package vendor

import (
	"context"
	"fmt"
	"time"

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

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

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

// ============================================================================
// Vendor CRUD Operations
// ============================================================================

// CreateVendor creates a new vendor
func (s *Store) CreateVendor(ctx context.Context, v *Vendor) error {
	v.ID = uuid.New()
	v.CreatedAt = time.Now().UTC()
	v.UpdatedAt = v.CreatedAt
	if v.Status == "" {
		v.Status = VendorStatusPendingReview
	}

	_, err := s.pool.Exec(ctx, `
		INSERT INTO vendor_vendors (
			id, tenant_id,
			name, legal_form, country, address, website,
			contact_name, contact_email, contact_phone, contact_department,
			role, service_category, service_description, data_access_level,
			processing_locations, certifications,
			inherent_risk_score, residual_risk_score, manual_risk_adjustment,
			review_frequency, last_review_date, next_review_date,
			processing_activity_ids,
			status, template_id,
			created_at, updated_at, created_by
		) VALUES (
			$1, $2,
			$3, $4, $5, $6, $7,
			$8, $9, $10, $11,
			$12, $13, $14, $15,
			$16, $17,
			$18, $19, $20,
			$21, $22, $23,
			$24,
			$25, $26,
			$27, $28, $29
		)
	`,
		v.ID, v.TenantID,
		v.Name, v.LegalForm, v.Country, v.Address, v.Website,
		v.ContactName, v.ContactEmail, v.ContactPhone, v.ContactDepartment,
		string(v.Role), v.ServiceCategory, v.ServiceDescription, v.DataAccessLevel,
		v.ProcessingLocations, v.Certifications,
		v.InherentRiskScore, v.ResidualRiskScore, v.ManualRiskAdjustment,
		v.ReviewFrequency, v.LastReviewDate, v.NextReviewDate,
		v.ProcessingActivityIDs,
		string(v.Status), v.TemplateID,
		v.CreatedAt, v.UpdatedAt, v.CreatedBy,
	)

	return err
}

// GetVendor retrieves a vendor by ID and tenant
func (s *Store) GetVendor(ctx context.Context, tenantID, id string) (*Vendor, error) {
	tid, err := uuid.Parse(tenantID)
	if err != nil {
		return nil, fmt.Errorf("invalid tenant_id: %w", err)
	}
	vid, err := uuid.Parse(id)
	if err != nil {
		return nil, fmt.Errorf("invalid vendor id: %w", err)
	}

	var v Vendor
	var role, status string

	err = s.pool.QueryRow(ctx, `
		SELECT
			id, tenant_id,
			name, legal_form, country, address, website,
			contact_name, contact_email, contact_phone, contact_department,
			role, service_category, service_description, data_access_level,
			processing_locations, certifications,
			inherent_risk_score, residual_risk_score, manual_risk_adjustment,
			review_frequency, last_review_date, next_review_date,
			processing_activity_ids,
			status, template_id,
			created_at, updated_at, created_by
		FROM vendor_vendors WHERE id = $1 AND tenant_id = $2
	`, vid, tid).Scan(
		&v.ID, &v.TenantID,
		&v.Name, &v.LegalForm, &v.Country, &v.Address, &v.Website,
		&v.ContactName, &v.ContactEmail, &v.ContactPhone, &v.ContactDepartment,
		&role, &v.ServiceCategory, &v.ServiceDescription, &v.DataAccessLevel,
		&v.ProcessingLocations, &v.Certifications,
		&v.InherentRiskScore, &v.ResidualRiskScore, &v.ManualRiskAdjustment,
		&v.ReviewFrequency, &v.LastReviewDate, &v.NextReviewDate,
		&v.ProcessingActivityIDs,
		&status, &v.TemplateID,
		&v.CreatedAt, &v.UpdatedAt, &v.CreatedBy,
	)

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

	v.Role = VendorRole(role)
	v.Status = VendorStatus(status)

	return &v, nil
}

// ListVendors lists all vendors for a tenant ordered by name
func (s *Store) ListVendors(ctx context.Context, tenantID string) ([]*Vendor, error) {
	tid, err := uuid.Parse(tenantID)
	if err != nil {
		return nil, fmt.Errorf("invalid tenant_id: %w", err)
	}

	rows, err := s.pool.Query(ctx, `
		SELECT
			id, tenant_id,
			name, legal_form, country, address, website,
			contact_name, contact_email, contact_phone, contact_department,
			role, service_category, service_description, data_access_level,
			processing_locations, certifications,
			inherent_risk_score, residual_risk_score, manual_risk_adjustment,
			review_frequency, last_review_date, next_review_date,
			processing_activity_ids,
			status, template_id,
			created_at, updated_at, created_by
		FROM vendor_vendors WHERE tenant_id = $1
		ORDER BY name ASC
	`, tid)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var vendors []*Vendor
	for rows.Next() {
		v, err := scanVendor(rows)
		if err != nil {
			return nil, err
		}
		vendors = append(vendors, v)
	}

	return vendors, nil
}

// UpdateVendor updates an existing vendor
func (s *Store) UpdateVendor(ctx context.Context, v *Vendor) error {
	v.UpdatedAt = time.Now().UTC()

