/**
 * Build `/proc/bare_os/host_os.json` text (Holepunch `bare-os`-shaped snapshot).
 *
 * Always uses the **`bare-os`** package (ESM on Node and Bare). On Bare, **`bare-module`**
 * `createRequire` is used when needed; there is no `node:os` / `node:module` path.
 */

/**
 * @param {Record<string, string>} env
 * @returns {Promise<string>}
 */
export async function buildBareOsHostProcJsonText(env) {
  const rawInject = String(env.BARE_OS_HOST_OS_JSON || '').trim()
  if (rawInject) {
    try {
      const parsed = JSON.parse(rawInject)
      return `${JSON.stringify({
        schema: 1,
        source: 'BARE_OS_HOST_OS_JSON',
        host: parsed,
        atMs: Date.now()
      })}\n`
    } catch {
      return `${JSON.stringify({
        schema: 1,
        error: 'invalid BARE_OS_HOST_OS_JSON',
        atMs: Date.now()
      })}\n`
    }
  }
  const probe =
    env.BARE_OS_HOST_BARE_OS_PROC === '1' ||
    env.BARE_OS_HOST_BARE_OS_PROC === 'true'
  if (!probe) {
    return `${JSON.stringify({
      schema: 1,
      note: 'Set BARE_OS_HOST_BARE_OS_PROC=1 or inject BARE_OS_HOST_OS_JSON.',
      atMs: Date.now()
    })}\n`
  }
  try {
    let os
    if (typeof Bare !== 'undefined') {
      const bm = await import('bare-module')
      const createRequire = bm.createRequire || bm.default?.createRequire
      if (typeof createRequire !== 'function') {
        throw new Error('bare-module createRequire unavailable')
      }
      const _require = createRequire(import.meta.url)
      os = _require('bare-os')
    } else {
      const m = await import('bare-os')
      os = m.default ?? m
    }
    return `${JSON.stringify(hostPayloadFromBareOsLike(os, 'bare-os'))}\n`
  } catch {
    return `${JSON.stringify({
      schema: 1,
      note: 'Host OS probe failed; use BARE_OS_HOST_OS_JSON on this runtime.',
      atMs: Date.now()
    })}\n`
  }
}

/**
 * @param {Record<string, unknown>} os
 * @param {string} source
 */
function hostPayloadFromBareOsLike(os, source) {
  const snap = {
    platform: typeof os.platform === 'function' ? os.platform() : null,
    arch: typeof os.arch === 'function' ? os.arch() : null,
    hostname: typeof os.hostname === 'function' ? os.hostname() : null,
    release: typeof os.release === 'function' ? os.release() : null
  }
  let ifaces = null
  try {
    if (typeof os.networkInterfaces === 'function') {
      const n = os.networkInterfaces()
      if (n && typeof n === 'object') {
        ifaces = Object.keys(n)
          .slice(0, 32)
          .map((name) => ({
            name,
            count: Array.isArray(n[name]) ? n[name].length : 0
          }))
      }
    }
  } catch {
    ifaces = null
  }
  return {
    schema: 1,
    source,
    host: { ...snap, networkInterfaceNames: ifaces },
    atMs: Date.now()
  }
}