<?php

/*
 * This file is part of Twig.
 *
 * (c) Fabien Potencier
 * (c) Armin Ronacher
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Twig;

use Twig\Node\Node;

/**
 * @author Fabien Potencier <fabien@symfony.com>
 */
class Compiler
{
    private ?int $lastLine;
    private string $source;
    private int $indentation;
    private array $debugInfo;
    private int $sourceOffset;
    private int $sourceLine;
    private int $varNameSalt;

    public function __construct(
        private Environment $env,
    ) {
        $this->reset();
    }

    public function getEnvironment(): Environment
    {
        return $this->env;
    }

    public function getSource(): string
    {
        return $this->source;
    }

    /**
     * @return $this
     */
    public function reset(int $indentation = 0)
    {
        $this->lastLine = null;
        $this->source = '';
        $this->debugInfo = [];
        $this->sourceOffset = 0;
        // source code starts at 1 (as we then increment it when we encounter new lines)
        $this->sourceLine = 1;
        $this->indentation = $indentation;
        $this->varNameSalt = 0;

        return $this;
    }

    /**
     * @return $this
     */
    public function compile(Node $node, int $indentation = 0)
    {
        $this->reset($indentation);
        $node->compile($this);

        return $this;
    }

    /**
     * @return $this
     */
    public function subcompile(Node $node, bool $raw = true)
    {
        if (!$raw) {
            $this->source .= str_repeat(' ', $this->indentation * 4);
        }

        $node->compile($this);

        return $this;
    }

    /**
     * Adds a raw string to the compiled code.
     *
     * @return $this
     */
    public function raw(string $string)
    {
        $this->source .= $string;

        return $this;
    }

    /**
     * Writes a string to the compiled code by adding indentation.
     *
     * @return $this
     */
    public function write(...$strings)
    {
        foreach ($strings as $string) {
            $this->source .= str_repeat(' ', $this->indentation * 4).$string;
        }

        return $this;
    }

    /**
     * Adds a quoted string to the compiled code.
     *
     * @return $this
     */
    public function string(string $value)
    {
        // Single quotes are encoded as \x27 (not \') as a defense-in-depth measure:
        // it guarantees that the compiled output never contains a literal "'" derived
        // from user input, which prevents breaking out of a surrounding single-quoted
        // PHP context if a caller mistakenly concatenates the result into one.
        // \' is not a recognized escape sequence in PHP double-quoted strings (the
        // backslash would be kept literally), so \x27 is used instead.
        $this->source .= \sprintf('"%s"', str_replace("'", '\\x27', addcslashes($value, "\0\t\"\$\\")));

        return $this;
    }

    /**
     * Returns a PHP representation of a given value.
     *
     * @return $this
     */
    public function repr($value)
    {
        if (\is_int($value) || \is_float($value)) {
            if (false !== $locale = setlocale(\LC_NUMERIC, '0')) {
                setlocale(\LC_NUMERIC, 'C');
            }

            $this->raw(var_export($value, true));

            if (false !== $locale) {
                setlocale(\LC_NUMERIC, $locale);
            }
        } elseif (null === $value) {
            $this->raw('null');
        } elseif (\is_bool($value)) {
            $this->raw($value ? 'true' : 'false');
        } elseif (\is_array($value)) {
            $this->raw('[');
            $first = true;
            foreach ($value as $key => $v) {
                if (!$first) {
                    $this->raw(', ');
                }
                $first = false;
                $this->repr($key);
                $this->raw(' => ');
                $this->repr($v);
            }
            $this->raw(']');
        } else {
            $this->string($value);
        }

        return $this;
    }

    /**
     * @return $this
     */
    public function addDebugInfo(Node $node)
    {
        if ($node->getTemplateLine() != $this->lastLine) {
            $this->write(\sprintf("// line %d\n", $node->getTemplateLine()));

            $this->sourceLine += substr_count($this->source, "\n", $this->sourceOffset);
            $this->sourceOffset = \strlen($this->source);
            $this->debugInfo[$this->sourceLine] = $node->getTemplateLine();

            $this->lastLine = $node->getTemplateLine();
        }

        return $this;
    }

    public function getDebugInfo(): array
    {
        ksort($this->debugInfo);

        return $this->debugInfo;
    }

    /**
     * @return $this
     */
    public function indent(int $step = 1)
    {
        $this->indentation += $step;

        return $this;
    }

    /**
     * @return $this
     *
     * @throws \LogicException When trying to outdent too much so the indentation would become negative
     */
    public function outdent(int $step = 1)
    {
        // can't outdent by more steps than the current indentation level
        if ($this->indentation < $step) {
            throw new \LogicException('Unable to call outdent() as the indentation would become negative.');
        }

        $this->indentation -= $step;

        return $this;
    }

    public function getVarName(): string
    {
        return \sprintf('_v%d', $this->varNameSalt++);
    }
}