package fr.xephi.authme.command;

import fr.xephi.authme.AuthMe;
import fr.xephi.authme.command.help.HelpProvider;
import org.bukkit.ChatColor;
import org.bukkit.command.CommandSender;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 */
public class CommandHandler {

    /**
     * The command manager instance.
     */
    private CommandManager commandManager;

    /**
     * Constructor.
     *
     * @param init True to immediately initialize.
     */
    public CommandHandler(boolean init) {
        // Initialize
        if (init)
            init();
    }

    /**
     * Initialize the command handler.
     *
     * @return True if succeed, false on failure. True will also be returned if the command handler was already
     * initialized.
     */
    public boolean init() {
        // Make sure the handler isn't initialized already
        if (isInit())
            return true;

        // Initialize the command manager
        this.commandManager = new CommandManager(false);
        this.commandManager.registerCommands();

        // Return the result
        return true;
    }

    /**
     * Check whether the command handler is initialized.
     *
     * @return True if the command handler is initialized.
     */
    public boolean isInit() {
        return this.commandManager != null;
    }

    /**
     * Destroy the command handler.
     *
     * @return True if the command handler was destroyed successfully, false otherwise. True will also be returned if
     * the command handler wasn't initialized.
     */
    public boolean destroy() {
        // Make sure the command handler is initialized
        if (!isInit())
            return true;

        // Unset the command manager
        this.commandManager = null;
        return true;
    }

    /**
     * Get the command manager.
     *
     * @return Command manager instance.
     */
    public CommandManager getCommandManager() {
        return this.commandManager;
    }

    /**
     * Process a command.
     *
     * @param sender             The command sender (Bukkit).
     * @param bukkitCommand      The command (Bukkit).
     * @param bukkitCommandLabel The command label (Bukkit).
     * @param bukkitArgs         The command arguments (Bukkit).
     * @return True if the command was executed, false otherwise.
     */
    public boolean onCommand(CommandSender sender, org.bukkit.command.Command bukkitCommand, String bukkitCommandLabel, String[] bukkitArgs) {
        // Process the arguments
        List<String> args = processArguments(bukkitArgs);

        // Create a command reference, and make sure at least one command part is available
        CommandParts commandReference = new CommandParts(bukkitCommandLabel, args);
        if (commandReference.getCount() == 0)
            return false;

        // Get a suitable command for this reference, and make sure it isn't null
        FoundCommandResult result = this.commandManager.findCommand(commandReference);
        if (result == null) {
            sender.sendMessage(ChatColor.DARK_RED + "Failed to parse " + AuthMe.getPluginName() + " command!");
            return false;
        }

        // Get the base command
        String baseCommand = commandReference.get(0);

        // Make sure the difference between the command reference and the actual command isn't too big
        final double commandDifference = result.getDifference();
        if (commandDifference > 0.12) {
            // Show the unknown command warning
            sender.sendMessage(ChatColor.DARK_RED + "Unknown command!");

            // Show a command suggestion if available and the difference isn't too big
            if (commandDifference < 0.75)
                if (result.getCommandDescription() != null)
                    sender.sendMessage(ChatColor.YELLOW + "Did you mean " + ChatColor.GOLD + "/" + result.getCommandDescription().getCommandReference(commandReference) + ChatColor.YELLOW + "?");

            // Show the help command
            sender.sendMessage(ChatColor.YELLOW + "Use the command " + ChatColor.GOLD + "/" + baseCommand + " help" + ChatColor.YELLOW + " to view help.");
            return true;
        }

        // Show a message when the command handler is assuming a command
        if (commandDifference > 0) {
            // Get the suggested command
            CommandParts suggestedCommandParts = new CommandParts(result.getCommandDescription().getCommandReference(commandReference));

            // Show the suggested command
            sender.sendMessage(ChatColor.DARK_RED + "Unknown command, assuming " + ChatColor.GOLD + "/" + suggestedCommandParts +
                    ChatColor.DARK_RED + "!");
        }

        // Make sure the command is executable
        if (!result.isExecutable()) {
            // Get the command reference
            CommandParts helpCommandReference = new CommandParts(result.getCommandReference().getRange(1));

            // Show the unknown command warning
            sender.sendMessage(ChatColor.DARK_RED + "Invalid command!");

            // Show the help command
            sender.sendMessage(ChatColor.YELLOW + "Use the command " + ChatColor.GOLD + "/" + baseCommand + " help " + helpCommandReference + ChatColor.YELLOW + " to view help.");
            return true;
        }

        // Make sure the command sender has permission
        if (!result.hasPermission(sender)) {
            // Show the no permissions warning
            sender.sendMessage(ChatColor.DARK_RED + "You don't have permission to use this command!");
            return true;
        }

        // Make sure the command sender has permission
        if (!result.hasProperArguments()) {
            // Get the command and the suggested command reference
            CommandParts suggestedCommandReference = new CommandParts(result.getCommandDescription().getCommandReference(commandReference));
            CommandParts helpCommandReference = new CommandParts(suggestedCommandReference.getRange(1));

            // Show the invalid arguments warning
            sender.sendMessage(ChatColor.DARK_RED + "Incorrect command arguments!");

            // Show the command argument help
            HelpProvider.showHelp(sender, commandReference, suggestedCommandReference, true, false, true, false, false, false);

            // Show the command to use for detailed help
            sender.sendMessage(ChatColor.GOLD + "Detailed help: " + ChatColor.WHITE + "/" + baseCommand + " help " + helpCommandReference);
            return true;
        }

        // Execute the command if it's suitable
        return result.executeCommand(sender);
    }

    /**
     * Process the command arguments, and return them as an array list.
     *
     * @param args The command arguments to process.
     * @return The processed command arguments.
     */
    private List<String> processArguments(String[] args) {
        // Convert the array into a list of arguments
        List<String> arguments = new ArrayList<>(Arrays.asList(args));

        /// Remove all empty arguments
        for (int i = 0; i < arguments.size(); i++) {
            // Get the argument value
            final String arg = arguments.get(i);

            // Check whether the argument value is empty
            if (arg.trim().length() == 0) {
                // Remove the current argument
                arguments.remove(i);

                // Decrease the index by one, continue to the next argument
                i--;
            }
        }

        // Return the argument
        return arguments;
    }
}