<?php

namespace app\common\service\ai;

use app\common\model\ai\AiChatMessage;
use app\common\model\ai\AiChatSession;
use app\common\model\ai\AiConfig;
use app\common\model\ai\AiLog;
use think\facade\Cache;

class AiAssistantService
{
    public const AI_LOG_TYPE_ASSISTANT = 7;

    public static function chat(string $message, int $userId, string $clientId, int $sessionId = 0, string $ip = ''): array
    {
        $message = trim(mb_substr($message, 0, 1000));
        if ($message === '') {
            return ['success' => false, 'error' => '请输入要咨询的问题'];
        }
        if ($userId <= 0 && $clientId === '') {
            return ['success' => false, 'error' => '缺少会话标识'];
        }
        if (!self::checkRateLimit($userId, $clientId, $ip)) {
            return ['success' => false, 'error' => '提问太频繁，请稍后再试'];
        }

        $session = self::resolveSession($sessionId, $userId, $clientId, $message);
        if (!$session) {
            return ['success' => false, 'error' => '会话不存在或无权访问'];
        }

        $history = self::historyMessages((int) $session->id);
        $context = AiAssistantContextService::build($message, $userId, (int) $session->id);

        AiChatMessage::create([
            'session_id' => (int) $session->id,
            'user_id' => $userId,
            'client_id' => $clientId,
            'role' => AiChatMessage::ROLE_USER,
            'content' => $message,
            'sources_json' => '[]',
            'status' => AiChatMessage::STATUS_SUCCESS,
            'create_time' => time(),
            'update_time' => time(),
        ]);

        $messages = self::buildModelMessages($history, $message, $context);
        $result = self::callAssistantModel($messages);

        $status = !empty($result['success']) ? AiChatMessage::STATUS_SUCCESS : AiChatMessage::STATUS_FAILED;
        $answer = !empty($result['success'])
            ? trim((string) ($result['content'] ?? ''))
            : 'AI助手暂时没有生成成功，请稍后再试。';
        if ($answer === '') {
            $answer = '我暂时没有找到足够的站内依据，请换个关键词再问一次。';
        }

        $assistantMessage = AiChatMessage::create([
            'session_id' => (int) $session->id,
            'user_id' => $userId,
            'client_id' => $clientId,
            'role' => AiChatMessage::ROLE_ASSISTANT,
            'content' => $answer,
            'sources_json' => json_encode($context['sources'] ?? [], JSON_UNESCAPED_UNICODE),
            'model' => (string) ($result['model'] ?? self::defaultModelOptions()['model']),
            'tokens_used' => (int) ($result['tokens'] ?? 0),
            'cost_ms' => (int) ($result['cost_ms'] ?? 0),
            'status' => $status,
            'error_msg' => mb_substr((string) ($result['error'] ?? ''), 0, 500),
            'create_time' => time(),
            'update_time' => time(),
        ]);

        self::touchSession((int) $session->id, $message, $answer);
        self::recordAiLog($userId, (int) $session->id, $result, $status);

        if (empty($result['success'])) {
            return ['success' => false, 'error' => self::sanitizeModelError((string) ($result['error'] ?? ''))];
        }

        $session = AiChatSession::findOrEmpty((int) $session->id);
        return [
            'success' => true,
            'data' => [
                'session' => self::formatSession($session->toArray()),
                'message' => self::formatMessage($assistantMessage->toArray()),
                'sources' => $context['sources'] ?? [],
            ],
        ];
    }

    public static function sessions(int $userId, string $clientId): array
    {
        if ($userId <= 0 && $clientId === '') {
            return [];
        }

        $query = AiChatSession::order('last_active_time desc')->order('id desc')->limit(30);
        self::applyOwnerWhere($query, $userId, $clientId);
        return array_map([self::class, 'formatSession'], $query->select()->toArray());
    }

    public static function messages(int $sessionId, int $userId, string $clientId): array
    {
        $session = self::getOwnedSession($sessionId, $userId, $clientId);
        if (!$session) {
            return ['success' => false, 'error' => '会话不存在或无权访问'];
        }

