import fs from 'fs';
import path from 'path';
import matter from 'gray-matter';
import { Locale } from './i18n';

export interface NewsArticle {
    id: string;
    title: string;
    category: string;
    date: string;
    excerpt: string;
    author: string;
    readTime: string;
    tags: string[];
    featured: boolean;
    content: string;
    locale: Locale;
}

const DOCS_PATH = path.join(process.cwd(), 'docs', 'news');

export async function getNewsArticle(id: string, locale: Locale): Promise<NewsArticle | null> {
    try {
        const filePath = path.join(DOCS_PATH, locale, `${id}.md`);

        if (!fs.existsSync(filePath)) {
            return null;
        }

        const fileContents = fs.readFileSync(filePath, 'utf8');
        const { data, content } = matter(fileContents);

        return {
            id,
            title: data.title,
            category: data.category,
            date: data.date,
            excerpt: data.excerpt,
            author: data.author,
            readTime: data.readTime,
            tags: data.tags || [],
            featured: data.featured || false,
            content,
            locale,
        };
    } catch (error) {
        console.error(`Error reading article ${id} for locale ${locale}:`, error);
        return null;
    }
}

export async function getAllNewsArticles(locale: Locale): Promise<NewsArticle[]> {
    try {
        const articlesDir = path.join(DOCS_PATH, locale);

        if (!fs.existsSync(articlesDir)) {
            return [];
        }

        const filenames = fs.readdirSync(articlesDir);
        const articles: NewsArticle[] = [];

        for (const filename of filenames) {
            if (filename.endsWith('.md')) {
                const id = filename.replace(/\.md$/, '');
                const article = await getNewsArticle(id, locale);
                if (article) {
                    articles.push(article);
                }
            }
        }

        // Sort by date (newest first)
        // Handle Chinese date format (e.g., "2024年1月15日")
        const parseChineseDate = (dateStr: string): Date => {
            // Try to parse Chinese date format first
            const chineseDateMatch = dateStr.match(/(\d{4})年(\d{1,2})月(\d{1,2})日/);
            if (chineseDateMatch) {
                const [, year, month, day] = chineseDateMatch;
                return new Date(parseInt(year), parseInt(month) - 1, parseInt(day));
            }
            // Fallback to regular Date parsing
            return new Date(dateStr);
        };

        return articles.sort((a, b) => {
            const dateA = parseChineseDate(a.date);
            const dateB = parseChineseDate(b.date);
            return dateB.getTime() - dateA.getTime();
        });
    } catch (error) {
        console.error(`Error reading articles for locale ${locale}:`, error);
        return [];
    }
}

export async function getAvailableLocalesForArticle(id: string): Promise<Locale[]> {
    const availableLocales: Locale[] = [];
    const locales: Locale[] = ['zh-CN', 'zh-TW', 'en'];

    for (const locale of locales) {
        const filePath = path.join(DOCS_PATH, locale, `${id}.md`);
        if (fs.existsSync(filePath)) {
            availableLocales.push(locale);
        }
    }

    return availableLocales;
}

export function checkArticleExists(id: string, locale: Locale): boolean {
    const filePath = path.join(DOCS_PATH, locale, `${id}.md`);
    return fs.existsSync(filePath);
}

/**
 * 获取最新的新闻文章（用于首页显示）
 * @param locale 语言
 * @param limit 限制文章数量，默认为3
 * @returns 最新的新闻文章数组
 */
export async function getLatestNewsArticles(locale: Locale, limit: number = 3): Promise<NewsArticle[]> {
    const allArticles = await getAllNewsArticles(locale);
    return allArticles.slice(0, limit);
}