/*
 * Copyright OpenSearch Contributors
 * SPDX-License-Identifier: Apache-2.0
 */

package org.opensearch.dataprepper.model.configuration;

import java.util.Collections;
import java.util.List;
import java.util.Map;

public class PluginSetting implements PipelineDescription {

    private static final String UNEXPECTED_ATTRIBUTE_TYPE_MSG = "Unexpected type [%s] for attribute [%s]";

    private final String name;
    private final Map<String, Object> settings;
    private int processWorkers;
    private String pipelineName;

    public PluginSetting(final String name, final Map<String, Object> settings) {
        this.name = name;
        this.settings = settings;
    }

    public String getName() {
        return name;
    }

    public Map<String, Object> getSettings() {
        return settings;
    }

    /**
     * Returns the number of process workers the pipeline is using; This is only required for special plugin use-cases
     * where plugin implementation depends on the number of process workers. For example, Trace analytics service map
     * prepper plugin uses memory mapped databases and it requires to know the number of workers that operate on it
     * concurrently.
     * @return Number of process workers
     */
    public int getNumberOfProcessWorkers() {
        return processWorkers;
    }

    /**
     * This method is solely for pipeline execution to set the process workers and it is recommended not to be used.
     * @param processWorkers number of process workers
     */
    public void setProcessWorkers(final int processWorkers) {
        this.processWorkers = processWorkers;
    }

    /**
     * Returns the name of the associated pipeline.
     * @return name of the associated pipeline
     */
    public String getPipelineName() {
        return this.pipelineName;
    }

    /**
     * This method is solely for pipeline execution to set the associated pipeline name and it is recommended not to be
     * used.
     * @param pipelineName associated pipeline name
     */
    public void setPipelineName(final String pipelineName) {
        this.pipelineName = pipelineName;
    }

    /**
     * Returns the value of the specified attribute, or null if this settings contains no value for the attribute.
     *
     * @param attribute name of the attribute
     * @return value of the attribute from the metadata
     */
    public Object getAttributeFromSettings(final String attribute) {
        return settings == null ? null : settings.get(attribute);
    }

    /**
     * Returns the value of the specified attribute, or {@code defaultValue} if this settings contains no value for
     * the attribute.
     *
     * @param attribute    name of the attribute
     * @param defaultValue default value for the setting
     * @return the value of the specified attribute, or {@code defaultValue} if this settings contains no value for
     * the attribute
     */
    public Object getAttributeOrDefault(final String attribute, final Object defaultValue) {
        return settings == null ? defaultValue : settings.getOrDefault(attribute, defaultValue);
    }

    /**
     * Returns the value of the specified attribute as integer, or {@code defaultValue} if this settings contains no
     * value for the attribute.
     *
     * @param attribute    name of the attribute
     * @param defaultValue default value for the setting
     * @return the value of the specified attribute, or {@code defaultValue} if this settings contains no value for
     * the attribute. If the value is null, null will be returned.
     */
    public Integer getIntegerOrDefault(final String attribute, final int defaultValue) {
        Object object = getAttributeOrDefault(attribute, defaultValue);
        if (object == null) {
            return null;
        } else if (object instanceof Number) {
            return ((Number) object).intValue();
        } else if (object instanceof String) {
            return Integer.valueOf(String.valueOf(object));
        }

        throw new IllegalArgumentException(String.format(UNEXPECTED_ATTRIBUTE_TYPE_MSG, object.getClass(), attribute));
    }

    /**
     * Returns the value of the specified attribute as String, or {@code defaultValue} if this settings contains no
     * value for the attribute. If the value is null, null will be returned.
     *
     * @param attribute    name of the attribute
     * @param defaultValue default value for the setting
     * @return the value of the specified attribute, or {@code defaultValue} if this settings contains no value for
     * the attribute. If the value is null, null will be returned.
     */
    public String getStringOrDefault(final String attribute, final String defaultValue) {
        Object object = getAttributeOrDefault(attribute, defaultValue);
        if (object == null) {
            return null;
        } else if (object instanceof String) {
            return String.valueOf(object);
        }

        throw new IllegalArgumentException(String.format(UNEXPECTED_ATTRIBUTE_TYPE_MSG, object.getClass(), attribute));
    }

