/*
 * Copyright (C) 2011 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.mockwebserver;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.TimeUnit;

import static java.nio.charset.StandardCharsets.US_ASCII;

/**
 * A scripted response to be replayed by the mock web server.
 */
public final class MockResponse implements Cloneable {
    private static final String CHUNKED_BODY_HEADER = "Transfer-encoding: chunked";

    private String status = "HTTP/1.1 200 OK";
    private List<String> headers = new ArrayList<String>();

    /** The response body content, or null if {@code bodyStream} is set. */
    private byte[] body;
    /** The response body content, or null if {@code body} is set. */
    private InputStream bodyStream;

    private int throttleBytesPerPeriod = Integer.MAX_VALUE;
    private long throttlePeriod = 1;
    private TimeUnit throttleUnit = TimeUnit.SECONDS;

    private SocketPolicy socketPolicy = SocketPolicy.KEEP_OPEN;

    private int bodyDelayTimeMs = 0;

    /**
     * Creates a new mock response with an empty body.
     */
    public MockResponse() {
        setBody(new byte[0]);
    }

    @Override public MockResponse clone() {
        try {
            MockResponse result = (MockResponse) super.clone();
            result.headers = new ArrayList<String>(result.headers);
            return result;
        } catch (CloneNotSupportedException e) {
            throw new AssertionError();
        }
    }

    /**
     * Returns the HTTP response line, such as "HTTP/1.1 200 OK".
     */
    public String getStatus() {
        return status;
    }

    public MockResponse setResponseCode(int code) {
        this.status = "HTTP/1.1 " + code + " OK";
        return this;
    }

    public MockResponse setStatus(String status) {
        this.status = status;
        return this;
    }

    /**
     * Returns the HTTP headers, such as "Content-Length: 0".
     */
    public List<String> getHeaders() {
        return headers;
    }

    /**
     * Removes all HTTP headers including any "Content-Length" and
     * "Transfer-encoding" headers that were added by default.
     */
    public MockResponse clearHeaders() {
        headers.clear();
        return this;
    }

    /**
     * Adds {@code header} as an HTTP header. For well-formed HTTP {@code
     * header} should contain a name followed by a colon and a value.
     */
    public MockResponse addHeader(String header) {
        headers.add(header);
        return this;
    }

    /**
     * Adds a new header with the name and value. This may be used to add
     * multiple headers with the same name.
     */
    public MockResponse addHeader(String name, Object value) {
        return addHeader(name + ": " + String.valueOf(value));
    }

    /**
     * Removes all headers named {@code name}, then adds a new header with the
     * name and value.
     */
    public MockResponse setHeader(String name, Object value) {
        removeHeader(name);
        return addHeader(name, value);
    }

    /**
     * Removes all headers named {@code name}.
     */
    public MockResponse removeHeader(String name) {
        name += ":";
        for (Iterator<String> i = headers.iterator(); i.hasNext(); ) {
            String header = i.next();
            if (name.regionMatches(true, 0, header, 0, name.length())) {
                i.remove();
            }
        }
        return this;
    }

    /**
     * Returns the raw HTTP payload, or null if this response is streamed.
     */
    public byte[] getBody() {
        return body;
    }

    /**
     * Returns an input stream containing the raw HTTP payload.
     */
    InputStream getBodyStream() {
        return bodyStream != null ? bodyStream : new ByteArrayInputStream(body);
    }

    public MockResponse setBody(byte[] body) {
        setHeader("Content-Length", body.length);
        this.body = body;
        this.bodyStream = null;
        return this;
    }

    public MockResponse setBody(InputStream bodyStream, long bodyLength) {
        setHeader("Content-Length", bodyLength);
        this.body = null;
        this.bodyStream = bodyStream;
        return this;
    }

    /**
     * Sets the response body to the UTF-8 encoded bytes of {@code body}.
     */
    public MockResponse setBody(String body) {
        try {
            return setBody(body.getBytes("UTF-8"));
        } catch (UnsupportedEncodingException e) {
            throw new AssertionError();
        }
    }

    /**
     * Sets the response body to {@code body}, chunked every {@code
     * maxChunkSize} bytes.
     */
    public MockResponse setChunkedBody(byte[] body, int maxChunkSize) {
        removeHeader("Content-Length");
        headers.add(CHUNKED_BODY_HEADER);

        try {
            ByteArrayOutputStream bytesOut = new ByteArrayOutputStream();
            int pos = 0;
            while (pos < body.length) {
                int chunkSize = Math.min(body.length - pos, maxChunkSize);
                bytesOut.write(Integer.toHexString(chunkSize).getBytes(US_ASCII));
                bytesOut.write("\r\n".getBytes(US_ASCII));
                bytesOut.write(body, pos, chunkSize);
                bytesOut.write("\r\n".getBytes(US_ASCII));
                pos += chunkSize;
            }
            bytesOut.write("0\r\n\r\n".getBytes(US_ASCII)); // last chunk + empty trailer + crlf

            this.body = bytesOut.toByteArray();
            return this;
        } catch (IOException e) {
            throw new AssertionError(); // In-memory I/O doesn't throw IOExceptions.
        }
    }

    /**
     * Sets the response body to the UTF-8 encoded bytes of {@code body},
     * chunked every {@code maxChunkSize} bytes.
     */
    public MockResponse setChunkedBody(String body, int maxChunkSize) {
        try {
            return setChunkedBody(body.getBytes("UTF-8"), maxChunkSize);
        } catch (UnsupportedEncodingException e) {
            throw new AssertionError();
        }
    }

    public SocketPolicy getSocketPolicy() {
        return socketPolicy;
    }

    public MockResponse setSocketPolicy(SocketPolicy socketPolicy) {
        this.socketPolicy = socketPolicy;
        return this;
    }

    /**
     * Throttles the response body writer to sleep for the given period after each
     * series of {@code bytesPerPeriod} bytes are written. Use this to simulate
     * network behavior.
     */
    public MockResponse throttleBody(int bytesPerPeriod, long period, TimeUnit unit) {
        this.throttleBytesPerPeriod = bytesPerPeriod;
        this.throttlePeriod = period;
        this.throttleUnit = unit;
        return this;
    }

    public int getThrottleBytesPerPeriod() {
        return throttleBytesPerPeriod;
    }

    public long getThrottlePeriod() {
        return throttlePeriod;
    }

    public TimeUnit getThrottleUnit() {
        return throttleUnit;
    }

    /**
     * Set the delayed time of the response body to {@code delay}. This applies to the
     * response body only; response headers are not affected.
     */
    public MockResponse setBodyDelayTimeMs(int delay) {
        bodyDelayTimeMs = delay;
        return this;
    }

    public int getBodyDelayTimeMs() {
        return bodyDelayTimeMs;
    }

    @Override public String toString() {
        return "MockResponse{" + status + "}";
    }
}