<?php declare(strict_types=1);
/*
 * This file is part of sebastian/diff.
 *
 * (c) Sebastian Bergmann <sebastian@phpunit.de>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace SebastianBergmann\Diff;

use const PHP_INT_SIZE;
use const PREG_SPLIT_DELIM_CAPTURE;
use const PREG_SPLIT_NO_EMPTY;
use function array_shift;
use function array_unshift;
use function array_values;
use function count;
use function current;
use function end;
use function get_class;
use function gettype;
use function is_array;
use function is_object;
use function is_string;
use function key;
use function min;
use function preg_split;
use function prev;
use function reset;
use function sprintf;
use function substr;
use SebastianBergmann\Diff\Output\DiffOutputBuilderInterface;
use SebastianBergmann\Diff\Output\UnifiedDiffOutputBuilder;

final class Differ
{
    public const OLD                     = 0;

    public const ADDED                   = 1;

    public const REMOVED                 = 2;

    public const DIFF_LINE_END_WARNING   = 3;

    public const NO_LINE_END_EOF_WARNING = 4;

    /**
     * @var DiffOutputBuilderInterface
     */
    private $outputBuilder;

    /**
     * @param DiffOutputBuilderInterface $outputBuilder
     *
     * @throws InvalidArgumentException
     */
    public function __construct($outputBuilder = null)
    {
        if ($outputBuilder instanceof DiffOutputBuilderInterface) {
            $this->outputBuilder = $outputBuilder;
        } elseif (null === $outputBuilder) {
            $this->outputBuilder = new UnifiedDiffOutputBuilder;
        } elseif (is_string($outputBuilder)) {
            // PHPUnit 6.1.4, 6.2.0, 6.2.1, 6.2.2, and 6.2.3 support
            // @see https://github.com/sebastianbergmann/phpunit/issues/2734#issuecomment-314514056
            // @deprecated
            $this->outputBuilder = new UnifiedDiffOutputBuilder($outputBuilder);
        } else {
            throw new InvalidArgumentException(
                sprintf(
                    'Expected builder to be an instance of DiffOutputBuilderInterface, <null> or a string, got %s.',
                    is_object($outputBuilder) ? 'instance of "' . get_class($outputBuilder) . '"' : gettype($outputBuilder) . ' "' . $outputBuilder . '"'
                )
            );
        }
    }

    /**
     * Returns the diff between two arrays or strings as string.
     *
     * @param array|string $from
     * @param array|string $to
     */
    public function diff($from, $to, ?LongestCommonSubsequenceCalculator $lcs = null): string
    {
        $diff = $this->diffToArray(
            $this->normalizeDiffInput($from),
            $this->normalizeDiffInput($to),
            $lcs
        );

        return $this->outputBuilder->getDiff($diff);
    }

    /**
     * Returns the diff between two arrays or strings as array.
     *
     * Each array element contains two elements:
     *   - [0] => mixed $token
     *   - [1] => 2|1|0
     *
     * - 2: REMOVED: $token was removed from $from
     * - 1: ADDED: $token was added to $from
     * - 0: OLD: $token is not changed in $to
     *
     * @param array|string                       $from
     * @param array|string                       $to
     * @param LongestCommonSubsequenceCalculator $lcs
     */
    public function diffToArray($from, $to, ?LongestCommonSubsequenceCalculator $lcs = null): array
    {
        if (is_string($from)) {
            $from = $this->splitStringByLines($from);
        } elseif (!is_array($from)) {
            throw new InvalidArgumentException('"from" must be an array or string.');
        }

        if (is_string($to)) {
            $to = $this->splitStringByLines($to);
        } elseif (!is_array($to)) {
            throw new InvalidArgumentException('"to" must be an array or string.');
        }

        [$from, $to, $start, $end] = self::getArrayDiffParted($from, $to);

        if ($lcs === null) {
            $lcs = $this->selectLcsImplementation($from, $to);
        }

        $common = $lcs->calculate(array_values($from), array_values($to));
        $diff   = [];

        foreach ($start as $token) {
            $diff[] = [$token, self::OLD];
        }

        reset($from);
        reset($to);

        foreach ($common as $token) {
            while (($fromToken = reset($from)) !== $token) {
                $diff[] = [array_shift($from), self::REMOVED];
            }

            while (($toToken = reset($to)) !== $token) {
                $diff[] = [array_shift($to), self::ADDED];
            }

