<?php

namespace app\common;

use app\common\service\LocalModelService;
use think\Db;
use think\Env;
use think\Exception;
use think\Queue;

/**
 * Expert 领域总结（方案 C）
 * 1. 优先尝试 email 关联 user.field_ai（少量）
 * 2. 主流程：根据 expert 论文/单位/检索词 AI 总结 field_ai
 */
class ExpertFieldAiService
{
    const QUEUE_NAME = 'ExpertFieldAi';

    const STATUS_PENDING = 0;
    const STATUS_DONE = 1;
    const STATUS_INSUFFICIENT = 2;
    const STATUS_FAILED = 3;
    const STATUS_NO_USER_LINK = 4;

    const SOURCE_USER_LINK = 'user_link';
    const SOURCE_AI = 'ai';

    private $logFile;

    /** @var bool|null */
    private static $schemaReady = null;

    public function __construct()
    {
        $this->logFile = ROOT_PATH . 'runtime' . DS . 'expert_field_ai.log';
        try {
            $this->ensureSchema();
        } catch (\Throwable $e) {
            $this->log('[ExpertFieldAi] ensureSchema fail: ' . $e->getMessage());
        }
    }

    // ===================== 链式队列 =====================

    /**
     * 启动链式处理（关联 + AI，主入口）。
     */
    public function startChain($force = false, $delay = 1, $queue = '')
    {
        return $this->enqueueNext($delay, $queue, 0, $force);
    }

    /** @deprecated 兼容旧名 */
    public function startLinkChain($force = false, $delay = 1, $queue = '')
    {
        return $this->startChain($force, $delay, $queue);
    }

    public function enqueueNext($delay = 1, $queue = '', $afterExpertId = 0, $force = false)
    {
        if ($queue === '') {
            $queue = self::QUEUE_NAME;
        }
        $afterExpertId = intval($afterExpertId);
        $expertId = $this->findNextPendingExpertId($afterExpertId, $force);
        if ($expertId <= 0) {
            $this->log('[ExpertFieldAi] chain finished after expert_id=' . $afterExpertId);
            return false;
        }

        $data = [
            'expert_id' => $expertId,
            'queue'     => $queue,
            'force'     => $force ? 1 : 0,
        ];
        $jobClass = 'app\\api\\job\\ExpertFieldAiFill@fire';
        if ($delay > 0) {
            Queue::later($delay, $jobClass, $data, $queue);
        } else {
            Queue::push($jobClass, $data, $queue);
        }
        $this->log('[ExpertFieldAi] enqueued expert_id=' . $expertId . ' queue=' . $queue);
        return true;
    }

    /** @deprecated */
    public function enqueueNextLink($delay = 1, $queue = '', $afterExpertId = 0, $force = false)
    {
        return $this->enqueueNext($delay, $queue, $afterExpertId, $force);
    }

    // ===================== 主流程 =====================

    /**
     * 处理单个 expert：先关联 user，失败则 AI 总结。
     */
    public function processExpert($expertId, $force = false)
    {
        $expertId = intval($expertId);
        if ($expertId <= 0) {
            return ['ok' => false, 'error' => 'invalid expert_id'];
        }

        $expert = Db::name('expert')->where('expert_id', $expertId)->find();
        if (!$expert) {
            return ['ok' => false, 'error' => 'expert not found'];
        }

        if (!$force
            && intval($expert['field_ai_status']) === self::STATUS_DONE
            && trim((string)$expert['field_ai']) !== '') {
            return [
                'ok'       => true,
                'skipped'  => true,
                'field_ai' => (string)$expert['field_ai'],
                'source'   => (string)($expert['field_ai_source'] ?? ''),
            ];
        }

