<?php

declare(strict_types=1);

namespace App\Config;

use InvalidArgumentException;

/**
 * YAML-backed resolver for language cleanup profiles.
 *
 * The resolver is intentionally additive in p22: existing runtime callers keep
 * using their legacy lists until later patches wire profiles into Commerce and
 * Agent logic.
 */
final class LanguageCleanupConfig
{
    /**
     * @param array<string, mixed> $config
     */
    public function __construct(private readonly array $config)
    {
    }

    /** @return string[] */
    public function getLegacyStopWords(): array
    {
        return $this->requiredTopLevelStringList('words');
    }

    /** @return string[] */
    public function getProtectedTerms(): array
    {
        return $this->requiredTopLevelStringList('protected_terms');
    }

    public function isProtectedTerm(string $term): bool
    {
        $term = $this->normalizeToken($term);
        if ($term === '') {
            return false;
        }

        return in_array($term, $this->getProtectedTerms(), true);
    }

    /** @return array<string, string> */
    public function getAsciiTransliterationMap(): array
    {
        $normalization = $this->requiredMap('normalization');
        if (!array_key_exists('ascii_transliteration', $normalization)) {
            throw $this->invalid('normalization.ascii_transliteration', 'is missing');
        }

        return $this->stringMapFromValue($normalization['ascii_transliteration'], 'normalization.ascii_transliteration', true);
    }

    public function transliterateToAscii(string $value): string
    {
        $map = $this->getAsciiTransliterationMap();
        if ($map === []) {
            return $value;
        }

        return strtr($value, $map);
    }

    /** @return string[] */
    public function getCleanupProfileNames(): array
    {
        return array_keys($this->requiredMap('cleanup_profiles'));
    }

    /** @return string[] */
    public function getStopWordsForProfile(string $profileName): array
    {
        return $this->removeProtectedTerms(
            $this->resolveGroupedTerms($profileName, 'stopword_groups', 'stopword_groups')
        );
    }

    /** @return string[] */
    public function getPhrasesForProfile(string $profileName): array
    {
        return $this->removeProtectedTerms(
            $this->resolveGroupedTerms($profileName, 'phrase_groups', 'phrase_groups')
        );
    }

    /** @return string[] */
    public function getMetaTermsForProfile(string $profileName): array
    {
        return $this->removeProtectedTerms(
            $this->resolveGroupedTerms($profileName, 'meta_term_groups', 'meta_term_groups')
        );
    }

    /** @return array{stopwords:string[], phrases:string[], meta_terms:string[], protected_terms:string[]} */
    public function getCleanupProfile(string $profileName): array
    {
        return [
            'stopwords' => $this->getStopWordsForProfile($profileName),
            'phrases' => $this->getPhrasesForProfile($profileName),
            'meta_terms' => $this->getMetaTermsForProfile($profileName),
            'protected_terms' => $this->getProtectedTermsForProfile($profileName),
        ];
    }

    /** @return string[] */
    public function getProtectedTermsForProfile(string $profileName): array
    {
        $profile = $this->requiredCleanupProfile($profileName);
        $groupNames = $this->stringListFromValue(
            $this->profileValue($profile, 'protected_term_groups'),
            sprintf('cleanup_profiles.%s.protected_term_groups', $profileName),
            false
        );

        if ($groupNames === []) {
            return $this->getProtectedTerms();
        }

        $out = [];
        foreach ($groupNames as $groupName) {
            if ($groupName === 'protected_terms') {
                $out = $this->mergeUnique($out, $this->getProtectedTerms());
                continue;
            }

            throw $this->invalid(
                sprintf('cleanup_profiles.%s.protected_term_groups', $profileName),
                sprintf('references unknown protected term group "%s"', $groupName)
            );
        }

        return $out;
    }

    /** @return string[] */
    private function resolveGroupedTerms(string $profileName, string $profileKey, string $rootKey): array
    {
        $profile = $this->requiredCleanupProfile($profileName);
        $groupNames = $this->stringListFromValue(
            $this->profileValue($profile, $profileKey),
            sprintf('cleanup_profiles.%s.%s', $profileName, $profileKey),
            false
        );

        if ($groupNames === []) {
            return [];
        }

        $groups = $this->requiredMap($rootKey);
        $out = [];

        foreach ($groupNames as $groupName) {
            if (!array_key_exists($groupName, $groups)) {
                throw $this->invalid(
                    sprintf('cleanup_profiles.%s.%s', $profileName, $profileKey),
                    sprintf('references unknown group "%s"', $groupName)
                );
            }

