package envoy.data;

import java.util.*;

import envoy.exception.EnvoyException;

/**
 * Manages all application settings that are set during application startup by
 * either loading them from the {@link Properties} file
 * {@code client.properties} or parsing them from the command line arguments of
 * the application.<br>
 * <br>
 * Project: <strong>envoy-client</strong><br>
 * File: <strong>Config.java</strong><br>
 * Created: <strong>12 Oct 2019</strong><br>
 *
 * @author Kai S. K. Engelbart
 * @since Envoy Common v0.1-beta
 */
public class Config {

	protected Map<String, ConfigItem<?>> items = new HashMap<>();

	/**
	 * Parses config items from a properties object.
	 *
	 * @param properties the properties object to parse
	 * @since Envoy Common v0.1-beta
	 */
	public void load(Properties properties) {
		items.entrySet()
			.stream()
			.filter(e -> properties.containsKey(e.getKey()))
			.forEach(e -> e.getValue().parse(properties.getProperty(e.getKey())));
	}

	/**
	 * Parses config items from an array of command line arguments.
	 *
	 * @param args the command line arguments to parse
	 * @throws EnvoyException if the command line arguments contain an unknown token
	 * @since Envoy Common v0.1-beta
	 */
	public void load(String[] args) throws EnvoyException {
		for (int i = 0; i < args.length; i++)
			for (ConfigItem<?> item : items.values())
				if (args[i].startsWith("--")) {
					if (args[i].length() == 2) throw new EnvoyException("Malformed command line argument at position " + i);
					final String commandLong = args[i].substring(2);
					if (item.getCommandLong().equals(commandLong)) {
						item.parse(args[++i]);
						break;
					}
				} else if (args[i].startsWith("-")) {
					if (args[i].length() == 1) throw new EnvoyException("Malformed command line argument at position " + i);
					final String commandShort = args[i].substring(1);
					if (item.getCommandShort().equals(commandShort)) {
						item.parse(args[++i]);
						break;
					}
				} else throw new EnvoyException("Malformed command line argument at position " + i);
	}

	/**
	 * Initializes config items from a map.
	 * 
	 * @param items the items to include in this config
	 * @since Envoy Common v0.1-beta
	 */
	public void load(Map<String, ConfigItem<?>> items) { this.items.putAll(items); }

	/**
	 * @return {@code true} if all mandatory config items are initialized
	 * @since Envoy Common v0.1-beta
	 */
	public boolean isInitialized() {
		return items.values().stream().filter(ConfigItem::isMandatory).map(ConfigItem::get).noneMatch(Objects::isNull);
	}

	/**
	 * @param name the name of the config item to return
	 * @return the config item with the specified name
	 * @since Envoy Common v0.1-beta
	 */
	public ConfigItem<?> get(String name) { return items.get(name); }
}