<?php

declare(strict_types=1);

namespace app\common\service\followupaudio;

/** Server-only provider identity. Changing any request identity invalidates the audio gate. */
final class FollowupAudioProviderConfig
{
    public static function resolve(string $profile, ?array $settings = null, ?array $legacy = null): array
    {
        if (!in_array($profile, ['qwen', 'openai'], true)) { throw new FollowupAudioException('INVALID_PROFILE'); }
        $settings = $settings ?? (array) config('followup_audio', []);
        $legacy = $legacy ?? (array) config('prescription_ai', []);
        $provider = (array) ($settings['providers'][$profile] ?? []);
        $driver = (string) ($provider['driver'] ?? 'dify');
        if (!in_array($driver, ['dify', 'openai_audio', 'asr_then_llm'], true)) { throw new FollowupAudioException('CONFIG_INVALID'); }
        if ($driver === 'asr_then_llm') { return self::pipeline($provider, $settings, $profile); }
        $base = (string) ($provider['base_url'] ?? '');
        $key = (string) ($provider['api_key'] ?? '');
        if ($driver === 'dify') {
            if ($base === '') { $base = (string) ($legacy['base_url'] ?? ''); }
            if ($key === '') { $key = (string) ($legacy['models'][$profile]['api_key'] ?? ''); }
        }
        $model = (string) ($provider['model'] ?? '');
        $label = trim((string) ($provider['label'] ?? ''));
        if ($label === '') { $label = $model !== '' ? $model : $profile; }
        if ($base === '' || $key === '' || ($driver === 'openai_audio' && $model === '')) { throw new FollowupAudioException('CONFIG_MISSING'); }
        $parts = parse_url($base);
        if (!is_array($parts) || !in_array($parts['scheme'] ?? '', ['http', 'https'], true)
            || empty($parts['host']) || isset($parts['user']) || isset($parts['pass']) || isset($parts['query']) || isset($parts['fragment'])
            || preg_match('/[\x00-\x20\x7f\\\\]/', $base) || preg_match('/[\x00-\x20\x7f]/', $key)
            || strlen($model) > 200 || preg_match('/[\x00-\x20\x7f]/', $model)
            || trim($label) === '' || strlen($label) > 200 || preg_match('/[\x00-\x1f\x7f]/', $label)) {
            throw new FollowupAudioException('CONFIG_INVALID');
        }
        $base = rtrim($base, '/');
        $path = rtrim((string) ($parts['path'] ?? ''), '/');
        if ($driver === 'dify' && str_ends_with($path, '/chat/completions')) {
            throw new FollowupAudioException('DIFY_APPLICATION_REQUIRED');
        }
        if ($driver === 'openai_audio' && str_ends_with($path, '/chat-messages')) {
            throw new FollowupAudioException('CONFIG_INVALID');
        }
        $endpoint = $driver === 'dify' ? '/chat-messages' : '/chat/completions';
        if (str_ends_with($base, $endpoint)) { $base = substr($base, 0, -strlen($endpoint)); }
        elseif (!str_ends_with($base, '/v1')) { $base .= '/v1'; }
        $fingerprint = hash('sha256', json_encode([$driver, $base, $model, $key], JSON_UNESCAPED_SLASHES | JSON_THROW_ON_ERROR));
        return ['driver' => $driver, 'base_url' => $base, 'api_key' => $key, 'model' => $model, 'label' => $label, 'fingerprint' => $fingerprint];
    }

    /** No endpoint, model credential or plaintext provider data in capability responses. */
    public static function status(string $profile, ?array $settings = null, ?array $legacy = null): array
    {
        try {
            $provider = self::resolve($profile, $settings, $legacy);
            return ['configured' => true, 'profile' => $profile, 'code' => 'OK', 'application_fingerprint' => $provider['fingerprint']];
        } catch (FollowupAudioException $error) {
            return ['configured' => false, 'profile' => in_array($profile, ['qwen', 'openai'], true) ? $profile : 'invalid', 'code' => $error->errorCode];
        }
    }

    public static function isVerified(string $profile): bool
    {
        return self::verified($profile, (array) config('followup_audio', []), (array) config('prescription_ai', []));
    }

    /** Shared with injected-config transport tests; enabled remains an independent operational switch. */
    public static function verified(string $profile, array $settings, array $legacy): bool
    {
        if (empty($settings['audio_verified']) || !in_array($profile, (array) ($settings['verified_profiles'] ?? []), true)) { return false; }
        try { $provider = self::resolve($profile, $settings, $legacy); }
        catch (FollowupAudioException $error) { return false; }
        $verified = (string) ($settings['providers'][$profile]['verified_fingerprint'] ?? '');
        $secure = $provider['driver'] === 'asr_then_llm'
            ? self::secureEndpoint($provider['asr']['base_url'], $provider['allow_loopback_tunnel'])
                && self::secureEndpoint($provider['extraction']['base_url'], $provider['allow_loopback_tunnel'])
            : str_starts_with($provider['base_url'], 'https://');
        return $secure && preg_match('/^[a-f0-9]{64}$/D', $verified)
            && hash_equals($provider['fingerprint'], $verified);
    }

