<?php

namespace App\Services;

use App\Models\EtsyAppCredential;
use App\Models\EtsyConnection;
use Illuminate\Support\Facades\Http;
use RuntimeException;

class Etsy
{
    private const API_URL = 'https://api.etsy.com/v3';

    /** @var array{keystring: ?string, shared_secret: ?string, shop_name: string, redirect_uri: ?string}|null */
    private ?array $credentials = null;

    public function configured(): bool
    {
        $credentials = $this->credentials();

        return filled($credentials['keystring']) && filled($credentials['shared_secret']);
    }

    public function authorizationUrl(string $state, string $verifier): string
    {
        if (! $this->configured()) {
            throw new RuntimeException('Etsy application credentials are not configured.');
        }
        $challenge = rtrim(strtr(base64_encode(hash('sha256', $verifier, true)), '+/', '-_'), '=');

        return 'https://www.etsy.com/oauth/connect?'.http_build_query([
            'response_type' => 'code', 'redirect_uri' => $this->redirectUri(),
            'scope' => 'transactions_r listings_r', 'client_id' => $this->credentials()['keystring'],
            'state' => $state, 'code_challenge' => $challenge, 'code_challenge_method' => 'S256',
        ], '', '&', PHP_QUERY_RFC3986);
    }

    public function connect(string $code, string $verifier): EtsyConnection
    {
        $tokens = Http::asForm()->acceptJson()->connectTimeout(3)->timeout(10)
            ->post(self::API_URL.'/public/oauth/token', [
                'grant_type' => 'authorization_code', 'client_id' => $this->credentials()['keystring'],
                'redirect_uri' => $this->redirectUri(), 'code' => $code, 'code_verifier' => $verifier,
            ])->throw()->json();
        $userId = explode('.', $tokens['access_token'] ?? '')[0];
        if (! ctype_digit($userId) || empty($tokens['refresh_token'])) {
            throw new RuntimeException('Etsy returned an invalid OAuth response.');
        }

        $shop = $this->get('application/users/'.$userId.'/shops', $tokens['access_token']);
        if (empty($shop['shop_id'])) {
            throw new RuntimeException('This Etsy account does not own a shop.');
        }
        if (strcasecmp($shop['shop_name'] ?? '', $this->credentials()['shop_name']) !== 0) {
            throw new RuntimeException('The Etsy account does not own the configured HickLab3D shop.');
        }

        return EtsyConnection::updateOrCreate(['shop_id' => $shop['shop_id']], [
            'shop_name' => $shop['shop_name'] ?? 'Etsy shop',
            'access_token' => $tokens['access_token'], 'refresh_token' => $tokens['refresh_token'],
            'expires_at' => now()->addSeconds(max(60, (int) ($tokens['expires_in'] ?? 3600) - 60)),
        ]);
    }

    public function receipts(EtsyConnection $connection): array
    {
        return $this->get('application/shops/'.$connection->shop_id.'/receipts', $this->accessToken($connection), [
            'was_paid' => 'true', 'was_shipped' => 'false', 'limit' => 20,
        ]);
    }

    public function listings(EtsyConnection $connection): array
    {
        return $this->get('application/shops/'.$connection->shop_id.'/listings', $this->accessToken($connection), [
            'state' => 'active', 'limit' => 20,
        ]);
    }

    private function accessToken(EtsyConnection $connection): string
    {
        if ($connection->expires_at->isFuture()) {
            return $connection->access_token;
        }
        $tokens = Http::asForm()->acceptJson()->connectTimeout(3)->timeout(10)
            ->post(self::API_URL.'/public/oauth/token', [
                'grant_type' => 'refresh_token', 'client_id' => $this->credentials()['keystring'],
                'refresh_token' => $connection->refresh_token,
            ])->throw()->json();
        if (empty($tokens['access_token']) || empty($tokens['refresh_token'])) {
            throw new RuntimeException('Etsy did not refresh the shop connection.');
        }
        $connection->update([
            'access_token' => $tokens['access_token'], 'refresh_token' => $tokens['refresh_token'],
            'expires_at' => now()->addSeconds(max(60, (int) ($tokens['expires_in'] ?? 3600) - 60)),
        ]);

        return $tokens['access_token'];
    }

    private function get(string $path, string $accessToken, array $query = []): array
    {
        $credentials = $this->credentials();

        return Http::withHeaders(['x-api-key' => $credentials['keystring'].':'.$credentials['shared_secret']])
            ->withToken($accessToken)->acceptJson()->connectTimeout(3)->timeout(10)
            ->get(self::API_URL.'/'.$path, $query)->throw()->json() ?? [];
    }

    public function redirectUri(): string
    {
        return $this->credentials()['redirect_uri'] ?: route('etsy.callback');
    }

    /** @return array{keystring: ?string, shared_secret: ?string, shop_name: string, redirect_uri: ?string} */
    private function credentials(): array
    {
        if ($this->credentials !== null) {
            return $this->credentials;
        }

        $stored = EtsyAppCredential::find(1);

        return $this->credentials = [
            'keystring' => $stored?->keystring ?: config('services.etsy.keystring'),
            'shared_secret' => $stored?->shared_secret ?: config('services.etsy.shared_secret'),
            'shop_name' => $stored?->shop_name ?: config('services.etsy.shop_name', 'HickLab3D'),
            'redirect_uri' => $stored?->redirect_uri ?: config('services.etsy.redirect_uri'),
        ];
    }
}