<?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 RectorPrefix202509\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 is_string;
use function key;
use function min;
use function preg_split;
use function prev;
use function reset;
use function str_ends_with;
use function substr;
use RectorPrefix202509\SebastianBergmann\Diff\Output\DiffOutputBuilderInterface;
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;
    private DiffOutputBuilderInterface $outputBuilder;
    public function __construct(DiffOutputBuilderInterface $outputBuilder)
    {
        $this->outputBuilder = $outputBuilder;
    }
    /**
     * @param list<string>|string $from
     * @param list<string>|string $to
     */
    public function diff($from, $to, ?LongestCommonSubsequenceCalculator $lcs = null) : string
    {
        $diff = $this->diffToArray($from, $to, $lcs);
        return $this->outputBuilder->getDiff($diff);
    }
    /**
     * @param list<string>|string $from
     * @param list<string>|string $to
     */
    public function diffToArray($from, $to, ?LongestCommonSubsequenceCalculator $lcs = null) : array
    {
        if (is_string($from)) {
            $from = $this->splitStringByLines($from);
        }
        if (is_string($to)) {
            $to = $this->splitStringByLines($to);
        }
        [$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;
    }
    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();
    }
    /**
     * @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;
    }
    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" !== $lc) {
            return '';
        }
        if (\substr_compare($line, "\r\n", -\strlen("\r\n")) === 0) {
            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];
    }
}
