package mining;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Logger;
import org.apache.commons.codec.Charsets;
import org.apache.http.NameValuePair;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONObject;
import support.ConsumerKeySecret;
import utils.Configuration;

/**
 * Accessors to the Twitter API.
 */
public class TwitterApi {

    private static final String CFG_BEARER_TOKEN = "bearer-token";
    private final Requester requester;

    public TwitterApi(Requester requester) {
        this.requester = requester;
    }

    /**
     * Establishes an instance using application-only authentication using a
     * file as cache.
     *
     * @return An API context usable for requests using app-only auth.
     * @throws IOException
     */
    public static TwitterApi getAppOnly() throws IOException {
        Configuration cfg = Configuration.getConfig();
        String token;
        BearerRequester breq = null;
        token = cfg.getProperty(CFG_BEARER_TOKEN);
        if (token != null) {
            breq = new BearerRequester(token);
            if (!breq.isValid()) {
                Logger.getLogger(TwitterApi.class.getName())
                        .info("Bearer token invalid, trying a new one...");
                breq = null;
            }
        }
        if (breq == null) {
            ConsumerKeySecret cks = getConsumerKeySecret();
            breq = new BearerRequester(cks);
            cfg.setProperty(CFG_BEARER_TOKEN, breq.getAccessToken());
        }
        return new TwitterApi(breq);
    }

    private static ConsumerKeySecret getConsumerKeySecret() {
        // static consumer keys retrieved from dev.twitter.com
        return new ConsumerKeySecret(Configuration.CONSUMER_KEY,
                Configuration.CONSUMER_SECRET);
    }

    /**
     * @param resource The resource to be requested.
     * @return A builder for an API request.
     */
    public Builder build(String resource) {
        return new Builder(resource);
    }

    public class Builder {

        private final String resource;
        private final List<NameValuePair> params;

        public Builder(String resource) {
            this.resource = resource;
            this.params = new ArrayList<>();
        }

        public Builder param(String key, String val) {
            params.add(new BasicNameValuePair(key, val));
            return this;
        }

        @Override
        public String toString() {
            return URLEncodedUtils.format(params, Charsets.UTF_8);
        }

        public JSONObject request() throws IOException {
            return TwitterApi.this.requester.getJSON(toString());
        }
    }
}