            $diff[] = [$token, self::OLD];

            array_shift($from);
            array_shift($to);
        }

        while (($token = array_shift($from)) !== null) {
            $diff[] = [$token, self::REMOVED];
        }

        while (($token = array_shift($to)) !== null) {
            $diff[] = [$token, self::ADDED];
        }

        foreach ($end as $token) {
            $diff[] = [$token, self::OLD];
        }

        if ($this->detectUnmatchedLineEndings($diff)) {
            array_unshift($diff, ["#Warning: Strings contain different line endings!\n", self::DIFF_LINE_END_WARNING]);
        }

        return $diff;
    }

    /**
     * Casts variable to string if it is not a string or array.
     *
     * @return array|string
     */
    private function normalizeDiffInput($input)
    {
        if (!is_array($input) && !is_string($input)) {
            return (string) $input;
        }

        return $input;
    }

    /**
     * Checks if input is string, if so it will split it line-by-line.
     */
    private function splitStringByLines(string $input): array
    {
        return preg_split('/(.*\R)/', $input, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
    }

    private function selectLcsImplementation(array $from, array $to): LongestCommonSubsequenceCalculator
    {
        // We do not want to use the time-efficient implementation if its memory
        // footprint will probably exceed this value. Note that the footprint
        // calculation is only an estimation for the matrix and the LCS method
        // will typically allocate a bit more memory than this.
        $memoryLimit = 100 * 1024 * 1024;

        if ($this->calculateEstimatedFootprint($from, $to) > $memoryLimit) {
            return new MemoryEfficientLongestCommonSubsequenceCalculator;
        }

        return new TimeEfficientLongestCommonSubsequenceCalculator;
    }

    /**
     * Calculates the estimated memory footprint for the DP-based method.
     *
     * @return float|int
     */
    private function calculateEstimatedFootprint(array $from, array $to)
    {
        $itemSize = PHP_INT_SIZE === 4 ? 76 : 144;

        return $itemSize * min(count($from), count($to)) ** 2;
    }

    /**
     * Returns true if line ends don't match in a diff.
     */
    private function detectUnmatchedLineEndings(array $diff): bool
    {
        $newLineBreaks = ['' => true];
        $oldLineBreaks = ['' => true];

        foreach ($diff as $entry) {
            if (self::OLD === $entry[1]) {
                $ln                 = $this->getLinebreak($entry[0]);
                $oldLineBreaks[$ln] = true;
                $newLineBreaks[$ln] = true;
            } elseif (self::ADDED === $entry[1]) {
                $newLineBreaks[$this->getLinebreak($entry[0])] = true;
            } elseif (self::REMOVED === $entry[1]) {
                $oldLineBreaks[$this->getLinebreak($entry[0])] = true;
            }
        }

        // if either input or output is a single line without breaks than no warning should be raised
        if (['' => true] === $newLineBreaks || ['' => true] === $oldLineBreaks) {
            return false;
        }

        // two way compare
        foreach ($newLineBreaks as $break => $set) {
            if (!isset($oldLineBreaks[$break])) {
                return true;
            }
        }

        foreach ($oldLineBreaks as $break => $set) {
            if (!isset($newLineBreaks[$break])) {
                return true;
            }
        }

        return false;
    }

    private function getLinebreak($line): string
    {
        if (!is_string($line)) {
            return '';
        }

        $lc = substr($line, -1);

        if ("\r" === $lc) {
            return "\r";
        }

        if ("\n" !== $lc) {
            return '';
        }

        if ("\r\n" === substr($line, -2)) {
            return "\r\n";
        }

        return "\n";
    }

    private static function getArrayDiffParted(array &$from, array &$to): array
    {
        $start = [];
        $end   = [];

        reset($to);

        foreach ($from as $k => $v) {
            $toK = key($to);

            if ($toK === $k && $v === $to[$k]) {
                $start[$k] = $v;

                unset($from[$k], $to[$k]);
            } else {
                break;
            }
        }

        end($from);
        end($to);

        do {
            $fromK = key($from);
            $toK   = key($to);

            if (null === $fromK || null === $toK || current($from) !== current($to)) {
                break;
            }

            prev($from);
            prev($to);

            $end = [$fromK => $from[$fromK]] + $end;
            unset($from[$fromK], $to[$toK]);
        } while (true);

        return [$from, $to, $start, $end];
    }
}

• [D] Exception
• [D] Output
• [F] Chunk.php
  Delete
• [F] Diff.php
  Delete
• [F] Differ.php
  Delete
• [F] Line.php
  Delete
• [F] LongestCommonSubsequenceCalculator.php
  Delete
• [F] MemoryEfficientLongestCommonSubsequenceCalculator.php
  Delete
• [F] Parser.php
  Delete
• [F] TimeEfficientLongestCommonSubsequenceCalculator.php
  Delete

About Section

About NFC Pay: Our Story and Mission

NFC Pay was founded with a vision to transform the way people handle transactions. Our journey is defined by a commitment to innovation, security, and convenience. We strive to deliver seamless, user-friendly payment solutions that make everyday transactions effortless and secure. Our mission is to empower you to pay with ease and confidence, anytime, anywhere.

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FAQ Section

Frequently Asked Questions About NFC Pay

Here are answers to some common questions about NFC Pay. We aim to provide clear and concise information to help you understand how our platform works and how it can benefit you. If you have any further inquiries, please don’t hesitate to contact our support team.

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