        $linkResult = $this->tryLinkFromUser($expertId, $expert, $force);
        if (!empty($linkResult['linked'])) {
            return array_merge(['ok' => true, 'method' => 'user_link'], $linkResult);
        }

        if (!$this->isEligible($expertId, $expert)) {
            $this->updateFieldAi($expertId, '', self::STATUS_INSUFFICIENT, '', 'insufficient papers/affiliation');
            return ['ok' => true, 'insufficient' => true, 'method' => 'ai'];
        }

        try {
            $context = $this->buildContext($expertId, $expert);
            $fieldAi = $this->summarizeWithLlm($context);
            if ($fieldAi === '') {
                throw new Exception('LLM returned empty field_ai');
            }
            $this->updateFieldAi($expertId, $fieldAi, self::STATUS_DONE, self::SOURCE_AI, 'ai summarized');
            return [
                'ok'       => true,
                'method'   => 'ai',
                'field_ai' => $fieldAi,
                'source'   => self::SOURCE_AI,
            ];
        } catch (\Throwable $e) {
            $this->updateFieldAi($expertId, '', self::STATUS_FAILED, '', mb_substr($e->getMessage(), 0, 500));
            $this->log('[ExpertFieldAi] expert_id=' . $expertId . ' ai fail: ' . $e->getMessage());
            return ['ok' => false, 'method' => 'ai', 'error' => $e->getMessage()];
        }
    }

    public function batchProcess(array $expertIds, $force = false)
    {
        $stats = ['total' => 0, 'linked' => 0, 'ai' => 0, 'skipped' => 0, 'insufficient' => 0, 'failed' => 0];
        $details = [];

        foreach ($expertIds as $expertId) {
            $expertId = intval($expertId);
            if ($expertId <= 0) {
                continue;
            }
            $result = $this->processExpert($expertId, $force);
            $stats['total']++;
            if (empty($result['ok'])) {
                $stats['failed']++;
            } elseif (!empty($result['skipped'])) {
                $stats['skipped']++;
            } elseif (!empty($result['linked']) || (isset($result['method']) && $result['method'] === 'user_link')) {
                $stats['linked']++;
            } elseif (!empty($result['insufficient'])) {
                $stats['insufficient']++;
            } elseif (isset($result['method']) && $result['method'] === 'ai') {
                $stats['ai']++;
            }
            $details[] = array_merge(['expert_id' => $expertId], $result);
        }

        return array_merge($stats, ['details' => $details]);
    }

    // ===================== 关联 user（辅助） =====================

    /**
     * 仅做 user 关联（不触发 AI），供调试。
     */
    public function linkFromUser($expertId, $force = false)
    {
        $expertId = intval($expertId);
        $expert = Db::name('expert')->where('expert_id', $expertId)->find();
        if (!$expert) {
            return ['ok' => false, 'error' => 'expert not found'];
        }

        $result = $this->tryLinkFromUser($expertId, $expert, $force);
        if (empty($result['linked']) && empty($result['skipped'])) {
            $this->updateFieldAi($expertId, '', self::STATUS_NO_USER_LINK, '', 'link only: no user match');
        }
        return array_merge(['ok' => true], $result);
    }

    public function batchLinkFromUser(array $expertIds, $force = false)
    {
        $linked = 0;
        $skipped = 0;
        $noLink = 0;
        $failed = 0;
        $details = [];

        foreach ($expertIds as $expertId) {
            $expertId = intval($expertId);
            if ($expertId <= 0) {
                continue;
            }
            $result = $this->linkFromUser($expertId, $force);
            if (empty($result['ok'])) {
                $failed++;
            } elseif (!empty($result['skipped'])) {
                $skipped++;
            } elseif (!empty($result['linked'])) {
                $linked++;
            } else {
                $noLink++;
            }
            $details[] = array_merge(['expert_id' => $expertId], $result);
        }

        return [
            'total'   => count($details),
            'linked'  => $linked,
            'skipped' => $skipped,
            'no_link' => $noLink,
            'failed'  => $failed,
            'details' => $details,
        ];
    }