        $messages = AiChatMessage::where('session_id', $sessionId)
            ->order('id', 'asc')
            ->limit(200)
            ->select()
            ->toArray();

        return [
            'success' => true,
            'data' => [
                'session' => self::formatSession($session->toArray()),
                'messages' => array_map([self::class, 'formatMessage'], $messages),
            ],
        ];
    }

    public static function clear(int $sessionId, int $userId, string $clientId): array
    {
        if ($sessionId > 0) {
            $session = self::getOwnedSession($sessionId, $userId, $clientId);
            if (!$session) {
                return ['success' => false, 'error' => '会话不存在或无权访问'];
            }
            AiChatMessage::where('session_id', $sessionId)->delete();
            $session->delete();
            return ['success' => true];
        }

        if ($userId <= 0 && $clientId === '') {
            return ['success' => false, 'error' => '缺少会话标识'];
        }

        $query = AiChatSession::field('id');
        self::applyOwnerWhere($query, $userId, $clientId);
        $ids = $query->column('id');
        if (!empty($ids)) {
            AiChatMessage::whereIn('session_id', $ids)->delete();
            AiChatSession::whereIn('id', $ids)->delete();
        }

        return ['success' => true];
    }

    private static function resolveSession(int $sessionId, int $userId, string $clientId, string $message): ?AiChatSession
    {
        if ($sessionId > 0) {
            return self::getOwnedSession($sessionId, $userId, $clientId);
        }

        $now = time();
        return AiChatSession::create([
            'user_id' => $userId,
            'client_id' => $clientId,
            'title' => self::makeTitle($message),
            'last_message' => $message,
            'last_active_time' => $now,
            'message_count' => 0,
            'create_time' => $now,
            'update_time' => $now,
        ]);
    }

    private static function getOwnedSession(int $sessionId, int $userId, string $clientId): ?AiChatSession
    {
        $query = AiChatSession::where('id', $sessionId);
        self::applyOwnerWhere($query, $userId, $clientId);
        $session = $query->findOrEmpty();
        return $session->isEmpty() ? null : $session;
    }

    private static function applyOwnerWhere($query, int $userId, string $clientId): void
    {
        if ($userId > 0) {
            $query->where('user_id', $userId);
            return;
        }
        $query->where('user_id', 0)->where('client_id', $clientId);
    }

    private static function historyMessages(int $sessionId): array
    {
        $limit = max(2, min(20, (int) AiConfig::getVal('assistant_history_limit', '8')));
        $rows = AiChatMessage::where('session_id', $sessionId)
            ->where('status', AiChatMessage::STATUS_SUCCESS)
            ->order('id', 'desc')
            ->limit($limit)
            ->select()
            ->toArray();
        return array_reverse($rows);
    }

    private static function buildModelMessages(array $history, string $message, array $context): array
    {
        $messages = [
            [
                'role' => 'system',
                'content' => AiConfig::getVal('assistant_system_prompt', self::defaultSystemPrompt()),
            ],
        ];

        foreach ($history as $row) {
            $role = $row['role'] === AiChatMessage::ROLE_ASSISTANT ? 'assistant' : 'user';
            $content = trim((string) ($row['content'] ?? ''));
            if ($content !== '') {
                $messages[] = ['role' => $role, 'content' => mb_substr($content, 0, 1000)];
            }
        }

        $messages[] = [
            'role' => 'user',
            'content' => "用户问题：\n{$message}\n\n站内资料与实时上下文：\n"
                . ($context['context_text'] ?? '{}')
                . "\n\n请按照“直接结论、依据摘要、相关内容、风险提示”的结构回答。"
                . "如果站内资料不足，请明确说明，不要编造。彩票、赛事预测、加密行情必须提示不构成投资或购彩建议。",
        ];

        return $messages;
    }

    private static function callAssistantModel(array $messages): array
    {
        $client = new DeepSeekClient();
        $optionsList = [self::defaultModelOptions()];

        $failedErrors = [];
        $lastResult = ['success' => false, 'error' => 'AI助手模型服务暂时不可用', 'tokens' => 0];
        foreach ($optionsList as $options) {
            $result = $client->chatMessages($messages, $options);
            if (!empty($result['success'])) {
                return $result;
            }

            $lastResult = $result;
            $provider = (string) ($result['provider_label'] ?? ($options['provider_label'] ?? 'AI模型'));
            $failedErrors[] = $provider . ': ' . (string) ($result['error'] ?? '调用失败');
        }

        if (!empty($failedErrors)) {
            $lastResult['error'] = implode(' | ', $failedErrors);
        }
        return $lastResult;
    }

    private static function sanitizeModelError(string $error): string
    {
        $error = trim($error);
        if ($error === '') {
            return 'AI助手模型调用失败：未知错误';
        }

