breakpilot-compliance/ai-compliance-sdk/internal/training/store.go

package training

import (
	"context"
	"encoding/json"
	"fmt"
	"time"

	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgxpool"
)

// Store handles training data persistence
type Store struct {
	pool *pgxpool.Pool
}

// NewStore creates a new training store
func NewStore(pool *pgxpool.Pool) *Store {
	return &Store{pool: pool}
}

// ============================================================================
// Module CRUD Operations
// ============================================================================

// CreateModule creates a new training module
func (s *Store) CreateModule(ctx context.Context, module *TrainingModule) error {
	module.ID = uuid.New()
	module.CreatedAt = time.Now().UTC()
	module.UpdatedAt = module.CreatedAt
	if !module.IsActive {
		module.IsActive = true
	}

	isoControls, _ := json.Marshal(module.ISOControls)

	_, err := s.pool.Exec(ctx, `
		INSERT INTO training_modules (
			id, tenant_id, academy_course_id, module_code, title, description,
			regulation_area, nis2_relevant, iso_controls, frequency_type,
			validity_days, risk_weight, content_type, duration_minutes,
			pass_threshold, is_active, sort_order, created_at, updated_at
		) VALUES (
			$1, $2, $3, $4, $5, $6,
			$7, $8, $9, $10,
			$11, $12, $13, $14,
			$15, $16, $17, $18, $19
		)
	`,
		module.ID, module.TenantID, module.AcademyCourseID, module.ModuleCode, module.Title, module.Description,
		string(module.RegulationArea), module.NIS2Relevant, isoControls, string(module.FrequencyType),
		module.ValidityDays, module.RiskWeight, module.ContentType, module.DurationMinutes,
		module.PassThreshold, module.IsActive, module.SortOrder, module.CreatedAt, module.UpdatedAt,
	)

	return err
}

// GetModule retrieves a module by ID
func (s *Store) GetModule(ctx context.Context, id uuid.UUID) (*TrainingModule, error) {
	var module TrainingModule
	var regulationArea, frequencyType string
	var isoControls []byte

	err := s.pool.QueryRow(ctx, `
		SELECT
			id, tenant_id, academy_course_id, module_code, title, description,
			regulation_area, nis2_relevant, iso_controls, frequency_type,
			validity_days, risk_weight, content_type, duration_minutes,
			pass_threshold, is_active, sort_order, created_at, updated_at
		FROM training_modules WHERE id = $1
	`, id).Scan(
		&module.ID, &module.TenantID, &module.AcademyCourseID, &module.ModuleCode, &module.Title, &module.Description,
		&regulationArea, &module.NIS2Relevant, &isoControls, &frequencyType,
		&module.ValidityDays, &module.RiskWeight, &module.ContentType, &module.DurationMinutes,
		&module.PassThreshold, &module.IsActive, &module.SortOrder, &module.CreatedAt, &module.UpdatedAt,
	)

	if err == pgx.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}

	module.RegulationArea = RegulationArea(regulationArea)
	module.FrequencyType = FrequencyType(frequencyType)
	json.Unmarshal(isoControls, &module.ISOControls)
	if module.ISOControls == nil {
		module.ISOControls = []string{}
	}

	return &module, nil
}

// ListModules lists training modules for a tenant with optional filters
func (s *Store) ListModules(ctx context.Context, tenantID uuid.UUID, filters *ModuleFilters) ([]TrainingModule, int, error) {
	countQuery := "SELECT COUNT(*) FROM training_modules WHERE tenant_id = $1"
	countArgs := []interface{}{tenantID}
	countArgIdx := 2

	query := `
		SELECT
			id, tenant_id, academy_course_id, module_code, title, description,
			regulation_area, nis2_relevant, iso_controls, frequency_type,
			validity_days, risk_weight, content_type, duration_minutes,
			pass_threshold, is_active, sort_order, created_at, updated_at
		FROM training_modules WHERE tenant_id = $1`

	args := []interface{}{tenantID}
	argIdx := 2

	if filters != nil {
		if filters.RegulationArea != "" {
			query += fmt.Sprintf(" AND regulation_area = $%d", argIdx)
			args = append(args, string(filters.RegulationArea))
			argIdx++
			countQuery += fmt.Sprintf(" AND regulation_area = $%d", countArgIdx)
			countArgs = append(countArgs, string(filters.RegulationArea))
			countArgIdx++
		}
		if filters.FrequencyType != "" {
			query += fmt.Sprintf(" AND frequency_type = $%d", argIdx)
			args = append(args, string(filters.FrequencyType))
			argIdx++
			countQuery += fmt.Sprintf(" AND frequency_type = $%d", countArgIdx)
			countArgs = append(countArgs, string(filters.FrequencyType))
			countArgIdx++
		}
		if filters.IsActive != nil {
			query += fmt.Sprintf(" AND is_active = $%d", argIdx)
			args = append(args, *filters.IsActive)
			argIdx++
			countQuery += fmt.Sprintf(" AND is_active = $%d", countArgIdx)
			countArgs = append(countArgs, *filters.IsActive)
			countArgIdx++
		}
		if filters.NIS2Relevant != nil {
			query += fmt.Sprintf(" AND nis2_relevant = $%d", argIdx)
			args = append(args, *filters.NIS2Relevant)
			argIdx++
			countQuery += fmt.Sprintf(" AND nis2_relevant = $%d", countArgIdx)
			countArgs = append(countArgs, *filters.NIS2Relevant)
			countArgIdx++
		}
		if filters.Search != "" {
			query += fmt.Sprintf(" AND (title ILIKE $%d OR description ILIKE $%d OR module_code ILIKE $%d)", argIdx, argIdx, argIdx)
			args = append(args, "%"+filters.Search+"%")
			argIdx++
			countQuery += fmt.Sprintf(" AND (title ILIKE $%d OR description ILIKE $%d OR module_code ILIKE $%d)", countArgIdx, countArgIdx, countArgIdx)
			countArgs = append(countArgs, "%"+filters.Search+"%")
			countArgIdx++
		}
	}

	var total int
	err := s.pool.QueryRow(ctx, countQuery, countArgs...).Scan(&total)
	if err != nil {
		return nil, 0, err
	}

	query += " ORDER BY sort_order ASC, created_at DESC"

	if filters != nil && filters.Limit > 0 {
		query += fmt.Sprintf(" LIMIT $%d", argIdx)
		args = append(args, filters.Limit)
		argIdx++
		if filters.Offset > 0 {
			query += fmt.Sprintf(" OFFSET $%d", argIdx)
			args = append(args, filters.Offset)
			argIdx++
		}
	}

	rows, err := s.pool.Query(ctx, query, args...)
	if err != nil {
		return nil, 0, err
	}
	defer rows.Close()

	var modules []TrainingModule
	for rows.Next() {
		var module TrainingModule
		var regulationArea, frequencyType string
		var isoControls []byte

		err := rows.Scan(
			&module.ID, &module.TenantID, &module.AcademyCourseID, &module.ModuleCode, &module.Title, &module.Description,
			&regulationArea, &module.NIS2Relevant, &isoControls, &frequencyType,
			&module.ValidityDays, &module.RiskWeight, &module.ContentType, &module.DurationMinutes,
			&module.PassThreshold, &module.IsActive, &module.SortOrder, &module.CreatedAt, &module.UpdatedAt,
		)
		if err != nil {
			return nil, 0, err
		}

		module.RegulationArea = RegulationArea(regulationArea)
		module.FrequencyType = FrequencyType(frequencyType)
		json.Unmarshal(isoControls, &module.ISOControls)
		if module.ISOControls == nil {
			module.ISOControls = []string{}
		}

		modules = append(modules, module)
	}

	if modules == nil {
		modules = []TrainingModule{}
	}

	return modules, total, nil
}

// UpdateModule updates a training module
func (s *Store) UpdateModule(ctx context.Context, module *TrainingModule) error {
	module.UpdatedAt = time.Now().UTC()
	isoControls, _ := json.Marshal(module.ISOControls)

