gistfile1.txt

Product.relations = {
  'comments': {
    'type': 'hasMany',
    'model': 'Comment',
    'foreignKey': 'product_id'
  },
  'tags': {
    'type': 'hasManyAndBelongsTo',
    'model': 'Tag',
    'through': 'ProductTag',
    'foreignKey': 'product_id'
  },
  'store': {
    'type': 'belongsTo',
    'model': 'Store',
    'foreignKey': 'product_id'
  }
}

_.chain(Registry.getModel('ProductTag').relations).toPairs().find(function(pair) {
  return pair[1].model == meta.modelName;
}).value();

['product', {
  'type': 'belongsTo',
  'model': 'Product',
  'foreignKey': 'product_id'
}]

ProductTag.relations = {
  'product': {
    'type': 'belongsTo',
    'model': 'Product',
    'foreignKey': 'product_id'
  },
  'tag': {
    'type': 'belongsTo',
    'model': 'Tag',
    'foreignKey': 'tag_id'
  }
}

Tag.relations = {
  'products': {
    'type': 'hasManyAndBelongsTo',
    'model': 'Product',
    'through': 'ProductTag',
    'foreignKey': 'tag_id'
  }
}

{
  include: {
    relation: 'comments',
    filter: {
      include: {
        relation: 'votes'
      }
    }
  }
}


for (var i in data) {
  var d = data[i];
  var join = 'LEFT JOIN';
  var select = '', on = '';

  switch (d.type) {
    case 'hasMany':
    case 'hasOne':
      select = `(SELECT ${d.target.modelName}.*, ROW_NUMBER() OVER (PARTITION BY ${d.target.modelName}.${d.target.foreignKey}) as rn FROM ${d.target.modelName}) AS ${d.relation}`;
      on = `ON ${d.parent ? d.parent : d.modelName}.${d.target.referenceKey} = ${d.relation}.${d.target.foreignKey}`;
      break;
    case 'belongsTo':
      select = `${d.target.modelName} AS ${d.relation}`;
      on = `ON ${d.relation}.${d.target.referenceKey} = ${d.parent ? d.parent : d.modelName}.${d.target.foreignKey}`;
      break;
    case 'hasManyAndBelongsTo':
      select = `(SELECT ${d.through.modelName}.*, ROW_NUMBER() OVER (PARTITION BY ${d.through.modelName}.${d.through.foreignKey}) as rn FROM ${d.through.modelName}) AS ${d.through.modelName}`;
      on = `ON ${d.through.modelName}.${d.through.foreignKey} = ${d.parent ? d.parent : d.modelName}.${d.through.referenceKey} LEFT JOIN ${d.target.modelName} ON ${d.through.modelName}.${d.target.foreignKey} = ${d.target.modelName}.${d.target.referenceKey}`;
  }

  console.log([join, select, on].join(' '));
}


[
  {
    'relation': 'comments',
    'modelName': 'Product',
    'type': 'hasMany',
    'properties': [],
    'target': {
      'modelName': 'Comment',
      'foreignKey': 'product_id',
      'referenceKey': 'id',
      'properties': [],
      'filter': {}
    }
  },
  {
    'relation': 'author',
    'modelName': 'Comment',
    'type': 'belongsTo',
    'properties': [],
    'parent': 'comments',
    'target': {
      'modelName': 'User',
      'foreignKey': 'user_id',
      'referenceKey': 'id',
      'properties': [],
      'filter': {}
    }
  },
  {
    'relation': 'votes',
    'modelName': 'Comment',
    'type': 'hasMany',
    'properties': [],
    'parent': 'comments',
    'target': {
      'modelName': 'Vote',
      'foreignKey': 'comment_id',
      'referenceKey': 'id',
      'properties': [],
      'filter': {},
    }
  },
  {
    'relation': 'tags',
    'modelName': 'Product',
    'type': 'hasManyAndBelongsTo',
    'properties': [],
    'through': {
      'modelName': 'ProductTag',
      'foreignKey': 'product_id',
      'referenceKey': 'id'
    },
    'target': {
      'modelName': 'Tag',
      'foreignKey': 'tag_id',
      'referenceKey': 'id',
      'properties': [],
      'filter': {}
    }
  },
  {
    'relation': 'user',
    'modelName': 'Product',
    'type': 'belongsTo',
    'properties': [],
    'target': {
      'modelName': 'User',
      'foreignKey': 'user_id',
      'referenceKey': 'id',
      'properties': [],
      'filter': {}
    }
  }
]