/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.jooby.internal;

import static java.util.Objects.requireNonNull;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLEncoder;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.function.Consumer;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;

import org.jooby.Asset;
import org.jooby.Cookie;
import org.jooby.Cookie.Definition;
import org.jooby.Deferred;
import org.jooby.MediaType;
import org.jooby.Mutant;
import org.jooby.Renderer;
import org.jooby.Response;
import org.jooby.Result;
import org.jooby.Results;
import org.jooby.Route;
import org.jooby.Route.After;
import org.jooby.Route.Complete;
import org.jooby.Status;
import org.jooby.internal.parser.ParserExecutor;
import org.jooby.spi.NativeResponse;
import org.slf4j.LoggerFactory;

import com.google.common.collect.ImmutableList;

import javaslang.control.Try;

public class ResponseImpl implements Response {

  private static final String LOCATION = "Location";

  /** Char encoded content disposition. */
  private static final String CONTENT_DISPOSITION = "attachment; filename=\"%s\"; filename*=%s''%s";

  private final NativeResponse rsp;

  private final Map<String, Object> locals;

  private Route route;

  private Charset charset;

  private final Optional<String> referer;

  private Status status;

  private MediaType type;

  private long len = -1;

  private Map<String, Cookie> cookies = new HashMap<>();

  private List<Renderer> renderers;

  private ParserExecutor parserExecutor;

  private Map<String, Renderer> rendererMap;

  private List<Route.After> after = new ArrayList<>();

  private List<Route.Complete> complete = new ArrayList<>();

  private RequestImpl req;

  private boolean failure;

  private Optional<String> byteRange;

  public ResponseImpl(final RequestImpl req, final ParserExecutor parserExecutor,
      final NativeResponse rsp, final Route route, final List<Renderer> renderers,
      final Map<String, Renderer> rendererMap, final Map<String, Object> locals,
      final Charset charset, final Optional<String> referer, final Optional<String> byteRange) {
    this.req = req;
    this.parserExecutor = parserExecutor;
    this.rsp = rsp;
    this.route = route;
    this.locals = locals;
    this.renderers = renderers;
    this.rendererMap = rendererMap;
    this.charset = charset;
    this.referer = referer;
    this.byteRange = byteRange;
  }

  @Override
  public void download(final String filename, final InputStream stream) throws Throwable {
    requireNonNull(filename, "A file's name is required.");
    requireNonNull(stream, "A stream is required.");

    // handle type
    type(type().orElseGet(() -> MediaType.byPath(filename).orElse(MediaType.octetstream)));

    Asset asset = new InputStreamAsset(stream, filename, type().get());
    contentDisposition(filename);
    send(Results.with(asset.stream()));
  }

  @Override
  public void download(final String filename, final String location) throws Throwable {
    URL url = getClass().getResource(location.startsWith("/") ? location : "/" + location);
    if (url == null) {
      throw new FileNotFoundException(location);
    }
    // handle type
    type(type().orElseGet(() -> MediaType.byPath(filename).orElse(MediaType.byPath(location)
        .orElse(MediaType.octetstream))));

    URLAsset asset = new URLAsset(url, location, type().get());
    length(asset.length());

    contentDisposition(filename);
    send(Results.with(asset));
  }

  @Override
  public Response clearCookie(final String name) {
    requireNonNull(name, "Cookie's name required.");
    return cookie(new Cookie.Definition(name).maxAge(0));
  }

  @Override
  public Response cookie(final Definition cookie) {
    requireNonNull(cookie, "Cookie required.");
    // use default path if none-set
    cookie.path(cookie.path().orElse(Route.normalize(req.contextPath() + "/")));
    return cookie(cookie.toCookie());
  }

  @Override
  public Response cookie(final Cookie cookie) {
    requireNonNull(cookie, "Cookie required.");
    String name = cookie.name();
    // clear cookie?
    if (cookie.maxAge() == 0) {
      // clear previously set cookie, otherwise ignore them
      if (cookies.remove(name) == null) {
        // cookie was set in a previous req, we must send a expire header.
        cookies.put(name, cookie);
      }
    } else {
      cookies.put(name, cookie);
    }
    return this;
  }

  @Override
  public Mutant header(final String name) {
    requireNonNull(name, "A header's name is required.");
    return new MutantImpl(parserExecutor,
        new StrParamReferenceImpl("header", name, rsp.headers(name)));
  }

  @Override
  public Response header(final String name, final Object value) {
    requireNonNull(name, "Header's name is required.");
    requireNonNull(value, "Header's value is required.");

    return setHeader(name, value);
  }

  @Override
  public Response header(final String name, final Iterable<Object> values) {
    requireNonNull(name, "Header's name is required.");
    requireNonNull(values, "Header's values are required.");

    return setHeader(name, values);
  }

  @Override
  public Charset charset() {
    return charset;
  }

  @Override
  public Response charset(final Charset charset) {
    this.charset = requireNonNull(charset, "A charset is required.");
    type(type().orElse(MediaType.html));
    return this;
  }

  @Override
  public Response length(final long length) {
    len = length;
    rsp.header("Content-Length", Long.toString(length));
    return this;
  }

  @Override
  public Optional<MediaType> type() {
    return Optional.ofNullable(type);
  }

  @Override
  public Response type(final MediaType type) {
    this.type = type;
    if (type.isText()) {
      setHeader("Content-Type", type.name() + ";charset=" + charset.name());
    } else {
      setHeader("Content-Type", type.name());
    }
    return this;
  }

