package io.dropwizard.jetty;

import com.fasterxml.jackson.annotation.JsonProperty;
import com.google.common.collect.Iterables;
import io.dropwizard.util.Size;
import org.eclipse.jetty.server.Handler;

import javax.annotation.Nullable;
import javax.validation.constraints.Max;
import javax.validation.constraints.Min;
import javax.validation.constraints.NotNull;
import java.util.HashSet;
import java.util.Set;
import java.util.zip.Deflater;

import static java.util.Objects.requireNonNull;

Builds GZIP filters.

Configuration Parameters:

    

        
Name
        
Default
        
Description
    
    

        
enabled
        
true
        
If true, all requests with `gzip` or `deflate` in the `Accept-Encoding` header will have their
            response entities compressed and requests with `gzip` or `deflate` in the `Content-Encoding`
            header will have their request entities decompressed.
    
    

        
minimumEntitySize
        
256 bytes
        
All response entities under this size are not compressed.
    
    

        
bufferSize
        
8KiB
        
The size of the buffer to use when compressing.
    
    

        
excludedUserAgentPatterns
        
(none)
        
The set of user agent patterns to exclude from compression. 
    
    

        
compressedMimeTypes
        
(Jetty's default)
        
The list of mime types to compress. The default is all types apart the
        commonly known image, video, audio and compressed types.
    
    

        
includedMethods
        
(Jetty's default)
        
The list list of HTTP methods to compress. The default is to compress
        only GET responses.
    
    

        
deflateCompressionLevel
        
-1
        
The compression level used for ZLIB deflation(compression).
    
    

        
gzipCompatibleInflation
        
true
        
If true, then ZLIB inflation(decompression) will be performed in the GZIP-compatible mode.
    

/**
 * Builds GZIP filters.
 *
 * <p/>
 * <b>Configuration Parameters:</b>
 * <table>
 *     <tr>
 *         <td>Name</td>
 *         <td>Default</td>
 *         <td>Description</td>
 *     </tr>
 *     <tr>
 *         <td>{@code enabled}</td>
 *         <td>true</td>
 *         <td>If true, all requests with `gzip` or `deflate` in the `Accept-Encoding` header will have their
 *             response entities compressed and requests with `gzip` or `deflate` in the `Content-Encoding`
 *             header will have their request entities decompressed.</td>
 *     </tr>
 *     <tr>
 *         <td>{@code minimumEntitySize}</td>
 *         <td>256 bytes</td>
 *         <td>All response entities under this size are not compressed.</td>
 *     </tr>
 *     <tr>
 *         <td>{@code bufferSize}</td>
 *         <td>8KiB</td>
 *         <td>The size of the buffer to use when compressing.</td>
 *     </tr>
 *     <tr>
 *         <td>{@code excludedUserAgentPatterns}</td>
 *         <td>(none)</td>
 *         <td>The set of user agent patterns to exclude from compression. </td>
 *     </tr>
 *     <tr>
 *         <td>{@code compressedMimeTypes}</td>
 *         <td>(Jetty's default)</td>
 *         <td>The list of mime types to compress. The default is all types apart the
 *         commonly known image, video, audio and compressed types.</td>
 *     </tr>
 *     <tr>
 *         <td>{@code includedMethods}</td>
 *         <td>(Jetty's default)</td>
 *         <td>The list list of HTTP methods to compress. The default is to compress
 *         only GET responses.</td>
 *     </tr>
 *     <tr>
 *         <td>{@code deflateCompressionLevel}</td>
 *         <td>-1</td>
 *         <td>The compression level used for ZLIB deflation(compression).</td>
 *     </tr>
 *     <tr>
 *         <td>{@code gzipCompatibleInflation}</td>
 *         <td>true</td>
 *         <td>If true, then ZLIB inflation(decompression) will be performed in the GZIP-compatible mode.</td>
 *     </tr>
 * </table>
 */
public class GzipHandlerFactory {

    private boolean enabled = true;

