/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * 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.android.voicemail.impl.mail.internet;

import com.android.voicemail.impl.mail.MessagingException;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.util.ArrayList;

public class MimeHeader {
  /**
   * Application specific header that contains Store specific information about an attachment. In
   * IMAP this contains the IMAP BODYSTRUCTURE part id so that the ImapStore can later retrieve the
   * attachment at will from the server. The info is recorded from this header on
   * LocalStore.appendMessage and is put back into the MIME data by LocalStore.fetch.
   */
  public static final String HEADER_ANDROID_ATTACHMENT_STORE_DATA =
      "X-Android-Attachment-StoreData";

  public static final String HEADER_CONTENT_TYPE = "Content-Type";
  public static final String HEADER_CONTENT_TRANSFER_ENCODING = "Content-Transfer-Encoding";
  public static final String HEADER_CONTENT_DISPOSITION = "Content-Disposition";
  public static final String HEADER_CONTENT_ID = "Content-ID";
  public static final String HEADER_CONTENT_DURATION = "Content-Duration";

  /** Fields that should be omitted when writing the header using writeTo() */
  private static final String[] WRITE_OMIT_FIELDS = {
    //        HEADER_ANDROID_ATTACHMENT_DOWNLOADED,
    //        HEADER_ANDROID_ATTACHMENT_ID,
    HEADER_ANDROID_ATTACHMENT_STORE_DATA
  };

  protected final ArrayList<Field> fields = new ArrayList<Field>();

  public void clear() {
    fields.clear();
  }

  public String getFirstHeader(String name) throws MessagingException {
    String[] header = getHeader(name);
    if (header == null) {
      return null;
    }
    return header[0];
  }

  public void addHeader(String name, String value) throws MessagingException {
    fields.add(new Field(name, value));
  }

  public void setHeader(String name, String value) throws MessagingException {
    if (name == null || value == null) {
      return;
    }
    removeHeader(name);
    addHeader(name, value);
  }

  public String[] getHeader(String name) throws MessagingException {
    ArrayList<String> values = new ArrayList<String>();
    for (Field field : fields) {
      if (field.name.equalsIgnoreCase(name)) {
        values.add(field.value);
      }
    }
    if (values.size() == 0) {
      return null;
    }
    return values.toArray(new String[] {});
  }

  public void removeHeader(String name) throws MessagingException {
    ArrayList<Field> removeFields = new ArrayList<Field>();
    for (Field field : fields) {
      if (field.name.equalsIgnoreCase(name)) {
        removeFields.add(field);
      }
    }
    fields.removeAll(removeFields);
  }

  /**
   * Write header into String
   *
   * @return CR-NL separated header string except the headers in writeOmitFields null if header is
   *     empty
   */
  public String writeToString() {
    if (fields.size() == 0) {
      return null;
    }
    StringBuilder builder = new StringBuilder();
    for (Field field : fields) {
      if (!arrayContains(WRITE_OMIT_FIELDS, field.name)) {
        builder.append(field.name + ": " + field.value + "\r\n");
      }
    }
    return builder.toString();
  }

  public void writeTo(OutputStream out) throws IOException, MessagingException {
    BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(out), 1024);
    for (Field field : fields) {
      if (!arrayContains(WRITE_OMIT_FIELDS, field.name)) {
        writer.write(field.name + ": " + field.value + "\r\n");
      }
    }
    writer.flush();
  }

  private static class Field {
    final String name;
    final String value;

    public Field(String name, String value) {
      this.name = name;
      this.value = value;
    }

    @Override
    public String toString() {
      return name + "=" + value;
    }
  }

  @Override
  public String toString() {
    return (fields == null) ? null : fields.toString();
  }

  public static final boolean arrayContains(Object[] a, Object o) {
    int index = arrayIndex(a, o);
    return (index >= 0);
  }

  public static final int arrayIndex(Object[] a, Object o) {
    for (int i = 0, count = a.length; i < count; i++) {
      if (a[i].equals(o)) {
        return i;
      }
    }
    return -1;
  }
}