import { exprToSQL } from './expr'

import { hasVal, identifierToSql, toUpper } from './util'

import { overToSQL } from './over'

function castToSQL(expr) {

const { target, expr: expression, symbol, as: alias } = expr

const { length, dataType, parentheses, scale } = target

let str = ''

if (length) str = scale ? `${length}, ${scale}` : length

if (parentheses) str = `(${str})`

let prefix = exprToSQL(expression)

let symbolChar = '::'

let suffix = ''

if (symbol === 'as') {

prefix = `CAST(${prefix}`

suffix = ')'

symbolChar = ` ${symbol.toUpperCase()} `

}

if (alias) suffix += ` AS ${identifierToSql(alias)}`

return `${prefix}${symbolChar}${dataType}${str}${suffix}`

}

function extractFunToSQL(stmt) {

const { args, type } = stmt

const { field, cast_type: castType, source } = args

const result = [`${toUpper(type)}(${toUpper(field)}`, 'FROM', toUpper(castType), exprToSQL(source)]

return `${result.filter(hasVal).join(' ')})`

}

function funcToSQL(expr) {

const { args, name } = expr

if (!args) return name

const { parentheses, over } = expr

const str = `${name}(${exprToSQL(args).join(', ')})`

const overStr = overToSQL(over)

return [parentheses ? `(${str})` : str, overStr].filter(hasVal).join(' ')

}

export {

castToSQL,

extractFunToSQL,

funcToSQL,

}