import { join } from './fn.js'
import { alpha, alphanumeric, any, char, many, map, noCaseString, parse, seq, skip } from './parser.js'

// MATCH (a:Label)-[e:Label]->(b:Label)
// RETURN a, b

const Identifier = (name, label) => ({ name, label })

const ObjectType = Object.freeze({
  Node: 0,
  Edge: 1
})

const GraphObject = ({ name, label }, type, properties = []) => Object.freeze({
  name,
  label,
  type,
  properties
})

const whitespace = char(' ')
const matchKeyword = noCaseString('match')
const returnKeyword = noCaseString('return')

const name = map(
  join(''),
  seq(alpha, many(alphanumeric))
)
const colon = char(':')
const label = seq(skip(colon), name)

const id = any(
  map(
    ([name, label]) => Identifier(name, label),
    seq(name, label)
  ),
  map(
    ([name]) => Identifier(name),
    name
  ),
  map(
    ([label]) => Identifier(undefined, label),
    label
  )
)

const lparen = char('(')
const rparen = char(')')
const node = map(
  ([id]) => GraphObject(id, ObjectType.Node),
  seq(skip(lparen), id, skip(rparen))
)

const lsquare = char('[')
const rsquare = char(']')
const edge = map(
  ([id]) => GraphObject(id, ObjectType.Edge),
  seq(skip(lsquare), id, skip(rsquare))
)

const hyphen = char('-')
const rchevron = char('>')
const arrow = seq(hyphen, rchevron)
const relationship = seq(skip(hyphen), edge, skip(arrow), node)

const matchParameters = seq(node, many(relationship))
const matchStmt = seq(skip(matchKeyword), skip(many(whitespace)), matchParameters)

const query = 'MATCH (:Label)-[e:Label]->(b:Label)'
const result = parse(matchStmt, query)
console.log(result.value[0])