    /** Literal loopback only, explicitly configured for a locally established SSH tunnel. No DNS exception. */
    public static function secureEndpoint(string $base, bool $allowLoopback): bool
    {
        $parts = parse_url($base);
        return ($parts['scheme'] ?? '') === 'https' || ($allowLoopback && ($parts['scheme'] ?? '') === 'http'
            && in_array($parts['host'] ?? '', ['127.0.0.1', '[::1]'], true));
    }

    private static function pipeline(array $provider, array $settings, string $profile): array
    {
        $allowLoopback = ($provider['allow_loopback_tunnel'] ?? false) === true;
        $resolved = ['driver' => 'asr_then_llm', 'allow_loopback_tunnel' => $allowLoopback];
        foreach (['asr' => '/audio/transcriptions', 'extraction' => '/chat/completions'] as $stage => $endpoint) {
            $input = (array) ($provider[$stage] ?? []);
            // Use existing endpoint/key/model syntax validation without inheriting any legacy service.
            $part = self::resolve($profile, ['providers' => [$profile => array_merge($input, ['driver' => 'openai_audio'])]], []);
            $base = $part['base_url'];
            if ($stage === 'asr') {
                $original = rtrim((string) ($input['base_url'] ?? ''), '/');
                if (str_ends_with($original, $endpoint)) { $base = substr($original, 0, -strlen($endpoint)); }
            }
            if (!self::secureEndpoint($base, $allowLoopback)) { throw new FollowupAudioException('HTTPS_REQUIRED'); }
            $resolved[$stage] = ['base_url' => $base, 'api_key' => $part['api_key'], 'model' => $part['model']];
        }
        $chunkSeconds = (int) ($settings['asr_chunk_seconds'] ?? 120);
        if ($chunkSeconds < 1 || $chunkSeconds > 120) { throw new FollowupAudioException('CONFIG_INVALID'); }
        $resolved['chunk_seconds'] = $chunkSeconds;
        $stereoSeconds = (int) ($settings['asr_stereo_chunk_seconds'] ?? 15);
        if ($stereoSeconds < 1 || $stereoSeconds > 30) { throw new FollowupAudioException('CONFIG_INVALID'); }
        $resolved['stereo_chunk_seconds'] = $stereoSeconds;
        $resolved['channel_policy'] = FollowupAudioPipelineCheckpoint::CHANNEL_POLICY;
        $resolved['silence_policy'] = FollowupAudioPipelineMedia::SILENCE_POLICY;
        $mode = $provider['extraction']['response_format'] ?? 'json_schema';
        $maxTokens = $provider['extraction']['max_tokens'] ?? 8192;
        $thinking = $provider['extraction']['enable_thinking'] ?? null;
        if (!in_array($mode, ['json_schema', 'json_object', 'prompt_json'], true)
            || !is_int($maxTokens) || $maxTokens < 256 || $maxTokens > 8192
            || ($thinking !== null && !is_bool($thinking))) { throw new FollowupAudioException('CONFIG_INVALID'); }
        $resolved['extraction'] += ['response_format' => $mode, 'max_tokens' => $maxTokens, 'enable_thinking' => $thinking];
        $resolved['output_schema'] = FollowupAudioExtractionSchema::VERSION;
        $resolved['citation_policy'] = FollowupAudioTranscriptPrompt::CITATION_POLICY;
        $resolved['schema_dialect'] = FollowupAudioExtractionSchema::DIALECT;
        $resolved['label'] = trim((string) ($provider['label'] ?? $profile));
        if ($resolved['label'] === '' || strlen($resolved['label']) > 200 || preg_match('/[\x00-\x1f\x7f]/', $resolved['label'])) {
            throw new FollowupAudioException('CONFIG_INVALID');
        }
        $resolved['fingerprint'] = hash('sha256', json_encode([$resolved['driver'], $resolved['asr'], $resolved['extraction'],
            $allowLoopback, $chunkSeconds, 'pcm-s16le-mono-16000-v1', $resolved['output_schema'], $resolved['citation_policy'], $resolved['schema_dialect'], $resolved['channel_policy'], $stereoSeconds, $resolved['silence_policy'], 'checkpoint-v2'], JSON_UNESCAPED_SLASHES | JSON_THROW_ON_ERROR));
        return $resolved;
    }

    public static function publicModels(): array
    {
        $models = [];
        foreach (['qwen', 'openai'] as $profile) {
            if (self::isVerified($profile)) { $models[] = ['value' => $profile, 'label' => self::resolve($profile)['label']]; }
        }
        return $models;
    }
}