<?php

declare(strict_types=1);

namespace Mod\Chain\Services;

use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Http;

/**
 * Lethean daemon JSON-RPC client.
 *
 *   $rpc = app(DaemonRpc::class);
 *   $info = $rpc->getInfo();
 *   $block = $rpc->getBlockByHeight(12345);
 */
class DaemonRpc implements \Mod\Chain\Contracts\ChainDaemon, \Mod\Chain\Contracts\HealthCheckable
{
    private string $endpoint;
    private int $cacheTtl;

    public function __construct()
    {
        $this->endpoint = config('chain.daemon_rpc', 'http://127.0.0.1:46941/json_rpc');
        $this->cacheTtl = config('chain.cache_ttl', 10);
    }

    /**
     *   $info = $rpc->getInfo();
     *   echo $info['height'];
     */
    public function getInfo(): array
    {
        return Cache::remember('chain.info', $this->cacheTtl, function () {
            return $this->call('getinfo');
        });
    }

    /**
     *   $header = $rpc->getBlockByHeight(12345);
     */
    public function getBlockByHeight(int $height): array
    {
        // Blocks are immutable — cache for 1 hour
        return Cache::remember("chain.block.{$height}", 3600, function () use ($height) {
            return $this->call('getblockheaderbyheight', ['height' => $height]);
        });
    }

    /**
     *   $header = $rpc->getBlockByHash('abc123...');
     */
    public function getBlockByHash(string $hash): array
    {
        return $this->call('getblockheaderbyhash', ['hash' => $hash]);
    }

    /**
     *   $header = $rpc->getLastBlockHeader();
     */
    public function getLastBlockHeader(): array
    {
        return Cache::remember('chain.lastblock', $this->cacheTtl, function () {
            return $this->call('getlastblockheader');
        });
    }

    /**
     *   $aliases = $rpc->getAllAliases();
     */
    public function getAllAliases(): array
    {
        return Cache::remember('chain.aliases', 60, function () {
            return $this->call('get_all_alias_details');
        });
    }

    /**
     *   $alias = $rpc->getAliasByName('charon');
     */
    public function getAliasByName(string $name): ?array
    {
        $result = $this->call('get_alias_details', ['alias' => $name]);

        if (($result['status'] ?? '') === 'NOT_FOUND' || empty($result['alias_details']['address'] ?? '')) {
            return null;
        }

        return $result['alias_details'] ?? null;
    }

    /**
     *   $count = $rpc->getBlockCount();
     */
    public function getBlockCount(): int
    {
        $result = $this->call('getblockcount');

        return $result['count'] ?? 0;
    }

    /**
     *   $tx = $rpc->getTransaction('abc123...');
     */
    public function getTransaction(string $hash): array
    {
        return $this->call('get_tx_details', ['tx_hash' => $hash]);
    }

    /**
     * Raw JSON-RPC call.
     *
     *   $result = $rpc->call('getinfo');
     */
    public function call(string $method, array $params = []): array
    {
        $payload = [
            'jsonrpc' => '2.0',
            'id' => '0',
            'method' => $method,
        ];

        if ($params) {
            $payload['params'] = $params;
        }

        try {
            $response = Http::timeout(5)
                ->accept('application/json')
                ->post($this->endpoint, $payload);

            if ($response->failed()) {
                return ['error' => 'Daemon unreachable', '_offline' => true];
            }

            $data = $response->json();
            $result = $data["result"] ?? $data["error"] ?? [];

            // Only cache successful responses as stale fallback
            if (isset($data['result'])) {
                Cache::put("chain.stale.{$method}", $result, 3600);
            }

            return $result;
        } catch (\Throwable $e) {
            // Return stale cached data if daemon is down
            $stale = Cache::get("chain.stale.{$method}");
            if ($stale) {
                $stale['_stale'] = true;

                return $stale;
            }

            return ['error' => 'Daemon unreachable', '_offline' => true];
        }
    }

    public function healthCheck(): array
    {
        $info = $this->getInfo();

        if (isset($info['_offline'])) {
            return ['status' => 'unhealthy', 'detail' => 'Unreachable'];
        }

        if (isset($info['_stale'])) {
            return [
                'status' => 'degraded',
                'detail' => 'Stale data — height ' . number_format($info['height'] ?? 0),
                'stale' => true,
            ];
        }

        return [
            'status' => 'healthy',
            'detail' => 'Height ' . number_format($info['height'] ?? 0) . ' — ' . ($info['status'] ?? 'OK'),
        ];
    }
}