import Tokenizr from 'tokenizr'

export const lexr = new Tokenizr()

lexr.rule(/[AND|OR]/, (ctx, m) => {
  ctx.accept('conjunction', m[0])
})

export const orderByLexr = new Tokenizr()

orderByLexr.rule(/,/, (ctx, m) => {
  ctx.accept('spacer')
})

orderByLexr.rule(/ASC|DESC/, (ctx, m) => {
  ctx.accept('direction', m[0])
})

orderByLexr.rule(/[a-zA-Z]+/, (ctx, m) => {
  ctx.accept('column', m[0])
})

orderByLexr.rule(/\s/, (ctx, m) => {
  ctx.ignore()
})

export function parseOrderByString(orderBy: string) {
  const output = []
  let holding = []
  orderByLexr
    .input(orderBy)
    .tokens()
    .forEach((token) => {
      switch (token.type) {
        case 'spacer':
          output.push(holding)
          holding = []
          break
        case 'column':
        case 'direction':
          holding.push(token.value)
          break
      }
    })
  if (holding) {
    output.push(holding)
  }
  return output
}