	_, err := s.pool.Exec(ctx, `
		UPDATE training_modules SET
			title = $2, description = $3, nis2_relevant = $4,
			iso_controls = $5, validity_days = $6, risk_weight = $7,
			duration_minutes = $8, pass_threshold = $9, is_active = $10,
			sort_order = $11, updated_at = $12
		WHERE id = $1
	`,
		module.ID, module.Title, module.Description, module.NIS2Relevant,
		isoControls, module.ValidityDays, module.RiskWeight,
		module.DurationMinutes, module.PassThreshold, module.IsActive,
		module.SortOrder, module.UpdatedAt,
	)

	return err
}

// DeleteModule deletes a training module by ID
func (s *Store) DeleteModule(ctx context.Context, id uuid.UUID) error {
	_, err := s.pool.Exec(ctx, `DELETE FROM training_modules WHERE id = $1`, id)
	return err
}

// SetAcademyCourseID links a training module to an academy course
func (s *Store) SetAcademyCourseID(ctx context.Context, moduleID, courseID uuid.UUID) error {
	_, err := s.pool.Exec(ctx, `
		UPDATE training_modules SET academy_course_id = $2, updated_at = $3 WHERE id = $1
	`, moduleID, courseID, time.Now().UTC())
	return err
}

// ============================================================================
// Matrix Operations
// ============================================================================

// GetMatrixForRole returns all matrix entries for a given role
func (s *Store) GetMatrixForRole(ctx context.Context, tenantID uuid.UUID, roleCode string) ([]TrainingMatrixEntry, error) {
	rows, err := s.pool.Query(ctx, `
		SELECT
			tm.id, tm.tenant_id, tm.role_code, tm.module_id,
			tm.is_mandatory, tm.priority, tm.created_at,
			m.module_code, m.title
		FROM training_matrix tm
		JOIN training_modules m ON m.id = tm.module_id
		WHERE tm.tenant_id = $1 AND tm.role_code = $2
		ORDER BY tm.priority ASC
	`, tenantID, roleCode)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var entries []TrainingMatrixEntry
	for rows.Next() {
		var entry TrainingMatrixEntry
		err := rows.Scan(
			&entry.ID, &entry.TenantID, &entry.RoleCode, &entry.ModuleID,
			&entry.IsMandatory, &entry.Priority, &entry.CreatedAt,
			&entry.ModuleCode, &entry.ModuleTitle,
		)
		if err != nil {
			return nil, err
		}
		entries = append(entries, entry)
	}

	if entries == nil {
		entries = []TrainingMatrixEntry{}
	}

	return entries, nil
}

// GetMatrixForTenant returns the full CTM for a tenant
func (s *Store) GetMatrixForTenant(ctx context.Context, tenantID uuid.UUID) ([]TrainingMatrixEntry, error) {
	rows, err := s.pool.Query(ctx, `
		SELECT
			tm.id, tm.tenant_id, tm.role_code, tm.module_id,
			tm.is_mandatory, tm.priority, tm.created_at,
			m.module_code, m.title
		FROM training_matrix tm
		JOIN training_modules m ON m.id = tm.module_id
		WHERE tm.tenant_id = $1
		ORDER BY tm.role_code ASC, tm.priority ASC
	`, tenantID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var entries []TrainingMatrixEntry
	for rows.Next() {
		var entry TrainingMatrixEntry
		err := rows.Scan(
			&entry.ID, &entry.TenantID, &entry.RoleCode, &entry.ModuleID,
			&entry.IsMandatory, &entry.Priority, &entry.CreatedAt,
			&entry.ModuleCode, &entry.ModuleTitle,
		)
		if err != nil {
			return nil, err
		}
		entries = append(entries, entry)
	}

	if entries == nil {
		entries = []TrainingMatrixEntry{}
	}

	return entries, nil
}

// SetMatrixEntry creates or updates a CTM entry
func (s *Store) SetMatrixEntry(ctx context.Context, entry *TrainingMatrixEntry) error {
	entry.ID = uuid.New()
	entry.CreatedAt = time.Now().UTC()

	_, err := s.pool.Exec(ctx, `
		INSERT INTO training_matrix (
			id, tenant_id, role_code, module_id, is_mandatory, priority, created_at
		) VALUES ($1, $2, $3, $4, $5, $6, $7)
		ON CONFLICT (tenant_id, role_code, module_id)
		DO UPDATE SET is_mandatory = EXCLUDED.is_mandatory, priority = EXCLUDED.priority
	`,
		entry.ID, entry.TenantID, entry.RoleCode, entry.ModuleID,
		entry.IsMandatory, entry.Priority, entry.CreatedAt,
	)

	return err
}

// DeleteMatrixEntry removes a CTM entry
func (s *Store) DeleteMatrixEntry(ctx context.Context, tenantID uuid.UUID, roleCode string, moduleID uuid.UUID) error {
	_, err := s.pool.Exec(ctx,
		"DELETE FROM training_matrix WHERE tenant_id = $1 AND role_code = $2 AND module_id = $3",
		tenantID, roleCode, moduleID,
	)
	return err
}

// ============================================================================
// Assignment Operations
// ============================================================================

// CreateAssignment creates a new training assignment
func (s *Store) CreateAssignment(ctx context.Context, assignment *TrainingAssignment) error {
	assignment.ID = uuid.New()
	assignment.CreatedAt = time.Now().UTC()
	assignment.UpdatedAt = assignment.CreatedAt
	if assignment.Status == "" {
		assignment.Status = AssignmentStatusPending
	}

