<?php

namespace app\common;

/**
 * 使用本地 chat/completions 接口，从 affiliation 文本推断国家。
 *
 * 输出约定：返回数组 ['code' => 'US', 'en_name' => 'United States']，任一可为空。
 */
class CountryResolverService
{
    private $chatUrl = '';
    private $chatModel = '';
    private $apiKey = '';
    private $timeout = 60;

    public function __construct(array $config = [])
    {
        if (isset($config['chat_url'])) $this->chatUrl = (string)$config['chat_url'];
        if (isset($config['chat_model'])) $this->chatModel = (string)$config['chat_model'];
        if (isset($config['api_key'])) $this->apiKey = (string)$config['api_key'];
        if (isset($config['timeout'])) $this->timeout = max(5, intval($config['timeout']));
    }

    public function resolve(string $affiliation): array
    {
        $affiliation = trim($affiliation);
        if ($affiliation === '' || $this->chatUrl === '' || $this->chatModel === '') {
            return [];
        }

        $messages = [
            [
                'role' => 'system',
                'content' => 'You extract the country from an academic affiliation string. Reply ONLY with minified JSON.',
            ],
            [
                'role' => 'user',
                'content' => "Affiliation:\n" . $affiliation . "\n\nReturn JSON with keys:\n- code: ISO 3166-1 alpha-3 (preferred)\n- en_name: English country name (optional)\nIf uncertain, return {\"code\":\"\",\"en_name\":\"\"}.",
            ],
        ];

        $payload = [
            'model' => $this->chatModel,
            'temperature' => 0,
            'messages' => $messages,
        ];

        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $this->chatUrl);
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($payload, JSON_UNESCAPED_UNICODE));
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, min(10, $this->timeout));
        curl_setopt($ch, CURLOPT_TIMEOUT, $this->timeout);

        $headers = [
            'Content-Type: application/json',
        ];
        if ($this->apiKey !== '') {
            $headers[] = 'Authorization: Bearer ' . $this->apiKey;
        }
        curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

        $raw = curl_exec($ch);
        if ($raw === false) {
            curl_close($ch);
            return [];
        }
        $httpCode = intval(curl_getinfo($ch, CURLINFO_HTTP_CODE));
        curl_close($ch);
        if ($httpCode < 200 || $httpCode >= 300) {
            return [];
        }

        $data = json_decode($raw, true);
        if (!is_array($data)) return [];

        // 兼容 OpenAI chat/completions 结构：choices[0].message.content
        $content = '';
        if (isset($data['choices'][0]['message']['content'])) {
            $content = (string)$data['choices'][0]['message']['content'];
        } elseif (isset($data['content'])) {
            $content = (string)$data['content'];
        }

        $content = trim($content);
        if ($content === '') return [];

        // 尝试提取 JSON（允许模型包裹 ```json）
        if (preg_match('/\{.*\}/s', $content, $m)) {
            $content = $m[0];
        }

        $obj = json_decode($content, true);
        if (!is_array($obj)) return [];

        $code = isset($obj['code']) ? strtoupper(trim((string)$obj['code'])) : '';
        $enName = isset($obj['en_name']) ? trim((string)$obj['en_name']) : '';

        // 防止模型乱回长段文本
        if (strlen($code) > 8) $code = '';
        if (strlen($enName) > 128) $enName = mb_substr($enName, 0, 128);

        return ['code' => $code, 'en_name' => $enName];
    }
}