/*
 * SonarQube
 * Copyright (C) 2009-2017 SonarSource SA
 * mailto:info AT sonarsource DOT com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package org.sonar.api.config;

import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.base.Strings;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Properties;
import java.util.stream.Collectors;
import javax.annotation.CheckForNull;
import javax.annotation.Nullable;
import org.apache.commons.lang.ArrayUtils;
import org.apache.commons.lang.StringUtils;
import org.sonar.api.batch.ScannerSide;
import org.sonar.api.ce.ComputeEngineSide;
import org.sonar.api.server.ServerSide;
import org.sonar.api.utils.DateUtils;

import static java.util.Objects.requireNonNull;
import static org.apache.commons.lang.StringUtils.trim;

/**
 * Component to get effective settings. Values of properties depend on the runtime environment:
 * <ul>
 *   <li>project settings in scanner.</li>
 *   <li>global settings in web server. It does not allow to get the settings overridden on projects.</li>
 *   <li>project settings in Compute Engine.</li>
 * </ul>
 *
 * <h3>Usage</h3>
 * <pre>
 * public class MyExtension {
 *
 *   private final Settings settings;
 *
 *   public MyExtension(Settings settings) {
 *     this.settings = settings;
 *   }
 *   public void doSomething() {
 *     String fooValue = settings.getString("sonar.foo");
 *     // ..
 *   }
 * }
 * </pre>
 *
 * <h3>Scanner example</h3>
 * Scanner sensor can get the reference on Settings directly through SensorContext,
 * without injecting the component into constructor.
 *
 * <pre>
 * public class MySensor implements Sensor {
 *   {@literal @}Override
 *   public void execute(SensorContext context) {
 *     String fooValue = context.settings().getString("sonar.foo");
 *     // ..
 *   }
 * }
 * </pre>
 *
 * <p>
 * For testing, and only for testing, the in-memory implementation {@link MapSettings} can be used.
 * <pre>
 * {@literal @}Test
 * public void my_test() {
 *   Settings settings = new MapSettings();
 *   settings.setProperty("foo", "bar");
 *   MyExtension underTest = new MyExtension(settings);
 *   // ...
 * }
 * </pre>
 *
 * History - this class is abstract since 6.1.
 *
 * @see MapSettings
 * @see PropertyDefinition
 * @since 2.12
 */
@ScannerSide
@ServerSide
@ComputeEngineSide
public abstract class Settings {

  private final PropertyDefinitions definitions;
  private final Encryption encryption;

  protected Settings(PropertyDefinitions definitions, Encryption encryption) {
    this.definitions = requireNonNull(definitions);
    this.encryption = requireNonNull(encryption);
  }

  protected abstract Optional<String> get(String key);

  protected abstract void set(String key, String value);

  protected abstract void remove(String key);

  /**
   * Immutable map of the properties that have non-default values.
   * The default values defined by {@link PropertyDefinitions} are ignored,
   * so the returned values are not the effective values. Basically only
   * the non-empty results of {@link #getRawString(String)} are returned.
   * <p>
   * Values are not decrypted if they are encrypted with a secret key.
   * </p>
   */
  public abstract Map<String, String> getProperties();

  public Encryption getEncryption() {
    return encryption;
  }

  /**
   * The value that overrides the default value. It
   * may be encrypted with a secret key. Use {@link #getString(String)} to get
   * the effective and decrypted value.
   *
   * @since 6.1
   */
  public Optional<String> getRawString(String key) {
    return get(definitions.validKey(requireNonNull(key)));
  }

  /**
   * All the property definitions declared by core and plugins.
   */
  public PropertyDefinitions getDefinitions() {
    return definitions;
  }

  /**
   * The definition related to the specified property. It may
   * be empty.
   *
   * @since 6.1
   */
  public Optional<PropertyDefinition> getDefinition(String key) {
    return Optional.ofNullable(definitions.get(key));
  }

  /**
   * @return {@code true} if the property has a non-default value, else {@code false}.
   */
  public boolean hasKey(String key) {
    return getRawString(key).isPresent();
  }

  @CheckForNull
  public String getDefaultValue(String key) {
    return definitions.getDefaultValue(key);
  }

  public boolean hasDefaultValue(String key) {
    return StringUtils.isNotEmpty(getDefaultValue(key));
  }

  /**
   * The effective value of the specified property. Can return
   * {@code null} if the property is not set and has no
   * defined default value.
   * <p>
   * If the property is encrypted with a secret key,
   * then the returned value is decrypted.
   * </p>
   *
   * @throws IllegalStateException if value is encrypted but fails to be decrypted.
   */
  @CheckForNull
  public String getString(String key) {
    String effectiveKey = definitions.validKey(key);
    Optional<String> value = getRawString(effectiveKey);
    if (!value.isPresent()) {
      // default values cannot be encrypted, so return value as-is.
      return getDefaultValue(effectiveKey);
    }
    if (encryption.isEncrypted(value.get())) {
      try {
        return encryption.decrypt(value.get());
      } catch (Exception e) {
        throw new IllegalStateException("Fail to decrypt the property " + effectiveKey + ". Please check your secret key.", e);
      }
    }
    return value.get();
  }

