package com.comphenix.protocol.error;

import java.io.File;
import java.net.URLDecoder;
import java.security.CodeSource;

import com.google.common.base.Preconditions;

import org.bukkit.Bukkit;
import org.bukkit.plugin.Plugin;

public final class PluginContext {
    // Determine plugin folder
    private static File pluginFolder;
    
    private PluginContext() {
        // Not constructable
    }
    
    /**
     * Retrieve the name of the plugin that called the last method(s) in the exception.
     * @param ex - the exception.
     * @return The name of the plugin, or NULL.
     */
    public static String getPluginCaller(Exception ex) {
        StackTraceElement[] elements = ex.getStackTrace();
        String current = getPluginName(elements[0]);
        
        for (int i = 1; i < elements.length; i++) {
            String caller = getPluginName(elements[i]);
            if (caller != null && !caller.equals(current)) {
                return caller;
            }
        }

        return null;
    }
    
    /**
     * Lookup the plugin that this method invocation belongs to, and return its file name.
     * @param element - the method invocation.
     * @return Plugin name, or NULL if not found.
     */
    public static String getPluginName(StackTraceElement element) {
        try {
            if (Bukkit.getServer() == null) {
                return null;
            }
    
            CodeSource codeSource = Class.forName(element.getClassName()).getProtectionDomain().getCodeSource();
            if (codeSource != null) {
                String encoding = codeSource.getLocation().getPath();
                File path = new File(URLDecoder.decode(encoding, "UTF-8"));
                File plugins = getPluginFolder();
                
                if (plugins != null && folderContains(plugins, path)) {
                    return path.getName().replaceAll(".jar", "");
                }
            }
        } catch (Throwable ex) {
            // throw new RuntimeException("Cannot lookup plugin name.", ex);
        }

        return null; // Cannot find it
    }
    
    /**
     * Determine if a folder contains the given file.
     * @param folder - the folder.
     * @param file - the file.
     * @return TRUE if it does, FALSE otherwise.
     */
    private static boolean folderContains(File folder, File file) {
        Preconditions.checkNotNull(folder, "folder cannot be NULL");
        Preconditions.checkNotNull(file, "file cannot be NULL");
        
        // Get absolute versions
        folder = folder.getAbsoluteFile();
        file = file.getAbsoluteFile();

        while (file != null) {
            if (folder.equals(file))
                return true;
            file = file.getParentFile();
        }

        return false;
    }
    
    /**
     * Retrieve the folder that contains every plugin on the server.
     * @return Folder with every plugin, or NULL if Bukkit has not been initialized yet.
     */
    private static File getPluginFolder() {
        File folder = pluginFolder;
        
        if (folder == null && Bukkit.getServer() != null) {
            Plugin[] plugins = Bukkit.getPluginManager().getPlugins();
            
            if (plugins.length > 0) {
                folder = plugins[0].getDataFolder().getParentFile();
                pluginFolder = folder;
            }
        }

        return folder;
    }
}