#!/usr/bin/env php
<?php

define('VERSION', '1.0.24');
define('DEFAULT_PIXEL', "\xE2\x96\x84");
define('RC', "\e[0m");
define('RCNL', RC . PHP_EOL);
define('CURRENT_FILE', array_shift($argv));

error_reporting(0);

if (PHP_MAJOR_VERSION < 7) {
    die('Minimum PHP v7.0' . PHP_EOL);
}

// --------------------------------------------------------
// Flags in use

$flags = [
    '-h' => [
        'value' => false,
        'value_required' => false,
        'description' => 'Show this help message',
        'callback' => null
    ],
    '-v' => [
        'value' => false,
        'value_required' => false,
        'description' => 'Show version',
        'callback' => function () {
            echo colorHelp(sprintf("Paint (`%s`) v%s, (c) 2017-2018 <robopuff>\n", CURRENT_FILE, VERSION));
            return false;
        }
    ],
    '-b' => [
        'value' => true,
        'value_required' => false,
        'description' => 'Resize to [VALUE] box, if no value provided then terminal height is used',
        'callback' => function (&$width, &$height, $value = null) {
            if ($value) {
                $height = $value;
            } else {
                $height = ((int)exec('tput lines'));
            }

            $width = $height;
        }
    ],
    '-w' => [
        'value' => true,
        'value_required' => true,
        'description' => 'Set width',
        'callback' => function (&$width, $_, $value) {
            $width = $value;
        }
    ],
    '-t' => [
        'value' => false,
        'value_required' => false,
        'description' => 'Test terminal color & font capabilities. It should show two lines of different color.',
        'callback' => function () {
            echo drawChar([255,80,105], [105, 80, 255]) . str_repeat(DEFAULT_PIXEL, 3) . RC .
                drawChar([105, 80, 255], [255,80,105]) . str_repeat(DEFAULT_PIXEL, 3) . RC .
                ' ' . drawChar([105, 80, 255], [255, 80, 105]) . RC . drawChar([255, 80, 105], [105, 80, 255]) . RC .
                ' ' . drawChar([105, 80, 255], [255, 80, 105]) . RC .
                ' -' . DEFAULT_PIXEL . drawChar([255, 80, 105], [105, 80, 255]) . RC . DEFAULT_PIXEL . '-' .
                ' ' . drawChar([255, 80, 105], [255, 80, 105]) . RC . DEFAULT_PIXEL . PHP_EOL;
            return false;
        }
    ],
    '-x' => [
        'value' => true,
        'value_required' => true,
        'description' => 'Pixelate image before showing'
    ],
    '-p' => [
        'value' => false,
        'value_required' => false,
        'description' => 'Draw palette of colours, good for terminal test',
        'callback' => function ($width, $height, $_, $context) {
            $source = imagecreatetruecolor(255, 255);

            for ($y = 0; $y < 255; $y++) {
                for ($x = 0; $x < 255 * 2; $x++) {
                    $r = 255 - $x;
                    $g = 255 - $y;
                    $b = (($x + $y) / 2);
                    imagesetpixel($source, $x, $y, imagecolorallocate($source, $r, $g, $b));
                }
            }
            drawImage($source, 255, 255, $width, $height, $context);
            return false;
        }
    ],
    '-f' => [
        'value' => true,
        'value_required' => true,
        'description' => 'Draw image provided in [VALUE], can combine with `-b, -w` but `-f` must be provided last.' .
                         ' Can be skipped if <FILE> is provided.',
        'callback' => function ($width, $height, $value, $context) {
            $content = null;
            if (!$value) {
                throw new \Exception('Improper usage of `-f`, should be `-f`=[IMAGE]');
            }

            if (strpos($value, 'http') === 0 || strpos($value, 'ftp') === 0) {
                $curl = curl_init($value);
                curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
                curl_setopt($curl, CURLOPT_HEADER, false);
                $content = curl_exec($curl);
                curl_close($curl);
            } elseif (!file_exists($value) || !is_readable($value)) {
                throw new \Exception("Cannot find file `{$value}`", 0x1f1);
            }

            if (!$content) {
                $content = file_get_contents($value);
            }

            $source = imagecreatefromstring($content);

            if (!$source) {
                throw new \Exception("Cannot read `{$value}` as image", 0x1f2);
            }

            $imW = imagesx($source);
            $imH = imagesy($source);
            imagefilter($source, IMG_FILTER_PIXELATE, 2, true);
            drawImage($source, $imW, $imH, $width, $height, $context);
            imagedestroy($source);
        }
    ]
];

// --------------------------------------------------------
// Helper functions

// Draw single pixel with sub-pixel as lower block char
function drawChar(array $upper, array $lower = [], $char = DEFAULT_PIXEL, $clean = false) // •
{
    if (empty($upper) && empty($lower)) {
        return $char;
    }

    if ($upper == $lower) {
        return drawUpperPixel($upper) .' ' . ($clean ? RC : '');
    }

    return drawUpperPixel($upper) .
           drawLowerPixel(empty($lower) ? $upper : $lower, $char) .
           ($clean ? RC : '');
};

// Draw background color (upper pixel)
function drawUpperPixel(array $color)
{
    $color = implode(';', $color);
    return "\e[48;2;{$color}m";
}

// Draw foreground color (lower pixel)
function drawLowerPixel(array $color = [], $char = DEFAULT_PIXEL)
{
    if (empty($color)) {
        return $char;
    }