	_, err := s.pool.Exec(ctx, `
		UPDATE vendor_vendors SET
			name = $3, legal_form = $4, country = $5, address = $6, website = $7,
			contact_name = $8, contact_email = $9, contact_phone = $10, contact_department = $11,
			role = $12, service_category = $13, service_description = $14, data_access_level = $15,
			processing_locations = $16, certifications = $17,
			inherent_risk_score = $18, residual_risk_score = $19, manual_risk_adjustment = $20,
			review_frequency = $21, last_review_date = $22, next_review_date = $23,
			processing_activity_ids = $24,
			status = $25, template_id = $26,
			updated_at = $27
		WHERE id = $1 AND tenant_id = $2
	`,
		v.ID, v.TenantID,
		v.Name, v.LegalForm, v.Country, v.Address, v.Website,
		v.ContactName, v.ContactEmail, v.ContactPhone, v.ContactDepartment,
		string(v.Role), v.ServiceCategory, v.ServiceDescription, v.DataAccessLevel,
		v.ProcessingLocations, v.Certifications,
		v.InherentRiskScore, v.ResidualRiskScore, v.ManualRiskAdjustment,
		v.ReviewFrequency, v.LastReviewDate, v.NextReviewDate,
		v.ProcessingActivityIDs,
		string(v.Status), v.TemplateID,
		v.UpdatedAt,
	)

	return err
}

// DeleteVendor deletes a vendor by ID and tenant
func (s *Store) DeleteVendor(ctx context.Context, tenantID, id string) error {
	tid, err := uuid.Parse(tenantID)
	if err != nil {
		return fmt.Errorf("invalid tenant_id: %w", err)
	}
	vid, err := uuid.Parse(id)
	if err != nil {
		return fmt.Errorf("invalid vendor id: %w", err)
	}

	_, err = s.pool.Exec(ctx,
		"DELETE FROM vendor_vendors WHERE id = $1 AND tenant_id = $2",
		vid, tid,
	)
	return err
}

// ============================================================================
// Contract CRUD Operations
// ============================================================================

// CreateContract creates a new contract document
func (s *Store) CreateContract(ctx context.Context, c *Contract) error {
	c.ID = uuid.New()
	c.CreatedAt = time.Now().UTC()
	c.UpdatedAt = c.CreatedAt
	if c.ReviewStatus == "" {
		c.ReviewStatus = "PENDING"
	}

	_, err := s.pool.Exec(ctx, `
		INSERT INTO vendor_contracts (
			id, tenant_id, vendor_id,
			file_name, original_name, mime_type, file_size, storage_path,
			document_type, parties,
			effective_date, expiration_date, auto_renewal, renewal_notice_period,
			review_status, review_completed_at, compliance_score,
			version, previous_version_id,
			extracted_text, page_count,
			created_at, updated_at, created_by
		) VALUES (
			$1, $2, $3,
			$4, $5, $6, $7, $8,
			$9, $10,
			$11, $12, $13, $14,
			$15, $16, $17,
			$18, $19,
			$20, $21,
			$22, $23, $24
		)
	`,
		c.ID, c.TenantID, c.VendorID,
		c.FileName, c.OriginalName, c.MimeType, c.FileSize, c.StoragePath,
		string(c.DocumentType), c.Parties,
		c.EffectiveDate, c.ExpirationDate, c.AutoRenewal, c.RenewalNoticePeriod,
		c.ReviewStatus, c.ReviewCompletedAt, c.ComplianceScore,
		c.Version, c.PreviousVersionID,
		c.ExtractedText, c.PageCount,
		c.CreatedAt, c.UpdatedAt, c.CreatedBy,
	)

	return err
}

// GetContract retrieves a contract by ID and tenant
func (s *Store) GetContract(ctx context.Context, tenantID, id string) (*Contract, error) {
	tid, err := uuid.Parse(tenantID)
	if err != nil {
		return nil, fmt.Errorf("invalid tenant_id: %w", err)
	}
	cid, err := uuid.Parse(id)
	if err != nil {
		return nil, fmt.Errorf("invalid contract id: %w", err)
	}

