import { createRequire } from 'node:module'
import fs from 'node:fs'
import path from 'node:path'
import visit from 'unist-util-visit'

export type RehypeHeroTemplateOptions = {
  demosPackage?: string // package name to resolve (e.g. '@tamagui/demos')
  demosPath?: string // or direct path to demos directory
}

export const rehypeHeroTemplate = (options: RehypeHeroTemplateOptions = {}) => {
  let demosRoot: string

  if (options.demosPath) {
    demosRoot = options.demosPath
  } else if (options.demosPackage) {
    // @ts-ignore
    const requireFn =
      typeof require === 'undefined' ? createRequire(import.meta.url) : require
    const resolved = requireFn.resolve(options.demosPackage)
    demosRoot = path.join(resolved, '..', '..', '..')
  } else {
    throw new Error('rehypeHeroTemplate requires either demosPackage or demosPath option')
  }

  return (tree: any) => {
    visit(tree, 'element', (node: any) => {
      if (node.tagName !== 'code' || !node.properties.template) return
      const templateName = node.properties.template
      if (!templateName) return
      const templatePath = path.join(demosRoot, 'src', `${templateName}Demo.tsx`)
      try {
        const source = fs.readFileSync(templatePath, 'utf8')
        node.children[0].value = source
      } catch (err: any) {
        console.warn(`Error setting template`, err.message)
      }
    })
  }
}