<?php
declare(strict_types=1);

namespace app\service;

/**
 * NAC 量子浏览器 API 服务层
 * 所有对后端 9551 端口的调用均在此类完成
 * 前端模板不直接调用任何外部接口
 */
class ExplorerApi
{
    // 后端 API 地址（服务端调用，不暴露给前端）
    private static string $apiBase = 'http://127.0.0.1:9551';
    private static int $timeout = 5;

    /**
     * 通用 GET 请求
     */
    private static function get(string $path, array $params = []): ?array
    {
        $url = self::$apiBase . $path;
        if (!empty($params)) {
            $url .= '?' . http_build_query($params);
        }

        $ch = curl_init();
        curl_setopt_array($ch, [
            CURLOPT_URL            => $url,
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_TIMEOUT        => self::$timeout,
            CURLOPT_CONNECTTIMEOUT => 3,
            CURLOPT_HTTPHEADER     => ['Accept: application/json'],
            CURLOPT_FOLLOWLOCATION => false,
        ]);
        $body   = curl_exec($ch);
        $status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);

        if ($body === false || $status < 200 || $status >= 300) {
            return null;
        }
        $json = json_decode($body, true);
        return is_array($json) ? $json : null;
    }

    /**
     * 获取网络统计数据
     * 从 /health + /api/v1/blocks/latest 组合（/api/v1/network/stats 不存在）
     */
    public static function getStats(): array
    {
        $health = self::get('/health');
        $latest = self::get('/api/v1/blocks/latest');

        $h = $health['data'] ?? [];
        $b = $latest['data'] ?? [];

        return [
            'currentBlock'      => $b['number']              ?? ($h['block']['height'] ?? 0),
            'cbppConsensus'     => $h['cbpp_consensus']       ?? ($b['cbppConsensus'] ?? 'unknown'),
            'csnpNetwork'       => $h['csnp_network']         ?? 'unknown',
            'constitutionLayer' => $h['constitution_layer']   ?? ($b['constitutionLayer'] ?? false),
            'fluidBlockMode'    => $h['fluid_block_mode']     ?? ($b['isFluid'] ?? false),
            'nvmVersion'        => $h['nvm_version']          ?? 'N/A',
            'chainId'           => 20260131,
            'network'           => 'mainnet',
            'nodeCount'         => 1,
            'totalTransactions' => 0,
            'totalAddresses'    => 0,
            'totalAssets'       => 0,
            'tps'               => 0,
            'avgBlockTime'      => 3.0,
            'latestValidator'   => $b['validator']            ?? 'N/A',
            'latestHash'        => $b['hash']                 ?? '',
        ];
    }

    /**
     * 获取区块列表
     * API 返回格式: {data: {blocks: [], total: N}}
     * 注意：blocks 中的 txCount 字段来自 transactionCount
     */
    public static function getBlocks(int $limit = 20, int $page = 1): array
    {
        $res = self::get('/api/v1/blocks', ['limit' => $limit, 'page' => $page]);
        if ($res && isset($res['data']['blocks'])) {
            // 统一字段名：transactionCount → txCount
            $blocks = array_map(function ($b) {
                $b['txCount'] = $b['transactionCount'] ?? $b['txCount'] ?? 0;
                return $b;
            }, $res['data']['blocks']);
            return [
                'blocks' => $blocks,
                'total'  => $res['data']['total'] ?? count($blocks),
                'page'   => $page,
                'limit'  => $limit,
            ];
        }
        return ['blocks' => [], 'total' => 0, 'page' => 1, 'limit' => $limit];
    }

    /**
     * 获取单个区块详情
     */
    public static function getBlock(int $number): ?array
    {
        $res = self::get('/api/v1/blocks/' . $number);
        return $res['data'] ?? null;
    }

    /**
     * 获取最新区块
     */
    public static function getLatestBlock(): ?array
    {
        $res = self::get('/api/v1/blocks/latest');
        return $res['data'] ?? null;
    }

    /**
     * 搜索（区块号/交易哈希/地址）
     */
    public static function search(string $query): ?array
    {
        return self::get('/api/v1/search', ['q' => $query]);
    }

    /**
     * 获取地址信息
     */
    public static function getAddress(string $address): ?array
    {
        $res = self::get('/api/v1/addresses/' . urlencode($address));
        return $res['data'] ?? null;
    }

    /**
     * 健康检查
     */
    public static function health(): ?array
    {
        $res = self::get('/health');
        return $res['data'] ?? null;
    }

    // ===== 工具函数 =====

    /**
     * 格式化时间戳
     */
    public static function formatTime(int $ts): string
    {
        return date('Y-m-d H:i:s', $ts);
    }

    /**
     * 多久前
     */
    public static function timeAgo(int $ts): string
    {
        $diff = time() - $ts;
        if ($diff < 60)    return $diff . ' 秒前';
        if ($diff < 3600)  return floor($diff / 60) . ' 分钟前';
        if ($diff < 86400) return floor($diff / 3600) . ' 小时前';
        return floor($diff / 86400) . ' 天前';
    }

    /**
     * 截断哈希显示
     */
    public static function shortHash(string $hash, int $front = 10, int $back = 8): string
    {
        if (strlen($hash) <= $front + $back + 3) return $hash;
        return substr($hash, 0, $front) . '...' . substr($hash, -$back);
    }

    /**
     * 状态徽章样式
     */
    public static function statusBadge(string $status): string
    {
        return match ($status) {
            'active', 'connected', 'ok' => 'badge bg-success',
            'unknown'                    => 'badge bg-secondary',
            default                      => 'badge bg-danger',
        };
    }
}