import type { NextApiRequest, NextApiResponse } from "next"
import fs from "fs"
import path from "path"

const CHAT_HISTORY_FILE = path.join(process.cwd(), "chat-history.json")

interface ChatMessage {
  role: "user" | "assistant" | "system"
  content: string
}

// Get Ollama base URL from environment variable
const OLLAMA_BASE_URL = process.env.OLLAMA_BASE_URL || "http://localhost:11434"

// Read chat history from file
function readChatHistory(): ChatMessage[] {
  try {
    if (fs.existsSync(CHAT_HISTORY_FILE)) {
      const data = fs.readFileSync(CHAT_HISTORY_FILE, "utf-8")
      const history = JSON.parse(data)
      // Convert stored messages to Ollama format (only user and assistant roles)
      return history.messages
        .filter((msg: any) => msg.role === "user" || msg.role === "assistant")
        .map((msg: any) => ({
          role: msg.role,
          content: msg.content,
        }))
    }
  } catch (error) {
    console.error("Error reading chat history:", error)
  }
  return []
}

export default async function handler(
  req: NextApiRequest,
  res: NextApiResponse
) {
  if (req.method !== "POST") {
    return res.status(405).json({ error: "Method not allowed" })
  }

  const { model, prompt } = req.body

  try {
    // Get conversation history
    const conversationHistory = readChatHistory()
    
    // Add current user message to the conversation
    const messages = [
      ...conversationHistory,
      { role: "user" as const, content: prompt },
    ]

    // Use chat endpoint instead of generate to maintain conversation context
    const ollamaRes = await fetch(`${OLLAMA_BASE_URL}/api/chat`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({
        model,
        messages,
        stream: false,
      }),
    })

    const data = await ollamaRes.json()
    res.status(200).json(data)
  } catch (err) {
    console.error("Ollama API error:", err)
    res.status(500).json({ error: "Failed to connect to Ollama" })
  }
}