'use strict'

const path = require('path')

/**
 * Application storage layout (ADR architecture).
 * $STORAGE/
 *   worlds/<id>/
 *     anvil/
 *     meta.json
 *   corestore/   (future)
 *   identity/    (future)
 */

function worldsRoot(storageDir) {
  return path.join(storageDir, 'worlds')
}

function worldDir(storageDir, worldId) {
  return path.join(worldsRoot(storageDir), safeId(worldId))
}

function worldAnvilDir(storageDir, worldId) {
  return path.join(worldDir(storageDir, worldId), 'anvil')
}

function worldMetaPath(storageDir, worldId) {
  return path.join(worldDir(storageDir, worldId), 'meta.json')
}

function safeId(id) {
  const s = String(id || '')
    .trim()
    .toLowerCase()
    .replace(/[^a-z0-9_-]+/g, '-')
    .replace(/^-+|-+$/g, '')
  if (!s || s === '.' || s === '..') {
    throw new Error(`Invalid world id: ${id}`)
  }
  if (s.length > 64) throw new Error('World id too long (max 64)')
  return s
}

module.exports = {
  worldsRoot,
  worldDir,
  worldAnvilDir,
  worldMetaPath,
  safeId
}