    @NotNull
    private Size minimumEntitySize = Size.bytes(256);

    @NotNull
    private Size bufferSize = Size.kilobytes(8);

    // By default compress responses for all user-agents
    private Set<String> excludedUserAgentPatterns = new HashSet<>();

    @Nullable
    private Set<String> compressedMimeTypes;

    @Nullable
    private Set<String> includedMethods;

    @Min(Deflater.DEFAULT_COMPRESSION)
    @Max(Deflater.BEST_COMPRESSION)
    private int deflateCompressionLevel = Deflater.DEFAULT_COMPRESSION;

    private boolean gzipCompatibleInflation = true;

    private boolean syncFlush = false;

    @JsonProperty
    public boolean isEnabled() {
        return enabled;
    }

    @JsonProperty
    public void setEnabled(boolean enabled) {
        this.enabled = enabled;
    }

    @JsonProperty
    public Size getMinimumEntitySize() {
        return minimumEntitySize;
    }

    @JsonProperty
    public void setMinimumEntitySize(Size size) {
        this.minimumEntitySize = requireNonNull(size);
    }

    @JsonProperty
    public Size getBufferSize() {
        return bufferSize;
    }

    @JsonProperty
    public void setBufferSize(Size size) {
        this.bufferSize = requireNonNull(size);
    }

    @JsonProperty
    @Nullable
    public Set<String> getCompressedMimeTypes() {
        return compressedMimeTypes;
    }

    @JsonProperty
    public void setCompressedMimeTypes(Set<String> mimeTypes) {
        this.compressedMimeTypes = mimeTypes;
    }

    @JsonProperty
    public int getDeflateCompressionLevel() {
        return deflateCompressionLevel;
    }

    @JsonProperty
    public void setDeflateCompressionLevel(int level) {
        this.deflateCompressionLevel = level;
    }

    @JsonProperty
    public boolean isGzipCompatibleInflation() {
        return gzipCompatibleInflation;
    }

    @JsonProperty
    public void setGzipCompatibleInflation(boolean gzipCompatibleInflation) {
        this.gzipCompatibleInflation = gzipCompatibleInflation;
    }

    public Set<String> getExcludedUserAgentPatterns() {
        return excludedUserAgentPatterns;
    }

    public void setExcludedUserAgentPatterns(Set<String> excludedUserAgentPatterns) {
        this.excludedUserAgentPatterns = excludedUserAgentPatterns;
    }

    @JsonProperty
    @Nullable
    public Set<String> getIncludedMethods() {
        return includedMethods;
    }

    @JsonProperty
    public void setIncludedMethods(Set<String> methods) {
        this.includedMethods = methods;
    }

    @JsonProperty
    public boolean isSyncFlush() {
        return syncFlush;
    }

    @JsonProperty
    public void setSyncFlush(boolean syncFlush) {
        this.syncFlush = syncFlush;
    }

    public BiDiGzipHandler build(@Nullable Handler handler) {
        final BiDiGzipHandler gzipHandler = new BiDiGzipHandler();
        gzipHandler.setHandler(handler);
        gzipHandler.setMinGzipSize((int) minimumEntitySize.toBytes());
        gzipHandler.setInputBufferSize((int) bufferSize.toBytes());
        gzipHandler.setCompressionLevel(deflateCompressionLevel);
        gzipHandler.setSyncFlush(syncFlush);

        if (compressedMimeTypes != null) {
            gzipHandler.setIncludedMimeTypes(Iterables.toArray(compressedMimeTypes, String.class));
        }

        if (includedMethods != null) {
            gzipHandler.setIncludedMethods(Iterables.toArray(includedMethods, String.class));
        }

        gzipHandler.setExcludedAgentPatterns(Iterables.toArray(excludedUserAgentPatterns, String.class));
        gzipHandler.setInflateNoWrap(gzipCompatibleInflation);

        return gzipHandler;
    }
}