package org.bukkit.command;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.bukkit.ChatColor;
import org.bukkit.Server;

import org.bukkit.plugin.Plugin;
import org.bukkit.plugin.PluginDescriptionFile;
import static org.bukkit.util.Java15Compat.Arrays_copyOfRange;

public final class SimpleCommandMap implements CommandMap {
    private final Map<String, Command> knownCommands = new HashMap<String, Command>();
    private final Set<String> aliases = new HashSet<String>();
    private final Server server;

    public SimpleCommandMap(final Server server) {
        this.server = server;
        setDefaultCommands(server);
    }

    private void setDefaultCommands(final Server server) {
        register("bukkit", new VersionCommand("version", server));
        register("bukkit", new ReloadCommand("reload", server));
        register("bukkit", new PluginsCommand("plugins", server));
    }

    /**
     * Registers multiple commands. Returns name of first command for which fallback had to be used if any.
     * @param plugin
     * @return
     */
    public void registerAll(String fallbackPrefix, List<Command> commands) {
        if (commands != null) {
            for (Command c : commands) {
                register(fallbackPrefix, c);
            }
        }
    }

    private void register(String fallbackPrefix, Command command) {
        register(command.getName(), fallbackPrefix, command);
    }

    /**
     * {@inheritDoc}
     */
    public boolean register(String name, String fallbackPrefix, Command command) {
        boolean registerdPassedName = register(name, fallbackPrefix, command, false);

        for (String alias : command.getAliases()) {
            register(alias, fallbackPrefix, command, true);
        }

        return registerdPassedName;
    }

    private boolean register(String name, String fallbackPrefix, Command command, boolean isAlias) {
        String lowerName = name.toLowerCase();
        boolean registerdPassedName = true;

        // If the command exists but is an alias we overwrite it, otherwise we rename it based on the fallbackPrefix
        while (knownCommands.containsKey(lowerName) && !aliases.contains(lowerName)) {
            lowerName = fallbackPrefix + ":" + lowerName;
            registerdPassedName = false;
        }

        knownCommands.put(lowerName, command);
        if (isAlias) {
            aliases.add(lowerName);
        } else {
            // Ensure this isn't listed as a alias anymore
            aliases.remove(lowerName);
        }
        return registerdPassedName;
    }

    /**
     * {@inheritDoc}
     */
    public boolean dispatch(CommandSender sender, String commandLine) {
        String[] args = commandLine.split(" ");

        if (args.length == 0) {
            return false;
        }

        String sentCommandLabel = args[0].toLowerCase();

        args = Arrays_copyOfRange(args, 1, args.length);

        Command target = getCommand(sentCommandLabel);
        boolean isRegisteredCommand = (target != null);

        if (isRegisteredCommand) {
            try {
                target.execute(sender, sentCommandLabel, args);
            } catch (CommandException ex) {
                throw ex;
            } catch (Throwable ex) {
                throw new CommandException("Unhandled exception executing '" + commandLine + "' in " + target, ex);
            }
        }
        return isRegisteredCommand;
    }

    public void clearCommands() {
        synchronized (this) {
            knownCommands.clear();
            aliases.clear();
            setDefaultCommands(server);
        }
    }

    public Command getCommand(String name) {
        return knownCommands.get(name.toLowerCase());
    }

    private static class VersionCommand extends Command {
        private final Server server;

        public VersionCommand(String name, Server server) {
            super(name);
            this.server = server;
            this.description = "Gets the version of this server including any plugins in use";
            this.usageMessage = "/version [plugin name]";
            this.setAliases(Arrays.asList("ver", "about"));
        }

        @Override
        public boolean execute(CommandSender sender, String currentAlias, String[] args) {
            if (args.length == 0) {
                sender.sendMessage("This server is running " + ChatColor.GREEN + server.getName() + ChatColor.WHITE + " version " + ChatColor.GREEN + server.getVersion());
                sender.sendMessage("This server is also sporting some funky dev build of Bukkit!");
            } else {
                StringBuilder name = new StringBuilder();

                for (String arg : args) {
                    if (name.length() > 0) {
                        name.append(' ');
                    }
                    name.append(arg);
                }

                Plugin plugin = server.getPluginManager().getPlugin(name.toString());

                if (plugin != null) {
                    PluginDescriptionFile desc = plugin.getDescription();

                    sender.sendMessage(ChatColor.GREEN + desc.getName() + ChatColor.WHITE + " version " + ChatColor.GREEN + desc.getVersion());

                    if (desc.getDescription() != null) {
                        sender.sendMessage(desc.getDescription());
                    }

                    if (desc.getWebsite() != null) {
                        sender.sendMessage("Website: " + ChatColor.GREEN + desc.getWebsite());
                    }

                    if (!desc.getAuthors().isEmpty()) {
                        if (desc.getAuthors().size() == 1) {
                            sender.sendMessage("Author: " + getAuthors(desc));
                        } else {
                            sender.sendMessage("Authors: " + getAuthors(desc));
                        }
                    }
                } else {
                    sender.sendMessage("This server is not running any plugin by that name.");
                    sender.sendMessage("Use /plugins to get a list of plugins.");
                }
            }

            return true;
        }

        private String getAuthors(final PluginDescriptionFile desc) {
            StringBuilder result = new StringBuilder();
            ArrayList<String> authors = desc.getAuthors();

            for (int i = 0; i < authors.size(); i++) {
                if (result.length() > 0) {
                    result.append(ChatColor.WHITE);

                    if (i < authors.size() - 1) {
                        result.append(", ");
                    } else {
                        result.append(" and ");
                    }
                }

                result.append(ChatColor.GREEN);
                result.append(authors.get(i));
            }

            return result.toString();
        }
    }

    private static class ReloadCommand extends Command {

        private final Server server;

        public ReloadCommand(String name, Server server) {
            super(name);
            this.server = server;
            this.description = "Reloads the server configuration and plugins";
            this.usageMessage = "/reload";
            this.setAliases(Arrays.asList("rl"));
        }

        @Override
        public boolean execute(CommandSender sender, String currentAlias, String[] args) {
            if (sender.isOp()) {
                server.reload();
                sender.sendMessage(ChatColor.GREEN + "Reload complete.");
            } else {
                sender.sendMessage(ChatColor.RED + "You do not have sufficient access to reload this server.");
            }
            return true;
        }
    }

    private static class PluginsCommand extends Command {

        private final Server server;

        public PluginsCommand(String name, Server server) {
            super(name);
            this.server = server;
            this.description = "Gets a list of plugins running on the server";
            this.usageMessage = "/plugins";
            this.setAliases(Arrays.asList("pl"));
        }

        @Override
        public boolean execute(CommandSender sender, String currentAlias, String[] args) {
            sender.sendMessage("Plugins: " + getPluginList());
            return true;
        }

        private String getPluginList() {
            StringBuilder pluginList = new StringBuilder();
            Plugin[] plugins = server.getPluginManager().getPlugins();

            for (Plugin plugin : plugins) {
                if (pluginList.length() > 0) {
                    pluginList.append(ChatColor.WHITE);
                    pluginList.append(", ");
                }

                pluginList.append(plugin.isEnabled() ? ChatColor.GREEN : ChatColor.RED);
                pluginList.append(plugin.getDescription().getName());
            }

            return pluginList.toString();
        }
    }
}