	var c Contract
	var documentType string

	err = s.pool.QueryRow(ctx, `
		SELECT
			id, tenant_id, vendor_id,
			file_name, original_name, mime_type, file_size, storage_path,
			document_type, parties,
			effective_date, expiration_date, auto_renewal, renewal_notice_period,
			review_status, review_completed_at, compliance_score,
			version, previous_version_id,
			extracted_text, page_count,
			created_at, updated_at, created_by
		FROM vendor_contracts WHERE id = $1 AND tenant_id = $2
	`, cid, tid).Scan(
		&c.ID, &c.TenantID, &c.VendorID,
		&c.FileName, &c.OriginalName, &c.MimeType, &c.FileSize, &c.StoragePath,
		&documentType, &c.Parties,
		&c.EffectiveDate, &c.ExpirationDate, &c.AutoRenewal, &c.RenewalNoticePeriod,
		&c.ReviewStatus, &c.ReviewCompletedAt, &c.ComplianceScore,
		&c.Version, &c.PreviousVersionID,
		&c.ExtractedText, &c.PageCount,
		&c.CreatedAt, &c.UpdatedAt, &c.CreatedBy,
	)

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

	c.DocumentType = DocumentType(documentType)

	return &c, nil
}

// ListContracts lists contracts for a tenant, optionally filtered by vendor
func (s *Store) ListContracts(ctx context.Context, tenantID string, vendorID *string) ([]*Contract, error) {
	tid, err := uuid.Parse(tenantID)
	if err != nil {
		return nil, fmt.Errorf("invalid tenant_id: %w", err)
	}

	query := `
		SELECT
			id, tenant_id, vendor_id,
			file_name, original_name, mime_type, file_size, storage_path,
			document_type, parties,
			effective_date, expiration_date, auto_renewal, renewal_notice_period,
			review_status, review_completed_at, compliance_score,
			version, previous_version_id,
			extracted_text, page_count,
			created_at, updated_at, created_by
		FROM vendor_contracts WHERE tenant_id = $1`

	args := []interface{}{tid}
	if vendorID != nil {
		vid, err := uuid.Parse(*vendorID)
		if err != nil {
			return nil, fmt.Errorf("invalid vendor_id: %w", err)
		}
		query += " AND vendor_id = $2"
		args = append(args, vid)
	}

	query += " ORDER BY created_at DESC"

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

	var contracts []*Contract
	for rows.Next() {
		c, err := scanContract(rows)
		if err != nil {
			return nil, err
		}
		contracts = append(contracts, c)
	}

	return contracts, nil
}

// UpdateContract updates an existing contract
func (s *Store) UpdateContract(ctx context.Context, c *Contract) error {
	c.UpdatedAt = time.Now().UTC()

	_, err := s.pool.Exec(ctx, `
		UPDATE vendor_contracts SET
			vendor_id = $3,
			file_name = $4, original_name = $5, mime_type = $6, file_size = $7, storage_path = $8,
			document_type = $9, parties = $10,
			effective_date = $11, expiration_date = $12, auto_renewal = $13, renewal_notice_period = $14,
			review_status = $15, review_completed_at = $16, compliance_score = $17,
			version = $18, previous_version_id = $19,
			extracted_text = $20, page_count = $21,
			updated_at = $22
		WHERE id = $1 AND tenant_id = $2
	`,
		c.ID, c.TenantID,
		c.VendorID,
		c.FileName, c.OriginalName, c.MimeType, c.FileSize, c.StoragePath,
		string(c.DocumentType), c.Parties,
		c.EffectiveDate, c.ExpirationDate, c.AutoRenewal, c.RenewalNoticePeriod,
		c.ReviewStatus, c.ReviewCompletedAt, c.ComplianceScore,
		c.Version, c.PreviousVersionID,
		c.ExtractedText, c.PageCount,
		c.UpdatedAt,
	)

	return err
}

// DeleteContract deletes a contract by ID and tenant
func (s *Store) DeleteContract(ctx context.Context, tenantID, id string) error {
	tid, err := uuid.Parse(tenantID)
	if err != nil {
		return fmt.Errorf("invalid tenant_id: %w", err)
	}
	cid, err := uuid.Parse(id)
	if err != nil {
		return fmt.Errorf("invalid contract id: %w", err)
	}

