import { getLogger } from "@logtape/logtape"
import {
  ChatSessionModelFunctions,
  defineChatSessionFunction,
  GbnfJsonSchema,
} from "npm:node-llama-cpp"

type RemoteFunction = {
  name: string
  description: string
  parameters?: Readonly<GbnfJsonSchema>
  [key: string]: unknown
}

const remoteLogger = getLogger(["remote-functions"])

export async function fetchRemoteFunctions(
  host = Deno.env.get("REMOTE_FUNCTIONS_HOST") ||
    "http://localhost:1337/",
): Promise<ChatSessionModelFunctions> {
  const url = new URL(host)
  url.pathname = url.pathname.replace(/\/$/, "") + "/client/functions.json"
  const response = await fetch(url.toString(), {
    headers: {
      "Content-Type": "application/json",
      Authorization: `Bearer ${Deno.env.get("REMOTE_FUNCTIONS_TOKEN") || ""}`,
    },
  })

  if (!response.ok) {
    throw new Error(`Failed to call remote function: ${response.statusText}`)
  }

  const functions = await response.json() as RemoteFunction[]

  if (!Array.isArray(functions)) {
    throw new Error("Invalid response format, expected an array of functions")
  }

  return functions.reduce((acc, func) => {
    if (!func.name || !func.description) {
      throw new Error(
        `Function ${JSON.stringify(func)} is missing required fields`,
      )
    }
    acc[func.name] = defineChatSessionFunction({
      description: func.description,
      params: func.parameters,
      handler: async (args) => {
        try {
          const url = new URL(host)
          url.pathname = url.pathname.replace(/\/$/, "") +
            "/client/remote-function/" + func.name
          const requestBody = {
            arguments: args,
          }
          const requestHeaders = {
            "Content-Type": "application/json",
            Authorization: `Bearer ${
              Deno.env.get("REMOTE_FUNCTIONS_TOKEN") || ""
            }`,
          }
          remoteLogger.info("Calling backend:", {
            url: url.toString(),
            headers: requestHeaders,
            body: requestBody,
          })
          const response = await fetch(url.toString(), {
            method: "POST",
            headers: requestHeaders,
            body: JSON.stringify(requestBody),
          })
          remoteLogger.info("Response status:", { status: response.status })

          if (!response.ok) {
            return (
              `Failed to call remote function: ${response.statusText} ${await response
                .text()}`
            )
          }

          const responseText = await response.text()
          remoteLogger.info("Response text:", { responseText })
          return responseText
        } catch (error) {
          console.error(
            `Error calling remote function ${func.name}: \n`,
            error,
          )
          throw error
        }
      },
    })
    return acc
  }, {} as Record<string, ReturnType<typeof defineChatSessionFunction>>)
}