            $out = $this->mergeUnique(
                $out,
                $this->stringListFromValue($groups[$groupName], sprintf('%s.%s', $rootKey, $groupName), true)
            );
        }

        return $out;
    }

    /** @return array<string, mixed> */
    private function requiredCleanupProfile(string $profileName): array
    {
        $profileName = trim($profileName);
        if ($profileName === '') {
            throw $this->invalid('cleanup_profiles', 'profile name must not be empty');
        }

        $profiles = $this->requiredMap('cleanup_profiles');
        if (!array_key_exists($profileName, $profiles) || !is_array($profiles[$profileName])) {
            throw $this->invalid('cleanup_profiles', sprintf('missing profile "%s"', $profileName));
        }

        /** @var array<string, mixed> $profile */
        $profile = $profiles[$profileName];

        return $profile;
    }

    private function profileValue(array $profile, string $key): mixed
    {
        if (!array_key_exists($key, $profile)) {
            return [];
        }

        return $profile[$key];
    }

    /** @return array<string, mixed> */
    private function requiredMap(string $key): array
    {
        if (!array_key_exists($key, $this->config) || !is_array($this->config[$key])) {
            throw $this->invalid($key, 'must be a map');
        }

        /** @var array<string, mixed> $map */
        $map = $this->config[$key];
        if ($map === []) {
            throw $this->invalid($key, 'must not be empty');
        }

        return $map;
    }

    /** @return string[] */
    private function requiredTopLevelStringList(string $key): array
    {
        if (!array_key_exists($key, $this->config)) {
            throw $this->invalid($key, 'is missing');
        }

        return $this->stringListFromValue($this->config[$key], $key, true);
    }

    /** @return string[] */
    private function stringListFromValue(mixed $value, string $path, bool $required): array
    {
        if (!is_array($value)) {
            if (!$required && $value === []) {
                return [];
            }

            throw $this->invalid($path, 'must be a list of non-empty strings');
        }

        $out = [];
        foreach ($value as $item) {
            if (!is_scalar($item)) {
                continue;
            }

            $item = $this->normalizeToken((string) $item);
            if ($item === '' || in_array($item, $out, true)) {
                continue;
            }

            $out[] = $item;
        }

        if ($required && $out === []) {
            throw $this->invalid($path, 'must contain at least one non-empty string');
        }

        return $out;
    }

    /** @return array<string, string> */
    private function stringMapFromValue(mixed $value, string $path, bool $required): array
    {
        if (!is_array($value)) {
            throw $this->invalid($path, 'must be a map of non-empty strings');
        }

        $out = [];
        foreach ($value as $key => $item) {
            if (!is_scalar($key) || !is_scalar($item)) {
                continue;
            }

            $key = trim((string) $key);
            $item = trim((string) $item);
            if ($key === '' || $item === '') {
                continue;
            }

            $out[$key] = $item;
        }

        if ($required && $out === []) {
            throw $this->invalid($path, 'must contain at least one non-empty map entry');
        }

        return $out;
    }

    /** @param string[] $terms */
    private function removeProtectedTerms(array $terms): array
    {
        $protected = $this->getProtectedTerms();

        return array_values(array_filter(
            $terms,
            static fn (string $term): bool => !in_array($term, $protected, true)
        ));
    }

    /**
     * @param string[] $left
     * @param string[] $right
     * @return string[]
     */
    private function mergeUnique(array $left, array $right): array
    {
        foreach ($right as $item) {
            if (!in_array($item, $left, true)) {
                $left[] = $item;
            }
        }

        return $left;
    }

    private function normalizeToken(string $token): string
    {
        $token = trim($token);

        return function_exists('mb_strtolower')
            ? mb_strtolower($token, 'UTF-8')
            : strtolower($token);
    }

    private function invalid(string $path, string $message): InvalidArgumentException
    {
        return new InvalidArgumentException(sprintf('Invalid RetrieX language cleanup config at "%s": %s.', $path, $message));
    }
}