	_, err = s.pool.Exec(ctx,
		"DELETE FROM vendor_contracts WHERE id = $1 AND tenant_id = $2",
		cid, tid,
	)
	return err
}

// ============================================================================
// Finding CRUD Operations
// ============================================================================

// CreateFinding creates a new finding
func (s *Store) CreateFinding(ctx context.Context, f *Finding) error {
	f.ID = uuid.New()
	f.CreatedAt = time.Now().UTC()
	f.UpdatedAt = f.CreatedAt
	if f.Status == "" {
		f.Status = FindingStatusOpen
	}

	_, err := s.pool.Exec(ctx, `
		INSERT INTO vendor_findings (
			id, tenant_id, contract_id, vendor_id,
			finding_type, category, severity,
			title, description, recommendation,
			citations,
			status, assignee, due_date, resolution, resolved_at, resolved_by,
			created_at, updated_at
		) VALUES (
			$1, $2, $3, $4,
			$5, $6, $7,
			$8, $9, $10,
			$11,
			$12, $13, $14, $15, $16, $17,
			$18, $19
		)
	`,
		f.ID, f.TenantID, f.ContractID, f.VendorID,
		string(f.FindingType), f.Category, f.Severity,
		f.Title, f.Description, f.Recommendation,
		f.Citations,
		string(f.Status), f.Assignee, f.DueDate, f.Resolution, f.ResolvedAt, f.ResolvedBy,
		f.CreatedAt, f.UpdatedAt,
	)

	return err
}

// GetFinding retrieves a finding by ID and tenant
func (s *Store) GetFinding(ctx context.Context, tenantID, id string) (*Finding, error) {
	tid, err := uuid.Parse(tenantID)
	if err != nil {
		return nil, fmt.Errorf("invalid tenant_id: %w", err)
	}
	fid, err := uuid.Parse(id)
	if err != nil {
		return nil, fmt.Errorf("invalid finding id: %w", err)
	}

	var f Finding
	var findingType, status string

	err = s.pool.QueryRow(ctx, `
		SELECT
			id, tenant_id, contract_id, vendor_id,
			finding_type, category, severity,
			title, description, recommendation,
			citations,
			status, assignee, due_date, resolution, resolved_at, resolved_by,
			created_at, updated_at
		FROM vendor_findings WHERE id = $1 AND tenant_id = $2
	`, fid, tid).Scan(
		&f.ID, &f.TenantID, &f.ContractID, &f.VendorID,
		&findingType, &f.Category, &f.Severity,
		&f.Title, &f.Description, &f.Recommendation,
		&f.Citations,
		&status, &f.Assignee, &f.DueDate, &f.Resolution, &f.ResolvedAt, &f.ResolvedBy,
		&f.CreatedAt, &f.UpdatedAt,
	)

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

	f.FindingType = FindingType(findingType)
	f.Status = FindingStatus(status)

	return &f, nil
}

// ListFindings lists findings for a tenant with optional vendor and contract filters
func (s *Store) ListFindings(ctx context.Context, tenantID string, vendorID *string, contractID *string) ([]*Finding, error) {
	tid, err := uuid.Parse(tenantID)
	if err != nil {
		return nil, fmt.Errorf("invalid tenant_id: %w", err)
	}

	query := `
		SELECT
			id, tenant_id, contract_id, vendor_id,
			finding_type, category, severity,
			title, description, recommendation,
			citations,
			status, assignee, due_date, resolution, resolved_at, resolved_by,
			created_at, updated_at
		FROM vendor_findings WHERE tenant_id = $1`

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

	if vendorID != nil {
		vid, err := uuid.Parse(*vendorID)
		if err != nil {
			return nil, fmt.Errorf("invalid vendor_id: %w", err)
		}
		query += fmt.Sprintf(" AND vendor_id = $%d", argIdx)
		args = append(args, vid)
		argIdx++
	}
	if contractID != nil {
		query += fmt.Sprintf(" AND contract_id = $%d", argIdx)
		args = append(args, *contractID)
		argIdx++
	}

	query += " ORDER BY created_at DESC"

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

	var findings []*Finding
	for rows.Next() {
		f, err := scanFinding(rows)
		if err != nil {
			return nil, err
		}
		findings = append(findings, f)
	}

	return findings, nil
}

// UpdateFinding updates an existing finding
func (s *Store) UpdateFinding(ctx context.Context, f *Finding) error {
	f.UpdatedAt = time.Now().UTC()

