<?php

namespace App\Ocr\Providers;

use App\Ocr\OcrProviderInterface;
use Carbon\CarbonImmutable;
use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;
use Throwable;

/**
 * Klippa OCR — a European (NL) document parsing API.
 *
 * @see https://custom-ocr.klippa.com/docs
 */
class KlippaProvider implements OcrProviderInterface
{
    private const ENDPOINT = 'https://custom-ocr.klippa.com/api/v1/parseDocument';

    /**
     * @return array{title?: string|null, expires_at?: string|null}
     */
    public function analyze(string $filePath, ?string $apiKey): array
    {
        if (blank($apiKey) || ! is_readable($filePath)) {
            return [];
        }

        $contents = file_get_contents($filePath);

        if ($contents === false) {
            Log::warning('Klippa OCR could not read the document.', ['path' => $filePath]);

            return [];
        }

        try {
            $response = Http::withHeaders(['X-Auth-Key' => $apiKey])
                ->timeout(30)
                ->attach('document', $contents, basename($filePath))
                ->post(self::ENDPOINT, ['template' => 'financial_full']);

            if ($response->failed()) {
                Log::warning('Klippa OCR request failed.', ['status' => $response->status()]);

                return [];
            }

            $parsed = $response->json('data.parsed', []);

            return array_filter([
                'title' => $this->extractTitle($parsed),
                'expires_at' => $this->extractDate($parsed),
            ], fn ($value) => $value !== null);
        } catch (Throwable $e) {
            Log::warning('Klippa OCR analysis threw an exception.', ['message' => $e->getMessage()]);

            return [];
        }
    }

    /**
     * @param  array<string, mixed>  $parsed
     */
    private function extractTitle(array $parsed): ?string
    {
        foreach (['document_subject', 'merchant_name', 'title'] as $key) {
            $value = data_get($parsed, $key);

            if (filled($value) && is_string($value)) {
                return trim($value);
            }
        }

        return null;
    }

    /**
     * @param  array<string, mixed>  $parsed
     */
    private function extractDate(array $parsed): ?string
    {
        foreach (['expiry_date', 'valid_until', 'date'] as $key) {
            $value = data_get($parsed, $key);

            if (filled($value) && is_string($value)) {
                try {
                    return CarbonImmutable::parse($value)->toDateString();
                } catch (Throwable) {
                    continue;
                }
            }
        }

        return null;
    }
}