        $error = preg_replace('/Bearer\s+[A-Za-z0-9._\-]+/i', 'Bearer ***', $error) ?: $error;
        $error = preg_replace('/sk-[A-Za-z0-9._\-]{8,}/i', 'sk-***', $error) ?: $error;
        return mb_substr($error, 0, 500);
    }

    private static function defaultModelOptions(): array
    {
        return DeepSeekClient::defaultModelOptions([
            'max_tokens' => 1600,
            'temperature' => 0.45,
        ]);
    }

    private static function checkRateLimit(int $userId, string $clientId, string $ip): bool
    {
        $limit = max(1, (int) AiConfig::getVal('assistant_rate_limit_per_minute', '10'));
        $identity = $userId > 0 ? 'u' . $userId : 'c' . md5($clientId . '|' . $ip);
        $key = 'assistant_rate_' . $identity . '_' . date('YmdHi');
        $count = (int) Cache::get($key);
        if ($count >= $limit) {
            return false;
        }
        Cache::set($key, $count + 1, 70);
        return true;
    }

    private static function touchSession(int $sessionId, string $question, string $answer): void
    {
        AiChatSession::where('id', $sessionId)->update([
            'last_message' => mb_substr($question, 0, 500),
            'last_answer' => mb_substr($answer, 0, 500),
            'last_active_time' => time(),
            'message_count' => AiChatMessage::where('session_id', $sessionId)->count(),
            'update_time' => time(),
        ]);
    }

    private static function recordAiLog(int $userId, int $sessionId, array $result, int $status): void
    {
        AiLog::create([
            'user_id' => $userId,
            'type' => self::AI_LOG_TYPE_ASSISTANT,
            'ref_id' => $sessionId,
            'tokens_used' => (int) ($result['tokens'] ?? 0),
            'cost_ms' => (int) ($result['cost_ms'] ?? 0),
            'status' => $status === AiChatMessage::STATUS_SUCCESS ? 1 : 2,
            'create_time' => time(),
        ]);
    }

    private static function formatSession(array $row): array
    {
        return [
            'id' => (int) ($row['id'] ?? 0),
            'title' => (string) ($row['title'] ?? ''),
            'last_message' => (string) ($row['last_message'] ?? ''),
            'last_answer' => (string) ($row['last_answer'] ?? ''),
            'message_count' => (int) ($row['message_count'] ?? 0),
            'last_active_time' => self::formatTime($row['last_active_time'] ?? 0),
            'create_time' => self::formatTime($row['create_time'] ?? 0),
        ];
    }

    private static function formatMessage(array $row): array
    {
        $sources = json_decode((string) ($row['sources_json'] ?? '[]'), true);
        return [
            'id' => (int) ($row['id'] ?? 0),
            'session_id' => (int) ($row['session_id'] ?? 0),
            'role' => (string) ($row['role'] ?? ''),
            'content' => (string) ($row['content'] ?? ''),
            'sources' => is_array($sources) ? $sources : [],
            'status' => (int) ($row['status'] ?? 1),
            'error_msg' => (string) ($row['error_msg'] ?? ''),
            'create_time' => self::formatTime($row['create_time'] ?? 0),
        ];
    }

    private static function formatTime($value): string
    {
        if (is_numeric($value) && (int) $value > 0) {
            return date('Y-m-d H:i:s', (int) $value);
        }
        return (string) ($value ?: '');
    }

    private static function makeTitle(string $message): string
    {
        $title = trim(preg_replace('/\s+/u', ' ', $message) ?: '');
        return mb_substr($title ?: '新的对话', 0, 24);
    }

    private static function defaultSystemPrompt(): string
    {
        return '你是世博头条 AI 助手，面向普通用户回答站内体育资讯、赛事、社区、彩票和加密行情相关问题。'
            . '必须优先依据提供的站内资料和实时上下文回答；资料不足时要直接说明不足并建议用户换关键词。'
            . '不要声称可以访问后台、源码、服务器或未提供的内部数据。'
            . '回答使用中文，结构清晰，语气专业克制。涉及赛事预测、彩票或加密行情时，必须说明仅供参考，不构成投资或购彩建议。';
    }
}