package db

import (
	"context"
	"strings"
)

const staffColumns = "id, tenant_id, location_id, display_name, active, created_at"

func (r *PGRepository) ListStaffByTenant(ctx context.Context, tenantID string) ([]StaffRecord, error) {
	rows, err := r.pool.Query(ctx, `
		SELECT `+staffColumns+`
		FROM staff
		WHERE tenant_id = $1
		ORDER BY created_at ASC
	`, tenantID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var records []StaffRecord
	for rows.Next() {
		var rec StaffRecord
		if err := rows.Scan(&rec.ID, &rec.TenantID, &rec.LocationID, &rec.DisplayName, &rec.Active, &rec.CreatedAt); err != nil {
			return nil, err
		}
		records = append(records, rec)
	}
	return records, rows.Err()
}

func (r *PGRepository) GetStaffByID(ctx context.Context, staffID string) (StaffRecord, error) {
	var rec StaffRecord
	err := r.pool.QueryRow(ctx, `
		SELECT `+staffColumns+`
		FROM staff
		WHERE id = $1
	`, staffID).Scan(&rec.ID, &rec.TenantID, &rec.LocationID, &rec.DisplayName, &rec.Active, &rec.CreatedAt)
	return rec, err
}

func (r *PGRepository) CreateStaff(ctx context.Context, params CreateStaffParams) (StaffRecord, error) {
	var rec StaffRecord
	err := r.pool.QueryRow(ctx, `
		INSERT INTO staff (tenant_id, location_id, display_name, active)
		VALUES ($1, $2, $3, $4)
		RETURNING `+staffColumns+`
	`, params.TenantID, params.LocationID, params.DisplayName, params.Active).Scan(
		&rec.ID, &rec.TenantID, &rec.LocationID, &rec.DisplayName, &rec.Active, &rec.CreatedAt)
	return rec, err
}

func (r *PGRepository) UpdateStaff(ctx context.Context, staffID string, params UpdateStaffParams) (StaffRecord, error) {
	// Tri-state location update: untouched when the request omits the field,
	// NULL when it is explicitly empty, otherwise reassigned.
	locationSet := params.LocationID != nil
	var locationValue any
	if locationSet && strings.TrimSpace(*params.LocationID) != "" {
		locationValue = strings.TrimSpace(*params.LocationID)
	}

	var rec StaffRecord
	err := r.pool.QueryRow(ctx, `
		UPDATE staff
		SET display_name = COALESCE($2, display_name),
		    location_id = CASE WHEN $3 THEN $4::uuid ELSE location_id END,
		    active = COALESCE($5, active)
		WHERE id = $1
		RETURNING `+staffColumns+`
	`, staffID, params.DisplayName, locationSet, locationValue, params.Active).Scan(
		&rec.ID, &rec.TenantID, &rec.LocationID, &rec.DisplayName, &rec.Active, &rec.CreatedAt)
	return rec, err
}

func (r *PGRepository) DeleteStaff(ctx context.Context, staffID string) error {
	_, err := r.pool.Exec(ctx, `DELETE FROM staff WHERE id = $1`, staffID)
	return err
}