import { Injectable, Logger } from '@nestjs/common';
import type { AiChatDto } from './dto/ai-chat.dto';
import { AdminConversationService } from '../admin-conversation/admin-conversation.service';

const HERMES_API_URL = 'http://10.2.0.7:8642/v1/chat/completions';
const HERMES_API_KEY = 'zhixi-hermes-key-2026';

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

  constructor(private readonly conversationService: AdminConversationService) {}

  async chat(dto: AiChatDto, adminUserId: string) {
    const sessionId = dto.conversationId
      ? await this.conversationService.getSessionId(dto.conversationId, adminUserId)
      : null;

    // Auto-create conversation if none provided
    const conversationId = dto.conversationId
      ?? (await this.conversationService.create(adminUserId)).id;

    // Save user message
    const userMsg = dto.messages[dto.messages.length - 1];
    if (userMsg && userMsg.role === 'user') {
      await this.conversationService.saveMessage(conversationId, 'user', userMsg.content);
    }

    const result = await this.callHermes(dto.messages, sessionId);

    // Save assistant reply
    await this.conversationService.saveMessage(conversationId, 'assistant', result.content);

    return { ...result, conversationId };
  }

  private async callHermes(
    messages: Array<{ role: string; content: string }>,
    sessionId: string | null,
  ) {
    const start = Date.now();
    const headers: Record<string, string> = {
      'Content-Type': 'application/json',
      Authorization: 'Bearer ' + HERMES_API_KEY,
    };
    if (sessionId) {
      headers['X-Hermes-Session-Id'] = sessionId;
    }

    const resp = await fetch(HERMES_API_URL, {
      method: 'POST',
      headers,
      body: JSON.stringify({
        model: 'hermes-agent',
        messages,
        temperature: 0.7,
        max_tokens: 4096,
      }),
      signal: AbortSignal.timeout(120_000),
    });

    if (!resp.ok) {
      const text = await resp.text().catch(() => '');
      throw new Error(`Hermes API error ${resp.status}: ${text}`);
    }

    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 } };
  }

  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',
    };
  }
}