package com.vincent.rsf.httpaudit.web;

import com.vincent.rsf.httpaudit.model.HttpAuditDecision;
import com.vincent.rsf.httpaudit.service.HttpAuditOutboundRecorder;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpRequest;
import org.springframework.http.client.ClientHttpRequestExecution;
import org.springframework.http.client.ClientHttpRequestInterceptor;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.util.StreamUtils;

import java.io.IOException;
import java.nio.charset.StandardCharsets;

/**
 * RestTemplate 出站审计
 */
@Slf4j
@RequiredArgsConstructor
public class OutboundHttpAuditInterceptor implements ClientHttpRequestInterceptor {

    private static final String FN_REST = "HTTP出站(RestTemplate)";

    private final HttpAuditOutboundRecorder outboundRecorder;

    @Override
    public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException {
        if (!outboundRecorder.isAuditEnabled()) {
            return execution.execute(request, body);
        }
        String url = request.getURI().toString();
        String method = request.getMethod().name();
        String reqText = body == null || body.length == 0 ? "" : new String(body, StandardCharsets.UTF_8);
        HttpAuditDecision dec = outboundRecorder.decideOutbound(url, method, reqText);
        long t0 = System.currentTimeMillis();
        ClientHttpResponse raw;
        try {
            raw = execution.execute(request, body);
        } catch (IOException e) {
            outboundRecorder.saveOutbound(FN_REST, url, method, reqText, dec, null, null, t0, e);
            throw e;
        }
        byte[] respBytes;
        try {
            respBytes = StreamUtils.copyToByteArray(raw.getBody());
        } catch (IOException e) {
            outboundRecorder.saveOutbound(FN_REST, url, method, reqText, dec, raw.getRawStatusCode(), null, t0, e);
            throw e;
        }
        if (!dec.isAudit()) {
            return new CopiedBodyClientHttpResponse(raw, respBytes);
        }
        String resText = new String(respBytes, StandardCharsets.UTF_8);
        outboundRecorder.saveOutbound(FN_REST, url, method, reqText, dec, raw.getRawStatusCode(), resText, t0, null);
        return new CopiedBodyClientHttpResponse(raw, respBytes);
    }

    private static class CopiedBodyClientHttpResponse implements ClientHttpResponse {

        private final ClientHttpResponse delegate;
        private final byte[] body;

        CopiedBodyClientHttpResponse(ClientHttpResponse delegate, byte[] body) {
            this.delegate = delegate;
            this.body = body != null ? body : new byte[0];
        }

        @Override
        public org.springframework.http.HttpStatus getStatusCode() throws IOException {
            return delegate.getStatusCode();
        }

        @Override
        public int getRawStatusCode() throws IOException {
            return delegate.getRawStatusCode();
        }

        @Override
        public String getStatusText() throws IOException {
            return delegate.getStatusText();
        }

        @Override
        public void close() {
            delegate.close();
        }

        @Override
        public org.springframework.http.HttpHeaders getHeaders() {
            return delegate.getHeaders();
        }

        @Override
        public java.io.InputStream getBody() throws IOException {
            return new java.io.ByteArrayInputStream(body);
        }
    }
}