	_, err := s.pool.Exec(ctx, `
		INSERT INTO training_assignments (
			id, tenant_id, module_id, user_id, user_name, user_email,
			role_code, trigger_type, trigger_event, status, progress_percent,
			quiz_score, quiz_passed, quiz_attempts,
			started_at, completed_at, deadline, certificate_id,
			escalation_level, last_escalation_at, enrollment_id,
			created_at, updated_at
		) VALUES (
			$1, $2, $3, $4, $5, $6,
			$7, $8, $9, $10, $11,
			$12, $13, $14,
			$15, $16, $17, $18,
			$19, $20, $21,
			$22, $23
		)
	`,
		assignment.ID, assignment.TenantID, assignment.ModuleID, assignment.UserID, assignment.UserName, assignment.UserEmail,
		assignment.RoleCode, string(assignment.TriggerType), assignment.TriggerEvent, string(assignment.Status), assignment.ProgressPercent,
		assignment.QuizScore, assignment.QuizPassed, assignment.QuizAttempts,
		assignment.StartedAt, assignment.CompletedAt, assignment.Deadline, assignment.CertificateID,
		assignment.EscalationLevel, assignment.LastEscalationAt, assignment.EnrollmentID,
		assignment.CreatedAt, assignment.UpdatedAt,
	)

	return err
}

// GetAssignment retrieves an assignment by ID
func (s *Store) GetAssignment(ctx context.Context, id uuid.UUID) (*TrainingAssignment, error) {
	var a TrainingAssignment
	var status, triggerType string

	err := s.pool.QueryRow(ctx, `
		SELECT
			ta.id, ta.tenant_id, ta.module_id, ta.user_id, ta.user_name, ta.user_email,
			ta.role_code, ta.trigger_type, ta.trigger_event, ta.status, ta.progress_percent,
			ta.quiz_score, ta.quiz_passed, ta.quiz_attempts,
			ta.started_at, ta.completed_at, ta.deadline, ta.certificate_id,
			ta.escalation_level, ta.last_escalation_at, ta.enrollment_id,
			ta.created_at, ta.updated_at,
			m.module_code, m.title
		FROM training_assignments ta
		JOIN training_modules m ON m.id = ta.module_id
		WHERE ta.id = $1
	`, id).Scan(
		&a.ID, &a.TenantID, &a.ModuleID, &a.UserID, &a.UserName, &a.UserEmail,
		&a.RoleCode, &triggerType, &a.TriggerEvent, &status, &a.ProgressPercent,
		&a.QuizScore, &a.QuizPassed, &a.QuizAttempts,
		&a.StartedAt, &a.CompletedAt, &a.Deadline, &a.CertificateID,
		&a.EscalationLevel, &a.LastEscalationAt, &a.EnrollmentID,
		&a.CreatedAt, &a.UpdatedAt,
		&a.ModuleCode, &a.ModuleTitle,
	)

	if err == pgx.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}

	a.Status = AssignmentStatus(status)
	a.TriggerType = TriggerType(triggerType)
	return &a, nil
}

// ListAssignments lists assignments for a tenant with optional filters
func (s *Store) ListAssignments(ctx context.Context, tenantID uuid.UUID, filters *AssignmentFilters) ([]TrainingAssignment, int, error) {
	countQuery := "SELECT COUNT(*) FROM training_assignments WHERE tenant_id = $1"
	countArgs := []interface{}{tenantID}
	countArgIdx := 2

	query := `
		SELECT
			ta.id, ta.tenant_id, ta.module_id, ta.user_id, ta.user_name, ta.user_email,
			ta.role_code, ta.trigger_type, ta.trigger_event, ta.status, ta.progress_percent,
			ta.quiz_score, ta.quiz_passed, ta.quiz_attempts,
			ta.started_at, ta.completed_at, ta.deadline, ta.certificate_id,
			ta.escalation_level, ta.last_escalation_at, ta.enrollment_id,
			ta.created_at, ta.updated_at,
			m.module_code, m.title
		FROM training_assignments ta
		JOIN training_modules m ON m.id = ta.module_id
		WHERE ta.tenant_id = $1`

	args := []interface{}{tenantID}
	argIdx := 2

	if filters != nil {
		if filters.ModuleID != nil {
			query += fmt.Sprintf(" AND ta.module_id = $%d", argIdx)
			args = append(args, *filters.ModuleID)
			argIdx++
			countQuery += fmt.Sprintf(" AND module_id = $%d", countArgIdx)
			countArgs = append(countArgs, *filters.ModuleID)
			countArgIdx++
		}
		if filters.UserID != nil {
			query += fmt.Sprintf(" AND ta.user_id = $%d", argIdx)
			args = append(args, *filters.UserID)
			argIdx++
			countQuery += fmt.Sprintf(" AND user_id = $%d", countArgIdx)
			countArgs = append(countArgs, *filters.UserID)
			countArgIdx++
		}
		if filters.RoleCode != "" {
			query += fmt.Sprintf(" AND ta.role_code = $%d", argIdx)
			args = append(args, filters.RoleCode)
			argIdx++
			countQuery += fmt.Sprintf(" AND role_code = $%d", countArgIdx)
			countArgs = append(countArgs, filters.RoleCode)
			countArgIdx++
		}
		if filters.Status != "" {
			query += fmt.Sprintf(" AND ta.status = $%d", argIdx)
			args = append(args, string(filters.Status))
			argIdx++
			countQuery += fmt.Sprintf(" AND status = $%d", countArgIdx)
			countArgs = append(countArgs, string(filters.Status))
			countArgIdx++
		}
		if filters.Overdue != nil && *filters.Overdue {
			query += " AND ta.deadline < NOW() AND ta.status IN ('pending', 'in_progress')"
			countQuery += " AND deadline < NOW() AND status IN ('pending', 'in_progress')"
		}
	}

	var total int
	err := s.pool.QueryRow(ctx, countQuery, countArgs...).Scan(&total)
	if err != nil {
		return nil, 0, err
	}

	query += " ORDER BY ta.deadline ASC"

	if filters != nil && filters.Limit > 0 {
		query += fmt.Sprintf(" LIMIT $%d", argIdx)
		args = append(args, filters.Limit)
		argIdx++
		if filters.Offset > 0 {
			query += fmt.Sprintf(" OFFSET $%d", argIdx)
			args = append(args, filters.Offset)
			argIdx++
		}
	}

	rows, err := s.pool.Query(ctx, query, args...)
	if err != nil {
		return nil, 0, err
	}
	defer rows.Close()

	var assignments []TrainingAssignment
	for rows.Next() {
		var a TrainingAssignment
		var status, triggerType string

		err := rows.Scan(
			&a.ID, &a.TenantID, &a.ModuleID, &a.UserID, &a.UserName, &a.UserEmail,
			&a.RoleCode, &triggerType, &a.TriggerEvent, &status, &a.ProgressPercent,
			&a.QuizScore, &a.QuizPassed, &a.QuizAttempts,
			&a.StartedAt, &a.CompletedAt, &a.Deadline, &a.CertificateID,
			&a.EscalationLevel, &a.LastEscalationAt, &a.EnrollmentID,
			&a.CreatedAt, &a.UpdatedAt,
			&a.ModuleCode, &a.ModuleTitle,
		)
		if err != nil {
			return nil, 0, err
		}

		a.Status = AssignmentStatus(status)
		a.TriggerType = TriggerType(triggerType)
		assignments = append(assignments, a)
	}

	if assignments == nil {
		assignments = []TrainingAssignment{}
	}

	return assignments, total, nil
}

// UpdateAssignmentStatus updates the status and related fields
func (s *Store) UpdateAssignmentStatus(ctx context.Context, id uuid.UUID, status AssignmentStatus, progress int) error {
	now := time.Now().UTC()

