/*
 * 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.eclipse.aether.util;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;

import org.eclipse.aether.RepositorySystemSession;

import static java.util.stream.Collectors.toList;

/**
 * A utility class to read configuration properties from a repository system session.
 *
 * @see RepositorySystemSession#getConfigProperties()
 */
public final class ConfigUtils {

    private ConfigUtils() {
        // hide constructor
    }

    /**
     * Gets the specified configuration property.
     *
     * @param properties the configuration properties to read, must not be {@code null}
     * @param defaultValue the default value to return in case none of the property keys are set, may be {@code null}
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a valid value is found.
     * @return the property value or {@code null} if none
     */
    public static Object getObject(Map<?, ?> properties, Object defaultValue, String... keys) {
        for (String key : keys) {
            Object value = properties.get(key);

            if (value != null) {
                return value;
            }
        }

        return defaultValue;
    }

    /**
     * Gets the specified configuration property.
     *
     * @param session the repository system session from which to read the configuration property, must not be
     *            {@code null}
     * @param defaultValue the default value to return in case none of the property keys are set, may be {@code null}
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a valid value is found.
     * @return the property value or {@code null} if none
     */
    public static Object getObject(RepositorySystemSession session, Object defaultValue, String... keys) {
        return getObject(session.getConfigProperties(), defaultValue, keys);
    }

    /**
     * Gets the specified configuration property.
     *
     * @param properties the configuration properties to read, must not be {@code null}
     * @param defaultValue the default value to return in case none of the property keys is set to a string, may be
     *            {@code null}
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a string value is found.
     * @return the property value or {@code null} if none
     */
    public static String getString(Map<?, ?> properties, String defaultValue, String... keys) {
        for (String key : keys) {
            Object value = properties.get(key);

            if (value instanceof String) {
                return (String) value;
            }
        }

        return defaultValue;
    }

    /**
     * Gets the specified configuration property.
     *
     * @param session the repository system session from which to read the configuration property, must not be
     *            {@code null}
     * @param defaultValue the default value to return in case none of the property keys is set to a string, may be
     *            {@code null}
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a string value is found.
     * @return the property value or {@code null} if none
     */
    public static String getString(RepositorySystemSession session, String defaultValue, String... keys) {
        return getString(session.getConfigProperties(), defaultValue, keys);
    }

    /**
     * Gets the specified configuration property.
     *
     * @param properties the configuration properties to read, must not be {@code null}
     * @param defaultValue the default value to return in case none of the property keys is set to a number
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a {@link Number} or a string representation of an {@link Integer} is found.
     * @return the property value
     */
    public static int getInteger(Map<?, ?> properties, int defaultValue, String... keys) {
        for (String key : keys) {
            Object value = properties.get(key);

            if (value instanceof Number) {
                return ((Number) value).intValue();
            } else if (value instanceof String) {
                try {
                    return Integer.parseInt((String) value);
                } catch (NumberFormatException e) {
                    // try next key
                }
            }
        }

        return defaultValue;
    }

    /**
     * Gets the specified configuration property.
     *
     * @param session the repository system session from which to read the configuration property, must not be
     *            {@code null}
     * @param defaultValue the default value to return in case none of the property keys is set to a number
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a {@link Number} or a string representation of an {@link Integer} is found.
     * @return the property value
     */
    public static int getInteger(RepositorySystemSession session, int defaultValue, String... keys) {
        return getInteger(session.getConfigProperties(), defaultValue, keys);
    }

