import { workerData, parentPort } from "worker_threads"
import type { MessagePort } from "worker_threads"
import { discoverSkillsInDirAsync } from "./async-loader"
import type { LoadedSkill, SkillScope } from "./types"

interface WorkerInput {
  dirs: string[]
  scopes: SkillScope[]
}

interface WorkerOutputSuccess {
  ok: true
  skills: LoadedSkill[]
}

interface WorkerOutputError {
  ok: false
  error: { message: string; stack?: string }
}

type WorkerOutput = WorkerOutputSuccess | WorkerOutputError

const { signal } = workerData as { signal: Int32Array }

if (!parentPort) {
  throw new Error("Worker must be run with parentPort")
}

parentPort.once("message", (data: { port: MessagePort }) => {
  const { port } = data

  port.on("message", async (input: WorkerInput) => {
    try {
      const results = await Promise.all(
        input.dirs.map(dir => discoverSkillsInDirAsync(dir))
      )
      
      const skills = results.flat()
      
      const output: WorkerOutputSuccess = { ok: true, skills }
      
      port.postMessage(output)
      Atomics.store(signal, 0, 1)
      Atomics.notify(signal, 0)
    } catch (error: unknown) {
      const output: WorkerOutputError = {
        ok: false,
        error: {
          message: error instanceof Error ? error.message : String(error),
          stack: error instanceof Error ? error.stack : undefined,
        },
      }
      
      port.postMessage(output)
      Atomics.store(signal, 0, 1)
      Atomics.notify(signal, 0)
    }
  })
})