// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
/**
 * A module to print ANSI terminal colors. Inspired by chalk, kleur, and colors
 * on npm.
 *
 * ```
 * import { bgBlue, red, bold } from "https://deno.land/std/fmt/colors.ts";
 * console.log(bgBlue(red(bold("Hello world!"))));
 * ```
 *
 * This module supports `NO_COLOR` environmental variable disabling any coloring
 * if `NO_COLOR` is set.
 */
const { noColor } = Deno;

interface Code {
  open: string;
  close: string;
  regexp: RegExp;
}

/** RGB 8-bits per channel. Each in range `0->255` or `0x00->0xff` */
interface Rgb {
  r: number;
  g: number;
  b: number;
}

let enabled = !noColor;

export function setColorEnabled(value: boolean): void {
  if (noColor) {
    return;
  }

  enabled = value;
}

export function getColorEnabled(): boolean {
  return enabled;
}

function code(open: number[], close: number): Code {
  return {
    open: `\x1b[${open.join(";")}m`,
    close: `\x1b[${close}m`,
    regexp: new RegExp(`\\x1b\\[${close}m`, "g"),
  };
}

function run(str: string, code: Code): string {
  return enabled
    ? `${code.open}${str.replace(code.regexp, code.open)}${code.close}`
    : str;
}

export function reset(str: string): string {
  return run(str, code([0], 0));
}

export function bold(str: string): string {
  return run(str, code([1], 22));
}

export function dim(str: string): string {
  return run(str, code([2], 22));
}

export function italic(str: string): string {
  return run(str, code([3], 23));
}

export function underline(str: string): string {
  return run(str, code([4], 24));
}

export function inverse(str: string): string {
  return run(str, code([7], 27));
}

export function hidden(str: string): string {
  return run(str, code([8], 28));
}

export function strikethrough(str: string): string {
  return run(str, code([9], 29));
}

export function black(str: string): string {
  return run(str, code([30], 39));
}

export function red(str: string): string {
  return run(str, code([31], 39));
}

export function green(str: string): string {
  return run(str, code([32], 39));
}

export function yellow(str: string): string {
  return run(str, code([33], 39));
}

export function blue(str: string): string {
  return run(str, code([34], 39));
}

export function magenta(str: string): string {
  return run(str, code([35], 39));
}

export function cyan(str: string): string {
  return run(str, code([36], 39));
}

export function white(str: string): string {
  return run(str, code([37], 39));
}

export function gray(str: string): string {
  return run(str, code([90], 39));
}

export function bgBlack(str: string): string {
  return run(str, code([40], 49));
}

export function bgRed(str: string): string {
  return run(str, code([41], 49));
}

export function bgGreen(str: string): string {
  return run(str, code([42], 49));
}

export function bgYellow(str: string): string {
  return run(str, code([43], 49));
}

export function bgBlue(str: string): string {
  return run(str, code([44], 49));
}

export function bgMagenta(str: string): string {
  return run(str, code([45], 49));
}

export function bgCyan(str: string): string {
  return run(str, code([46], 49));
}

export function bgWhite(str: string): string {
  return run(str, code([47], 49));
}

/* Special Color Sequences */

function clampAndTruncate(n: number, max = 255, min = 0): number {
  return Math.trunc(Math.max(Math.min(n, max), min));
}

/** Set text color using paletted 8bit colors.
 * https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit */
export function rgb8(str: string, color: number): string {
  return run(str, code([38, 5, clampAndTruncate(color)], 39));
}

/** Set background color using paletted 8bit colors.
 * https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit */
export function bgRgb8(str: string, color: number): string {
  return run(str, code([48, 5, clampAndTruncate(color)], 49));
}

/** Set text color using 24bit rgb. */
export function rgb24(str: string, color: Rgb): string {
  return run(
    str,
    code(
      [
        38,
        2,
        clampAndTruncate(color.r),
        clampAndTruncate(color.g),
        clampAndTruncate(color.b),
      ],
      39
    )
  );
}

/** Set background color using 24bit rgb. */
export function bgRgb24(str: string, color: Rgb): string {
  return run(
    str,
    code(
      [
        48,
        2,
        clampAndTruncate(color.r),
        clampAndTruncate(color.g),
        clampAndTruncate(color.b),
      ],
      49
    )
  );
}