package com.crawler.strategy;

import com.crawler.model.Article;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class DoubanTop250Strategy implements CrawlStrategy {

    private static final int TOTAL_MOVIES = 250;
    private static final int MOVIES_PER_PAGE = 25;

    @Override
    public List<Article> crawl(String url) {
        List<Article> allMovies = new ArrayList<>();
        try {
            System.out.println("🎬 开始爬取豆瓣电影 Top 250...");
            System.out.println("⏳ 预计需要爬取 " + (TOTAL_MOVIES / MOVIES_PER_PAGE) + " 页");

            for (int page = 0; page < TOTAL_MOVIES; page += MOVIES_PER_PAGE) {
                String pageUrl = "https://movie.douban.com/top250?start=" + page + "&filter=";
                System.out.println("📄 正在爬取第 " + (page / MOVIES_PER_PAGE + 1) + " 页...");
                
                List<Article> pageMovies = crawlPage(pageUrl, page / MOVIES_PER_PAGE + 1);
                allMovies.addAll(pageMovies);
                
                System.out.println("✅ 第 " + (page / MOVIES_PER_PAGE + 1) + " 页完成，已获取 " + allMovies.size() + " 部电影");
                
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    Thread.currentThread().interrupt();
                    break;
                }
            }

            System.out.println("🎉 完成！共爬取 " + allMovies.size() + " 部电影");
        } catch (Exception e) {
            System.err.println("❌ 爬取失败: " + e.getMessage());
            Article errorArticle = new Article();
            errorArticle.setTitle("Error crawling Douban Top 250");
            errorArticle.setUrl(url);
            errorArticle.setContent("Error details: " + e.getMessage());
            errorArticle.setSource("douban");
            allMovies.add(errorArticle);
        }
        return allMovies;
    }

    private List<Article> crawlPage(String url, int pageNum) {
        List<Article> movies = new ArrayList<>();
        try {
            URL urlObj = new URL(url);
            HttpURLConnection connection = (HttpURLConnection) urlObj.openConnection();
            connection.setRequestMethod("GET");
            connection.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36");
            connection.setRequestProperty("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
            connection.setConnectTimeout(15000);
            connection.setReadTimeout(15000);

            StringBuilder html = new StringBuilder();
            try (BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream(), "UTF-8"))) {
                String line;
                while ((line = reader.readLine()) != null) {
                    html.append(line).append("\n");
                }
            }

            movies = parseMovies(html.toString());
        } catch (Exception e) {
            System.err.println("⚠️ 第 " + pageNum + " 页爬取失败: " + e.getMessage());
        }
        return movies;
    }

    private List<Article> parseMovies(String html) {
        List<Article> movies = new ArrayList<>();
        
        String moviePattern = "<div class=\"item\">[\\s\\S]*?</div>\\s*</div>\\s*</div>";
        Pattern pattern = Pattern.compile(moviePattern, Pattern.DOTALL);
        Matcher matcher = pattern.matcher(html);

        while (matcher.find()) {
            try {
                Article movie = parseSingleMovie(matcher.group());
                if (movie != null) {
                    movies.add(movie);
                }
            } catch (Exception e) {
                continue;
            }
        }
        return movies;
    }

    private Article parseSingleMovie(String movieHtml) {
        Article movie = new Article();
        movie.setSource("douban");

        try {
            Pattern titlePattern = Pattern.compile("<span class=\"title\">(.*?)</span>");
            Matcher titleMatcher = titlePattern.matcher(movieHtml);
            if (titleMatcher.find()) {
                movie.setTitle(titleMatcher.group(1));
            }

            Pattern linkPattern = Pattern.compile("<a href=\"(.*?)\"");
            Matcher linkMatcher = linkPattern.matcher(movieHtml);
            if (linkMatcher.find()) {
                movie.setUrl(linkMatcher.group(1));
            }

            Pattern ratingPattern = Pattern.compile("<span class=\"rating_num\">(.*?)</span>");
            Matcher ratingMatcher = ratingPattern.matcher(movieHtml);
            String rating = "";
            if (ratingMatcher.find()) {
                rating = ratingMatcher.group(1);
            }

            Pattern yearPattern = Pattern.compile("(\\d{4})\\s*/");
            Matcher yearMatcher = yearPattern.matcher(movieHtml);
            String year = "";
            if (yearMatcher.find()) {
                year = yearMatcher.group(1);
            }

            Pattern quotePattern = Pattern.compile("<span class=\"inq\">(.*?)</span>");
            Matcher quoteMatcher = quotePattern.matcher(movieHtml);
            String quote = "";
            if (quoteMatcher.find()) {
                quote = quoteMatcher.group(1);
            }

            Pattern infoPattern = Pattern.compile("<p class=\"\">(.*?)</p>", Pattern.DOTALL);
            Matcher infoMatcher = infoPattern.matcher(movieHtml);
            String info = "";
            if (infoMatcher.find()) {
                info = infoMatcher.group(1).replaceAll("<br\\s*/?>", "\n").replaceAll("<[^>]+>", "").trim();
            }

            StringBuilder content = new StringBuilder();
            content.append("🎬 电影名称: ").append(movie.getTitle()).append("\n");
            content.append("⭐ 评分: ").append(rating).append("\n");
            content.append("📅 年份: ").append(year).append("\n");
            if (!quote.isEmpty()) {
                content.append("💬 简介: ").append(quote).append("\n");
            }
            content.append("\n📝 详细信息:\n").append(info);

            movie.setContent(content.toString());
            movie.setAuthor("豆瓣电影");

        } catch (Exception e) {
            return null;
        }

        return movie;
    }

    @Override
    public String getStrategyName() {
        return "douban";
    }
}