package main;

import java.lang.reflect.Array;
import java.util.Arrays;
import mining.TwitterApi;

/**
 * Class that creates executable commands from input.
 * @author Maurice Laveaux
 */
public class CommandParser {
    // the queue of commands.
    private final CommandQueue m_queue;
    
    // the twitter api.
    private final TwitterApi m_api;
    
    /** 
     * Default constructor, requires the TwitterApi 
     * @param queue A valid CommandQueue that can execute requests.
     * @param api the TwitterApi to use for the commands.
     */
    public CommandParser(CommandQueue queue, TwitterApi api) {
        m_queue = queue;
        m_api   = api;
    }
    
    /**
     * Parses a string and creates an executable command for it.
     * @param command The string to parse the command from.
     */
    final public void parse(final String command) {
        // split the code for each space ' '.
        String[] seperated = command.split(" ");
             
        // parse the seperated code for each argument.
        parse(seperated);
    }
    
    /**
     * Parses a string and creates an executable command for it.
     * @param seperated A space seperated string for each argument.
     */
    final public void parse(final String[] seperated) {   
        if (seperated.length == 0) {
            return;
        }    
        
        // The main command.
        String command = seperated[0];
                
        // the first command issued 
        switch (command) {
            case "help":
                showFullHelp();
                return;
            case "-h":
                showFullHelp();
                return;
            case "quit":
                // TODO: implement less hack way of quiting the program.
                System.exit(0);
            default:
                break;
        }        
        
        // there is a command without errors but it was not switched.
        if (seperated.length == 1) {
            showUsageHelp(command);
            return;
        }
        
        // commands with multiple parameters
        String[] extra = Arrays.copyOfRange(seperated, 1, seperated.length);
        
        if (seperated.length < 3) {
            showUsageHelp(extra.toString());
            return;
        }
        
        String[] parameters = Arrays.copyOfRange(extra, 1, extra.length);
                
        try {
            switch (command) {
                case "get":
                    m_queue.add(new RequestCommand(m_api, extra[0], parameters));
                    return;
            }
        }
        catch (IllegalArgumentException ex) {
            System.out.println(ex);
        }
    }
    
    /** Show the basic usage help in console */
    private void showUsageHelp(String unknown) {
        System.out.println("Unknown argument: \"" + unknown + "\".");
        System.out.println("    Use help, -h for more help.");
    }
    
    /** Show the full manual page in the console */
    private void showFullHelp() {
        System.out.println("Usage: [command] [arguments], see below for options.");
        
        System.out.println("\n command:");
        System.out.println("    set,    use the twitter Search/REST API.");
        System.out.println("    stream, use the twitter Stream API.");
        
        System.out.println("\n arguments:");        
        System.out.println("    <main>,        the information to get from api.twitter.com.");
        System.out.println("    <json_member>, any number of arguments for the information");
    }
}