import { fileURLToPath } from 'url'
import { dirname, resolve } from 'path'
import { addServerHandler, addTemplate, defineNuxtModule } from '@nuxt/kit'
import fs from 'fs-extra'

export interface ModuleOptions {}

export default defineNuxtModule<ModuleOptions>({
  meta: {
    name: 'trpc-nuxt',
    configKey: 'trpc',
  },
  defaults: {},
  async setup(_options, nuxt) {
    const srcDir = nuxt.options.srcDir
    // const root = nuxt.options.rootDir
    // const clientPath = join(nuxt.options.buildDir, 'trpc-client.ts')
    // const runtimeDir = fileURLToPath(new URL('./runtime', import.meta.url))
    // const serverPath = resolve(root, 'server/fn')
    const buildDir = fileURLToPath(new URL(nuxt.options.buildDir, import.meta.url))
    // const rootDir = fileURLToPath(new URL(root, import.meta.url))

    // nuxt.hook('config', (options) => {
    //   options.build.transpile.push('trpc-nuxt/client')
    // })

    // nuxt.hook('autoImports:extend', (imports) => {
    //   imports.push({
    //     from: clientPath,
    //     name: 'useServerFn',
    //     as: 'useServerFn',
    //   })
    // })

    const routePath = resolve(srcDir, 'server/fn/index.ts')
    await fs.ensureDir(dirname(routePath))
    if (!fs.existsSync(routePath)) {
      await fs.writeFile(routePath, `
      // generated by trpc-nuxt
      import * as trpc from '@trpc/server'
      
      export const router = trpc
        .router()
        .query('hello', {
          resolve: () => 'world',
        });
      
      export type Router = typeof router
    `.trimStart())
    }

    const handlerPath = resolve(srcDir, 'server/fn')
    addTemplate({
      filename: 'trpc-handler.mjs',
      write: true,
      getContents() {
        return `
            import { createTRPCHandler } from 'trpc-nuxt/api'
            import * as functions from "${handlerPath}"
            export default createTRPCHandler({
              router: functions.router
            })
          `.trimStart()
      },
    })

    addServerHandler({
      route: '/api/trpc/*',
      handler: resolve(buildDir, 'trpc-handler.mjs'),
    })
  },
})