import { spawn } from 'node:child_process'
import {
  isValidTeamMachineSessionId,
  teamMachineSessionIdFromCliIdentity,
} from './agent-identity.ts'
import type { AgentPromptEnvelope } from './agent-prompt.ts'

export { teamMachineSessionIdFromCliIdentity } from './agent-identity.ts'

export function formatTeamMachinePromptText(prompt: AgentPromptEnvelope): string {
  return typeof prompt.text === 'string' ? prompt.text.trim() : ''
}

function resolveTeamMachineCommand(explicit?: string): string {
  const fromArg = explicit?.trim()
  if (fromArg) return fromArg
  return 'tm'
}

export async function sendPromptToTeamMachineSession(input: {
  sessionId: string
  prompt: AgentPromptEnvelope
  command?: string
  timeoutMs?: number
}): Promise<void> {
  const sessionId = input.sessionId.trim()
  if (!isValidTeamMachineSessionId(sessionId)) {
    throw new Error(`invalid Team Machine session id: ${sessionId || '<empty>'}`)
  }
  const text = formatTeamMachinePromptText(input.prompt)
  if (!text) {
    throw new Error('prompt text is empty')
  }

  const command = resolveTeamMachineCommand(input.command)
  const timeoutMs = input.timeoutMs ?? 15_000
  await new Promise<void>((resolve, reject) => {
    const child = spawn(command, ['send', sessionId, text], {
      stdio: ['ignore', 'ignore', 'pipe'],
      env: process.env,
    })
    let stderr = ''
    const timer = setTimeout(() => {
      try {
        child.kill('SIGTERM')
      } catch {}
      reject(new Error(`tm send timed out after ${Math.round(timeoutMs / 1000)}s`))
    }, timeoutMs)

    child.stderr?.setEncoding('utf8')
    child.stderr?.on('data', (chunk) => {
      if (stderr.length < 4000) stderr += String(chunk)
    })
    child.on('error', (err) => {
      clearTimeout(timer)
      reject(err)
    })
    child.on('close', (code, signal) => {
      clearTimeout(timer)
      if (code === 0) {
        resolve()
        return
      }
      const detail = stderr.trim()
      reject(
        new Error(
          detail ||
            `tm send exited with ${signal ? `signal ${signal}` : `code ${code ?? 'unknown'}`}`,
        ),
      )
    })
  })
}