  /**
   * Effective value as boolean. It is {@code false} if {@link #getString(String)}
   * does not return {@code "true"}, even if it's not a boolean representation.
   * @return {@code true} if the effective value is {@code "true"}, else {@code false}.
   */
  public boolean getBoolean(String key) {
    String value = getString(key);
    return StringUtils.isNotEmpty(value) && Boolean.parseBoolean(value);
  }

  /**
   * Effective value as {@code int}.
   * @return the value as {@code int}. If the property does not have value nor default value, then {@code 0} is returned.
   * @throws NumberFormatException if value is not empty and is not a parsable integer
   */
  public int getInt(String key) {
    String value = getString(key);
    if (StringUtils.isNotEmpty(value)) {
      return Integer.parseInt(value);
    }
    return 0;
  }

  /**
   * Effective value as {@code long}.
   * @return the value as {@code long}. If the property does not have value nor default value, then {@code 0L} is returned.
   * @throws NumberFormatException if value is not empty and is not a parsable {@code long}
   */
  public long getLong(String key) {
    String value = getString(key);
    if (StringUtils.isNotEmpty(value)) {
      return Long.parseLong(value);
    }
    return 0L;
  }

  /**
   * Effective value as {@link Date}, without time fields. Format is {@link DateUtils#DATE_FORMAT}.
   *
   * @return the value as a {@link Date}. If the property does not have value nor default value, then {@code null} is returned.
   * @throws RuntimeException if value is not empty and is not in accordance with {@link DateUtils#DATE_FORMAT}.
   */
  @CheckForNull
  public Date getDate(String key) {
    String value = getString(key);
    if (StringUtils.isNotEmpty(value)) {
      return DateUtils.parseDate(value);
    }
    return null;
  }

  /**
   * Effective value as {@link Date}, with time fields. Format is {@link DateUtils#DATETIME_FORMAT}.
   *
   * @return the value as a {@link Date}. If the property does not have value nor default value, then {@code null} is returned.
   * @throws RuntimeException if value is not empty and is not in accordance with {@link DateUtils#DATETIME_FORMAT}.
   */
  @CheckForNull
  public Date getDateTime(String key) {
    String value = getString(key);
    if (StringUtils.isNotEmpty(value)) {
      return DateUtils.parseDateTime(value);
    }
    return null;
  }

  /**
   * Effective value as {@code Float}.
   * @return the value as {@code Float}. If the property does not have value nor default value, then {@code null} is returned.
   * @throws NumberFormatException if value is not empty and is not a parsable number
   */
  @CheckForNull
  public Float getFloat(String key) {
    String value = getString(key);
    if (StringUtils.isNotEmpty(value)) {
      try {
        return Float.valueOf(value);
      } catch (NumberFormatException e) {
        throw new IllegalStateException(String.format("The property '%s' is not a float value", key));
      }
    }
    return null;
  }

  /**
   * Effective value as {@code Double}.
   * @return the value as {@code Double}. If the property does not have value nor default value, then {@code null} is returned.
   * @throws NumberFormatException if value is not empty and is not a parsable number
   */
  @CheckForNull
  public Double getDouble(String key) {
    String value = getString(key);
    if (StringUtils.isNotEmpty(value)) {
      try {
        return Double.valueOf(value);
      } catch (NumberFormatException e) {
        throw new IllegalStateException(String.format("The property '%s' is not a double value", key));
      }
    }
    return null;
  }

  /**
   * Value is split by comma and trimmed. Never returns null.
   * <br>
   * Examples :
   * <ul>
   * <li>"one,two,three " -&gt; ["one", "two", "three"]</li>
   * <li>"  one, two, three " -&gt; ["one", "two", "three"]</li>
   * <li>"one, , three" -&gt; ["one", "", "three"]</li>
   * </ul>
   */
  public String[] getStringArray(String key) {
    Optional<PropertyDefinition> def = getDefinition(key);
    if ((def.isPresent()) && (def.get().multiValues())) {
      String value = getString(key);
      if (value == null) {
        return ArrayUtils.EMPTY_STRING_ARRAY;
      }