    /**
     * Gets the specified configuration property.
     *
     * @param properties the configuration properties to read, must not be {@code null}
     * @param defaultValue the default value to return in case none of the property keys is set to a number
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a {@link Number} or a string representation of a {@link Long} is found.
     * @return the property value
     */
    public static long getLong(Map<?, ?> properties, long defaultValue, String... keys) {
        for (String key : keys) {
            Object value = properties.get(key);

            if (value instanceof Number) {
                return ((Number) value).longValue();
            } else if (value instanceof String) {
                try {
                    return Long.parseLong((String) value);
                } catch (NumberFormatException e) {
                    // try next key
                }
            }
        }

        return defaultValue;
    }

    /**
     * Gets the specified configuration property.
     *
     * @param session the repository system session from which to read the configuration property, must not be
     *            {@code null}
     * @param defaultValue the default value to return in case none of the property keys is set to a number
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a {@link Number} or a string representation of a {@link Long} is found.
     * @return the property value
     */
    public static long getLong(RepositorySystemSession session, long defaultValue, String... keys) {
        return getLong(session.getConfigProperties(), defaultValue, keys);
    }

    /**
     * Gets the specified configuration property.
     *
     * @param properties the configuration properties to read, must not be {@code null}
     * @param defaultValue the default value to return in case none of the property keys is set to a number
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a {@link Number} or a string representation of a {@link Float} is found.
     * @return the property value
     */
    public static float getFloat(Map<?, ?> properties, float defaultValue, String... keys) {
        for (String key : keys) {
            Object value = properties.get(key);

            if (value instanceof Number) {
                return ((Number) value).floatValue();
            } else if (value instanceof String) {
                try {
                    return Float.parseFloat((String) value);
                } catch (NumberFormatException e) {
                    // try next key
                }
            }
        }

        return defaultValue;
    }

    /**
     * Gets the specified configuration property.
     *
     * @param session the repository system session from which to read the configuration property, must not be
     *            {@code null}
     * @param defaultValue the default value to return in case none of the property keys is set to a number
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a {@link Number} or a string representation of a {@link Float} is found.
     * @return the property value
     */
    public static float getFloat(RepositorySystemSession session, float defaultValue, String... keys) {
        return getFloat(session.getConfigProperties(), defaultValue, keys);
    }

    /**
     * Gets the specified configuration property.
     *
     * @param properties the configuration properties to read, must not be {@code null}
     * @param defaultValue the default value to return in case none of the property keys is set to a boolean
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a {@link Boolean} or a string (to be {@link Boolean#parseBoolean(String) parsed as boolean}) is found.
     * @return the property value
     */
    public static boolean getBoolean(Map<?, ?> properties, boolean defaultValue, String... keys) {
        for (String key : keys) {
            Object value = properties.get(key);

            if (value instanceof Boolean) {
                return (Boolean) value;
            } else if (value instanceof String) {
                return Boolean.parseBoolean((String) value);
            }
        }

        return defaultValue;
    }

    /**
     * Gets the specified configuration property.
     *
     * @param session the repository system session from which to read the configuration property, must not be
     *            {@code null}
     * @param defaultValue the default value to return in case none of the property keys is set to a boolean
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a {@link Boolean} or a string (to be {@link Boolean#parseBoolean(String) parsed as boolean}) is found.
     * @return the property value
     */
    public static boolean getBoolean(RepositorySystemSession session, boolean defaultValue, String... keys) {
        return getBoolean(session.getConfigProperties(), defaultValue, keys);
    }

    /**
     * Gets the specified configuration property.
     *
     * @param properties the configuration properties to read, must not be {@code null}
     * @param defaultValue the default value to return in case none of the property keys is set to a collection
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a collection is found.
     * @return the property value or {@code null} if none
     */
    public static List<?> getList(Map<?, ?> properties, List<?> defaultValue, String... keys) {
        for (String key : keys) {
            Object value = properties.get(key);

            if (value instanceof List) {
                return (List<?>) value;
            } else if (value instanceof Collection) {
                return Collections.unmodifiableList(new ArrayList<>((Collection<?>) value));
            }
        }

        return defaultValue;
    }

    /**
     * Gets the specified configuration property.
     *
     * @param session the repository system session from which to read the configuration property, must not be
     *            {@code null}
     * @param defaultValue the default value to return in case none of the property keys is set to a collection
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a collection is found.
     * @return the property value or {@code null} if none
     */
    public static List<?> getList(RepositorySystemSession session, List<?> defaultValue, String... keys) {
        return getList(session.getConfigProperties(), defaultValue, keys);
    }