    /**
     * Returns the value of the specified {@literal List<String>}, or {@code defaultValue} if this settings contains no value for
     * the attribute.
     *
     * @param attribute    name of the attribute
     * @param type the type stored in the List
     * @param <T> The type
     * @return the value of the specified attribute, or {@code defaultValue} if this settings contains no value for
     * the attribute
     */
    public <T> List<T> getTypedList(final String attribute, final Class<T> type) {
        Object object = getAttributeOrDefault(attribute, Collections.emptyList());
        if (object == null) {
            return null;
        }

        checkObjectForListType(attribute, object, type);

        return (List<T>) object;
    }

    /**
     * Returns the value of the specified {@literal Map<String, String> object}, or {@code defaultValue} if this settings contains no value for
     * the attribute.
     *
     * @param attribute    name of the attribute
     * @param keyType      key type of the Map
     * @param valueType    value type stored in the Map
     * @param <K> The key type
     * @param <V> The value type
     * @return the value of the specified attribute, or {@code defaultValue} if this settings contains no value for
     * the attribute
     */
    public <K, V> Map<K, V> getTypedMap(final String attribute, final Class<K> keyType, final Class<V> valueType) {
        Object object = getAttributeOrDefault(attribute, Collections.emptyMap());
        if (object == null) {
            return null;
        }

        checkObjectType(attribute, object, Map.class);

        ((Map<?, ?>) object).forEach((key, value) -> {
            checkObjectType(attribute, key, keyType);
            checkObjectType(attribute, value, valueType);
        });

        return (Map<K, V>) object;
    }

    /**
     * Returns the value of the specified {@literal Map<String, List<String>>}, or {@code defaultValue} if this settings contains no value for
     * the attribute.
     *
     * @param attribute    name of the attribute
     * @param keyType      key type of the Map
     * @param valueType    value type stored in the List value of the Map
     * @param <K> The key type
     * @param <V> The value type
     * @return the value of the specified attribute, or {@code defaultValue} if this settings contains no value for
     * the attribute
     */
    public <K, V> Map<K, List<V>> getTypedListMap(final String attribute, final Class<K> keyType, final Class<V> valueType) {
        Object object = getAttributeOrDefault(attribute, Collections.emptyMap());
        if (object == null) {
            return null;
        }

        checkObjectType(attribute, object, Map.class);

        ((Map<?, ?>) object).forEach((key, value) -> {
            checkObjectType(attribute, key, keyType);
            checkObjectForListType(attribute, value, valueType);
        });

        return (Map<K, List<V>>) object;
    }

    /**
     * Returns the value of the specified attribute as boolean, or {@code defaultValue} if this settings contains no
     * value for the attribute. If the value is null, null will be returned.
     *
     * @param attribute    name of the attribute
     * @param defaultValue default value for the setting
     * @return the value of the specified attribute, or {@code defaultValue} if this settings contains no value for
     * the attribute
     */
    public Boolean getBooleanOrDefault(final String attribute, final boolean defaultValue) {
        Object object = getAttributeOrDefault(attribute, defaultValue);
        if (object == null) {
            return null;
        } else if (object instanceof Boolean) {
            return (Boolean) object;
        } else if (object instanceof String) {
            return Boolean.valueOf(String.valueOf(object));
        }

        throw new IllegalArgumentException(String.format(UNEXPECTED_ATTRIBUTE_TYPE_MSG, object.getClass(), attribute));
    }

    /**
     * Returns the value of the specified attribute as long, or {@code defaultValue} if this settings contains no
     * value for the attribute. If the value is null, null will be returned.
     *
     * @param attribute    name of the attribute
     * @param defaultValue default value for the setting
     * @return the value of the specified attribute, or {@code defaultValue} if this settings contains no value for
     * the attribute
     */
    public Long getLongOrDefault(final String attribute, final long defaultValue) {
        Object object = getAttributeOrDefault(attribute, defaultValue);
        if (object == null) {
            return null;
        } else if (object instanceof Number) {
            return ((Number) object).longValue();
        } else if (object instanceof String) {
            return Long.valueOf(String.valueOf(object));
        }

        throw new IllegalArgumentException(String.format(UNEXPECTED_ATTRIBUTE_TYPE_MSG, object.getClass(), attribute));
    }

    private <T> void checkObjectType(final String attribute, final Object object, final Class<T> type) {
        if (object != null && !(type.isAssignableFrom(object.getClass()))){
            throw new IllegalArgumentException(String.format(UNEXPECTED_ATTRIBUTE_TYPE_MSG, object.getClass(), attribute));
        }
    }

    private <T> void checkObjectForListType(final String attribute, final Object object, final Class<T> type) {
        checkObjectType(attribute, object, List.class);

        ((List<?>) object).forEach(o -> {
            checkObjectType(attribute, o, type);
        });
    }
}