<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Console\Output;

use Symfony\Component\Console\Exception\InvalidArgumentException;

/**
 * @author Fabien Potencier <fabien@symfony.com>
 * @author Julien Boudry <julien@condorcet.vote>
 */
enum AnsiColorMode
{
    /*
     * Classical 4-bit Ansi colors, including 8 classical colors and 8 bright color. Output syntax is "ESC[${foreGroundColorcode};${backGroundColorcode}m"
     * Must be compatible with all terminals and it's the minimal version supported.
     */
    case Ansi4;

    /*
     * 8-bit Ansi colors (240 differents colors + 16 duplicate color codes, ensuring backward compatibility).
     * Output syntax is: "ESC[38;5;${foreGroundColorcode};48;5;${backGroundColorcode}m"
     * Should be compatible with most terminals.
     */
    case Ansi8;

    /*
     * 24-bit Ansi colors (RGB).
     * Output syntax is: "ESC[38;2;${foreGroundColorcodeRed};${foreGroundColorcodeGreen};${foreGroundColorcodeBlue};48;2;${backGroundColorcodeRed};${backGroundColorcodeGreen};${backGroundColorcodeBlue}m"
     * May be compatible with many modern terminals.
     */
    case Ansi24;

    /**
     * Converts an RGB hexadecimal color to the corresponding Ansi code.
     */
    public function convertFromHexToAnsiColorCode(string $hexColor): string
    {
        $hexColor = str_replace('#', '', $hexColor);

        if (3 === \strlen($hexColor)) {
            $hexColor = $hexColor[0].$hexColor[0].$hexColor[1].$hexColor[1].$hexColor[2].$hexColor[2];
        }

        if (6 !== \strlen($hexColor)) {
            throw new InvalidArgumentException(sprintf('Invalid "#%s" color.', $hexColor));
        }

        $color = hexdec($hexColor);

        $r = ($color >> 16) & 255;
        $g = ($color >> 8) & 255;
        $b = $color & 255;

        return match ($this) {
            self::Ansi4 => (string) $this->convertFromRGB($r, $g, $b),
            self::Ansi8 => '8;5;'.((string) $this->convertFromRGB($r, $g, $b)),
            self::Ansi24 => sprintf('8;2;%d;%d;%d', $r, $g, $b)
        };
    }

    private function convertFromRGB(int $r, int $g, int $b): int
    {
        return match ($this) {
            self::Ansi4 => $this->degradeHexColorToAnsi4($r, $g, $b),
            self::Ansi8 => $this->degradeHexColorToAnsi8($r, $g, $b),
            default => throw new InvalidArgumentException("RGB cannot be converted to {$this->name}.")
        };
    }

    private function degradeHexColorToAnsi4(int $r, int $g, int $b): int
    {
        if (0 === round($this->getSaturation($r, $g, $b) / 50)) {
            return 0;
        }

        return (int) ((round($b / 255) << 2) | (round($g / 255) << 1) | round($r / 255));
    }

    private function getSaturation(int $r, int $g, int $b): int
    {
        $r = $r / 255;
        $g = $g / 255;
        $b = $b / 255;
        $v = max($r, $g, $b);

        if (0 === $diff = $v - min($r, $g, $b)) {
            return 0;
        }

        return (int) ((int) $diff * 100 / $v);
    }

    /**
     * Inspired from https://github.com/ajalt/colormath/blob/e464e0da1b014976736cf97250063248fc77b8e7/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/Ansi256.kt code (MIT license).
     */
    private function degradeHexColorToAnsi8(int $r, int $g, int $b): int
    {
        if ($r === $g && $g === $b) {
            if ($r < 8) {
                return 16;
            }

            if ($r > 248) {
                return 231;
            }

            return (int) round(($r - 8) / 247 * 24) + 232;
        } else {
            return 16 +
                    (36 * (int) round($r / 255 * 5)) +
                    (6 * (int) round($g / 255 * 5)) +
                    (int) round($b / 255 * 5);
        }
    }
}
