<?php

declare(strict_types=1);

namespace Laminas\Router\Http;

use Laminas\Router\Exception;
use Laminas\Stdlib\ArrayUtils;
use Laminas\Stdlib\RequestInterface as Request;
use Laminas\Uri\UriInterface;
use Traversable;

use function array_merge;
use function count;
use function is_array;
use function method_exists;
use function preg_match;
use function preg_quote;
use function sprintf;
use function strlen;

/**
 * Hostname route.
 */
class Hostname implements RouteInterface
{
    /**
     * Parts of the route.
     *
     * @var array
     */
    protected $parts;

    /**
     * Regex used for matching the route.
     *
     * @var string
     */
    protected $regex;

    /**
     * Map from regex groups to parameter names.
     *
     * @var array
     */
    protected $paramMap = [];

    /**
     * Default values.
     *
     * @var array
     */
    protected $defaults;

    /**
     * List of assembled parameters.
     *
     * @var array
     */
    protected $assembledParams = [];

    /**
     * Create a new hostname route.
     *
     * @param  string $route
     * @param  array  $constraints
     * @param  array  $defaults
     */
    public function __construct($route, array $constraints = [], array $defaults = [])
    {
        $this->defaults = $defaults;
        $this->parts    = $this->parseRouteDefinition($route);
        $this->regex    = $this->buildRegex($this->parts, $constraints);
    }

    /**
     * factory(): defined by RouteInterface interface.
     *
     * @see    \Laminas\Router\RouteInterface::factory()
     *
     * @param  array|Traversable $options
     * @return Hostname
     * @throws Exception\InvalidArgumentException
     */
    public static function factory($options = [])
    {
        if ($options instanceof Traversable) {
            $options = ArrayUtils::iteratorToArray($options);
        } elseif (! is_array($options)) {
            throw new Exception\InvalidArgumentException(sprintf(
                '%s expects an array or Traversable set of options',
                __METHOD__
            ));
        }

        if (! isset($options['route'])) {
            throw new Exception\InvalidArgumentException('Missing "route" in options array');
        }

        if (! isset($options['constraints'])) {
            $options['constraints'] = [];
        }

        if (! isset($options['defaults'])) {
            $options['defaults'] = [];
        }

        return new static($options['route'], $options['constraints'], $options['defaults']);
    }

    /**
     * Parse a route definition.
     *
     * @param  string $def
     * @return array
     * @throws Exception\RuntimeException
     */
    protected function parseRouteDefinition($def)
    {
        $currentPos = 0;
        $length     = strlen($def);
        $parts      = [];
        $levelParts = [&$parts];
        $level      = 0;

        while ($currentPos < $length) {
            if (! preg_match('(\G(?P<literal>[a-z0-9-.]*)(?P<token>[:{\[\]]|$))', $def, $matches, 0, $currentPos)) {
                throw new Exception\RuntimeException('Matched hostname literal contains a disallowed character');
            }

            $currentPos += strlen($matches[0]);

            if (! empty($matches['literal'])) {
                $levelParts[$level][] = ['literal', $matches['literal']];
            }

            if ($matches['token'] === ':') {
                if (
                    ! preg_match(
                        '(\G(?P<name>[^:.{\[\]]+)(?:{(?P<delimiters>[^}]+)})?:?)',
                        $def,
                        $matches,
                        0,
                        $currentPos
                    )
                ) {
                    throw new Exception\RuntimeException('Found empty parameter name');
                }

                $levelParts[$level][] = [
                    'parameter',
                    $matches['name'],
                    $matches['delimiters'] ?? null,
                ];

                $currentPos += strlen($matches[0]);
            } elseif ($matches['token'] === '[') {
                $levelParts[$level][]   = ['optional', []];
                $levelParts[$level + 1] = &$levelParts[$level][count($levelParts[$level]) - 1][1];