	_, err := s.pool.Exec(ctx, `
		UPDATE vendor_findings SET
			finding_type = $3, category = $4, severity = $5,
			title = $6, description = $7, recommendation = $8,
			citations = $9,
			status = $10, assignee = $11, due_date = $12,
			resolution = $13, resolved_at = $14, resolved_by = $15,
			updated_at = $16
		WHERE id = $1 AND tenant_id = $2
	`,
		f.ID, f.TenantID,
		string(f.FindingType), f.Category, f.Severity,
		f.Title, f.Description, f.Recommendation,
		f.Citations,
		string(f.Status), f.Assignee, f.DueDate,
		f.Resolution, f.ResolvedAt, f.ResolvedBy,
		f.UpdatedAt,
	)

	return err
}

// ResolveFinding marks a finding as resolved with a resolution text
func (s *Store) ResolveFinding(ctx context.Context, tenantID, id, resolution string, resolvedBy string) error {
	tid, err := uuid.Parse(tenantID)
	if err != nil {
		return fmt.Errorf("invalid tenant_id: %w", err)
	}
	fid, err := uuid.Parse(id)
	if err != nil {
		return fmt.Errorf("invalid finding id: %w", err)
	}

	now := time.Now().UTC()

	_, err = s.pool.Exec(ctx, `
		UPDATE vendor_findings SET
			status = $3,
			resolution = $4,
			resolved_at = $5,
			resolved_by = $6,
			updated_at = $5
		WHERE id = $1 AND tenant_id = $2
	`,
		fid, tid,
		string(FindingStatusResolved),
		resolution, now, resolvedBy,
	)

	return err
}

// ============================================================================
// Control Instance Operations
// ============================================================================

// UpsertControlInstance inserts or updates a control instance
func (s *Store) UpsertControlInstance(ctx context.Context, ci *ControlInstance) error {
	if ci.ID == uuid.Nil {
		ci.ID = uuid.New()
	}
	now := time.Now().UTC()
	ci.CreatedAt = now
	ci.UpdatedAt = now

	_, err := s.pool.Exec(ctx, `
		INSERT INTO vendor_control_instances (
			id, tenant_id, vendor_id,
			control_id, control_domain,
			status, evidence_ids, notes,
			last_assessed_at, last_assessed_by, next_assessment_date,
			created_at, updated_at
		) VALUES (
			$1, $2, $3,
			$4, $5,
			$6, $7, $8,
			$9, $10, $11,
			$12, $13
		)
		ON CONFLICT (tenant_id, vendor_id, control_id) DO UPDATE SET
			status = EXCLUDED.status,
			evidence_ids = EXCLUDED.evidence_ids,
			notes = EXCLUDED.notes,
			last_assessed_at = EXCLUDED.last_assessed_at,
			last_assessed_by = EXCLUDED.last_assessed_by,
			next_assessment_date = EXCLUDED.next_assessment_date,
			updated_at = EXCLUDED.updated_at
	`,
		ci.ID, ci.TenantID, ci.VendorID,
		ci.ControlID, ci.ControlDomain,
		string(ci.Status), ci.EvidenceIDs, ci.Notes,
		ci.LastAssessedAt, ci.LastAssessedBy, ci.NextAssessmentDate,
		ci.CreatedAt, ci.UpdatedAt,
	)

	return err
}

// ListControlInstances lists control instances for a vendor within a tenant
func (s *Store) ListControlInstances(ctx context.Context, tenantID, vendorID string) ([]*ControlInstance, error) {
	tid, err := uuid.Parse(tenantID)
	if err != nil {
		return nil, fmt.Errorf("invalid tenant_id: %w", err)
	}
	vid, err := uuid.Parse(vendorID)
	if err != nil {
		return nil, fmt.Errorf("invalid vendor_id: %w", err)
	}

	rows, err := s.pool.Query(ctx, `
		SELECT
			id, tenant_id, vendor_id,
			control_id, control_domain,
			status, evidence_ids, notes,
			last_assessed_at, last_assessed_by, next_assessment_date,
			created_at, updated_at
		FROM vendor_control_instances
		WHERE tenant_id = $1 AND vendor_id = $2
		ORDER BY control_id ASC
	`, tid, vid)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var instances []*ControlInstance
	for rows.Next() {
		ci, err := scanControlInstance(rows)
		if err != nil {
			return nil, err
		}
		instances = append(instances, ci)
	}

	return instances, nil
}

// UpdateControlInstance updates an existing control instance
func (s *Store) UpdateControlInstance(ctx context.Context, ci *ControlInstance) error {
	ci.UpdatedAt = time.Now().UTC()

