const dlv = require('dlv')
import { State } from './state'
import removeMeta from './removeMeta'
import { TinyColor } from '@ctrl/tinycolor'
import { ensureArray, dedupe, flatten } from '../../util/array'

const COLOR_PROPS = [
  'caret-color',
  'color',
  'column-rule-color',
  'background-color',
  'border-color',
  'border-top-color',
  'border-right-color',
  'border-bottom-color',
  'border-left-color',
  'fill',
  'outline-color',
  'stop-color',
  'stroke',
  'text-decoration-color',
]

export function getColor(
  state: State,
  keys: string[]
): { documentation?: string } {
  const item = dlv(state.classNames.classNames, keys)
  if (!item.__rule) return null
  const props = Object.keys(removeMeta(item))
  if (props.length === 0) return null
  const nonCustomProps = props.filter((prop) => !prop.startsWith('--'))

  const areAllCustom = nonCustomProps.length === 0

  if (
    !areAllCustom &&
    nonCustomProps.some((prop) => !COLOR_PROPS.includes(prop))
  ) {
    // they should all be color-based props
    return null
  }

  const propsToCheck = areAllCustom ? props : nonCustomProps

  const colors = flatten(
    propsToCheck.map((prop) => ensureArray(item[prop]).map(createColor))
  )

  // check that all of the values are valid colors
  if (colors.some((color) => !color.isValid)) {
    return null
  }

  // check that all of the values are the same color
  const colorStrings = colors.map((color) => color.toRgbString())
  if (dedupe(colorStrings).length !== 1) {
    return null
  }

  return { documentation: colorStrings[0] }
}

export function getColorFromValue(value: unknown): string {
  if (typeof value !== 'string') return null
  if (value === 'transparent') {
    return 'rgba(0, 0, 0, 0.01)'
  }
  const color = new TinyColor(value)
  if (color.isValid) {
    return color.toRgbString()
  }
  return null
}

function createColor(str: string): TinyColor {
  if (str === 'transparent') {
    return new TinyColor({ r: 0, g: 0, b: 0, a: 0.01 })
  }

  // matches: rgba(<r>, <g>, <b>, var(--bg-opacity))
  // TODO: support other formats? e.g. hsla, css level 4
  const match = str.match(
    /^\s*rgba\(\s*(?<r>[0-9]{1,3})\s*,\s*(?<g>[0-9]{1,3})\s*,\s*(?<b>[0-9]{1,3})\s*,\s*var/
  )

  if (match) {
    return new TinyColor({
      r: match.groups.r,
      g: match.groups.g,
      b: match.groups.b,
    })
  }

  return new TinyColor(str)
}