	_, err := s.pool.Exec(ctx, `
		UPDATE training_assignments SET
			status = $2,
			progress_percent = $3,
			started_at = CASE
				WHEN started_at IS NULL AND $2 IN ('in_progress', 'completed') THEN $4
				ELSE started_at
			END,
			completed_at = CASE
				WHEN $2 = 'completed' THEN $4
				ELSE completed_at
			END,
			updated_at = $4
		WHERE id = $1
	`, id, string(status), progress, now)

	return err
}

// UpdateAssignmentDeadline updates the deadline of an assignment
func (s *Store) UpdateAssignmentDeadline(ctx context.Context, id uuid.UUID, deadline time.Time) error {
	now := time.Now().UTC()
	_, err := s.pool.Exec(ctx, `
		UPDATE training_assignments SET
			deadline = $2,
			updated_at = $3
		WHERE id = $1
	`, id, deadline, now)
	return err
}

// UpdateAssignmentQuizResult updates quiz-related fields on an assignment
func (s *Store) UpdateAssignmentQuizResult(ctx context.Context, id uuid.UUID, score float64, passed bool, attempts int) error {
	now := time.Now().UTC()

	_, err := s.pool.Exec(ctx, `
		UPDATE training_assignments SET
			quiz_score = $2,
			quiz_passed = $3,
			quiz_attempts = $4,
			status = CASE WHEN $3 = true THEN 'completed' ELSE status END,
			completed_at = CASE WHEN $3 = true THEN $5 ELSE completed_at END,
			progress_percent = CASE WHEN $3 = true THEN 100 ELSE progress_percent END,
			updated_at = $5
		WHERE id = $1
	`, id, score, passed, attempts, now)

	return err
}

// ListOverdueAssignments returns assignments past their deadline
func (s *Store) ListOverdueAssignments(ctx context.Context, tenantID uuid.UUID) ([]TrainingAssignment, error) {
	overdue := true
	assignments, _, err := s.ListAssignments(ctx, tenantID, &AssignmentFilters{
		Overdue: &overdue,
		Limit:   1000,
	})
	return assignments, err
}

// ============================================================================
// Quiz Operations
// ============================================================================

// CreateQuizQuestion creates a new quiz question
func (s *Store) CreateQuizQuestion(ctx context.Context, q *QuizQuestion) error {
	q.ID = uuid.New()
	q.CreatedAt = time.Now().UTC()
	if !q.IsActive {
		q.IsActive = true
	}

	options, _ := json.Marshal(q.Options)

	_, err := s.pool.Exec(ctx, `
		INSERT INTO training_quiz_questions (
			id, module_id, question, options, correct_index,
			explanation, difficulty, is_active, sort_order, created_at
		) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)
	`,
		q.ID, q.ModuleID, q.Question, options, q.CorrectIndex,
		q.Explanation, string(q.Difficulty), q.IsActive, q.SortOrder, q.CreatedAt,
	)

	return err
}

// ListQuizQuestions lists quiz questions for a module
func (s *Store) ListQuizQuestions(ctx context.Context, moduleID uuid.UUID) ([]QuizQuestion, error) {
	rows, err := s.pool.Query(ctx, `
		SELECT
			id, module_id, question, options, correct_index,
			explanation, difficulty, is_active, sort_order, created_at
		FROM training_quiz_questions
		WHERE module_id = $1 AND is_active = true
		ORDER BY sort_order ASC, created_at ASC
	`, moduleID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var questions []QuizQuestion
	for rows.Next() {
		var q QuizQuestion
		var options []byte
		var difficulty string

		err := rows.Scan(
			&q.ID, &q.ModuleID, &q.Question, &options, &q.CorrectIndex,
			&q.Explanation, &difficulty, &q.IsActive, &q.SortOrder, &q.CreatedAt,
		)
		if err != nil {
			return nil, err
		}

		q.Difficulty = Difficulty(difficulty)
		json.Unmarshal(options, &q.Options)
		if q.Options == nil {
			q.Options = []string{}
		}

		questions = append(questions, q)
	}

	if questions == nil {
		questions = []QuizQuestion{}
	}

	return questions, nil
}

// CreateQuizAttempt records a quiz attempt
func (s *Store) CreateQuizAttempt(ctx context.Context, attempt *QuizAttempt) error {
	attempt.ID = uuid.New()
	attempt.AttemptedAt = time.Now().UTC()

	answers, _ := json.Marshal(attempt.Answers)

	_, err := s.pool.Exec(ctx, `
		INSERT INTO training_quiz_attempts (
			id, assignment_id, user_id, answers, score,
			passed, correct_count, total_count, duration_seconds, attempted_at
		) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)
	`,
		attempt.ID, attempt.AssignmentID, attempt.UserID, answers, attempt.Score,
		attempt.Passed, attempt.CorrectCount, attempt.TotalCount, attempt.DurationSeconds, attempt.AttemptedAt,
	)

	return err
}

// ListQuizAttempts lists quiz attempts for an assignment
func (s *Store) ListQuizAttempts(ctx context.Context, assignmentID uuid.UUID) ([]QuizAttempt, error) {
	rows, err := s.pool.Query(ctx, `
		SELECT
			id, assignment_id, user_id, answers, score,
			passed, correct_count, total_count, duration_seconds, attempted_at
		FROM training_quiz_attempts
		WHERE assignment_id = $1
		ORDER BY attempted_at DESC
	`, assignmentID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var attempts []QuizAttempt
	for rows.Next() {
		var a QuizAttempt
		var answers []byte

		err := rows.Scan(
			&a.ID, &a.AssignmentID, &a.UserID, &answers, &a.Score,
			&a.Passed, &a.CorrectCount, &a.TotalCount, &a.DurationSeconds, &a.AttemptedAt,
		)
		if err != nil {
			return nil, err
		}

		json.Unmarshal(answers, &a.Answers)
		if a.Answers == nil {
			a.Answers = []QuizAnswer{}
		}

		attempts = append(attempts, a)
	}

	if attempts == nil {
		attempts = []QuizAttempt{}
	}

	return attempts, nil
}

// ============================================================================
// Content Operations
// ============================================================================

// CreateModuleContent creates new content for a module
func (s *Store) CreateModuleContent(ctx context.Context, content *ModuleContent) error {
	content.ID = uuid.New()
	content.CreatedAt = time.Now().UTC()
	content.UpdatedAt = content.CreatedAt

	// Auto-increment version
	var maxVersion int
	s.pool.QueryRow(ctx,
		"SELECT COALESCE(MAX(version), 0) FROM training_module_content WHERE module_id = $1",
		content.ModuleID).Scan(&maxVersion)
	content.Version = maxVersion + 1

