<?php

namespace App\Services;

use Illuminate\Support\Facades\Http;
use RuntimeException;

class FalTryOnService
{
    public function isAvailable(): bool
    {
        return trim((string) config('services.fal.api_key', '')) !== '';
    }

    public function generate(string $personImageUrl, string $clothingImageUrl, array $options = []): array
    {
        $apiKey = trim((string) config('services.fal.api_key', ''));
        $baseUrl = rtrim((string) config('services.fal.base_url', 'https://queue.fal.run'), '/');
        $model = trim((string) config('services.fal.tryon_model', 'fal-ai/image-apps-v2/virtual-try-on'));
        $pollIntervalMs = max(500, (int) config('services.fal.poll_interval_ms', 1500));
        $timeoutSec = max(20, (int) config('services.fal.timeout', 180));

        if ($apiKey === '') {
            throw new RuntimeException('FAL_KEY belum diisi di server, jadi Try On Outfit belum bisa diproses.');
        }

        $payload = [
            'person_image_url' => trim($personImageUrl),
            'clothing_image_url' => trim($clothingImageUrl),
            'preserve_pose' => (bool) ($options['preserve_pose'] ?? true),
            'aspect_ratio' => [
                'ratio' => $this->normalizeAspectRatio((string) ($options['aspect_ratio'] ?? '3:4')),
            ],
        ];

        $start = microtime(true);

        $submit = Http::timeout($timeoutSec)
            ->withHeaders([
                'Authorization' => 'Key '.$apiKey,
                'Content-Type' => 'application/json',
            ])
            ->post($baseUrl.'/'.$model, $payload);

        if (! $submit->successful()) {
            $error = trim((string) data_get($submit->json(), 'detail', data_get($submit->json(), 'error', $submit->body())));
            throw new RuntimeException('fal.ai Try On gagal: '.$submit->status().' - '.$error);
        }

        $submitJson = $submit->json();
        $directImage = $this->extractImage($submitJson);

        if ($directImage !== null) {
            return $this->normalizeResponse($directImage, $options, $submitJson);
        }

        $statusUrl = trim((string) data_get($submitJson, 'status_url', ''));
        if ($statusUrl === '') {
            throw new RuntimeException('fal.ai tidak mengembalikan status_url untuk Try On.');
        }

        while ((microtime(true) - $start) < $timeoutSec) {
            usleep($pollIntervalMs * 1000);

            $status = Http::timeout(30)
                ->withHeaders([
                    'Authorization' => 'Key '.$apiKey,
                    'Content-Type' => 'application/json',
                ])
                ->get($statusUrl);

            if (! $status->successful()) {
                continue;
            }

            $statusJson = $status->json();
            $image = $this->extractImage($statusJson);
            if ($image !== null) {
                return $this->normalizeResponse($image, $options, $statusJson);
            }

            $state = strtoupper((string) data_get($statusJson, 'status', ''));
            if (in_array($state, ['FAILED', 'ERROR', 'CANCELLED'], true)) {
                $error = (string) data_get($statusJson, 'error', 'unknown error');
                throw new RuntimeException('fal.ai Try On gagal: '.$error);
            }
        }

        throw new RuntimeException('fal.ai Try On timeout. Coba ulangi dengan foto dan outfit yang lebih jelas.');
    }

    private function normalizeAspectRatio(string $value): string
    {
        $ratio = trim($value);

        return in_array($ratio, ['1:1', '16:9', '9:16', '4:3', '3:4'], true)
            ? $ratio
            : '3:4';
    }

    private function extractImage(array $payload): ?array
    {
        $candidates = [
            data_get($payload, 'images.0'),
            data_get($payload, 'data.images.0'),
            data_get($payload, 'response.images.0'),
            data_get($payload, 'output.images.0'),
        ];

        foreach ($candidates as $candidate) {
            if (is_array($candidate) && trim((string) ($candidate['url'] ?? '')) !== '') {
                return $candidate;
            }
        }

        return null;
    }

    private function normalizeResponse(array $image, array $options, array $raw): array
    {
        $url = trim((string) ($image['url'] ?? ''));
        if ($url === '') {
            throw new RuntimeException('fal.ai Try On selesai, tapi URL hasilnya kosong.');
        }

        return [
            'url' => $url,
            'thumbnail_url' => $url,
            'width' => (int) ($image['width'] ?? 0),
            'height' => (int) ($image['height'] ?? 0),
            'provider' => 'fal-tryon',
            'prompt' => (string) ($options['prompt'] ?? 'Virtual try on result'),
            'aspect' => (string) ($options['aspect_ratio'] ?? '3:4'),
            'meta' => array_merge([
                'source' => 'tools_tryon',
                'request_id' => data_get($raw, 'request_id'),
                'model' => config('services.fal.tryon_model', 'fal-ai/image-apps-v2/virtual-try-on'),
                'person_image_url' => (string) ($options['person_image_url'] ?? ''),
                'clothing_image_url' => (string) ($options['clothing_image_url'] ?? ''),
                'preserve_pose' => (bool) ($options['preserve_pose'] ?? true),
            ], is_array($options['meta'] ?? null) ? $options['meta'] : []),
        ];
    }
}