	_, err := s.pool.Exec(ctx, `
		UPDATE vendor_control_instances SET
			status = $3,
			evidence_ids = $4,
			notes = $5,
			last_assessed_at = $6,
			last_assessed_by = $7,
			next_assessment_date = $8,
			updated_at = $9
		WHERE id = $1 AND tenant_id = $2
	`,
		ci.ID, ci.TenantID,
		string(ci.Status), ci.EvidenceIDs, ci.Notes,
		ci.LastAssessedAt, ci.LastAssessedBy, ci.NextAssessmentDate,
		ci.UpdatedAt,
	)

	return err
}

// ============================================================================
// Template Operations
// ============================================================================

// CreateTemplate creates a new template
func (s *Store) CreateTemplate(ctx context.Context, t *Template) error {
	if t.ID == uuid.Nil {
		t.ID = uuid.New()
	}
	t.CreatedAt = time.Now().UTC()
	t.UpdatedAt = t.CreatedAt

	_, err := s.pool.Exec(ctx, `
		INSERT INTO compliance_templates (
			id, tenant_id,
			template_type, template_id, category,
			name_de, name_en, description_de, description_en,
			template_data,
			industry, tags,
			is_system, is_active, usage_count,
			created_at, updated_at
		) VALUES (
			$1, $2,
			$3, $4, $5,
			$6, $7, $8, $9,
			$10,
			$11, $12,
			$13, $14, $15,
			$16, $17
		)
	`,
		t.ID, t.TenantID,
		t.TemplateType, t.TemplateID, t.Category,
		t.NameDE, t.NameEN, t.DescriptionDE, t.DescriptionEN,
		t.TemplateData,
		t.Industry, t.Tags,
		t.IsSystem, t.IsActive, t.UsageCount,
		t.CreatedAt, t.UpdatedAt,
	)

	return err
}

// GetTemplate retrieves a template by its template_id (not UUID)
func (s *Store) GetTemplate(ctx context.Context, templateID string) (*Template, error) {
	var t Template

	err := s.pool.QueryRow(ctx, `
		SELECT
			id, tenant_id,
			template_type, template_id, category,
			name_de, name_en, description_de, description_en,
			template_data,
			industry, tags,
			is_system, is_active, usage_count,
			created_at, updated_at
		FROM compliance_templates WHERE template_id = $1
	`, templateID).Scan(
		&t.ID, &t.TenantID,
		&t.TemplateType, &t.TemplateID, &t.Category,
		&t.NameDE, &t.NameEN, &t.DescriptionDE, &t.DescriptionEN,
		&t.TemplateData,
		&t.Industry, &t.Tags,
		&t.IsSystem, &t.IsActive, &t.UsageCount,
		&t.CreatedAt, &t.UpdatedAt,
	)

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

	return &t, nil
}

// ListTemplates lists templates filtered by type and optionally by category and industry
func (s *Store) ListTemplates(ctx context.Context, templateType string, category *string, industry *string) ([]*Template, error) {
	query := `
		SELECT
			id, tenant_id,
			template_type, template_id, category,
			name_de, name_en, description_de, description_en,
			template_data,
			industry, tags,
			is_system, is_active, usage_count,
			created_at, updated_at
		FROM compliance_templates WHERE template_type = $1`

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

	if category != nil {
		query += fmt.Sprintf(" AND category = $%d", argIdx)
		args = append(args, *category)
		argIdx++
	}
	if industry != nil {
		query += fmt.Sprintf(" AND industry = $%d", argIdx)
		args = append(args, *industry)
		argIdx++
	}

	query += " ORDER BY usage_count DESC, name_de ASC"

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

	var templates []*Template
	for rows.Next() {
		t, err := scanTemplate(rows)
		if err != nil {
			return nil, err
		}
		templates = append(templates, t)
	}

	return templates, nil
}

// IncrementTemplateUsage increments the usage count for a template
func (s *Store) IncrementTemplateUsage(ctx context.Context, templateID string) error {
	_, err := s.pool.Exec(ctx, `
		UPDATE compliance_templates SET
			usage_count = usage_count + 1,
			updated_at = NOW()
		WHERE template_id = $1
	`, templateID)

	return err
}

// SeedSystemTemplates performs a bulk upsert of system templates
func (s *Store) SeedSystemTemplates(ctx context.Context, templates []*Template) error {
	for _, t := range templates {
		t.IsSystem = true
		if t.ID == uuid.Nil {
			t.ID = uuid.New()
		}
		now := time.Now().UTC()
		t.CreatedAt = now
		t.UpdatedAt = now

