import { oklch } from "culori"
import type { Transform } from "style-dictionary/types"
import { isShadow } from "../filters/isShadow"
import { getValue } from "../helpers/get"
import type { TokenUnit } from "../helpers/interfaces"

type TokenShadow = {
  color: string
  offsetX: TokenUnit
  offsetY: TokenUnit
  blur: TokenUnit
  spread: TokenUnit
  inset: boolean
}

const formatShadow = ({
  offsetX = { value: 0, unit: "px" },
  offsetY = { value: 0, unit: "px" },
  blur = { value: 0, unit: "px" },
  spread = { value: 0, unit: "px" },
  color,
  inset = false,
}: TokenShadow): string => {
  const oklchColor = oklch(color)
  if (!oklchColor) {
    throw new Error("Invalid color value")
  }
  const l = Math.round(oklchColor.l * 1000) / 10
  const c = Math.round(oklchColor.c * 10000) / 100
  const h = Math.round((oklchColor?.h ?? 0) * 10) / 10
  const result = `oklch(${l}% ${c} ${h} / ${oklchColor.alpha})`

  return `${offsetX.value}${offsetX.unit} ${offsetY.value}${offsetY.unit} ${blur.value}${blur.unit} ${spread.value}${spread.unit} ${result} ${inset ? "inset" : ""}`.trim()
}

export function transformShadow(tokenValue: TokenShadow): string {
  if (Array.isArray(tokenValue)) {
    const shadow = tokenValue.map(formatShadow).join(", ")
    return shadow
  }

  if (typeof tokenValue === "object") {
    const shadow = formatShadow(tokenValue)
    return shadow
  }

  return tokenValue
}

export const shadowCssTransform: Transform = {
  name: "shadow/css-shorthand-dtcg",
  type: "value",
  transitive: true,
  filter: isShadow,
  transform: (token, _, options) => {
    const tokenValue = getValue<TokenShadow>(token, options, { useOriginalValue: true })
    return transformShadow(tokenValue)
  },
}