const pg = require('./pg')
const mappings = require('./mappings')
const joinjs = require('join-js').default;
const debug = require('debug')('sos:db')

const util = module.exports = {};
const validateFunctionName = name => /^[a-z_]+$/.test(name)
const getParamString = (length) => Array.from({length}, (_,i)=>i+1).map(i => '$' + i).join(', ')

util.executeQuery = async function({query, returnType, tablePrefix, single = false}){
  debug(query)

  const {rows} = await pg.query(query)

  if(returnType === 'raw')
    return rows

  const mappedObjs = joinjs.map(rows, mappings, returnType + 'Map', tablePrefix || (returnType + '_'))

  if(single)
    return mappedObjs[0]
  return mappedObjs
}

util.executeFunction = async function({name, params, returnType, single, tablePrefix}) {
  if(!validateFunctionName(name)) throw new Error("Invalid function name: " + name);

  const query = {
    text: `select * from sos.${name}( ${getParamString(params.length)} )`,
    values: params
  }

  const result = await util.executeQuery({query, returnType, single, tablePrefix})

  if(returnType === 'raw' && result[0][name] !== undefined)
    return result[0][name]

  return result
}