	_, err := s.pool.Exec(ctx, `
		INSERT INTO training_module_content (
			id, module_id, version, content_format, content_body,
			summary, generated_by, llm_model, is_published,
			reviewed_by, reviewed_at, created_at, updated_at
		) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13)
	`,
		content.ID, content.ModuleID, content.Version, string(content.ContentFormat), content.ContentBody,
		content.Summary, content.GeneratedBy, content.LLMModel, content.IsPublished,
		content.ReviewedBy, content.ReviewedAt, content.CreatedAt, content.UpdatedAt,
	)

	return err
}

// GetPublishedContent retrieves the published content for a module
func (s *Store) GetPublishedContent(ctx context.Context, moduleID uuid.UUID) (*ModuleContent, error) {
	var content ModuleContent
	var contentFormat string

	err := s.pool.QueryRow(ctx, `
		SELECT
			id, module_id, version, content_format, content_body,
			summary, generated_by, llm_model, is_published,
			reviewed_by, reviewed_at, created_at, updated_at
		FROM training_module_content
		WHERE module_id = $1 AND is_published = true
		ORDER BY version DESC
		LIMIT 1
	`, moduleID).Scan(
		&content.ID, &content.ModuleID, &content.Version, &contentFormat, &content.ContentBody,
		&content.Summary, &content.GeneratedBy, &content.LLMModel, &content.IsPublished,
		&content.ReviewedBy, &content.ReviewedAt, &content.CreatedAt, &content.UpdatedAt,
	)

	if err == pgx.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}

	content.ContentFormat = ContentFormat(contentFormat)
	return &content, nil
}

// GetLatestContent retrieves the latest content (published or not) for a module
func (s *Store) GetLatestContent(ctx context.Context, moduleID uuid.UUID) (*ModuleContent, error) {
	var content ModuleContent
	var contentFormat string

	err := s.pool.QueryRow(ctx, `
		SELECT
			id, module_id, version, content_format, content_body,
			summary, generated_by, llm_model, is_published,
			reviewed_by, reviewed_at, created_at, updated_at
		FROM training_module_content
		WHERE module_id = $1
		ORDER BY version DESC
		LIMIT 1
	`, moduleID).Scan(
		&content.ID, &content.ModuleID, &content.Version, &contentFormat, &content.ContentBody,
		&content.Summary, &content.GeneratedBy, &content.LLMModel, &content.IsPublished,
		&content.ReviewedBy, &content.ReviewedAt, &content.CreatedAt, &content.UpdatedAt,
	)

	if err == pgx.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}

	content.ContentFormat = ContentFormat(contentFormat)
	return &content, nil
}

// PublishContent marks a content version as published (unpublishes all others for that module)
func (s *Store) PublishContent(ctx context.Context, contentID uuid.UUID, reviewedBy uuid.UUID) error {
	now := time.Now().UTC()

	// Get module_id for this content
	var moduleID uuid.UUID
	err := s.pool.QueryRow(ctx,
		"SELECT module_id FROM training_module_content WHERE id = $1",
		contentID).Scan(&moduleID)
	if err != nil {
		return err
	}

	// Unpublish all existing content for this module
	_, err = s.pool.Exec(ctx,
		"UPDATE training_module_content SET is_published = false WHERE module_id = $1",
		moduleID)
	if err != nil {
		return err
	}

	// Publish the specified content
	_, err = s.pool.Exec(ctx, `
		UPDATE training_module_content SET
			is_published = true, reviewed_by = $2, reviewed_at = $3, updated_at = $3
		WHERE id = $1
	`, contentID, reviewedBy, now)

	return err
}

// ============================================================================
// Audit Log Operations
// ============================================================================

// LogAction creates an audit log entry
func (s *Store) LogAction(ctx context.Context, entry *AuditLogEntry) error {
	entry.ID = uuid.New()
	entry.CreatedAt = time.Now().UTC()

	details, _ := json.Marshal(entry.Details)

	_, err := s.pool.Exec(ctx, `
		INSERT INTO training_audit_log (
			id, tenant_id, user_id, action, entity_type,
			entity_id, details, ip_address, created_at
		) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)
	`,
		entry.ID, entry.TenantID, entry.UserID, string(entry.Action), string(entry.EntityType),
		entry.EntityID, details, entry.IPAddress, entry.CreatedAt,
	)

	return err
}

// ListAuditLog lists audit log entries for a tenant
func (s *Store) ListAuditLog(ctx context.Context, tenantID uuid.UUID, filters *AuditLogFilters) ([]AuditLogEntry, int, error) {
	countQuery := "SELECT COUNT(*) FROM training_audit_log WHERE tenant_id = $1"
	countArgs := []interface{}{tenantID}
	countArgIdx := 2

	query := `
		SELECT
			id, tenant_id, user_id, action, entity_type,
			entity_id, details, ip_address, created_at
		FROM training_audit_log WHERE tenant_id = $1`

	args := []interface{}{tenantID}
	argIdx := 2

	if filters != nil {
		if filters.UserID != nil {
			query += fmt.Sprintf(" AND user_id = $%d", argIdx)
			args = append(args, *filters.UserID)
			argIdx++
			countQuery += fmt.Sprintf(" AND user_id = $%d", countArgIdx)
			countArgs = append(countArgs, *filters.UserID)
			countArgIdx++
		}
		if filters.Action != "" {
			query += fmt.Sprintf(" AND action = $%d", argIdx)
			args = append(args, string(filters.Action))
			argIdx++
			countQuery += fmt.Sprintf(" AND action = $%d", countArgIdx)
			countArgs = append(countArgs, string(filters.Action))
			countArgIdx++
		}
		if filters.EntityType != "" {
			query += fmt.Sprintf(" AND entity_type = $%d", argIdx)
			args = append(args, string(filters.EntityType))
			argIdx++
			countQuery += fmt.Sprintf(" AND entity_type = $%d", countArgIdx)
			countArgs = append(countArgs, string(filters.EntityType))
			countArgIdx++
		}
	}

	var total int
	err := s.pool.QueryRow(ctx, countQuery, countArgs...).Scan(&total)
	if err != nil {
		return nil, 0, err
	}

	query += " ORDER BY created_at DESC"

	if filters != nil && filters.Limit > 0 {
		query += fmt.Sprintf(" LIMIT $%d", argIdx)
		args = append(args, filters.Limit)
		argIdx++
		if filters.Offset > 0 {
			query += fmt.Sprintf(" OFFSET $%d", argIdx)
			args = append(args, filters.Offset)
			argIdx++
		}
	}

	rows, err := s.pool.Query(ctx, query, args...)
	if err != nil {
		return nil, 0, err
	}
	defer rows.Close()

	var entries []AuditLogEntry
	for rows.Next() {
		var entry AuditLogEntry
		var action, entityType string
		var details []byte

		err := rows.Scan(
			&entry.ID, &entry.TenantID, &entry.UserID, &action, &entityType,
			&entry.EntityID, &details, &entry.IPAddress, &entry.CreatedAt,
		)
		if err != nil {
			return nil, 0, err
		}

		entry.Action = AuditAction(action)
		entry.EntityType = AuditEntityType(entityType)
		json.Unmarshal(details, &entry.Details)
		if entry.Details == nil {
			entry.Details = map[string]interface{}{}
		}

		entries = append(entries, entry)
	}

	if entries == nil {
		entries = []AuditLogEntry{}
	}

	return entries, total, nil
}

// ============================================================================
// Statistics
// ============================================================================

// GetTrainingStats returns aggregated training statistics for a tenant
func (s *Store) GetTrainingStats(ctx context.Context, tenantID uuid.UUID) (*TrainingStats, error) {
	stats := &TrainingStats{}

	// Total active modules
	s.pool.QueryRow(ctx,
		"SELECT COUNT(*) FROM training_modules WHERE tenant_id = $1 AND is_active = true",
		tenantID).Scan(&stats.TotalModules)

