#!/usr/bin/env node
const fse = require('fs-extra')
const globby = require('globby')

const DEP_FIELDS = [
  'dependencies',
]

const parseImports = filename => {
  return fse.readFile(filename, 'utf8')
    .then(scss => {
      const matches = scss.match(/\@import\s+"[-a-z]+\/index\.scss"/g)
      return matches
        ? Array.from(matches).map(stmt => stmt.match(/"([-a-z]+)\//)[1])
        : []
    })
}

const isPrimerModule = name => name.indexOf('primer') === 0

globby('modules/primer*')
  .then(paths => {
    return paths.reduce((modules, path) => {
      const pkg = require(`../${path}/package.json`)
      if (pkg.dependencies) {
        pkg.path = path
        modules.push(pkg)
      } else {
        console.warn('%s: no dependencies', pkg.name)
      }
      return modules
    }, [])
  })
  .then(modules => {
    console.log('⏱  checking %d modules...', modules.length)

    const maxNameLength = modules.reduce((len, {name}) => {
      return Math.max(len, name.length)
    }, 0)

    const map = new Map()
    modules.forEach(mod => map.set(mod.name, mod))

    const tasks = []
    const matches = []

    modules.forEach(mod => {
      const deps = Object.keys(mod.dependencies)
        .filter(isPrimerModule)

      tasks.push(
        parseImports(`${mod.path}/index.scss`)
          .then(imports => {
            console.warn('📦  %s: %s%d dependencies, %d import(s)',
                         mod.name, ' '.repeat(maxNameLength - mod.name.length),
                         deps.length, imports.length)
            imports.forEach(imported => {
              if (!deps.includes(imported)) {
                throw new Error(
                  `❌  ${mod.name} imports ${imported}, but is missing a dependency`
                )
              }
              matches.push({
                module: mod.name,
                imports: imported
              })
            })
          })
      )
    })
    return Promise.all(tasks)
      .then(() => {
        const primer = map.get('primer')

        const deps = new Set(
          Object.keys(primer.dependencies)
            .filter(isPrimerModule)
            .sort()
        )

        modules
          .map(mod => mod.name)
          .filter(mod => mod !== primer.name)
          .sort()
          .forEach(mod => {
            if (!deps.has(mod)) {
              throw new Error(
                `primer is missing dependency for ${mod}@${map.get(mod).version}`
              )
            }
          })
      })
      .then(() => matches)
  })
  .catch(error => {
    console.error(error)
    process.exit(1)
  })
  .then(matches => {
    console.warn('✅  checked %d dependency/import pairs', matches.length)
  })