      List<String> values = new ArrayList<>();
      for (String v : Splitter.on(",").trimResults().split(value)) {
        values.add(v.replace("%2C", ","));
      }
      return values.toArray(new String[values.size()]);
    }

    return getStringArrayBySeparator(key, ",");
  }

  /**
   * Value is split by carriage returns.
   *
   * @return non-null array of lines. The line termination characters are excluded.
   * @since 3.2
   */
  public String[] getStringLines(String key) {
    String value = getString(key);
    if (Strings.isNullOrEmpty(value)) {
      return ArrayUtils.EMPTY_STRING_ARRAY;
    }
    return value.split("\r?\n|\r", -1);
  }

  /**
   * Value is split and trimmed.
   */
  public String[] getStringArrayBySeparator(String key, String separator) {
    String value = getString(key);
    if (value != null) {
      String[] strings = StringUtils.splitByWholeSeparator(value, separator);
      String[] result = new String[strings.length];
      for (int index = 0; index < strings.length; index++) {
        result[index] = trim(strings[index]);
      }
      return result;
    }
    return ArrayUtils.EMPTY_STRING_ARRAY;
  }

  public Settings appendProperty(String key, @Nullable String value) {
    Optional<String> existingValue = getRawString(definitions.validKey(key));
    String newValue;
    if (!existingValue.isPresent()) {
      newValue = trim(value);
    } else {
      newValue = existingValue.get() + "," + trim(value);
    }
    return setProperty(key, newValue);
  }

  public Settings setProperty(String key, @Nullable String[] values) {
    Optional<PropertyDefinition> def = getDefinition(key);
    if (!def.isPresent() || (!def.get().multiValues())) {
      throw new IllegalStateException("Fail to set multiple values on a single value property " + key);
    }

    String text = null;
    if (values != null) {
      List<String> escaped = new ArrayList<>();
      for (String value : values) {
        if (null != value) {
          escaped.add(value.replace(",", "%2C"));
        } else {
          escaped.add("");
        }
      }

      String escapedValue = Joiner.on(',').join(escaped);
      text = trim(escapedValue);
    }
    return setProperty(key, text);
  }

  /**
   * Change a property value in a restricted scope only, depending on execution context. New value
   * is <b>never</b> persisted. New value is ephemeral and kept in memory only:
   * <ul>
   *   <li>during current analysis in the case of scanner stack</li>
   *   <li>during processing of current HTTP request in the case of web server stack</li>
   *   <li>during execution of current task in the case of Compute Engine stack</li>
   * </ul>
   *
   * Property is temporarily removed if the parameter {@code value} is {@code null}
   */
  public Settings setProperty(String key, @Nullable String value) {
    String validKey = definitions.validKey(key);
    if (value == null) {
      removeProperty(validKey);

    } else {
      set(validKey, trim(value));
    }
    return this;
  }

  /**
   * @see #setProperty(String, String)
   */
  public Settings setProperty(String key, @Nullable Boolean value) {
    return setProperty(key, value == null ? null : String.valueOf(value));
  }

  /**
   * @see #setProperty(String, String)
   */
  public Settings setProperty(String key, @Nullable Integer value) {
    return setProperty(key, value == null ? null : String.valueOf(value));
  }

  /**
   * @see #setProperty(String, String)
   */
  public Settings setProperty(String key, @Nullable Long value) {
    return setProperty(key, value == null ? null : String.valueOf(value));
  }

  /**
   * @see #setProperty(String, String)
   */
  public Settings setProperty(String key, @Nullable Double value) {
    return setProperty(key, value == null ? null : String.valueOf(value));
  }

  /**
   * @see #setProperty(String, String)
   */
  public Settings setProperty(String key, @Nullable Float value) {
    return setProperty(key, value == null ? null : String.valueOf(value));
  }

  /**
   * @see #setProperty(String, String)
   */
  public Settings setProperty(String key, @Nullable Date date) {
    return setProperty(key, date, false);
  }

  public Settings addProperties(Map<String, String> props) {
    for (Map.Entry<String, String> entry : props.entrySet()) {
      setProperty(entry.getKey(), entry.getValue());
    }
    return this;
  }

  public Settings addProperties(Properties props) {
    for (Map.Entry<Object, Object> entry : props.entrySet()) {
      setProperty(entry.getKey().toString(), entry.getValue().toString());
    }
    return this;
  }

  /**
   * @see #setProperty(String, String)
   */
  public Settings setProperty(String key, @Nullable Date date, boolean includeTime) {
    if (date == null) {
      return removeProperty(key);
    }
    return setProperty(key, includeTime ? DateUtils.formatDateTime(date) : DateUtils.formatDate(date));
  }

  public Settings removeProperty(String key) {
    remove(key);
    return this;
  }

  public List<String> getKeysStartingWith(String prefix) {
    return getProperties().keySet().stream()
      .filter(key -> StringUtils.startsWith(key, prefix))
      .collect(Collectors.toList());
  }

}