// Must not start with "/" or "./" or "../"
const NON_NODE_MODULE_RE = /^[^.\/]|^\.[^.\/]|^\.\.[^\/]/

module.exports = ({ patterns, skipNodeModulesBundle, disabled }) => {
  return {
    name: `external`,
    setup(build) {
      if (disabled) return
      if (skipNodeModulesBundle) {
        build.onResolve({ filter: NON_NODE_MODULE_RE }, (args) => ({
          path: args.path,
          external: true,
        }))
      }
      if (!patterns || patterns.length === 0) return
      build.onResolve({ filter: /.*/ }, (args) => {
        const external = patterns.some((p) => {
          if (p instanceof RegExp) {
            return p.test(args.path)
          }
          return args.path === p
        })
        if (external) {
          return { path: args.path, external }
        }
      })
    },
  }
}