const oldS = gatherDepSet(set, edge => !edge.optional)
const newS = gatherDepSet(set, edge => !set.has(edge.to))
if (!oldS.size !== newS.size) {
  graph(oldS, newS)
}

function graph (...sets) {
  const safe = (id) => id.replaceAll('@', '_')
  let code = 'flowchart\n'
  for (const node of sets[0].values().next().value.root.inventory.values()) {
    const rgb = sets.map(s => s.has(node) ? 'c' : '6').concat(...'666').slice(0, 3).join('')
    code += `style ${safe(node.pkgid)} fill:#${rgb},color:#000\n`
    for (const edge of node.edgesOut.values()) {
      code += `${safe(node.pkgid)}-${edge.optional ? '.' : ''}->|${edge.type} ${edge.error || ''}|${safe(edge.to?.pkgid || `${edge.name}@${edge.spec}`)}\n`
    }
  }
  const mermaid = JSON.stringify({ theme: 'neutral' })
  console.log(`https://mermaid.live/edit#pako:${require('zlib').deflateSync(JSON.stringify({ code, mermaid })).toString('base64')}`)
}