package org.schabi.newpipe.extractor.services.peertube.extractors;

import java.io.IOException;

import org.jsoup.helper.StringUtil;
import org.schabi.newpipe.extractor.InfoItem;
import org.schabi.newpipe.extractor.InfoItemExtractor;
import org.schabi.newpipe.extractor.InfoItemsCollector;
import org.schabi.newpipe.extractor.StreamingService;
import org.schabi.newpipe.extractor.downloader.Downloader;
import org.schabi.newpipe.extractor.downloader.Response;
import org.schabi.newpipe.extractor.exceptions.ExtractionException;
import org.schabi.newpipe.extractor.exceptions.ParsingException;
import org.schabi.newpipe.extractor.linkhandler.SearchQueryHandler;
import org.schabi.newpipe.extractor.search.InfoItemsSearchCollector;
import org.schabi.newpipe.extractor.search.SearchExtractor;
import org.schabi.newpipe.extractor.utils.JsonUtils;
import org.schabi.newpipe.extractor.utils.Parser;
import org.schabi.newpipe.extractor.utils.Parser.RegexException;

import com.grack.nanojson.JsonArray;
import com.grack.nanojson.JsonObject;
import com.grack.nanojson.JsonParser;

public class PeertubeSearchExtractor extends SearchExtractor {

    private static final String START_KEY = "start";
    private static final String COUNT_KEY = "count";
    private static final int ITEMS_PER_PAGE = 12;
    private static final String START_PATTERN = "start=(\\d*)";
    
    private InfoItemsPage<InfoItem> initPage;
    private long total;
    
    public PeertubeSearchExtractor(StreamingService service, SearchQueryHandler linkHandler) {
        super(service, linkHandler);
    }

    @Override
    public String getSearchSuggestion() throws ParsingException {
        return null;
    }
    
    @Override
    public InfoItemsPage<InfoItem> getInitialPage() throws IOException, ExtractionException {
        super.fetchPage();
        return initPage;
    }

    private InfoItemsCollector<InfoItem, InfoItemExtractor> collectStreamsFrom(JsonObject json) throws ParsingException {
        
        final InfoItemsSearchCollector collector = getInfoItemSearchCollector();
        
        JsonArray contents;
        try {
            contents = (JsonArray) JsonUtils.getValue(json, "data");
        }catch(Exception e) {
            throw new ParsingException("unable to extract search info", e);
        }
        
        for(Object c: contents) {
            if(c instanceof JsonObject) {
                final JsonObject item = (JsonObject) c;
                PeertubeStreamInfoItemExtractor extractor = new PeertubeStreamInfoItemExtractor(item);
                collector.commit(extractor);
            }
        }
        
        return collector;
        
    }

    @Override
    public String getNextPageUrl() throws IOException, ExtractionException {
        super.fetchPage();
        return initPage.getNextPageUrl();
    }

    @Override
    public InfoItemsPage<InfoItem> getPage(String pageUrl) throws IOException, ExtractionException {
        Response response = getDownloader().get(pageUrl);
        JsonObject json = null;
        if(null != response && !StringUtil.isBlank(response.responseBody())) {
            try {
                json = JsonParser.object().from(response.responseBody());
            } catch (Exception e) {
                throw new ParsingException("Could not parse json data for search info", e);
            }
        }
        
        if(json != null) {
            Number number = JsonUtils.getNumber(json, "total");
            if(number != null) this.total = number.longValue();
            return new InfoItemsPage<>(collectStreamsFrom(json), getNextPageUrl(pageUrl));
        } else {
            throw new ExtractionException("Unable to get peertube search info");
        }
    }

    @Override
    public void onFetchPage(Downloader downloader) throws IOException, ExtractionException {
        String pageUrl = getUrl() + "&" + START_KEY + "=0&" + COUNT_KEY + "=" + ITEMS_PER_PAGE;
        this.initPage = getPage(pageUrl);
    }
    
    private String getNextPageUrl(String prevPageUrl) {
        String prevStart;
        try {
            prevStart = Parser.matchGroup1(START_PATTERN, prevPageUrl);
        } catch (RegexException e) {
            return "";
        }
        if(StringUtil.isBlank(prevStart)) return "";
        long nextStart = 0;
        try {
            nextStart = Long.valueOf(prevStart) + ITEMS_PER_PAGE;
        } catch (NumberFormatException e) {
            return "";
        }
        
        if(nextStart >= total) {
            return "";
        }else {
            return prevPageUrl.replace(START_KEY + "=" + prevStart, START_KEY + "=" + String.valueOf(nextStart));
        }
    }
    

}