// step 4: RNX operations registered as just-bash commands.
//
// `rnx` inside a box shell is the same CLI, re-invoked as a child process with
// the shell's own cwd. that is deliberate — spelling the verbs a second time
// in shell-command form would be a second implementation of every command, and
// the spec is explicit that the CLI and the in-shell commands are clients of
// one implementation, not two.

import { spawn } from 'node:child_process'
import path from 'node:path'
import { defineCommand, type CustomCommand } from '@rnx/box/shell'
import { PROJECT_MOUNT } from '@rnx/box/shell'
import { rnxPublicBrand } from '../../../src/public-brand'
import { rnxSelfInvocation } from '../../self-invocation'
import { RNX_PLACEMENT_ENV } from '../../ws-bridge'

// map a shell path under /project back onto the real checkout, so a child
// process started from `cd src && rnx describe` sees the directory the user
// is actually standing in.
function hostCwd(root: string, shellCwd: string): string {
  if (shellCwd === PROJECT_MOUNT) return root
  if (!shellCwd.startsWith(`${PROJECT_MOUNT}/`)) return root
  return path.join(root, shellCwd.slice(PROJECT_MOUNT.length + 1))
}

export function createRnxCommand(options: {
  root: string
  shellCwd: () => string
}): CustomCommand {
  return defineCommand(rnxPublicBrand.commandName, async (args) => {
    const { executable, prefixArgs } = rnxSelfInvocation()
    const child = spawn(executable, [...prefixArgs, ...args], {
      cwd: hostCwd(options.root, options.shellCwd()),
      // mark the child as running inside a local box. this is the only thing
      // that sets a placement — nothing infers one from cwd — and it is what
      // lets `rnx box` refuse to nest inside itself.
      env: { ...process.env, [RNX_PLACEMENT_ENV]: 'local-box' },
      stdio: ['ignore', 'pipe', 'pipe'],
    })

    let stdout = ''
    let stderr = ''
    child.stdout.on('data', (chunk) => {
      stdout += String(chunk)
    })
    child.stderr.on('data', (chunk) => {
      stderr += String(chunk)
    })

    const exitCode = await new Promise<number>((resolve) => {
      child.once('error', (error) => {
        stderr += `${rnxPublicBrand.commandName}: ${error.message}\n`
        resolve(1)
      })
      child.once('close', (code) => resolve(code ?? 0))
    })

    return { stdout, stderr, exitCode }
  })
}