    private function tryLinkFromUser($expertId, $expert = null, $force = false)
    {
        if ($expert === null) {
            $expert = Db::name('expert')->where('expert_id', intval($expertId))->find();
        }
        if (!$expert) {
            return ['linked' => false, 'reason' => 'expert not found'];
        }

        if (!$force
            && intval($expert['field_ai_status']) === self::STATUS_DONE
            && trim((string)$expert['field_ai']) !== '') {
            return [
                'linked'   => false,
                'skipped'  => true,
                'field_ai' => (string)$expert['field_ai'],
                'source'   => (string)($expert['field_ai_source'] ?? ''),
            ];
        }

        $email = strtolower(trim((string)($expert['email'] ?? '')));
        if ($email === '') {
            return ['linked' => false, 'reason' => 'empty email'];
        }

        $user = Db::name('user')->where('email', $email)->where('state', 0)->field('user_id,email,realname')->find();
        if (!$user) {
            return ['linked' => false, 'reason' => 'user not found'];
        }

        $uri = Db::name('user_reviewer_info')
            ->where('reviewer_id', intval($user['user_id']))
            ->where('state', 0)
            ->find();

        $fieldAi = $uri ? trim((string)($uri['field_ai'] ?? '')) : '';
        if ($fieldAi === '' || intval($uri['field_ai_status'] ?? 0) !== UserFieldAiService::STATUS_DONE) {
            return ['linked' => false, 'user_id' => intval($user['user_id']), 'reason' => 'user has no field_ai'];
        }

        $this->updateFieldAi(intval($expertId), $fieldAi, self::STATUS_DONE, self::SOURCE_USER_LINK, 'linked from user_id=' . $user['user_id']);
        return [
            'linked'   => true,
            'field_ai' => $fieldAi,
            'user_id'  => intval($user['user_id']),
            'source'   => self::SOURCE_USER_LINK,
        ];
    }

    public function syncExpertsByUserId($userId, $force = false)
    {
        $userId = intval($userId);
        $user = Db::name('user')->where('user_id', $userId)->where('state', 0)->field('user_id,email')->find();
        if (!$user || trim((string)$user['email']) === '') {
            return ['ok' => false, 'error' => 'user not found'];
        }

        $email = strtolower(trim((string)$user['email']));
        $expertIds = Db::name('expert')->where('email', $email)->where('state', '<>', 5)->column('expert_id');
        if (empty($expertIds)) {
            return ['ok' => true, 'synced' => 0, 'msg' => 'no expert with same email'];
        }

        return array_merge(['ok' => true], $this->batchLinkFromUser($expertIds, $force));
    }

    // ===================== AI 上下文 =====================

    public function isEligible($expertId, $expert = null)
    {
        if ($expert === null) {
            $expert = Db::name('expert')->where('expert_id', intval($expertId))->find();
        }
        if (!$expert) {
            return false;
        }

        if (trim((string)($expert['affiliation'] ?? '')) !== '') {
            return true;
        }

        $fieldRows = Db::name('expert_field')
            ->where('expert_id', intval($expertId))
            ->where('state', 0)
            ->field('field,paper_title,paper_journal')
            ->select();

        foreach ($fieldRows as $row) {
            if (trim((string)($row['paper_title'] ?? '')) !== '') {
                return true;
            }
            if (trim((string)($row['field'] ?? '')) !== '') {
                return true;
            }
        }

        return false;
    }

    public function buildContext($expertId, $expert = null)
    {
        if ($expert === null) {
            $expert = Db::name('expert')->where('expert_id', intval($expertId))->find();
        }

        $fieldRows = Db::name('expert_field')
            ->where('expert_id', intval($expertId))
            ->where('state', 0)
            ->order('expert_field_id desc')
            ->select();

        $searchKeywords = [];
        $papers = [];
        $seenPaper = [];

        foreach ($fieldRows as $row) {
            $kw = trim((string)($row['field'] ?? ''));
            if ($kw !== '') {
                $searchKeywords[] = $kw;
            }

