<?php

namespace App\Services;

use App\Models\Recording;
use Illuminate\Support\Facades\Http;
use Illuminate\Support\Str;
use Laravel\Ai\Transcription;
use RuntimeException;

class TranscriptionService
{
    /**
     * Run transcription for a recording using the selected driver.
     */
    public function transcribe(Recording $recording): string
    {
        return match ($recording->transcription_driver) {
            'cloud' => $this->viaCloud($recording),
            'local' => $this->viaLocal($recording),
            'ollama' => $this->viaRemoteCompatible($recording),
            default => throw new RuntimeException('Unknown transcription driver: '.$recording->transcription_driver),
        };
    }

    private function viaCloud(Recording $recording): string
    {
        $transcript = Transcription::fromStorage($recording->file_path)
            ->timeout((int) config('ai.transcription_timeout', 600))
            ->generate('openai', 'whisper-1');

        return (string) $transcript;
    }

    private function viaLocal(Recording $recording): string
    {
        $model = config('ai.local_whisper_model', 'Systran/faster-whisper-base');

        $transcript = Transcription::fromStorage($recording->file_path)
            ->timeout((int) config('ai.transcription_timeout', 600))
            ->generate('local-whisper', $model);

        return (string) $transcript;
    }

    /**
     * Call an OpenAI-compatible /v1/audio/transcriptions endpoint at a user-supplied host URL.
     */
    private function viaRemoteCompatible(Recording $recording): string
    {
        if (! filled($recording->ollama_url)) {
            throw new RuntimeException('Ollama host URL is required for remote transcription.');
        }

        $base = $this->normalizeBaseUrl($recording->ollama_url);
        $model = config('ai.remote_whisper_model', config('ai.local_whisper_model', 'Systran/faster-whisper-base'));
        $path = $recording->absolutePath();

        if (! is_readable($path)) {
            throw new RuntimeException('Recording audio file is not readable.');
        }

        $response = Http::timeout((int) config('ai.transcription_timeout', 600))
            ->attach(
                'file',
                fopen($path, 'r'),
                $recording->original_filename ?: basename($path),
            )
            ->post($base.'/audio/transcriptions', [
                'model' => $model,
                'response_format' => 'json',
            ]);

        if (! $response->successful()) {
            throw new RuntimeException(
                'Remote transcription failed (HTTP '.$response->status().'): '.$response->body()
            );
        }

        $text = $response->json('text');

        if (! is_string($text) || $text === '') {
            throw new RuntimeException('Remote transcription returned an empty transcript. Ensure the host exposes OpenAI-compatible /v1/audio/transcriptions.');
        }

        return $text;
    }

    /**
     * Normalize a user URL to an OpenAI-style base ending in /v1.
     */
    private function normalizeBaseUrl(string $url): string
    {
        $url = rtrim(trim($url), '/');

        if (Str::endsWith($url, '/v1')) {
            return $url;
        }

        return $url.'/v1';
    }
}