  @Override
  public void redirect(final Status status, final String location) throws Throwable {
    requireNonNull(status, "Status required.");
    requireNonNull(location, "Location required.");

    send(Results.with(status).header(LOCATION, location));
  }

  @Override
  public Optional<Status> status() {
    return Optional.ofNullable(status);
  }

  @Override
  public Response status(final Status status) {
    this.status = requireNonNull(status, "Status required.");
    rsp.statusCode(status.value());
    failure = status.isError();
    return this;
  }

  @Override
  public boolean committed() {
    return rsp.committed();
  }

  public void done(final Optional<Throwable> cause) {
    if (complete.size() > 0) {
      for (Route.Complete h : complete) {
        Try.run(() -> h.handle(req, this, cause))
            .onFailure(x -> LoggerFactory.getLogger(Response.class)
                .error("complete listener resulted in error", x));
      }
      complete.clear();
    }
    end();
  }

  @Override
  public void end() {
    if (!rsp.committed()) {
      if (status == null) {
        status(rsp.statusCode());
      }

      writeCookies();

      /**
       * Do we need to figure it out Content-Length?
       */
      boolean lenSet = rsp.header("Content-Length").isPresent()
          || rsp.header("Transfer-Encoding").isPresent();
      if (!lenSet) {
        int statusCode = status.value();
        boolean hasBody = true;
        if (statusCode >= 100 && statusCode < 200) {
          hasBody = false;
        } else if (statusCode == 204 || statusCode == 304) {
          hasBody = false;
        }
        if (hasBody) {
          rsp.header("Content-Length", "0");
        }
      }
    }
    rsp.end();
  }

  @Override
  public void send(final Result result) throws Throwable {
    if (result instanceof Deferred) {
      throw new DeferredExecution((Deferred) result);
    }

    Result finalResult = result;

    if (!failure) {
      // after filter
      for (int i = after.size() - 1; i >= 0; i--) {
        finalResult = after.get(i).handle(req, this, finalResult);
      }
    }

    Optional<MediaType> rtype = finalResult.type();
    if (rtype.isPresent()) {
      type(rtype.get());
    }

    if (finalResult.status().isPresent()) {
      status(finalResult.status().get());
    } else if (this.status == null) {
      status(Status.OK);
    }

    Map<String, Object> headers = finalResult.headers();
    if (headers.size() > 0) {
      headers.forEach(this::setHeader);
    }

    writeCookies();

    if (Route.HEAD.equals(route.method())) {
      end();
      return;
    }

    /**
     * Do we need to figure it out Content-Length?
     */
    List<MediaType> produces = this.type == null ? route.produces() : ImmutableList.of(type);
    Object value = finalResult.get(produces);

    if (value != null) {
      Consumer<Long> setLen = len -> {
        if (this.len == -1 && len >= 0) {
          length(len);
        }
      };

      Consumer<MediaType> setType = type -> {
        if (this.type == null) {
          type(type);
        }
      };

      HttpRendererContext ctx = new HttpRendererContext(
          renderers,
          rsp,
          setLen,
          setType,
          locals,
          produces,
          charset,
          req.locale(),
          byteRange);

      // explicit renderer?
      Renderer renderer = rendererMap.get(route.renderer());
      if (renderer != null) {
        renderer.render(value, ctx);
      } else {
        ctx.render(value);
      }
    }
    // end response
    end();
  }

  @Override
  public void after(final After handler) {
    after.add(handler);
  }

  @Override
  public void complete(final Complete handler) {
    complete.add(handler);
  }

  private void writeCookies() {
    if (cookies.size() > 0) {
      List<String> setCookie = cookies.values().stream()
          .map(Cookie::encode)
          .collect(Collectors.toList());
      rsp.header("Set-Cookie", setCookie);
      cookies.clear();
    }
  }

  public void reset() {
    status = null;
    this.cookies.clear();
    rsp.reset();
  }

  void route(final Route route) {
    this.route = route;
  }

  private void contentDisposition(final String filename) throws IOException {
    List<String> headers = rsp.headers("Content-Disposition");
    if (headers.isEmpty()) {
      String basename = filename;
      int last = filename.lastIndexOf('/');
      if (last >= 0) {
        basename = basename.substring(last + 1);
      }

      String cs = charset.name();
      String ebasename = URLEncoder.encode(basename, cs).replaceAll("\\+", "%20");
      header("Content-Disposition", String.format(CONTENT_DISPOSITION, basename, cs, ebasename));
    }
  }

  @SuppressWarnings("unchecked")
  private Response setHeader(final String name, final Object value) {
    if (!committed()) {
      if (value instanceof Iterable) {
        List<String> values = StreamSupport.stream(((Iterable<Object>) value).spliterator(), false)
            .map(Headers::encode)
            .collect(Collectors.toList());
        rsp.header(name, values);
      } else {
        if (LOCATION.equalsIgnoreCase(name)) {
          String location = value.toString();
          String cpath = req.contextPath();
          if ("back".equalsIgnoreCase(location)) {
            location = referer.orElse(cpath + "/");
          } else if (location.startsWith("/") && !location.startsWith(cpath)) {
            location = cpath + location;
          }
          rsp.header(LOCATION, location);
        } else {
          if ("Content-Type".equalsIgnoreCase(name)) {
            // keep type reference
            this.type = MediaType.valueOf(value.toString());
          }
          rsp.header(name, Headers.encode(value));
        }
      }
    }

    return this;
  }

}