	// Total assignments
	s.pool.QueryRow(ctx,
		"SELECT COUNT(*) FROM training_assignments WHERE tenant_id = $1",
		tenantID).Scan(&stats.TotalAssignments)

	// Status counts
	s.pool.QueryRow(ctx,
		"SELECT COUNT(*) FROM training_assignments WHERE tenant_id = $1 AND status = 'pending'",
		tenantID).Scan(&stats.PendingCount)

	s.pool.QueryRow(ctx,
		"SELECT COUNT(*) FROM training_assignments WHERE tenant_id = $1 AND status = 'in_progress'",
		tenantID).Scan(&stats.InProgressCount)

	s.pool.QueryRow(ctx,
		"SELECT COUNT(*) FROM training_assignments WHERE tenant_id = $1 AND status = 'completed'",
		tenantID).Scan(&stats.CompletedCount)

	// Completion rate
	if stats.TotalAssignments > 0 {
		stats.CompletionRate = float64(stats.CompletedCount) / float64(stats.TotalAssignments) * 100
	}

	// Overdue count
	s.pool.QueryRow(ctx, `
		SELECT COUNT(*) FROM training_assignments
		WHERE tenant_id = $1
		AND status IN ('pending', 'in_progress')
		AND deadline < NOW()
	`, tenantID).Scan(&stats.OverdueCount)

	// Average quiz score
	s.pool.QueryRow(ctx, `
		SELECT COALESCE(AVG(quiz_score), 0) FROM training_assignments
		WHERE tenant_id = $1 AND quiz_score IS NOT NULL
	`, tenantID).Scan(&stats.AvgQuizScore)

	// Average completion days
	s.pool.QueryRow(ctx, `
		SELECT COALESCE(AVG(EXTRACT(EPOCH FROM (completed_at - started_at)) / 86400), 0)
		FROM training_assignments
		WHERE tenant_id = $1 AND status = 'completed'
		AND started_at IS NOT NULL AND completed_at IS NOT NULL
	`, tenantID).Scan(&stats.AvgCompletionDays)

	// Upcoming deadlines (within 7 days)
	s.pool.QueryRow(ctx, `
		SELECT COUNT(*) FROM training_assignments
		WHERE tenant_id = $1
		AND status IN ('pending', 'in_progress')
		AND deadline BETWEEN NOW() AND NOW() + INTERVAL '7 days'
	`, tenantID).Scan(&stats.UpcomingDeadlines)

	return stats, nil
}

// GetDeadlines returns upcoming deadlines for a tenant
func (s *Store) GetDeadlines(ctx context.Context, tenantID uuid.UUID, limit int) ([]DeadlineInfo, error) {
	if limit <= 0 {
		limit = 20
	}

	rows, err := s.pool.Query(ctx, `
		SELECT
			ta.id, m.module_code, m.title,
			ta.user_id, ta.user_name, ta.deadline, ta.status,
			EXTRACT(DAY FROM (ta.deadline - NOW()))::INT AS days_left
		FROM training_assignments ta
		JOIN training_modules m ON m.id = ta.module_id
		WHERE ta.tenant_id = $1
		AND ta.status IN ('pending', 'in_progress')
		ORDER BY ta.deadline ASC
		LIMIT $2
	`, tenantID, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var deadlines []DeadlineInfo
	for rows.Next() {
		var d DeadlineInfo
		var status string

		err := rows.Scan(
			&d.AssignmentID, &d.ModuleCode, &d.ModuleTitle,
			&d.UserID, &d.UserName, &d.Deadline, &status,
			&d.DaysLeft,
		)
		if err != nil {
			return nil, err
		}

		d.Status = AssignmentStatus(status)
		deadlines = append(deadlines, d)
	}

	if deadlines == nil {
		deadlines = []DeadlineInfo{}
	}

	return deadlines, nil
}

// ============================================================================
// Media CRUD Operations
// ============================================================================

// CreateMedia creates a new media record
func (s *Store) CreateMedia(ctx context.Context, media *TrainingMedia) error {
	media.ID = uuid.New()
	media.CreatedAt = time.Now().UTC()
	media.UpdatedAt = media.CreatedAt
	if media.Metadata == nil {
		media.Metadata = json.RawMessage("{}")
	}

	_, err := s.pool.Exec(ctx, `
		INSERT INTO training_media (
			id, module_id, content_id, media_type, status,
			bucket, object_key, file_size_bytes, duration_seconds,
			mime_type, voice_model, language, metadata,
			error_message, generated_by, is_published, created_at, updated_at
		) VALUES (
			$1, $2, $3, $4, $5,
			$6, $7, $8, $9,
			$10, $11, $12, $13,
			$14, $15, $16, $17, $18
		)
	`,
		media.ID, media.ModuleID, media.ContentID, string(media.MediaType), string(media.Status),
		media.Bucket, media.ObjectKey, media.FileSizeBytes, media.DurationSeconds,
		media.MimeType, media.VoiceModel, media.Language, media.Metadata,
		media.ErrorMessage, media.GeneratedBy, media.IsPublished, media.CreatedAt, media.UpdatedAt,
	)

	return err
}

// GetMedia retrieves a media record by ID
func (s *Store) GetMedia(ctx context.Context, id uuid.UUID) (*TrainingMedia, error) {
	var media TrainingMedia
	var mediaType, status string

	err := s.pool.QueryRow(ctx, `
		SELECT id, module_id, content_id, media_type, status,
			bucket, object_key, file_size_bytes, duration_seconds,
			mime_type, voice_model, language, metadata,
			error_message, generated_by, is_published, created_at, updated_at
		FROM training_media WHERE id = $1
	`, id).Scan(
		&media.ID, &media.ModuleID, &media.ContentID, &mediaType, &status,
		&media.Bucket, &media.ObjectKey, &media.FileSizeBytes, &media.DurationSeconds,
		&media.MimeType, &media.VoiceModel, &media.Language, &media.Metadata,
		&media.ErrorMessage, &media.GeneratedBy, &media.IsPublished, &media.CreatedAt, &media.UpdatedAt,
	)

	if err == pgx.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}

	media.MediaType = MediaType(mediaType)
	media.Status = MediaStatus(status)
	return &media, nil
}

// GetMediaForModule retrieves all media for a module
func (s *Store) GetMediaForModule(ctx context.Context, moduleID uuid.UUID) ([]TrainingMedia, error) {
	rows, err := s.pool.Query(ctx, `
		SELECT id, module_id, content_id, media_type, status,
			bucket, object_key, file_size_bytes, duration_seconds,
			mime_type, voice_model, language, metadata,
			error_message, generated_by, is_published, created_at, updated_at
		FROM training_media WHERE module_id = $1
		ORDER BY media_type, created_at DESC
	`, moduleID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var mediaList []TrainingMedia
	for rows.Next() {
		var media TrainingMedia
		var mediaType, status string
		if err := rows.Scan(
			&media.ID, &media.ModuleID, &media.ContentID, &mediaType, &status,
			&media.Bucket, &media.ObjectKey, &media.FileSizeBytes, &media.DurationSeconds,
			&media.MimeType, &media.VoiceModel, &media.Language, &media.Metadata,
			&media.ErrorMessage, &media.GeneratedBy, &media.IsPublished, &media.CreatedAt, &media.UpdatedAt,
		); err != nil {
			return nil, err
		}
		media.MediaType = MediaType(mediaType)
		media.Status = MediaStatus(status)
		mediaList = append(mediaList, media)
	}

	if mediaList == nil {
		mediaList = []TrainingMedia{}
	}
	return mediaList, nil
}

