package envoy.client.ui.chatscene;

import java.util.Random;
import java.util.function.*;
import java.util.logging.Level;

import javafx.scene.control.ListView;
import javafx.scene.control.skin.VirtualFlow;

import envoy.client.data.Context;
import envoy.client.data.commands.*;
import envoy.client.helper.ShutdownHelper;
import envoy.client.ui.SceneContext.SceneInfo;
import envoy.client.ui.controller.ChatScene;
import envoy.client.util.MessageUtil;
import envoy.data.Message;
import envoy.util.EnvoyLog;

/**
 * Contains all {@link SystemCommand}s used for
 * {@link envoy.client.ui.controller.ChatScene}.
 *
 * @author Leon Hofmeister
 * @since Envoy Client v0.3-beta
 */
public final class ChatSceneCommands {

	private final ListView<Message>		messageList;
	private final SystemCommandMap		messageTextAreaCommands	= new SystemCommandMap();
	private final SystemCommandBuilder	builder					= new SystemCommandBuilder(messageTextAreaCommands);

	private static final String messageDependantCommandDescription = " the given message. Use s/S to use the selected message. Otherwise expects a number relative to the uppermost completely visible message.";

	/**
	 *
	 * @param messageList the message list to use for some commands
	 * @param chatScene   the instance of {@code ChatScene} that uses this object
	 * @since Envoy Client v0.3-beta
	 */
	public ChatSceneCommands(ListView<Message> messageList, ChatScene chatScene) {
		this.messageList = messageList;

		// Do A Barrel roll initialization
		final var random = new Random();
		builder.setAction(text -> chatScene.doABarrelRoll(Integer.parseInt(text.get(0)), Double.parseDouble(text.get(1))))
			.setDefaults(Integer.toString(random.nextInt(3) + 1), Double.toString(random.nextDouble() * 3 + 1))
			.setDescription("See for yourself :)")
			.setNumberOfArguments(2)
			.build("dabr");

		// Logout initialization
		builder.setAction(text -> ShutdownHelper.logout()).setDescription("Logs you out.").buildNoArg("logout");

		// Exit initialization
		builder.setAction(text -> ShutdownHelper.exit()).setNumberOfArguments(0).setDescription("Exits the program.").build("exit", false);
		builder.build("q");

		// Open settings scene initialization
		builder.setAction(text -> Context.getInstance().getSceneContext().load(SceneInfo.SETTINGS_SCENE))
			.setDescription("Opens the settings screen")
			.buildNoArg("settings");

		// Selection of a new message initialization
		messageDependantAction("s",
				m -> { messageList.getSelectionModel().clearSelection(); messageList.getSelectionModel().select(m); },
				m -> true,
				"Selects");

		// Copy text of selection initialization
		messageDependantAction("cp", MessageUtil::copyMessageText, m -> !m.getText().isEmpty(), "Copies the text of");

		// Delete selection initialization
		messageDependantAction("del", MessageUtil::deleteMessage, m -> true, "Deletes");

		// Save attachment of selection initialization
		messageDependantAction("save-att", MessageUtil::saveAttachment, Message::hasAttachment, "Saves the attachment of");
	}

	private void messageDependantAction(String command, Consumer<Message> action, Predicate<Message> additionalCheck, String description) {
		builder.setAction(text -> {
			final var positionalArgument = text.get(0).toLowerCase();

			// the currently selected message was requested
			if (positionalArgument.startsWith("s")) {
				final var relativeString = positionalArgument.length() == 1 ? "" : positionalArgument.substring(1);

				// Only s has been used as input
				if (positionalArgument.length() == 1) {
					final var selectedMessage = messageList.getSelectionModel().getSelectedItem();
					if (selectedMessage != null && additionalCheck.test(selectedMessage)) action.accept(selectedMessage);
					return;

					// Either s++ or s-- has been requested
				} else if (relativeString.equals("++") || relativeString.equals("--")) selectionNeighbor(action, additionalCheck, positionalArgument);

				// A message relative to the currently selected message should be used (i.e.
				// s+4)
				else useRelativeMessage(command, action, additionalCheck, relativeString, true);

				// Either ++s or --s has been requested
			} else if (positionalArgument.equals("--s") || positionalArgument.equals("++s"))
				selectionNeighbor(action, additionalCheck, positionalArgument);

			// Just a number is expected: ((+)4)
			else useRelativeMessage(command, action, additionalCheck, positionalArgument, false);
		}).setDefaults("s").setNumberOfArguments(1).setDescription(description.concat(messageDependantCommandDescription)).build(command);
	}

	private void selectionNeighbor(Consumer<Message> action, Predicate<Message> additionalCheck, final String positionalArgument) {
		final var wantedIndex = messageList.getSelectionModel().getSelectedIndex() + (positionalArgument.contains("+") ? 1 : -1);
		messageList.getSelectionModel().clearAndSelect(wantedIndex);
		final var selectedMessage = messageList.getItems().get(wantedIndex);
		if (selectedMessage != null && additionalCheck.test(selectedMessage)) action.accept(selectedMessage);
	}

	private void useRelativeMessage(String command, Consumer<Message> action, Predicate<Message> additionalCheck, final String positionalArgument,
			boolean useSelectedMessage) throws NumberFormatException {
		final var	stripPlus	= positionalArgument.startsWith("+") ? positionalArgument.substring(1) : positionalArgument;
		final var	incDec		= Integer.valueOf(stripPlus);
		try {

			// The currently selected message is the base message
			if (useSelectedMessage) {
				final var messageToUse = messageList.getItems().get(messageList.getSelectionModel().getSelectedIndex() + incDec);
				if (messageToUse != null && additionalCheck.test(messageToUse)) action.accept(messageToUse);

				// The currently upmost completely visible message is the base message
			} else {
				final var messageToUse = messageList.getItems()
					.get(((VirtualFlow<?>) messageList.lookup(".virtual-flow")).getFirstVisibleCell().getIndex() + 1 + incDec);
				if (messageToUse != null && additionalCheck.test(messageToUse)) action.accept(messageToUse);
			}
		} catch (final IndexOutOfBoundsException e) {
			EnvoyLog.getLogger(ChatSceneCommands.class)
				.log(Level.INFO, " A non-existing message was requested by the user for System command " + command);
		}
	}

	/**
	 * @return the map used by this {@code ChatSceneCommands}
	 * @since Envoy Client v0.3-beta
	 */
	public SystemCommandMap getChatSceneCommands() { return messageTextAreaCommands; }
}