package jnpf.audit.sdk;

import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.Locale;
import java.util.Set;

/** Restricts SDK audit events to configured application request sources. */
public class AuditRequestScopeFilter {

    private static final String HEADER_APP_CODE = "App-Code";
    private static final String HEADER_APP_SCOPE = "Jnpf-App-Scope";

    private final boolean frontendOnly;
    private final Set<String> allowedAppCodes;

    public AuditRequestScopeFilter(boolean frontendOnly, String allowedAppCodes) {
        this.frontendOnly = frontendOnly;
        Set<String> normalized = new LinkedHashSet<>();
        if (allowedAppCodes != null) {
            for (String code : allowedAppCodes.split(",")) {
                if (code != null && !code.trim().isEmpty()) {
                    normalized.add(code.trim().toUpperCase(Locale.ROOT));
                }
            }
        }
        this.allowedAppCodes = normalized.isEmpty()
                ? Collections.emptySet() : Collections.unmodifiableSet(normalized);
    }

    public boolean acceptsCurrentRequest() {
        RequestAttributes attributes = RequestContextHolder.getRequestAttributes();
        if (!(attributes instanceof ServletRequestAttributes)) {
            return accepts(null, null);
        }
        ServletRequestAttributes servletAttributes = (ServletRequestAttributes) attributes;
        return accepts(servletAttributes.getRequest().getHeader(HEADER_APP_SCOPE),
                servletAttributes.getRequest().getHeader(HEADER_APP_CODE));
    }

    public boolean accepts(String appScope, String appCode) {
        if (frontendOnly && !"FRONTEND".equalsIgnoreCase(trim(appScope))) {
            return false;
        }
        return allowedAppCodes.isEmpty()
                || allowedAppCodes.contains(trim(appCode).toUpperCase(Locale.ROOT));
    }

    private static String trim(String value) {
        return value == null ? "" : value.trim();
    }
}