/** @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(' ')