		_, err := s.pool.Exec(ctx, `
			INSERT INTO compliance_templates (
				id, tenant_id,
				template_type, template_id, category,
				name_de, name_en, description_de, description_en,
				template_data,
				industry, tags,
				is_system, is_active, usage_count,
				created_at, updated_at
			) VALUES (
				$1, $2,
				$3, $4, $5,
				$6, $7, $8, $9,
				$10,
				$11, $12,
				$13, $14, $15,
				$16, $17
			)
			ON CONFLICT (template_id) DO UPDATE SET
				name_de = EXCLUDED.name_de,
				name_en = EXCLUDED.name_en,
				description_de = EXCLUDED.description_de,
				description_en = EXCLUDED.description_en,
				template_data = EXCLUDED.template_data,
				category = EXCLUDED.category,
				industry = EXCLUDED.industry,
				tags = EXCLUDED.tags,
				updated_at = EXCLUDED.updated_at
		`,
			t.ID, t.TenantID,
			t.TemplateType, t.TemplateID, t.Category,
			t.NameDE, t.NameEN, t.DescriptionDE, t.DescriptionEN,
			t.TemplateData,
			t.Industry, t.Tags,
			t.IsSystem, t.IsActive, t.UsageCount,
			t.CreatedAt, t.UpdatedAt,
		)
		if err != nil {
			return fmt.Errorf("failed to seed template %s: %w", t.TemplateID, err)
		}
	}

	return nil
}

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

// GetVendorStats returns aggregated vendor statistics for a tenant
func (s *Store) GetVendorStats(ctx context.Context, tenantID string) (*VendorStats, error) {
	tid, err := uuid.Parse(tenantID)
	if err != nil {
		return nil, fmt.Errorf("invalid tenant_id: %w", err)
	}

	stats := &VendorStats{
		ByStatus:    make(map[string]int),
		ByRole:      make(map[string]int),
		ByRiskLevel: make(map[string]int),
	}

	// Total vendors
	s.pool.QueryRow(ctx,
		"SELECT COUNT(*) FROM vendor_vendors WHERE tenant_id = $1",
		tid).Scan(&stats.TotalVendors)

	// By status
	rows, err := s.pool.Query(ctx,
		"SELECT status, COUNT(*) FROM vendor_vendors WHERE tenant_id = $1 GROUP BY status",
		tid)
	if err == nil {
		defer rows.Close()
		for rows.Next() {
			var status string
			var count int
			rows.Scan(&status, &count)
			stats.ByStatus[status] = count
		}
	}

	// By role
	rows, err = s.pool.Query(ctx,
		"SELECT role, COUNT(*) FROM vendor_vendors WHERE tenant_id = $1 GROUP BY role",
		tid)
	if err == nil {
		defer rows.Close()
		for rows.Next() {
			var role string
			var count int
			rows.Scan(&role, &count)
			stats.ByRole[role] = count
		}
	}

	// By risk level (based on residual_risk_score thresholds)
	var riskCount int
	s.pool.QueryRow(ctx, `
		SELECT COUNT(*) FROM vendor_vendors
		WHERE tenant_id = $1 AND residual_risk_score IS NOT NULL AND residual_risk_score <= 25
	`, tid).Scan(&riskCount)
	stats.ByRiskLevel["LOW"] = riskCount

	s.pool.QueryRow(ctx, `
		SELECT COUNT(*) FROM vendor_vendors
		WHERE tenant_id = $1 AND residual_risk_score IS NOT NULL AND residual_risk_score > 25 AND residual_risk_score <= 50
	`, tid).Scan(&riskCount)
	stats.ByRiskLevel["MEDIUM"] = riskCount

	s.pool.QueryRow(ctx, `
		SELECT COUNT(*) FROM vendor_vendors
		WHERE tenant_id = $1 AND residual_risk_score IS NOT NULL AND residual_risk_score > 50 AND residual_risk_score <= 75
	`, tid).Scan(&riskCount)
	stats.ByRiskLevel["HIGH"] = riskCount

	s.pool.QueryRow(ctx, `
		SELECT COUNT(*) FROM vendor_vendors
		WHERE tenant_id = $1 AND residual_risk_score IS NOT NULL AND residual_risk_score > 75
	`, tid).Scan(&riskCount)
	stats.ByRiskLevel["CRITICAL"] = riskCount

	// Pending reviews (vendors past next_review_date)
	s.pool.QueryRow(ctx, `
		SELECT COUNT(*) FROM vendor_vendors
		WHERE tenant_id = $1 AND next_review_date IS NOT NULL AND next_review_date < NOW()
	`, tid).Scan(&stats.PendingReviews)

