<?php

namespace Gettext\Utils;

use Gettext\Extractors\PhpCode;

class PhpFunctionsScanner extends FunctionsScanner
{
    /**
     * PHP tokens of the code to be parsed.
     *
     * @var array
     */
    protected $tokens;

    /**
     * If not false, comments will be extracted.
     *
     * @var string|false|array
     */
    protected $extractComments = false;

    /**
     * Enable extracting comments that start with a tag (if $tag is empty all the comments will be extracted).
     *
     * @param mixed $tag
     */
    public function enableCommentsExtraction($tag = '')
    {
        $this->extractComments = $tag;
    }

    /**
     * Disable comments extraction.
     */
    public function disableCommentsExtraction()
    {
        $this->extractComments = false;
    }

    /**
     * Constructor.
     *
     * @param string $code The php code to scan
     */
    public function __construct($code)
    {
        $this->tokens = array_values(
            array_filter(
                token_get_all($code),
                function ($token) {
                    return !is_array($token) || $token[0] !== T_WHITESPACE;
                }
            )
        );
    }

    /**
     * {@inheritdoc}
     */
    public function getFunctions(array $constants = [])
    {
        $count = count($this->tokens);
        /* @var ParsedFunction[] $bufferFunctions */
        $bufferFunctions = [];
        /* @var ParsedComment[] $bufferComments */
        $bufferComments = [];
        /* @var array $functions */
        $functions = [];

        for ($k = 0; $k < $count; ++$k) {
            $value = $this->tokens[$k];

            if (is_string($value)) {
                if (isset($bufferFunctions[0])) {
                    switch ($value) {
                        case ',':
                            $bufferFunctions[0]->nextArgument();
                            break;
                        case ')':
                            $functions[] = array_shift($bufferFunctions)->close();
                            break;
                        case '.':
                            break;
                        default:
                            $bufferFunctions[0]->stopArgument();
                            break;
                    }
                }
                continue;
            }

            switch ($value[0]) {
                case T_CONSTANT_ENCAPSED_STRING:
                    //add an argument to the current function
                    if (isset($bufferFunctions[0])) {
                        $bufferFunctions[0]->addArgumentChunk(PhpCode::convertString($value[1]));
                    }
                    break;

                case T_STRING:
                    if (isset($bufferFunctions[0])) {
                        if (isset($constants[$value[1]])) {
                            $bufferFunctions[0]->addArgumentChunk($constants[$value[1]]);
                            break;
                        }

                        if (strtolower($value[1]) === 'null') {
                            $bufferFunctions[0]->addArgumentChunk(null);
                            break;
                        }

                        $bufferFunctions[0]->stopArgument();
                    }

                    //new function found
                    for ($j = $k + 1; $j < $count; ++$j) {
                        $nextToken = $this->tokens[$j];

                        if (is_array($nextToken) && $nextToken[0] === T_COMMENT) {
                            continue;
                        }

                        if ($nextToken === '(') {
                            $newFunction = new ParsedFunction($value[1], $value[2]);

                            // add comment that was on the line before.
                            if (isset($bufferComments[0])) {
                                $comment = $bufferComments[0];

                                if ($comment->isRelatedWith($newFunction)) {
                                    $newFunction->addComment($comment->getComment());
                                }
                            }

                            array_unshift($bufferFunctions, $newFunction);
                            $k = $j;
                        }
                        break;
                    }
                    break;

                case T_COMMENT:
                    $comment = $this->parsePhpComment($value[1], $value[2]);

                    if ($comment) {
                        array_unshift($bufferComments, $comment);

                        // The comment is inside the function call.
                        if (isset($bufferFunctions[0])) {
                            $bufferFunctions[0]->addComment($comment->getComment());
                        }
                    }
                    break;

                default:
                    if (isset($bufferFunctions[0])) {
                        $bufferFunctions[0]->stopArgument();
                    }
                    break;
            }
        }

        return $functions;
    }

    /**
     * Extract the actual text from a PHP comment.
     *
     * If set, only returns comments that match the prefix(es).
     *
     * @param string $value The PHP comment.
     * @param int $line Line number.
     *
     * @return null|ParsedComment Comment or null if comment extraction is disabled or if there is a prefix mismatch.
     */
    protected function parsePhpComment($value, $line)
    {
        if ($this->extractComments === false) {
            return null;
        }

        //this returns a comment or null
        $comment = ParsedComment::create($value, $line);

        $prefixes = array_filter((array) $this->extractComments);

        if ($comment && $comment->checkPrefixes($prefixes)) {
            return $comment;
        }

        return null;
    }
}
