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package express.filter;

import com.sun.net.httpserver.HttpExchange;
import express.Express;
import express.ExpressException;
import express.http.HttpRequestHandler;
import express.http.request.Request;
import express.http.response.Response;

import java.util.function.Consumer;

/**
 * @author Simon Reinisch
 * 
 * Handler for multiple FilterLayer.
 */
public class FilterLayerHandler {

    private final FilterLayer[] layers;

    public FilterLayerHandler(int layers) {

        // Create & initialize layers
        this.layers = new FilterLayer[layers];
        for (int i = 0; i < this.layers.length; i++) {
            this.layers[i] = new FilterLayer<>();
        }
    }

    public void handle(HttpExchange httpExchange, Express express) {
        Request request = new Request(httpExchange, express);
        Response response = new Response(httpExchange);

        // First fire all middleware's, then the normal request filter
        for (FilterLayer chain : layers) {
            chain.filter(request, response);

            if (response.isClosed()) {
                return;
            }
        }
    }

    /**
     * Add an new handler for an specific handler layers.
     *
     * @param level   The layers.
     * @param handler The handler, will be append to the top of the layers.
     */
    @SuppressWarnings("unchecked")
    public void add(int level, HttpRequestHandler handler) {

        if (level >= layers.length) {
            throw new IndexOutOfBoundsException("Out of bounds: " + level + " > " + layers.length);
        }

        if (level < 0) {
            throw new IndexOutOfBoundsException("Cannot be under zero: " + level + " < 0");
        }

        layers[level].add(handler);
    }

    /**
     * Merge two FilterLayerHandler
     *
     * @param filterLayerHandler The FilterLayerHandler which you want to merge with this
     */
    @SuppressWarnings("unchecked")
    public void combine(FilterLayerHandler filterLayerHandler) {
        if (filterLayerHandler != null) {
            FilterLayer[] chains = filterLayerHandler.getLayers();

            if (chains.length != layers.length) {
                throw new ExpressException("Cannot add an filterLayerHandler with different layers sizes: " + chains.length + " != " + layers.length);
            }

            for (int i = 0; i < chains.length; i++) {
                layers[i].addAll(chains[i].getFilter());
            }
        }
    }

    /**
     * Iterate over the different FilterLayer
     *
     * @param layerConsumer An consumer for the layers
     */
    public void forEach(Consumer layerConsumer) {
        if (layerConsumer == null) {
            return;
        }

        for (FilterLayer layer : layers) {
            layerConsumer.accept(layer);
        }
    }

    private FilterLayer[] getLayers() {
        return layers;
    }

}