// Cloudflare Worker - 备忘录 API
// KV 绑定变量名：remind

export default {
  async fetch(request, env) {
    const url = new URL(request.url);
    const path = url.pathname;

    // 跨域头（允许网页调用）
    const corsHeaders = {
      'Access-Control-Allow-Origin': '*',
      'Access-Control-Allow-Methods': 'GET, POST, DELETE, OPTIONS',
      'Access-Control-Allow-Headers': 'Content-Type',
    };
    if (request.method === 'OPTIONS') {
      return new Response(null, { headers: corsHeaders });
    }

    // 仅处理 /api/memos
    if (path !== '/api/memos') {
      return new Response('Not Found', { status: 404, headers: corsHeaders });
    }

    // 获取当前储存的备忘录数组
    async function getMemos() {
      const data = await env.remind.get('memos');
      return data ? JSON.parse(data) : [];
    }

    // 保存数组到 KV
    async function saveMemos(memos) {
      await env.remind.put('memos', JSON.stringify(memos));
    }

    // ----- GET：获取所有备忘录 -----
    if (request.method === 'GET') {
      const memos = await getMemos();
      return new Response(JSON.stringify(memos), {
        headers: { 'Content-Type': 'application/json', ...corsHeaders },
      });
    }

    // ----- POST：添加一条备忘录 -----
    if (request.method === 'POST') {
      const body = await request.json();
      const { text } = body;
      if (!text || typeof text !== 'string') {
        return new Response(JSON.stringify({ error: '缺少 text 字段' }), {
          status: 400,
          headers: { 'Content-Type': 'application/json', ...corsHeaders },
        });
      }
      const memos = await getMemos();
      memos.push({ text, time: Date.now() });  // 带时间戳方便识别
      await saveMemos(memos);
      return new Response(JSON.stringify(memos), {
        headers: { 'Content-Type': 'application/json', ...corsHeaders },
      });
    }

    // ----- DELETE：根据 index 删除一条 -----
    if (request.method === 'DELETE') {
      const index = parseInt(url.searchParams.get('index'), 10);
      if (isNaN(index)) {
        return new Response(JSON.stringify({ error: '需要 index 参数' }), {
          status: 400,
          headers: { 'Content-Type': 'application/json', ...corsHeaders },
        });
      }
      const memos = await getMemos();
      if (index < 0 || index >= memos.length) {
        return new Response(JSON.stringify({ error: '索引超出范围' }), {
          status: 400,
          headers: { 'Content-Type': 'application/json', ...corsHeaders },
        });
      }
      memos.splice(index, 1);
      await saveMemos(memos);
      return new Response(JSON.stringify(memos), {
        headers: { 'Content-Type': 'application/json', ...corsHeaders },
      });
    }

    return new Response('Method Not Allowed', { status: 405, headers: corsHeaders });
  },
};