/**
 * UserBookmark Model
 * Junction table for user-saved questions
 */

const { DataTypes } = require('sequelize');
const { v4: uuidv4 } = require('uuid');

module.exports = (sequelize) => {
  const UserBookmark = sequelize.define('UserBookmark', {
    id: {
      type: DataTypes.UUID,
      defaultValue: () => uuidv4(),
      primaryKey: true,
      allowNull: false,
      comment: 'Primary key UUID'
    },
    userId: {
      type: DataTypes.UUID,
      allowNull: false,
      references: {
        model: 'users',
        key: 'id'
      },
      onDelete: 'CASCADE',
      comment: 'Reference to user who bookmarked'
    },
    questionId: {
      type: DataTypes.UUID,
      allowNull: false,
      references: {
        model: 'questions',
        key: 'id'
      },
      onDelete: 'CASCADE',
      comment: 'Reference to bookmarked question'
    },
    notes: {
      type: DataTypes.TEXT,
      allowNull: true,
      comment: 'Optional notes about the bookmark'
    },
    createdAt: {
      type: DataTypes.DATE,
      allowNull: false,
      defaultValue: DataTypes.NOW,
      field: 'created_at',
      comment: 'When the bookmark was created'
    },
    updatedAt: {
      type: DataTypes.DATE,
      allowNull: false,
      defaultValue: DataTypes.NOW,
      field: 'updated_at',
      comment: 'When the bookmark was last updated'
    }
  }, {
    tableName: 'user_bookmarks',
    timestamps: true,
    underscored: true,
    indexes: [
      {
        unique: true,
        fields: ['user_id', 'question_id'],
        name: 'idx_user_question_unique'
      },
      {
        fields: ['user_id'],
        name: 'idx_user_bookmarks_user'
      },
      {
        fields: ['question_id'],
        name: 'idx_user_bookmarks_question'
      },
      {
        fields: ['bookmarked_at'],
        name: 'idx_user_bookmarks_date'
      }
    ]
  });

  // Define associations
  UserBookmark.associate = function(models) {
    UserBookmark.belongsTo(models.User, {
      foreignKey: 'userId',
      as: 'User'
    });
    
    UserBookmark.belongsTo(models.Question, {
      foreignKey: 'questionId',
      as: 'Question'
    });
  };

  return UserBookmark;
};