<?php

namespace Tell;

class I18n implements MissingKeyInterface
{
    const DELIMITER = '.';

    protected string $locale = "en_US";

    protected string $language = "";

    protected array $data = [];

    protected array $fileStack = [];

    protected string $currentLanguage = "";

    protected Reader\ReaderInterface $dataReader;

    protected ? Reader\ReaderInterface $cacheReader = null;

    protected ? MissingKeyInterface $missingKey = null;

    public function __construct(
        Reader\ReaderInterface $dataReader,
        ? Reader\ReaderInterface $cacheReader = null,
        ? MissingKeyInterface $missingKey = null
    )
    {
        $this->dataReader = $dataReader;
        $this->cacheReader = $cacheReader;
        $this->missingKey = $missingKey;
    }

    public function initialize(bool $useCache) : bool
    {
        $loaded = $useCache && $this->fromReader($this->cacheReader) ?: $this->fromReader($this->dataReader);

        if ( ! $useCache ) {
            $this->cacheReader->save($this->locale, $this->data);
        }

        return $loaded;
    }

    public function fromKey(string $key, array $variables) : ?string
    {
        if ( null === ( $string = $this->get($key) ) ) {
            $string = $this->missingKey ? $this->missingKey->get($key) : null;            
        }
            
        if (is_array($string)) {
            $string = json_encode($string);
        }
                    
        return $string && $variables ? $this->placeVariables($string, $variables) : $string;
    }

    public function get(string $key)
    {
        # Testing full locale key first
        if ( null === ( $string = Iterate::arrayGet($this->data, "{$this->locale}.$key", static::DELIMITER)) ) {
            # Fallback on language only
            $string = Iterate::arrayGet($this->data, "{$this->language}.$key", static::DELIMITER);
        }

        return $string;
    }

    public function set(string $key, $value)
    {
        $cache = explode(static::DELIMITER, $key);

        while ( ! empty($cache) ) {
            $imp = implode(static::DELIMITER, $cache);
            array_pop($cache);
            unset( $this->cache[$imp] );
        }

        $this->cache[$key] = $value;

        return Iterate::arraySet($this->data, $key, $value, static::DELIMITER);
    }

    public function locale(?string $set = null)
    {
        $locale = $set === null ? ( $this->locale ?? null ) : $this->locale = strtolower(explode(".", $this->locale)[0]);

        if ( $set !== null ) {
            $this->language = explode('_', $locale)[0];
        }

        return $locale;
    }

    protected function mergeData($data) : void
    {
        $this->data = array_replace_recursive($this->data, Iterate::splitKeys($data));
    }

    protected function fromReader(Reader\ReaderInterface $reader) : bool
    {
        foreach($reader->pathList as $path) {
            foreach(Iterate::files($path) as $item) {
                if ( $reader->accept($item->getExtension() )) {
                    if ( null !== ( $data = $reader->load( $item ) )) {

                        if ( $reader->filenameAsKey ) {
                            # Adding folder to full key
                            $filekey = ltrim(substr($item->getPathname(), strlen($path)), DIRECTORY_SEPARATOR);

                            # Removing extension
                            $filekey = substr($filekey, 0, strrpos($filekey, '.'));

                            # Replacing directory separator with dots
                            $filekey = str_replace(DIRECTORY_SEPARATOR, '.', $filekey);

                            $this->mergeData([ '{' . $filekey . '}' => $data ]);
                        }
                        else {
                            $this->mergeData($data);
                        }
                    }
                }
            }
        }

        return false;
    }

    protected function placeVariables(string $string, array $parameters) {
        if ( preg_match_all('~{$(.*?)}~si', $string, $matches, PREG_SET_ORDER) ) {
            $search = [];

            foreach($matches as $item) {
                $search[ $item[0] ] = Iterate::arrayGet($parameters, $item[1]);
            }

            return str_replace(array_keys($search), array_values($search), $string);
        }

        return $string;
    }
}