1const semver = require('semver')
2const { basename } = require('path')
3const { URL } = require('url')
4module.exports = (name, tgz) => {
5  const base = basename(tgz)
6  if (!base.endsWith('.tgz')) {
7    return null
8  }
9
10  if (tgz.startsWith('http:/') || tgz.startsWith('https:/')) {
11    const u = new URL(tgz)
12    // registry url?  check for most likely pattern.
13    // either /@foo/bar/-/bar-1.2.3.tgz or
14    // /foo/-/foo-1.2.3.tgz, and fall through to
15    // basename checking.  Note that registries can
16    // be mounted below the root url, so /a/b/-/x/y/foo/-/foo-1.2.3.tgz
17    // is a potential option.
18    const tfsplit = u.pathname.slice(1).split('/-/')
19    if (tfsplit.length > 1) {
20      const afterTF = tfsplit.pop()
21      if (afterTF === base) {
22        const pre = tfsplit.pop()
23        const preSplit = pre.split(/\/|%2f/i)
24        const project = preSplit.pop()
25        const scope = preSplit.pop()
26        return versionFromBaseScopeName(base, scope, project)
27      }
28    }
29  }
30
31  const split = name.split(/\/|%2f/i)
32  const project = split.pop()
33  const scope = split.pop()
34  return versionFromBaseScopeName(base, scope, project)
35}
36
37const versionFromBaseScopeName = (base, scope, name) => {
38  if (!base.startsWith(name + '-')) {
39    return null
40  }
41
42  const parsed = semver.parse(base.substring(name.length + 1, base.length - 4))
43  return parsed ? {
44    name: scope && scope.charAt(0) === '@' ? `${scope}/${name}` : name,
45    version: parsed.version,
46  } : null
47}
48