const mongoose = require('mongoose');

const messageSchema = new mongoose.Schema({
  conversation: {
    type: mongoose.Schema.Types.ObjectId,
    ref: 'Conversation',
    required: true
  },
  sender: {
    type: mongoose.Schema.Types.ObjectId,
    ref: 'User',
    required: true
  },
  content: {
    type: String,
    required: function() { return !this.attachment; }
  },
  type: {
    type: String,
    enum: ['text', 'image', 'audio', 'file', 'system'],
    default: 'text'
  },
  attachment: {
    url: String,
    filename: String,
    originalName: String,
    mimeType: String,
    size: Number,
    thumbnail: String,
    duration: Number
  },
  replyTo: {
    type: mongoose.Schema.Types.ObjectId,
    ref: 'Message'
  },
  reactions: [{
    user: mongoose.Schema.Types.ObjectId,
    emoji: String,
    createdAt: { type: Date, default: Date.now }
  }],
  edits: [{
    content: String,
    editedAt: { type: Date, default: Date.now }
  }],
  isEdited: {
    type: Boolean,
    default: false
  },
  isDeleted: {
    type: Boolean,
    default: false
  },
  deletedAt: Date,
  readBy: [{
    user: mongoose.Schema.Types.ObjectId,
    readAt: { type: Date, default: Date.now }
  }],
  status: {
    type: String,
    enum: ['sending', 'sent', 'delivered', 'read'],
    default: 'sent'
  }
}, {
  timestamps: true
});

messageSchema.index({ conversation: 1, createdAt: -1 });
messageSchema.index({ sender: 1 });
messageSchema.index({ 'readBy.user': 1 });

module.exports = mongoose.model('Message', messageSchema);