const mongoose = require('mongoose');
const { Schema } = mongoose;

const TrendSchema = new Schema({
  title: { type: String, required: true, trim: true },
  summary: { type: String },
  body: { type: String },
  source: { type: String, default: '未知来源' },
  sourceUrl: { type: String },
  category: {
    type: String,
    enum: ['产品', '论文', '工具', '公司', '政策', '其他'],
    default: '其他'
  },
  tags: [String],
  hot: { type: Boolean, default: false },
  // 人话解读（AI 生成，治"看不懂AI新闻"的焦虑）
  plainExplain: { type: String, default: '' },  // 一句话说清这是什么
  takeAway: { type: String, default: '' },      // 对普通人意味着什么
  picked: { type: Boolean, default: false },
  newsDate: { type: Date, default: Date.now, index: true },
  viewCount: { type: Number, default: 0 },
  status: {
    type: String,
    enum: ['draft', 'published'],
    default: 'published'
  }
}, {
  timestamps: true,
  toJSON: { virtuals: true },
  toObject: { virtuals: true }
});

TrendSchema.index({ status: 1, newsDate: -1 });
TrendSchema.index({ category: 1, newsDate: -1 });

module.exports = mongoose.model('Trend', TrendSchema);