package com.myoa.engineering.crawl.ppomppu.processor.service;

import com.myoa.engineering.crawl.ppomppu.processor.domain.PpomppuArticle;
import com.myoa.engineering.crawl.ppomppu.processor.dto.PpomppuArticleParser;
import com.myoa.engineering.crawl.ppomppu.processor.infrastructure.client.PpomppuBoardFeedRetriever;
import com.myoa.engineering.crawl.ppomppu.support.dto.code.PpomppuBoardName;

import java.util.Comparator;
import java.util.List;
import lombok.extern.slf4j.Slf4j;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Element;
import org.springframework.stereotype.Component;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

/**
 * PpomppuFeedService
 *
 * @author Shin Woo-jin (woozu.shin@kakaoent.com)
 * @since 2021-09-08
 */
@Slf4j
@Component
public class PpomppuFeedService {

    private final PpomppuBoardFeedRetriever ppomppuBoardFeedRetriever;

    public PpomppuFeedService(PpomppuBoardFeedRetriever ppomppuBoardFeedRetriever) {
        this.ppomppuBoardFeedRetriever = ppomppuBoardFeedRetriever;
    }

    public Mono<List<PpomppuArticle>> getArticles(PpomppuBoardName boardName) {
        final Mono<String> html = ppomppuBoardFeedRetriever.getHtml(boardName.getResourcePath());
        final Mono<Element> tbody = extractTbodyFromHtml(html);
            // .doOnNext(e -> log.info("pre tbody - {}", e.html()));
        return extractArticlesFromTbody(tbody).map(this::convertFromElement)
                                              .map(e -> e.updateBoardName(boardName))
                                              .sort(Comparator.comparing(PpomppuArticle::getArticleId))
                                              // .doOnNext(e -> log.info("parsed Result: {}", e))
                                              .collectList();
    }

    private Mono<Element> extractTbodyFromHtml(Mono<String> html) {
        return html.map(Jsoup::parse)
                   .mapNotNull(e -> e.getElementById("revolution_main_table"))
                   .map(e -> e.getElementsByTag("tbody"))
                   // .doOnNext(e -> log.info("tbody - {}", e.html()))
                   .map(e -> e.stream()
                              .findFirst()
                              .orElseThrow(() -> new IndexOutOfBoundsException("no tbody")));
    }

    private Flux<Element> extractArticlesFromTbody(Mono<Element> tbody) {
        return Flux.concat(tbody.flatMapMany(e -> Flux.fromArray(e.select("tr.list0").toArray(Element[]::new))),
                           tbody.flatMapMany(e -> Flux.fromArray(e.select("tr.list1").toArray(Element[]::new))));
    }

    private PpomppuArticle convertFromElement(Element element) {
        return PpomppuArticleParser.toArticle(element.getElementsByTag("td"));
    }
}