import { NextRequest } from "next/server";
import ZAI from "z-ai-web-dev-sdk";

const SYSTEM_PROMPT = `You are Echo, a concise, helpful voice assistant. Follow these rules strictly:

1. **Verbal response**: Reply in ≤ 2 short sentences so it sounds natural when spoken aloud. Be direct and conversational.
2. **Local commands** (optional): If the user's request can be fulfilled by a local OS action, include a single JSON block at the very end of your response using this exact format:

\`\`\`json
{"action": "<command_name>", "params": {"key": "value"}}
\`\`\`

3. Do NOT include the JSON block in your spoken text.
4. Never use markdown formatting, bullet points, or headers in the spoken text.
5. If the user asks you to do something you cannot do, be honest about it briefly.`;

// Store conversation history per session
const sessionHistories = new Map<string, Array<{ role: string; content: string }>>();

export async function POST(request: NextRequest) {
  try {
    const { message, conversationId } = await request.json();

    if (!message) {
      return new Response(JSON.stringify({ error: "Message is required" }), {
        status: 400,
        headers: { "Content-Type": "application/json" },
      });
    }

    // Get or create session history
    const history = sessionHistories.get(conversationId) || [];
    history.push({ role: "user", content: message });

    // Keep last 20 messages for context
    const recentHistory = history.slice(-20);

    const zai = await ZAI.create();
    const completion = await zai.chat.completions.create({
      messages: [
        { role: "system", content: SYSTEM_PROMPT },
        ...recentHistory,
      ],
      temperature: 0.7,
      max_tokens: 300,
    });

    const assistantMessage =
      completion.choices[0]?.message?.content || "I'm sorry, I couldn't process that.";

    // Clean any thinking tags
    const cleanedMessage = assistantMessage
      .replace(/<think[^>]*>.*?<\/think\s*>/gs, "")
      .replace(/```json.*?```/gs, "")
      .trim();

    // Store in history
    history.push({ role: "assistant", content: cleanedMessage });
    sessionHistories.set(conversationId, history);

    return new Response(
      JSON.stringify({
        message: cleanedMessage,
        rawMessage: assistantMessage,
      }),
      {
        status: 200,
        headers: { "Content-Type": "application/json" },
      }
    );
  } catch (error) {
    console.error("Chat API error:", error);
    return new Response(
      JSON.stringify({
        message: "Sorry, I had trouble thinking about that. Please try again.",
        error: true,
      }),
      {
        status: 200,
        headers: { "Content-Type": "application/json" },
      }
    );
  }
}