package main;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import mining.TwitterApi;
import mining.TwitterApi.Builder;
import org.json.JSONException;
import org.json.JSONObject;

/**
 * Basic contained class for a Pair, because Java doesn't provide this.
 *
 * @author Maurice Laveaux
 */
class Parameter {

    public Parameter(String variable, String value) {
        this.variable = variable;
        this.value = value;
    }

    public String variable;
    public String value;
}

/**
 * A single request/response command that executes once.
 *
 * @author Maurice Laveaux
 */
public class RequestCommand implements ICommand {

    /**
     * The api to execute requests on
     */
    private final TwitterApi m_api;

    private final String m_command;

    /**
     * The list of parameters that are executed
     */
    private final ArrayList<Parameter> m_parameters;

    /**
     * Contruct a RequestCommand that executes the request and writes the
     * results into a file.
     *
     * @param api the main twitter api.
     * @param command the command of the twitter api f.e. users/show.
     * @param parameters the parameters for the executed command.
     */
    public RequestCommand(TwitterApi api, String command, String[] parameters) {
        m_api = api;
        m_command = command;

        m_parameters = new ArrayList();

        if (parameters.length < 1) {
            throw new IllegalArgumentException("Not enough parameters specified.");
        }

        for (String param : parameters) {
            // parse the parameter to a variable with a value.
            m_parameters.add(parseParam(param));
        }
    }

    @Override
    public void execute() {
        try {
            // create the building object with the command.
            Builder builder = m_api.build(m_command);

            // add every parameter to the builder.
            for (Parameter param : m_parameters) {
                builder = builder.param(param.variable, param.value);
            }

            JSONObject result = builder.request();

            // TODO: add the results to the main database.            
            // For now write to a file
            File file = new File("database.txt");

            FileWriter writer = new FileWriter(file, true);

            writer.write("\n\r" + result.toString());
            writer.flush();

            System.out.println(result.toString(4));
        } catch (JSONException ex) {
            /* cannot happen */
            throw new RuntimeException(ex);
        } catch (IOException ex) {
            // TODO: when ratelimit reached, add event back to queue.
            throw new RuntimeException(ex);
        }
    }

    /**
     * Parses the input string to a parameter.
     *
     * @param input A single line in the form variable=value.
     * @return A pair of strings for variable and value.
     */
    private Parameter parseParam(final String input) {
        String[] seperated = input.split("=");

        if (seperated.length < 2) {
            throw new IllegalArgumentException("parameter did not contain <variable>=<value>.");
        }

        return new Parameter(seperated[0], seperated[1]);
    }
}