class Template

final class Template {
    private string $template = '';
    private string $openDelimiter;
    private string $closeDelimiter;
    
    /**
     * @psalm-var array<string,string>
     */
    private array $values = [];
    
    /**
     * @throws InvalidArgumentException
     */
    public function __construct(string $file = '', string $openDelimiter = '{', string $closeDelimiter = '}') {
        $this->setFile($file);
        $this->openDelimiter = $openDelimiter;
        $this->closeDelimiter = $closeDelimiter;
    }
    
    /**
     * @throws InvalidArgumentException
     */
    public function setFile(string $file) : void {
        if (is_file($file)) {
            $this->template = file_get_contents($file);
            return;
        }
        $distFile = $file . '.dist';
        if (is_file($distFile)) {
            $this->template = file_get_contents($distFile);
            return;
        }
        throw new InvalidArgumentException(sprintf('Failed to load template "%s"', $file));
    }
    
    /**
     * @psalm-param array<string,string> $values
     */
    public function setVar(array $values, bool $merge = true) : void {
        if (!$merge || empty($this->values)) {
            $this->values = $values;
            return;
        }
        $this->values = array_merge($this->values, $values);
    }
    public function render() : string {
        $keys = [];
        foreach (array_keys($this->values) as $key) {
            $keys[] = $this->openDelimiter . $key . $this->closeDelimiter;
        }
        return str_replace($keys, $this->values, $this->template);
    }
    
    /**
     * @codeCoverageIgnore
     */
    public function renderTo(string $target) : void {
        if (!@file_put_contents($target, $this->render())) {
            throw new RuntimeException(sprintf('Writing rendered result to "%s" failed', $target));
        }
    }

}