	// Expired contracts
	s.pool.QueryRow(ctx, `
		SELECT COUNT(*) FROM vendor_contracts
		WHERE tenant_id = $1 AND expiration_date IS NOT NULL AND expiration_date < NOW()
	`, tid).Scan(&stats.ExpiredContracts)

	return stats, nil
}

// ============================================================================
// Row Scanning Helpers
// ============================================================================

// scanVendor scans a vendor row from pgx.Rows
func scanVendor(rows pgx.Rows) (*Vendor, error) {
	var v Vendor
	var role, status string

	err := rows.Scan(
		&v.ID, &v.TenantID,
		&v.Name, &v.LegalForm, &v.Country, &v.Address, &v.Website,
		&v.ContactName, &v.ContactEmail, &v.ContactPhone, &v.ContactDepartment,
		&role, &v.ServiceCategory, &v.ServiceDescription, &v.DataAccessLevel,
		&v.ProcessingLocations, &v.Certifications,
		&v.InherentRiskScore, &v.ResidualRiskScore, &v.ManualRiskAdjustment,
		&v.ReviewFrequency, &v.LastReviewDate, &v.NextReviewDate,
		&v.ProcessingActivityIDs,
		&status, &v.TemplateID,
		&v.CreatedAt, &v.UpdatedAt, &v.CreatedBy,
	)
	if err != nil {
		return nil, err
	}

	v.Role = VendorRole(role)
	v.Status = VendorStatus(status)

	return &v, nil
}

// scanContract scans a contract row from pgx.Rows
func scanContract(rows pgx.Rows) (*Contract, error) {
	var c Contract
	var documentType string

	err := rows.Scan(
		&c.ID, &c.TenantID, &c.VendorID,
		&c.FileName, &c.OriginalName, &c.MimeType, &c.FileSize, &c.StoragePath,
		&documentType, &c.Parties,
		&c.EffectiveDate, &c.ExpirationDate, &c.AutoRenewal, &c.RenewalNoticePeriod,
		&c.ReviewStatus, &c.ReviewCompletedAt, &c.ComplianceScore,
		&c.Version, &c.PreviousVersionID,
		&c.ExtractedText, &c.PageCount,
		&c.CreatedAt, &c.UpdatedAt, &c.CreatedBy,
	)
	if err != nil {
		return nil, err
	}

	c.DocumentType = DocumentType(documentType)

	return &c, nil
}

// scanFinding scans a finding row from pgx.Rows
func scanFinding(rows pgx.Rows) (*Finding, error) {
	var f Finding
	var findingType, status string

	err := rows.Scan(
		&f.ID, &f.TenantID, &f.ContractID, &f.VendorID,
		&findingType, &f.Category, &f.Severity,
		&f.Title, &f.Description, &f.Recommendation,
		&f.Citations,
		&status, &f.Assignee, &f.DueDate, &f.Resolution, &f.ResolvedAt, &f.ResolvedBy,
		&f.CreatedAt, &f.UpdatedAt,
	)
	if err != nil {
		return nil, err
	}

	f.FindingType = FindingType(findingType)
	f.Status = FindingStatus(status)

	return &f, nil
}

// scanControlInstance scans a control instance row from pgx.Rows
func scanControlInstance(rows pgx.Rows) (*ControlInstance, error) {
	var ci ControlInstance
	var status string

	err := rows.Scan(
		&ci.ID, &ci.TenantID, &ci.VendorID,
		&ci.ControlID, &ci.ControlDomain,
		&status, &ci.EvidenceIDs, &ci.Notes,
		&ci.LastAssessedAt, &ci.LastAssessedBy, &ci.NextAssessmentDate,
		&ci.CreatedAt, &ci.UpdatedAt,
	)
	if err != nil {
		return nil, err
	}

	ci.Status = ControlStatus(status)

	return &ci, nil
}

// scanTemplate scans a template row from pgx.Rows
func scanTemplate(rows pgx.Rows) (*Template, error) {
	var t Template

	err := rows.Scan(
		&t.ID, &t.TenantID,
		&t.TemplateType, &t.TemplateID, &t.Category,
		&t.NameDE, &t.NameEN, &t.DescriptionDE, &t.DescriptionEN,
		&t.TemplateData,
		&t.Industry, &t.Tags,
		&t.IsSystem, &t.IsActive, &t.UsageCount,
		&t.CreatedAt, &t.UpdatedAt,
	)
	if err != nil {
		return nil, err
	}

	return &t, nil
}