                $level++;
            } elseif ($matches['token'] === ']') {
                unset($levelParts[$level]);
                $level--;

                if ($level < 0) {
                    throw new Exception\RuntimeException('Found closing bracket without matching opening bracket');
                }
            } else {
                break;
            }
        }

        if ($level > 0) {
            throw new Exception\RuntimeException('Found unbalanced brackets');
        }

        return $parts;
    }

    /**
     * Build the matching regex from parsed parts.
     *
     * @param  array   $parts
     * @param  array   $constraints
     * @param  int $groupIndex
     * @return string
     * @throws Exception\RuntimeException
     */
    protected function buildRegex(array $parts, array $constraints, &$groupIndex = 1)
    {
        $regex = '';

        foreach ($parts as $part) {
            switch ($part[0]) {
                case 'literal':
                    $regex .= preg_quote($part[1]);
                    break;

                case 'parameter':
                    $groupName = '?P<param' . $groupIndex . '>';

                    if (isset($constraints[$part[1]])) {
                        $regex .= '(' . $groupName . $constraints[$part[1]] . ')';
                    } elseif ($part[2] === null) {
                        $regex .= '(' . $groupName . '[^.]+)';
                    } else {
                        $regex .= '(' . $groupName . '[^' . $part[2] . ']+)';
                    }

                    $this->paramMap['param' . $groupIndex++] = $part[1];
                    break;

                case 'optional':
                    $regex .= '(?:' . $this->buildRegex($part[1], $constraints, $groupIndex) . ')?';
                    break;
            }
        }

        return $regex;
    }

    /**
     * Build host.
     *
     * @param  array   $parts
     * @param  array   $mergedParams
     * @param  bool    $isOptional
     * @return string
     * @throws Exception\RuntimeException
     * @throws Exception\InvalidArgumentException
     */
    protected function buildHost(array $parts, array $mergedParams, $isOptional)
    {
        $host      = '';
        $skip      = true;
        $skippable = false;

        foreach ($parts as $part) {
            switch ($part[0]) {
                case 'literal':
                    $host .= $part[1];
                    break;

                case 'parameter':
                    $skippable = true;

                    if (! isset($mergedParams[$part[1]])) {
                        if (! $isOptional) {
                            throw new Exception\InvalidArgumentException(sprintf('Missing parameter "%s"', $part[1]));
                        }

                        return '';
                    } elseif (
                        ! $isOptional
                        || ! isset($this->defaults[$part[1]])
                        || $this->defaults[$part[1]] !== $mergedParams[$part[1]]
                    ) {
                        $skip = false;
                    }

                    $host .= $mergedParams[$part[1]];

                    $this->assembledParams[] = $part[1];
                    break;

                case 'optional':
                    $skippable    = true;
                    $optionalPart = $this->buildHost($part[1], $mergedParams, true);

                    if ($optionalPart !== '') {
                        $host .= $optionalPart;
                        $skip  = false;
                    }
                    break;
            }
        }

        if ($isOptional && $skippable && $skip) {
            return '';
        }

        return $host;
    }

    /**
     * match(): defined by RouteInterface interface.
     *
     * @see    \Laminas\Router\RouteInterface::match()
     *
     * @return RouteMatch|null
     */
    public function match(Request $request)
    {
        if (! method_exists($request, 'getUri')) {
            return null;
        }

        /** @var UriInterface $uri */
        $uri  = $request->getUri();
        $host = $uri->getHost() ?? '';

        $result = preg_match('(^' . $this->regex . '$)', $host, $matches);

        if (! $result) {
            return null;
        }

        $params = [];

        foreach ($this->paramMap as $index => $name) {
            if (isset($matches[$index]) && $matches[$index] !== '') {
                $params[$name] = $matches[$index];
            }
        }

        return new RouteMatch(array_merge($this->defaults, $params));
    }

    /**
     * assemble(): Defined by RouteInterface interface.
     *
     * @see    \Laminas\Router\RouteInterface::assemble()
     *
     * @param  array $params
     * @param  array $options
     * @return mixed
     */
    public function assemble(array $params = [], array $options = [])
    {
        $this->assembledParams = [];

        if (isset($options['uri'])) {
            $host = $this->buildHost(
                $this->parts,
                array_merge($this->defaults, $params),
                false
            );

            $options['uri']->setHost($host);
        }

        // A hostname does not contribute to the path, thus nothing is returned.
        return '';
    }

    /**
     * getAssembledParams(): defined by RouteInterface interface.
     *
     * @see    RouteInterface::getAssembledParams
     *
     * @return array
     */
    public function getAssembledParams()
    {
        return $this->assembledParams;
    }
}
