import { splitNonEscaped, escape, re } from '../utils'
import { compose, replace, forEach, type, trim, complement, isEmpty, qmap, qfilter } from 'pepka'
import { Levels } from '../classes/Levels'
import { analyseLine } from './analyseLine'
import { createFunctions } from './createFunctions'
import { StyleGenerator } from '../types'

export const parse = (() => {
  const delimiters = ['\n', '\r', ';']
  const isDelimiter = (s: string) => delimiters.includes(s)
  const commentRE = re.comment
  return (css: string, aug = false) => {
    const levels = new Levels()
    const names: string[] = [] // selector names, class names.
    return compose(
      () => levels.out,
      forEach((line: string | [string, StyleGenerator]) => {
        if(type(line) == 'Array') levels.merge(line[0], line[1])
        else {
          if(line) analyseLine(levels, line as string, names)
          if(levels.depth < 1)
            throw new Error('lit-css parse error: unbalanced {} braces !')
        }
      }),
      createFunctions(aug),
      qfilter(complement(isEmpty) as any),
      qmap(trim),
      splitNonEscaped(delimiters),
      replace(/(\{|\})/g, (_: any, brace: string, offset: number, full: string[]) => {
        if(!isDelimiter(full[offset-1])) brace = ';' + brace
        if(!isDelimiter(full[offset+1])) brace += ';'
        return brace
      }),
      escape,
      replace(commentRE, '')
    )(css)
  }
})()