
        $query = trim((string) ($filters['q'] ?? ''));
        $assignmentContactFilter = '';
        if ($query !== '') {
            $like = '%' . $query . '%';
            $assignmentContactFilter = ' AND EXISTS (
                SELECT 1
                FROM main_contact c
                WHERE c.id = a.main_contact_id
                  AND (c.name LIKE ? OR c.email LIKE ?)
            )';
            $joinTypes .= 'ss';
            $joinParams[] = $like;
            $joinParams[] = $like;
        }

        $sql = 'SELECT
            m.id AS method_id,
            m.method_type,
            m.is_required,
            m.sort_order,
            COUNT(DISTINCT a.id) AS assignment_count,
            SUM(
                CASE
                    WHEN a.id IS NULL THEN 0
                    WHEN EXISTS (
                        SELECT 1
                        FROM task_submission s2
                        WHERE s2.assignment_id = a.id
                          AND s2.method_id = m.id
                          AND s2.status IN ("auto_passed", "approved")
                    ) THEN 1
                    ELSE 0
                END
            ) AS fulfilled_count
        FROM task_method m
        LEFT JOIN task_assignment a
          ON a.task_id = m.task_id
         AND a.cycle_key = ?' . $assignmentContactFilter . '
        WHERE ' . implode(' AND ', $where) . '
        GROUP BY m.id, m.method_type, m.is_required, m.sort_order
        ORDER BY m.sort_order ASC, m.id ASC
        LIMIT ' . $limit;

        // Placeholder order: cycle key, JOIN filters, WHERE filters.
        $types = 's' . $joinTypes . $whereTypes;
        $params = array_merge([$cycleKey], $joinParams, $whereParams);

        return TaskCertDb::fetchAll($sql, $types, $params);
    }
}