            $title = trim((string)($row['paper_title'] ?? ''));
            if ($title === '') {
                continue;
            }
            $paperKey = md5($title . '|' . ($row['paper_article_id'] ?? ''));
            if (isset($seenPaper[$paperKey])) {
                continue;
            }
            $seenPaper[$paperKey] = true;
            $papers[] = [
                'title'   => mb_substr($title, 0, 300),
                'journal' => mb_substr(trim((string)($row['paper_journal'] ?? '')), 0, 120),
                'source'  => trim((string)($row['source'] ?? '')),
                'keyword' => $kw,
            ];
        }

        $maxPapers = max(1, min(15, (int)Env::get('expert_field_ai.max_papers', 8)));
        $papers = array_slice($papers, 0, $maxPapers);
        $searchKeywords = array_values(array_unique(array_filter($searchKeywords)));

        // t_expert.country 已存国家英文名，无需再查 country 表
        $countryName = trim((string)($expert['country'] ?? ''));
        if ($countryName === '') {
            $countryId = intval($expert['country_id'] ?? 0);
            if ($countryId > 0) {
                $row = Db::name('country')->where('country_id', $countryId)->find();
                if ($row) {
                    $countryName = (string)($row['en_name'] ?? ($row['zh_name'] ?? ''));
                }
            }
        }

        return [
            'expert' => [
                'name'        => trim((string)($expert['name'] ?? '')),
                'email'       => trim((string)($expert['email'] ?? '')),
                'affiliation' => trim((string)($expert['affiliation'] ?? '')),
                'country'     => $countryName,
                'source'      => trim((string)($expert['source'] ?? '')),
            ],
            'search_keywords' => $searchKeywords,
            'papers'          => $papers,
            'note'            => 'search_keywords 是 PubMed 检索词，不代表本人领域；请以论文标题与单位为准。',
        ];
    }

    // ===================== 预览 / 统计 =====================

    public function preview($expertId)
    {
        $expertId = intval($expertId);
        $expert = Db::name('expert')->where('expert_id', $expertId)->find();
        if (!$expert) {
            return ['ok' => false, 'error' => 'expert not found'];
        }

        $linkPreview = $this->previewLink($expertId);
        $eligible = $this->isEligible($expertId, $expert);
        $context = $eligible ? $this->buildContext($expertId, $expert) : null;

        return [
            'ok'                     => true,
            'expert_id'              => $expertId,
            'expert_field_ai'        => (string)($expert['field_ai'] ?? ''),
            'expert_field_ai_status' => intval($expert['field_ai_status'] ?? 0),
            'can_link_user'          => !empty($linkPreview['can_link']),
            'link_preview'           => $linkPreview,
            'eligible_for_ai'        => $eligible,
            'context_preview'        => $context,
        ];
    }

    public function previewLink($expertId)
    {
        $expertId = intval($expertId);
        $expert = Db::name('expert')->where('expert_id', $expertId)->find();
        if (!$expert) {
            return ['ok' => false, 'error' => 'expert not found'];
        }

        $email = strtolower(trim((string)($expert['email'] ?? '')));
        $user = null;
        $uri = null;
        if ($email !== '') {
            $user = Db::name('user')->where('email', $email)->where('state', 0)->field('user_id,email,realname')->find();
            if ($user) {
                $uri = Db::name('user_reviewer_info')
                    ->where('reviewer_id', intval($user['user_id']))
                    ->where('state', 0)
                    ->find();
            }
        }

