import { bigQueryToSQL, unionToSQL, multipleToSQL } from './union'

const surportedTypes = ['select', 'delete', 'update', 'insert', 'drop', 'rename', 'truncate', 'call', 'use', 'alter', 'set', 'create', 'lock', 'unlock', 'bigquery', 'declare', 'show']

function checkSupported(expr) {

const ast = expr && expr.ast ? expr.ast : expr

if (!surportedTypes.includes(ast.type)) throw new Error(`${ast.type} statements not supported at the moment`)

}

export default function toSQL(ast) {

if (Array.isArray(ast)) {

ast.forEach(checkSupported)

return multipleToSQL(ast)

}

checkSupported(ast)

const { type } = ast

if (type === 'bigquery') return bigQueryToSQL(ast)

return unionToSQL(ast)

}