    $color = implode(';', $color);
    return "\e[38;2;{$color}m{$char}";
}

// Draw image pixel by pixel (with resize)
function drawImage($source, $imW, $imH, $width, $height, $flags = [])
{
    $r = $imW / $imH;

    if ($height > 0) {
        if ($width > $height) {
            $height = $width / $r;
        } else {
            $width = $height * $r;
        }
    } else {
        $height = $width / $r;
    }

    if ($width > $imW) {
        $width  = $imW;
        $height = $imH;
    }

    $thumb = imagecreatetruecolor($width, $height);
    imagecopyresampled($thumb, $source, 0, 0, 0, 0, $width, $height, $imW, $imH);

    if (isset($flags['-x'])) {
        imagefilter($thumb, IMG_FILTER_PIXELATE, (int)$flags['-x'], true);
    }

    for ($y = 0; $y < imagesy($thumb) - 1; $y++) {
        if ($y % 2 != 0) {
            continue;
        }

        $lastUpper = [];
        $lastLower = [];

        for ($x = 0; $x < imagesx($thumb) - 1; $x++) {
            $c1 = imagecolorat($thumb, $x, $y);
            $c2 = imagecolorat($thumb, $x, $y + 1);

            $upper = [
                ($c1 >> 16) & 0xFF,
                ($c1 >> 8) & 0xFF,
                ($c1) & 0xFF,
            ];

            $lower = $drawLower = [
                ($c2 >> 16) & 0xFF,
                ($c2 >> 8) & 0xFF,
                ($c2) & 0xFF,
            ];

            if ($lastUpper != $upper) {
                echo drawUpperPixel($upper);
            }

            if ($lastLower == $lower) {
                $drawLower = [];
            }

            echo drawLowerPixel($drawLower);

            $lastLower = $lower;
            $lastUpper = $upper;
        }
        echo RCNL;
    }

    imagedestroy($thumb);
}

// Show an error
function showError($error)
{
    echo drawChar([200, 20, 70], [255,255,255], str_repeat(' ', 50)) . "\n";
    echo ' Error occurred' . str_repeat(' ', 50 - 15) . "\n";
    echo str_repeat(' ', 50) . RCNL . PHP_EOL;
    echo '  ' . colorHelp($error)  . "\n\n";
}

// Add color content
function colorHelp($content)
{
    return preg_replace_callback_array([
        '/\[(.*?)\]/' => function ($matches) {
            return drawChar([45, 35, 8], [255, 247, 97], $matches[0], true);
        },
        '/\`(.*?)\`/' => function ($matches) {
            return drawChar([35, 13, 14], [255, 100, 108], " {$matches[1]} ", true);
        },
        '/\<(.*?)\>/' => function ($matches) {
            return drawChar([10, 38, 13], [102, 245, 119], $matches[0], true);
        }
    ], $content);
}

// Show help message
function helpMessage($flags)
{
    echo drawLowerPixel([200, 20, 70], '');
    echo <<<ASCII
      :::::::::     :::    :::::::::::::::    :::::::::::::: 
     :+:    :+:  :+: :+:      :+:    :+:+:   :+:    :+:     
    +:+    +: ++:+   +:+     +:+    :+:+:+  +:+    +:+      
   +#++:++#+ +#++:++#++:    +#+    +#+ +:+ +#+    +#+       
  +#+       +#+     +#+    +#+    +#+  +#+#+#    +#+        
 #+#       #+#     #+#    #+#    #+#   #+#+#    #+#         
###       ###     #################    ####    ###   v
ASCII;
    echo VERSION . RCNL . PHP_EOL;

    $help = sprintf("Usage `%s` [PARAMS] <FILE>\n", CURRENT_FILE);
    foreach ($flags as $flag => $options) {
        $flagHelp = $flag;

        if ($options['value']) {
            if ($options['value_required']) {
                $flagHelp .= "=[VALUE]";
            } else {
                $flagHelp .= ", {$flag}=[VALUE]";
            }
        }

        $help .= "   {$flagHelp}\n      {$options['description']}\n";
    }

    echo colorHelp($help) . PHP_EOL;

    $flags['-v']['callback']();
    return false;
}

$flags['-h']['callback'] = function () use ($flags) {
    return helpMessage($flags);
};

// --------------------------------------------------------
// Terminal operations

$termWidth = (int)exec('tput cols') - 1;
$termHeight = 0;

$file = end($argv);
if ($file[0] != '-' && (file_exists($file) || strpos($file, 'http') === 0)) {
    array_pop($argv);
    $argv[] = "-f={$file}";
}

$context = [];
$callbacks   = [];
foreach (array_unique($argv) as $aid => $arg) {
    $key = $arg;
    $value = null;

    $pos = strpos($arg, '=');

    if ($pos > 0) {
        $key = substr($arg, 0, $pos);
        $value = substr($arg, $pos + 1);
    }

    if (isset($flags[$key])) {
        $context[$key] = $value;

        if (null !== $value && $flags[$key]['value'] === false) {
            showError("Param `{$key}` does not have a value");
            die();
        }

        if (isset($flags[$key]['callback'])) {
            $callbacks[] = [
                $flags[$key]['callback'],
                $value
            ];
        }
    } else {
        showError("Param `{$key}` not found.");
        die();
    }
}

if (empty($callbacks)) {
    if (!empty($context)) {
        showError(sprintf(
            'Provided flags `%s` cannot be used by themselves as they don\'t provide any action.',
            implode(', ', array_keys($context))
        ));
        die();
    }

    helpMessage($flags);
    die();
}

foreach ($callbacks as $vars) {
    [$callback, $value] = $vars;
    try {
        if ($callback($termWidth, $termHeight, $value, $context) === false) {
            break;
        }
    } catch (Throwable $e) {
        showError(sprintf('%s: %s', $e->getCode(), $e->getMessage()));
        die();
    }
}

__halt_compiler();