package com.hlab.yanalyst.domain.channel;

import com.hlab.yanalyst.web.dto.YoutubeSearchResultDto;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.List;

/**
 * 조회수 검색 결과(YoutubeSearchResultDto)를 수집함(ChannelVideo, source=SEARCH)으로 영속화한다.
 * 이미 수집된 videoId 는 건너뛴다(중복 방지).
 */
@Slf4j
@Service
@RequiredArgsConstructor
public class SearchCollectionService {

    private final ChannelVideoRepository channelVideoRepository;

    @Transactional
    public CollectResult collectFromSearch(List<YoutubeSearchResultDto> items) {
        if (items == null || items.isEmpty()) {
            return new CollectResult(0, 0, List.of());
        }

        int saved = 0;
        int skipped = 0;
        List<String> savedIds = new ArrayList<>();

        for (YoutubeSearchResultDto dto : items) {
            if (dto.getVideoId() == null || dto.getVideoId().isBlank()) {
                skipped++;
                continue;
            }
            if (channelVideoRepository.existsByVideoId(dto.getVideoId())) {
                skipped++; // 이미 수집된 영상
                continue;
            }

            BigDecimal viewsPerHour = VideoMetrics.viewsPerHour(dto.getViewCount(), dto.getPublishedAt());
            BigDecimal viewsPerSubRatio = VideoMetrics.viewsPerSubRatio(dto.getViewCount(), dto.getSubscriberCount());
            String hashtags = (dto.getHashtags() == null || dto.getHashtags().isEmpty())
                    ? null : String.join(",", dto.getHashtags());

            ChannelVideo video = ChannelVideo.fromSearch(
                    dto.getVideoId(), dto.getTitle(), dto.getThumbnailUrl(), dto.getPublishedAt(),
                    dto.getViewCount(), dto.getChannelId(), dto.getChannelTitle(), dto.getSubscriberCount(),
                    dto.getDurationSec(), viewsPerHour, viewsPerSubRatio, hashtags);

            channelVideoRepository.save(video);
            saved++;
            savedIds.add(dto.getVideoId());
        }

        log.info("Search collection done. saved={}, skipped(duplicate/invalid)={}", saved, skipped);
        return new CollectResult(saved, skipped, savedIds);
    }

    /** 수집 결과 요약. */
    public record CollectResult(int saved, int skipped, List<String> savedVideoIds) {}
}