// UpdateMediaStatus updates the status and related fields of a media record
func (s *Store) UpdateMediaStatus(ctx context.Context, id uuid.UUID, status MediaStatus, sizeBytes int64, duration float64, errMsg string) error {
	_, err := s.pool.Exec(ctx, `
		UPDATE training_media
		SET status = $2, file_size_bytes = $3, duration_seconds = $4,
			error_message = $5, updated_at = NOW()
		WHERE id = $1
	`, id, string(status), sizeBytes, duration, errMsg)
	return err
}

// PublishMedia publishes or unpublishes a media record
func (s *Store) PublishMedia(ctx context.Context, id uuid.UUID, publish bool) error {
	_, err := s.pool.Exec(ctx, `
		UPDATE training_media SET is_published = $2, updated_at = NOW() WHERE id = $1
	`, id, publish)
	return err
}

// GetPublishedAudio gets the published audio for a module
func (s *Store) GetPublishedAudio(ctx context.Context, moduleID uuid.UUID) (*TrainingMedia, error) {
	var media TrainingMedia
	var mediaType, status string

	err := s.pool.QueryRow(ctx, `
		SELECT id, module_id, content_id, media_type, status,
			bucket, object_key, file_size_bytes, duration_seconds,
			mime_type, voice_model, language, metadata,
			error_message, generated_by, is_published, created_at, updated_at
		FROM training_media
		WHERE module_id = $1 AND media_type = 'audio' AND is_published = true
		ORDER BY created_at DESC LIMIT 1
	`, moduleID).Scan(
		&media.ID, &media.ModuleID, &media.ContentID, &mediaType, &status,
		&media.Bucket, &media.ObjectKey, &media.FileSizeBytes, &media.DurationSeconds,
		&media.MimeType, &media.VoiceModel, &media.Language, &media.Metadata,
		&media.ErrorMessage, &media.GeneratedBy, &media.IsPublished, &media.CreatedAt, &media.UpdatedAt,
	)

	if err == pgx.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}

	media.MediaType = MediaType(mediaType)
	media.Status = MediaStatus(status)
	return &media, nil
}

// SetCertificateID sets the certificate ID on an assignment
func (s *Store) SetCertificateID(ctx context.Context, assignmentID, certID uuid.UUID) error {
	_, err := s.pool.Exec(ctx, `
		UPDATE training_assignments SET certificate_id = $2, updated_at = NOW() WHERE id = $1
	`, assignmentID, certID)
	return err
}

// GetAssignmentByCertificateID finds an assignment by its certificate ID
func (s *Store) GetAssignmentByCertificateID(ctx context.Context, certID uuid.UUID) (*TrainingAssignment, error) {
	var assignmentID uuid.UUID
	err := s.pool.QueryRow(ctx,
		"SELECT id FROM training_assignments WHERE certificate_id = $1",
		certID).Scan(&assignmentID)
	if err == pgx.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}
	return s.GetAssignment(ctx, assignmentID)
}

// ListCertificates lists assignments that have certificates for a tenant
func (s *Store) ListCertificates(ctx context.Context, tenantID uuid.UUID) ([]TrainingAssignment, error) {
	rows, err := s.pool.Query(ctx, `
		SELECT
			ta.id, ta.tenant_id, ta.module_id, ta.user_id, ta.user_name, ta.user_email,
			ta.role_code, ta.trigger_type, ta.trigger_event, ta.status, ta.progress_percent,
			ta.quiz_score, ta.quiz_passed, ta.quiz_attempts,
			ta.started_at, ta.completed_at, ta.deadline, ta.certificate_id,
			ta.escalation_level, ta.last_escalation_at, ta.enrollment_id,
			ta.created_at, ta.updated_at,
			m.module_code, m.title
		FROM training_assignments ta
		JOIN training_modules m ON m.id = ta.module_id
		WHERE ta.tenant_id = $1 AND ta.certificate_id IS NOT NULL
		ORDER BY ta.completed_at DESC
	`, tenantID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var assignments []TrainingAssignment
	for rows.Next() {
		var a TrainingAssignment
		var status, triggerType string

		err := rows.Scan(
			&a.ID, &a.TenantID, &a.ModuleID, &a.UserID, &a.UserName, &a.UserEmail,
			&a.RoleCode, &triggerType, &a.TriggerEvent, &status, &a.ProgressPercent,
			&a.QuizScore, &a.QuizPassed, &a.QuizAttempts,
			&a.StartedAt, &a.CompletedAt, &a.Deadline, &a.CertificateID,
			&a.EscalationLevel, &a.LastEscalationAt, &a.EnrollmentID,
			&a.CreatedAt, &a.UpdatedAt,
			&a.ModuleCode, &a.ModuleTitle,
		)
		if err != nil {
			return nil, err
		}

		a.Status = AssignmentStatus(status)
		a.TriggerType = TriggerType(triggerType)
		assignments = append(assignments, a)
	}

	if assignments == nil {
		assignments = []TrainingAssignment{}
	}

	return assignments, nil
}

// GetPublishedVideo gets the published video for a module
func (s *Store) GetPublishedVideo(ctx context.Context, moduleID uuid.UUID) (*TrainingMedia, error) {
	var media TrainingMedia
	var mediaType, status string

	err := s.pool.QueryRow(ctx, `
		SELECT id, module_id, content_id, media_type, status,
			bucket, object_key, file_size_bytes, duration_seconds,
			mime_type, voice_model, language, metadata,
			error_message, generated_by, is_published, created_at, updated_at
		FROM training_media
		WHERE module_id = $1 AND media_type = 'video' AND is_published = true
		ORDER BY created_at DESC LIMIT 1
	`, moduleID).Scan(
		&media.ID, &media.ModuleID, &media.ContentID, &mediaType, &status,
		&media.Bucket, &media.ObjectKey, &media.FileSizeBytes, &media.DurationSeconds,
		&media.MimeType, &media.VoiceModel, &media.Language, &media.Metadata,
		&media.ErrorMessage, &media.GeneratedBy, &media.IsPublished, &media.CreatedAt, &media.UpdatedAt,
	)

	if err == pgx.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}

	media.MediaType = MediaType(mediaType)
	media.Status = MediaStatus(status)
	return &media, nil
}

// ============================================================================
// Checkpoint Operations
// ============================================================================

// CreateCheckpoint inserts a new checkpoint
func (s *Store) CreateCheckpoint(ctx context.Context, cp *Checkpoint) error {
	cp.ID = uuid.New()
	cp.CreatedAt = time.Now().UTC()