        $canLink = $user && $uri
            && trim((string)($uri['field_ai'] ?? '')) !== ''
            && intval($uri['field_ai_status']) === UserFieldAiService::STATUS_DONE;

        return [
            'ok'                    => true,
            'expert_id'             => $expertId,
            'expert_email'          => $email,
            'matched_user_id'       => $user ? intval($user['user_id']) : 0,
            'matched_user_name'     => $user ? (string)$user['realname'] : '',
            'user_field_ai'         => $uri ? (string)($uri['field_ai'] ?? '') : '',
            'user_field_ai_status'  => $uri ? intval($uri['field_ai_status']) : 0,
            'can_link'              => $canLink,
        ];
    }

    // ===================== LLM =====================

    private function summarizeWithLlm(array $context)
    {
        $payloadJson = json_encode($context, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
        $systemPrompt = '你是学术领域分类助手。根据专家的单位、论文标题与 PubMed 检索上下文，用简体中文总结该专家最主要的研究领域。'
            . '注意：search_keywords 只是检索词，不可直接当作领域结论，应结合 paper 标题与 affiliation 判断。'
            . '要求：精确、简洁，1～3 个中文领域词或短短语，用顿号分隔；不要解释、不要英文。'
            . '只输出 JSON：{"field_ai":"..."}。';
        $userPrompt = "请根据以下 JSON 资料总结该专家的主要研究领域：\n" . $payloadJson;

        // 按上下文长度动态选模型（小: base.model_url1 / 大: base.model_url）
        $svc = new LocalModelService();
        $res = $svc->chat([
            ['role' => 'system', 'content' => $systemPrompt],
            ['role' => 'user',   'content' => $userPrompt],
        ], ['temperature' => 0.2]);

        if (empty($res['ok'])) {
            throw new Exception('LLM error: ' . (string)($res['error'] ?? 'unknown'));
        }

        $this->log('[ExpertFieldAi] llm tier=' . ($res['tier'] ?? '') . ' ctx_len=' . ($res['context_len'] ?? 0) . ' url=' . ($res['url'] ?? ''));

        $content = trim((string)($res['content'] ?? ''));
        $fieldAi = $this->parseFieldAiFromContent($content);
        if ($fieldAi === '' && $content !== '') {
            $fieldAi = $this->cleanFieldAiText($content);
        }
        return $fieldAi;
    }

    private function parseFieldAiFromContent($content)
    {
        $content = trim((string)$content);
        if ($content === '') {
            return '';
        }
        $content = preg_replace('/^```[a-zA-Z]*\s*|```$/m', '', $content);
        if (preg_match('/\{.*\}/s', $content, $m)) {
            $obj = json_decode($m[0], true);
            if (is_array($obj) && !empty($obj['field_ai'])) {
                return $this->cleanFieldAiText((string)$obj['field_ai']);
            }
        }
        $obj = json_decode($content, true);
        if (is_array($obj) && !empty($obj['field_ai'])) {
            return $this->cleanFieldAiText((string)$obj['field_ai']);
        }
        return '';
    }

    private function cleanFieldAiText($text)
    {
        $text = trim((string)$text);
        $text = trim($text, "\"' \t\n\r");
        $text = preg_replace('/\s+/u', '', $text);
        if (mb_strlen($text) > 200) {
            $text = mb_substr($text, 0, 200);
        }
        return $text;
    }

    // ===================== 内部工具 =====================

    private function findNextPendingExpertId($afterExpertId, $force)
    {
        $batch = 50;
        $cursor = intval($afterExpertId);

        while (true) {
            $query = Db::name('expert')
                ->where('expert_id', '>', $cursor)
                ->where('state', '<>', 5);

            if (!$force) {
                $query->where(function ($q) {
                    $q->where('field_ai_status', self::STATUS_PENDING)
                        ->whereOr('field_ai_status', self::STATUS_FAILED)
                        ->whereOr('field_ai_status', self::STATUS_NO_USER_LINK);
                });
            }

