import { exprToSQL, orderOrPartitionByToSQL } from './expr'
import { hasVal, literalToSQL, toUpper } from './util'
import { overToSQL } from './over'

function aggrToSQL(expr) {
  /** @type {Object} */
  const { args, filter, over, within_group_orderby } = expr
  let str = exprToSQL(args.expr)
  str = Array.isArray(str) ? str.join(', ') : str
  const fnName = expr.name
  const overStr = overToSQL(over)
  const separator = ' '
  if (args.distinct) str = ['DISTINCT', str].join(separator)
  if (args.separator && args.separator.delimiter) str = [str, literalToSQL(args.separator.delimiter)].join(`${args.separator.symbol} `)
  if (args.separator && args.separator.expr) str = [str, exprToSQL(args.separator.expr)].join(' ')
  if (args.orderby) str = [str, orderOrPartitionByToSQL(args.orderby, 'order by')].join(' ')
  if (args.separator && args.separator.value) str = [str, toUpper(args.separator.keyword), literalToSQL(args.separator.value)].filter(hasVal).join(' ')
  const withinGroup = within_group_orderby ? `WITHIN GROUP (${orderOrPartitionByToSQL(within_group_orderby, 'order by')})` : ''
  const filterStr = filter ? `FILTER (WHERE ${exprToSQL(filter.where)})` : ''
  return [`${fnName}(${str})`, withinGroup, overStr, filterStr].filter(hasVal).join(' ')
}

export {
  aggrToSQL,
}