import fs from 'fs'
import path from 'path'
import { transformSync } from '@babel/core'
import { parseComponent, compileTemplate } from 'vue/compiler-sfc'

// 沿用项目的 Vue 2.7 SFC 测试方式，避免调用不匹配的旧 vue-jest 编译器。
const cache = new Map()
export function load(filename) {
  if (cache.has(filename)) return cache.get(filename)
  const parts = parseComponent(fs.readFileSync(filename, 'utf8'))
  const code = transformSync(parts.script.content, { babelrc: false, configFile: false, plugins: [require.resolve('@babel/plugin-transform-modules-commonjs')] }).code
  const module = { exports: {}}
  const localRequire = id => {
    if (id.startsWith('.') || id.startsWith('@/')) {
      let resolved = id.startsWith('.') ? path.resolve(path.dirname(filename), id) : path.resolve('src', id.slice(2))
      if (fs.existsSync(resolved) && fs.statSync(resolved).isDirectory()) resolved = path.join(resolved, 'index.js')
      else if (!path.extname(resolved)) resolved += '.js'
      return resolved.endsWith('.vue') ? load(resolved) : require(resolved)
    }
    return require(id)
  }
  new Function('require', 'module', 'exports', code)(localRequire, module, module.exports)
  const compiled = compileTemplate({ source: parts.template.content, filename })
  if (compiled.errors.length) throw new Error(compiled.errors.join('\n'))
  Object.assign(module.exports.default, new Function(compiled.code + ';return { render, staticRenderFns }')())
  cache.set(filename, module.exports.default)
  return module.exports.default
}