<?php

namespace Leantime\Domain\Ai\Services;

use Illuminate\Support\Facades\Http;
use Laravel\Mcp\Server\Tool;
use Leantime\Core\Domains\BaseService;
use Leantime\Domain\Setting\Services\Setting as SettingService;

/**
 * OneBot 界面内 AI 聊天代理。
 *
 * 调用 OpenAI 兼容的 /chat/completions（DeepSeek 官方 API 或本地千问 Ollama），
 * 支持 function-calling：把 MCP Tools 类转成 OpenAI tools 定义，LLM 请求工具调用时
 * 执行对应 Tool::handle()，结果回填 messages 继续，直到 LLM 返回最终文本。
 */
class AiChat extends BaseService
{
    /** 默认 LLM 配置（.env 或 settings 可覆盖） */
    private const DEFAULTS = [
        'provider' => 'deepseek',               // deepseek | ollama
        'baseUrl' => 'https://api.deepseek.com/v1',
        'model' => 'deepseek-chat',
        'apiKey' => '',
        'temperature' => '0.7',
        'maxTokens' => '2048',
    ];

    public function __construct(
        private SettingService $settingService,
    ) {}

    /**
     * 发送一条用户消息，返回 AI 最终回复文本（已执行工具调用）。
     *
     * @param  array<int,array{role:string,content:string}>  $messages  历史消息（含本次 user 消息）
     * @return array{success:bool,content?:string,error?:string}
     */
    public function chat(array $messages): array
    {
        $cfg = $this->config();

        if (empty($cfg['apiKey'])) {
            return ['success' => false, 'error' => '尚未配置 AI 服务（apiKey 为空）。请在 .env 或「AI 设置」中填写 provider/baseUrl/model/apiKey。'];
        }

        $tools = $this->buildTools();

        // 最多循环 8 轮，防止工具调用死循环
        for ($round = 0; $round < 8; $round++) {
            $resp = Http::withToken($cfg['apiKey'])
                ->withoutVerifying()
                ->timeout(120)
                ->post(rtrim($cfg['baseUrl'], '/').'/chat/completions', [
                    'model' => $cfg['model'],
                    'messages' => $messages,
                    'temperature' => (float) $cfg['temperature'],
                    'max_tokens' => (int) $cfg['maxTokens'],
                    'tools' => $tools,
                    'tool_choice' => 'auto',
                ]);

            if (! $resp->successful()) {
                return ['success' => false, 'error' => "LLM 调用失败 HTTP {$resp->status()}: ".substr($resp->body(), 0, 300)];
            }

            $body = $resp->json();
            $choice = $body['choices'][0] ?? null;
            if ($choice === null) {
                return ['success' => false, 'error' => 'LLM 返回为空'];
            }

            $message = $choice['message'] ?? [];
            $toolCalls = $message['tool_calls'] ?? [];

            // 无工具调用 → 最终回复
            if (empty($toolCalls)) {
                return ['success' => true, 'content' => (string) ($message['content'] ?? '')];
            }

            // 有工具调用 → 把 assistant 消息（含 tool_calls）追加，逐个执行工具，回填 tool 结果
            $messages[] = $message;

            foreach ($toolCalls as $tc) {
                $toolName = $tc['function']['name'] ?? '';
                $toolArgs = json_decode($tc['function']['arguments'] ?? '{}', true) ?: [];

                $toolResult = $this->callTool($toolName, $toolArgs);

                $messages[] = [
                    'role' => 'tool',
                    'tool_call_id' => $tc['id'] ?? '',
                    'content' => $toolResult,
                ];
            }
        }

        return ['success' => false, 'error' => '工具调用轮次过多，已中止。'];
    }

    /**
     * 当前 AI 配置（settings 优先，其次 .env，最后默认值）。
     */
    private function config(): array
    {
        $cfg = self::DEFAULTS;
        foreach (['provider', 'baseUrl', 'model', 'apiKey', 'temperature', 'maxTokens'] as $k) {
            $envKey = 'AI_'.strtoupper(preg_replace('/(?<!^)[A-Z]/', '_$0', $k));
            $env = env($envKey);
            $stored = $this->settingService->getSetting('ai.'.$k, false);

            if ($stored !== false && $stored !== '' && $stored !== null) {
                $cfg[$k] = $stored;
            } elseif ($env !== null && $env !== '') {
                $cfg[$k] = $env;
            }
        }

        return $cfg;
    }

    /**
     * 返回当前 AI 配置（脱敏版，apiKey 只显示前 6 位）。
     * 供前端「AI 设置」面板展示。
     */
    public function publicConfig(): array
    {
        $cfg = $this->config();
        $key = (string) $cfg['apiKey'];
        $cfg['apiKeyMasked'] = $key === '' ? '' : substr($key, 0, 6).'...';
        $cfg['apiKey'] = ''; // 不向前端回传完整 key

        return $cfg;
    }

    /**
     * 把 MCP Tools 类转成 OpenAI function-calling 的 tools 定义。
     */
    private function buildTools(): array
    {
        $tools = [];
        $pattern = app()->basePath('app/Domain/*/Tools/*Tool.php');
        foreach (glob($pattern) ?: [] as $file) {
            $class = $this->classFromFile($file);
            if ($class === null || ! class_exists($class) || ! is_subclass_of($class, Tool::class)) {
                continue;
            }

            try {
                /** @var Tool $instance */
                $instance = app()->make($class);
                $arr = $instance->toArray();
                $tools[] = [
                    'type' => 'function',
                    'function' => [
                        'name' => $arr['name'],
                        'description' => $arr['description'],
                        'parameters' => $arr['inputSchema'],
                    ],
                ];
            } catch (\Throwable $e) {
                // 单个工具失败不阻断
            }
        }

        return $tools;
    }

    /**
     * 执行一个工具（按 name 匹配 Tools 类），返回文本结果。
     */
    private function callTool(string $toolName, array $args): string
    {
        $pattern = app()->basePath('app/Domain/*/Tools/*Tool.php');
        foreach (glob($pattern) ?: [] as $file) {
            $class = $this->classFromFile($file);
            if ($class === null || ! class_exists($class) || ! is_subclass_of($class, Tool::class)) {
                continue;
            }

            try {
                /** @var Tool $instance */
                $instance = app()->make($class);
                if ($instance->name() !== $toolName) {
                    continue;
                }

                $result = $instance->handle($args);
                $arr = $result->toArray();
                // ToolResult 的 content 是 [{type,text}] 结构
                $texts = [];
                foreach (($arr['content'] ?? []) as $c) {
                    if (isset($c['text'])) {
                        $texts[] = $c['text'];
                    }
                }

                return $texts !== [] ? implode("\n", $texts) : json_encode($arr, JSON_UNESCAPED_UNICODE);
            } catch (\Throwable $e) {
                return '工具执行出错: '.$e->getMessage();
            }
        }

        return "未知工具: {$toolName}";
    }

    /**
     * 从文件路径推导类名：app/Domain/Projects/Tools/GetAllProjectsTool.php
     * → Leantime\Domain\Projects\Tools\GetAllProjectsTool
     */
    private function classFromFile(string $file): ?string
    {
        $appRoot = rtrim(app()->basePath('app'), '/\\');
        if (! str_starts_with($file, $appRoot)) {
            return null;
        }

        $relative = substr($file, strlen($appRoot));
        $relative = ltrim(str_replace(['/', '\\'], '\\', $relative), '\\');
        $relative = preg_replace('/\.php$/', '', $relative);

        if ($relative === '' || $relative === null) {
            return null;
        }

        return app()->getNamespace().$relative;
    }
}