    /**
     * Gets the specified configuration property.
     *
     * @param properties the configuration properties to read, must not be {@code null}
     * @param defaultValue the default value to return in case none of the property keys is set to a map
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a map is found.
     * @return the property value or {@code null} if none
     */
    public static Map<?, ?> getMap(Map<?, ?> properties, Map<?, ?> defaultValue, String... keys) {
        for (String key : keys) {
            Object value = properties.get(key);

            if (value instanceof Map) {
                return (Map<?, ?>) value;
            }
        }

        return defaultValue;
    }

    /**
     * Gets the specified configuration property.
     *
     * @param session the repository system session from which to read the configuration property, must not be
     *            {@code null}
     * @param defaultValue the default value to return in case none of the property keys is set to a map
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a map is found.
     * @return the property value or {@code null} if none
     */
    public static Map<?, ?> getMap(RepositorySystemSession session, Map<?, ?> defaultValue, String... keys) {
        return getMap(session.getConfigProperties(), defaultValue, keys);
    }

    /**
     * Gets the specified configuration property.
     * @param <T> the enum type
     *
     * @param properties the configuration properties to read, must not be {@code null}
     * @param enumClass the enum class to read, must not be {@code null}
     * @param defaultValue the default value to return in case none of the property keys is set to a convertible String or T.
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a enum type {@code T} or a string (parsed using {@link Enum#valueOf(Class, String)} is found.
     * @return the property value or {@code defaultValue} if none found
     * @since 2.0.21
     */
    public static <T extends Enum<T>> T getEnum(
            Map<?, ?> properties, Class<T> enumClass, T defaultValue, String... keys) {
        for (String key : keys) {
            Object value = properties.get(key);

            if (enumClass.isInstance(value)) { // validate type
                return enumClass.cast(value);
            } else if (value instanceof String) {
                return Enum.valueOf(enumClass, (String) value);
            }
        }
        return defaultValue;
    }

    /**
     * Gets the specified configuration property.
     * @param <T> the enum type
     *
     * @param session the repository system session from which to read the configuration property, must not be
     *            {@code null}
     * @param enumClass the enum class to read, must not be {@code null}
     * @param defaultValue the default value to return in case none of the property keys is set to a convertible String or T.
     * @param keys the property keys to read, must not be {@code null}. The specified keys are read one after one until
     *            a enum type {@code T} or a string (parsed using {@link Enum#valueOf(Class, String)} is found.
     * @return the property value or {@code defaultValue} if none found
     * @since 2.0.21
     */
    public static <T extends Enum<T>> T getEnum(
            RepositorySystemSession session, Class<T> enumClass, T defaultValue, String... keys) {
        return getEnum(session.getConfigProperties(), enumClass, defaultValue, keys);
    }

    /**
     * Utility method to parse configuration string that contains comma separated list of names into
     * {@code List<String>}, never returns {@code null}.
     *
     * @since 1.9.0
     */
    public static List<String> parseCommaSeparatedNames(String commaSeparatedNames) {
        if (commaSeparatedNames == null || commaSeparatedNames.trim().isEmpty()) {
            return Collections.emptyList();
        }
        return Arrays.stream(commaSeparatedNames.split(","))
                .filter(s -> !s.trim().isEmpty())
                .collect(toList());
    }

    /**
     * Utility method to parse configuration string that contains comma separated list of names into
     * {@code List<String>} with unique elements (duplicates, if any, are discarded), never returns {@code null}.
     *
     * @since 1.9.0
     */
    public static List<String> parseCommaSeparatedUniqueNames(String commaSeparatedNames) {
        return parseCommaSeparatedNames(commaSeparatedNames).stream().distinct().collect(toList());
    }
}