            $ids = $query->order('expert_id asc')->limit($batch)->column('expert_id');
            if (empty($ids)) {
                return 0;
            }

            foreach ($ids as $expertId) {
                $expertId = intval($expertId);
                $cursor = $expertId;

                if (!$force) {
                    $row = Db::name('expert')->where('expert_id', $expertId)->field('field_ai,field_ai_status')->find();
                    if ($row
                        && intval($row['field_ai_status']) === self::STATUS_DONE
                        && trim((string)$row['field_ai']) !== '') {
                        continue;
                    }
                }

                return $expertId;
            }
        }
    }

    private function updateFieldAi($expertId, $fieldAi, $status, $source, $note)
    {
        $this->ensureSchema();

        $data = [
            'field_ai'        => mb_substr(trim((string)$fieldAi), 0, 512),
            'field_ai_status' => intval($status),
            'field_ai_utime'  => time(),
        ];
        if ($this->hasColumn('field_ai_source')) {
            $data['field_ai_source'] = mb_substr(trim((string)$source), 0, 32);
        }

        Db::name('expert')->where('expert_id', intval($expertId))->update($data);
        if ($note !== '') {
            $this->log('[ExpertFieldAi] expert_id=' . $expertId . ' status=' . $status . ' note=' . $note);
        }
    }

    /**
     * 自动补全 t_expert 上缺失的 field_ai 字段（可重复执行）。
     */
    public function ensureSchema()
    {
        if (self::$schemaReady === true) {
            return;
        }

        $table = config('database.prefix') . 'expert';
        $columns = Db::query('SHOW COLUMNS FROM `' . $table . '`');
        $existing = [];
        foreach ($columns as $col) {
            $existing[$col['Field']] = true;
        }

        $alters = [];
        if (!isset($existing['field_ai'])) {
            $alters[] = "ADD COLUMN `field_ai` VARCHAR(512) NOT NULL DEFAULT '' COMMENT 'AI总结的主要研究领域(中文)' AFTER `affiliation`";
            $existing['field_ai'] = true;
        }
        if (!isset($existing['field_ai_status'])) {
            $alters[] = "ADD COLUMN `field_ai_status` TINYINT NOT NULL DEFAULT 0 COMMENT '0待处理 1已生成 2资料不足 3失败 4无user待AI' AFTER `field_ai`";
            $existing['field_ai_status'] = true;
        }
        if (!isset($existing['field_ai_utime'])) {
            $alters[] = "ADD COLUMN `field_ai_utime` INT NOT NULL DEFAULT 0 COMMENT 'field_ai更新时间' AFTER `field_ai_status`";
            $existing['field_ai_utime'] = true;
        }
        if (!isset($existing['field_ai_source'])) {
            $alters[] = "ADD COLUMN `field_ai_source` VARCHAR(32) NOT NULL DEFAULT '' COMMENT '来源: user_link / ai' AFTER `field_ai_utime`";
            $existing['field_ai_source'] = true;
        }

        if (!empty($alters)) {
            Db::execute('ALTER TABLE `' . $table . '` ' . implode(', ', $alters));
            $this->log('[ExpertFieldAi] schema patched: ' . implode('; ', $alters));
        }

        self::$schemaReady = true;
    }

    private function hasColumn($column)
    {
        $this->ensureSchema();
        $table = config('database.prefix') . 'expert';
        $columns = Db::query('SHOW COLUMNS FROM `' . $table . '` LIKE \'' . addslashes($column) . '\'');
        return !empty($columns);
    }

    public function statusLabel($status)
    {
        $map = [
            self::STATUS_PENDING      => 'pending',
            self::STATUS_DONE         => 'done',
            self::STATUS_INSUFFICIENT => 'insufficient',
            self::STATUS_FAILED       => 'failed',
            self::STATUS_NO_USER_LINK   => 'no_user_link',
        ];
        return isset($map[$status]) ? $map[$status] : 'unknown';
    }

    public function log($msg)
    {
        $line = date('Y-m-d H:i:s') . ' ' . $msg . PHP_EOL;
        @file_put_contents($this->logFile, $line, FILE_APPEND);
    }
}