import std/parseutils
import std/strformat

import ./math/vector

func hexToColor*(value: string): Vec3f =
  assert value != ""
  var hex = value
  if hex[0] == '#':
    hex = hex[1 .. ^0]
  assert hex.len == 3 or hex.len == 6
  if hex.len == 3:
    hex = hex[0] & hex[0] & hex[1] & hex[1] & hex[2] & hex[2]
  var r, g, b: uint8
  assert hex.len == 6
  discard parseHex(hex[0 .. 1], r) == 2
  discard parseHex(hex[2 .. 3], g) == 2
  discard parseHex(hex[4 .. 5], b) == 2
  return Vec3f([float32(r), float32(g), float32(b)]) / 255'f

func colorToHex*(color: Vec3f): string =
  &"{int(color.r * 255):02X}{int(color.g * 255):02X}{int(color.b * 255):02X}"

func colorToHex*(color: Vec4f): string =
  &"{int(color.r * 255):02X}{int(color.g * 255):02X}{int(color.b * 255):02X}{int(color.a * 255):02X}"

func hexToColorAlpha*(value: string): Vec4f =
  assert value != ""
  var hex = value
  if hex[0] == '#':
    hex = hex[1 .. ^0]
  # when 3 or 6 -> set alpha to 1.0
  assert hex.len == 3 or hex.len == 6 or hex.len == 4 or hex.len == 8
  if hex.len == 3:
    hex = hex & "f"
  if hex.len == 4:
    hex = hex[0] & hex[0] & hex[1] & hex[1] & hex[2] & hex[2] & hex[3] & hex[3]
  if hex.len == 6:
    hex = hex & "ff"
  assert hex.len == 8
  var r, g, b, a: uint8
  discard parseHex(hex[0 .. 1], r)
  discard parseHex(hex[2 .. 3], g)
  discard parseHex(hex[4 .. 5], b)
  discard parseHex(hex[6 .. 7], a)
  return Vec4f([float32(r), float32(g), float32(b), float32(a)]) / 255'f

func gamma*[T: Vec3f|Vec4f](color: T, gamma: float32): T =
  return pow(color, gamma)