import { Injectable, Logger } from '@nestjs/common';
import { DeepSeekProvider } from '../ai/providers/deepseek.provider';
import type { AiChatDto } from './dto/ai-chat.dto';

const HERMES_API_URL = 'http://10.2.0.7:8642/v1/chat/completions';
const HERMES_API_KEY = 'zhixi-hermes-key-2026';
const SYSTEM_PROMPT = '你是知习管理后台的 AI 任务助理，帮助管理员处理日常任务、解答问题。请用简洁专业的中文回复。';

@Injectable()
export class AdminAiChatService {
  private readonly logger = new Logger(AdminAiChatService.name);

  constructor(private readonly deepseek: DeepSeekProvider) {}

  async chat(dto: AiChatDto) {
    const systemMessages = dto.messages.filter(m => m.role === 'system');
    const hasSystemPrompt = systemMessages.length > 0;

    const messages = hasSystemPrompt
      ? dto.messages
      : [{ role: 'system' as const, content: SYSTEM_PROMPT }, ...dto.messages];

    // Try Hermes Agent first, fall back to DeepSeek
    try {
      return await this.callHermes(messages);
    } catch (err: any) {
      this.logger.warn('Hermes unavailable, falling back to DeepSeek: ' + err.message);
      return await this.callDeepSeek(messages);
    }
  }

  private async callHermes(messages: Array<{ role: string; content: string }>) {
    const start = Date.now();
    const resp = await fetch(HERMES_API_URL, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        Authorization: 'Bearer ' + HERMES_API_KEY,
      },
      body: JSON.stringify({
        model: 'hermes-agent',
        messages,
        temperature: 0.7,
        max_tokens: 4096,
      }),
      signal: AbortSignal.timeout(120_000),
    });

    if (!resp.ok) {
      throw new Error('Hermes returned ' + resp.status);
    }

    const data = await resp.json();
    const content = data.choices?.[0]?.message?.content || '';
    const usage = data.usage || {};

    this.logger.log('Hermes chat: ' + (Date.now() - start) + 'ms, tokens: ' +
      (usage.prompt_tokens || 0) + '/' + (usage.completion_tokens || 0));
    return { content, usage: { model: 'hermes-agent', inputTokens: usage.prompt_tokens, outputTokens: usage.completion_tokens } };
  }

  private async callDeepSeek(messages: Array<{ role: string; content: string }>) {
    const start = Date.now();
    const result = await this.deepseek.generate({
      model: 'deepseek-chat',
      messages: messages as Array<{ role: 'system' | 'user' | 'assistant'; content: string }>,
      temperature: 0.7,
      maxTokens: 4096,
    });
    this.logger.log('DeepSeek chat: ' + (Date.now() - start) + 'ms');
    return { content: result.rawText, usage: result.usage };
  }

  getDashboardConfig() {
    return {
      url: 'http://10.2.0.7:9119',
      apiUrl: 'http://10.2.0.7:8642/v1',
      description: 'Hermes Agent Dashboard — 4核4G 上的 AI Agent',
    };
  }
}