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 {
  id: string
  role: "user" | "assistant"
  content: string
  timestamp: number
  model?: string
}

interface ChatHistory {
  messages: ChatMessage[]
}

// Read chat history from file
function readChatHistory(): ChatHistory {
  try {
    if (fs.existsSync(CHAT_HISTORY_FILE)) {
      const data = fs.readFileSync(CHAT_HISTORY_FILE, "utf-8")
      return JSON.parse(data)
    }
  } catch (error) {
    console.error("Error reading chat history:", error)
  }
  return { messages: [] }
}

// Write chat history to file
function writeChatHistory(history: ChatHistory): void {
  try {
    fs.writeFileSync(CHAT_HISTORY_FILE, JSON.stringify(history, null, 2))
  } catch (error) {
    console.error("Error writing chat history:", error)
  }
}

export default async function handler(
  req: NextApiRequest,
  res: NextApiResponse
) {
  if (req.method === "GET") {
    // Get chat history
    const history = readChatHistory()
    return res.status(200).json(history)
  } else if (req.method === "POST") {
    // Add message to chat history
    const { message } = req.body as { message: ChatMessage }
    
    if (!message || !message.role || !message.content) {
      return res.status(400).json({ error: "Invalid message format" })
    }

    const history = readChatHistory()
    history.messages.push(message)
    writeChatHistory(history)
    
    return res.status(200).json({ success: true })
  } else if (req.method === "DELETE") {
    // Clear chat history
    writeChatHistory({ messages: [] })
    return res.status(200).json({ success: true })
  } else {
    return res.status(405).json({ error: "Method not allowed" })
  }
}