	_, err := s.pool.Exec(ctx, `
		INSERT INTO training_checkpoints (id, module_id, checkpoint_index, title, timestamp_seconds, created_at)
		VALUES ($1, $2, $3, $4, $5, $6)
	`, cp.ID, cp.ModuleID, cp.CheckpointIndex, cp.Title, cp.TimestampSeconds, cp.CreatedAt)

	return err
}

// ListCheckpoints returns all checkpoints for a module ordered by index
func (s *Store) ListCheckpoints(ctx context.Context, moduleID uuid.UUID) ([]Checkpoint, error) {
	rows, err := s.pool.Query(ctx, `
		SELECT id, module_id, checkpoint_index, title, timestamp_seconds, created_at
		FROM training_checkpoints
		WHERE module_id = $1
		ORDER BY checkpoint_index
	`, moduleID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var checkpoints []Checkpoint
	for rows.Next() {
		var cp Checkpoint
		if err := rows.Scan(&cp.ID, &cp.ModuleID, &cp.CheckpointIndex, &cp.Title, &cp.TimestampSeconds, &cp.CreatedAt); err != nil {
			return nil, err
		}
		checkpoints = append(checkpoints, cp)
	}

	if checkpoints == nil {
		checkpoints = []Checkpoint{}
	}
	return checkpoints, nil
}

// DeleteCheckpointsForModule removes all checkpoints for a module (used before regenerating)
func (s *Store) DeleteCheckpointsForModule(ctx context.Context, moduleID uuid.UUID) error {
	_, err := s.pool.Exec(ctx, `DELETE FROM training_checkpoints WHERE module_id = $1`, moduleID)
	return err
}

// GetCheckpointProgress retrieves progress for a specific checkpoint+assignment
func (s *Store) GetCheckpointProgress(ctx context.Context, assignmentID, checkpointID uuid.UUID) (*CheckpointProgress, error) {
	var cp CheckpointProgress
	err := s.pool.QueryRow(ctx, `
		SELECT id, assignment_id, checkpoint_id, passed, attempts, last_attempt_at, created_at
		FROM training_checkpoint_progress
		WHERE assignment_id = $1 AND checkpoint_id = $2
	`, assignmentID, checkpointID).Scan(
		&cp.ID, &cp.AssignmentID, &cp.CheckpointID, &cp.Passed, &cp.Attempts, &cp.LastAttemptAt, &cp.CreatedAt,
	)
	if err == pgx.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}
	return &cp, nil
}

// UpsertCheckpointProgress creates or updates checkpoint progress
func (s *Store) UpsertCheckpointProgress(ctx context.Context, progress *CheckpointProgress) error {
	progress.ID = uuid.New()
	now := time.Now().UTC()
	progress.LastAttemptAt = &now
	progress.CreatedAt = now

	_, err := s.pool.Exec(ctx, `
		INSERT INTO training_checkpoint_progress (id, assignment_id, checkpoint_id, passed, attempts, last_attempt_at, created_at)
		VALUES ($1, $2, $3, $4, $5, $6, $7)
		ON CONFLICT (assignment_id, checkpoint_id) DO UPDATE SET
			passed = EXCLUDED.passed,
			attempts = training_checkpoint_progress.attempts + 1,
			last_attempt_at = EXCLUDED.last_attempt_at
	`, progress.ID, progress.AssignmentID, progress.CheckpointID, progress.Passed, progress.Attempts, progress.LastAttemptAt, progress.CreatedAt)

	return err
}

// GetCheckpointQuestions retrieves quiz questions for a specific checkpoint
func (s *Store) GetCheckpointQuestions(ctx context.Context, checkpointID uuid.UUID) ([]QuizQuestion, error) {
	rows, err := s.pool.Query(ctx, `
		SELECT id, module_id, question, options, correct_index, explanation, difficulty, is_active, sort_order, created_at
		FROM training_quiz_questions
		WHERE checkpoint_id = $1 AND is_active = true
		ORDER BY sort_order
	`, checkpointID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var questions []QuizQuestion
	for rows.Next() {
		var q QuizQuestion
		var options []byte
		var difficulty string
		if err := rows.Scan(&q.ID, &q.ModuleID, &q.Question, &options, &q.CorrectIndex, &q.Explanation, &difficulty, &q.IsActive, &q.SortOrder, &q.CreatedAt); err != nil {
			return nil, err
		}
		json.Unmarshal(options, &q.Options)
		q.Difficulty = Difficulty(difficulty)
		questions = append(questions, q)
	}

	if questions == nil {
		questions = []QuizQuestion{}
	}
	return questions, nil
}

// CreateCheckpointQuizQuestion creates a quiz question linked to a checkpoint
func (s *Store) CreateCheckpointQuizQuestion(ctx context.Context, q *QuizQuestion, checkpointID uuid.UUID) error {
	q.ID = uuid.New()
	q.CreatedAt = time.Now().UTC()
	q.IsActive = true

	options, _ := json.Marshal(q.Options)

	_, err := s.pool.Exec(ctx, `
		INSERT INTO training_quiz_questions (id, module_id, checkpoint_id, question, options, correct_index, explanation, difficulty, is_active, sort_order, created_at)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11)
	`, q.ID, q.ModuleID, checkpointID, q.Question, options, q.CorrectIndex, q.Explanation, string(q.Difficulty), q.IsActive, q.SortOrder, q.CreatedAt)

	return err
}

// AreAllCheckpointsPassed checks if all checkpoints for a module are passed by an assignment
func (s *Store) AreAllCheckpointsPassed(ctx context.Context, assignmentID, moduleID uuid.UUID) (bool, error) {
	var totalCheckpoints, passedCheckpoints int

	err := s.pool.QueryRow(ctx, `
		SELECT COUNT(*) FROM training_checkpoints WHERE module_id = $1
	`, moduleID).Scan(&totalCheckpoints)
	if err != nil {
		return false, err
	}

	if totalCheckpoints == 0 {
		return true, nil
	}

	err = s.pool.QueryRow(ctx, `
		SELECT COUNT(*) FROM training_checkpoint_progress cp
		JOIN training_checkpoints c ON cp.checkpoint_id = c.id
		WHERE cp.assignment_id = $1 AND c.module_id = $2 AND cp.passed = true
	`, assignmentID, moduleID).Scan(&passedCheckpoints)
	if err != nil {
		return false, err
	}

	return passedCheckpoints >= totalCheckpoints, nil
}

// ListCheckpointProgress returns all checkpoint progress for an assignment
func (s *Store) ListCheckpointProgress(ctx context.Context, assignmentID uuid.UUID) ([]CheckpointProgress, error) {
	rows, err := s.pool.Query(ctx, `
		SELECT id, assignment_id, checkpoint_id, passed, attempts, last_attempt_at, created_at
		FROM training_checkpoint_progress
		WHERE assignment_id = $1
		ORDER BY created_at
	`, assignmentID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var progress []CheckpointProgress
	for rows.Next() {
		var cp CheckpointProgress
		if err := rows.Scan(&cp.ID, &cp.AssignmentID, &cp.CheckpointID, &cp.Passed, &cp.Attempts, &cp.LastAttemptAt, &cp.CreatedAt); err != nil {
			return nil, err
		}
		progress = append(progress, cp)
	}

	if progress == nil {
		progress = []CheckpointProgress{}
	}
	return progress, nil
}