import { pathToFileURL } from 'node:url'
import { createApp, createError, defineEventHandler, defineLazyEventHandler } from 'h3'
import { ViteNodeServer } from 'vite-node/server'
import fse from 'fs-extra'
import { resolve } from 'pathe'
import { addServerMiddleware } from '@nuxt/kit'
import type { Plugin as VitePlugin, ViteDevServer } from 'vite'
import { ExternalsOptions, isExternal, ExternalsDefaults } from 'externality'
import { resolve as resolveModule } from 'mlly'
import { distDir } from './dirs'
import type { ViteBuildContext } from './vite'
import { isCSS } from './utils'

// TODO: Remove this in favor of registerViteNodeMiddleware
// after Nitropack or h3 fixed for adding middlewares after setup
export function viteNodePlugin (ctx: ViteBuildContext): VitePlugin {
  return {
    name: 'nuxt:vite-node-server',
    enforce: 'pre',
    configureServer (server) {
      server.middlewares.use('/__nuxt_vite_node__', createViteNodeMiddleware(ctx))
    }
  }
}

export function registerViteNodeMiddleware (ctx: ViteBuildContext) {
  addServerMiddleware({
    route: '/__nuxt_vite_node__/',
    handler: createViteNodeMiddleware(ctx)
  })
}

function getManifest (server: ViteDevServer) {
  const ids = Array.from(server.moduleGraph.urlToModuleMap.keys())
    .filter(i => isCSS(i))

  const entries = [
    '@vite/client',
    'entry.mjs',
    ...ids.map(i => i.slice(1))
  ]

  return {
    publicPath: '',
    all: entries,
    initial: entries,
    async: [],
    modules: {}
  }
}

function createViteNodeMiddleware (ctx: ViteBuildContext) {
  const app = createApp()

  app.use('/manifest', defineEventHandler(() => {
    const manifest = getManifest(ctx.ssrServer)
    return manifest
  }))

  app.use('/module', defineLazyEventHandler(() => {
    const viteServer = ctx.ssrServer
    const node: ViteNodeServer = new ViteNodeServer(viteServer, {
      deps: {
        inline: [
          /\/(nuxt|nuxt3)\//,
          /^#/,
          ...ctx.nuxt.options.build.transpile as string[]
        ]
      },
      transformMode: {
        ssr: [/.*/],
        web: []
      }
    })
    const externalOpts: ExternalsOptions = {
      inline: [
        /virtual:/,
        /\.ts$/,
        ...ExternalsDefaults.inline,
        ...viteServer.config.ssr.noExternal as string[]
      ],
      external: [
        ...viteServer.config.ssr.external,
        /node_modules/
      ],
      resolve: {
        type: 'module',
        extensions: ['.ts', '.js', '.json', '.vue', '.mjs', '.jsx', '.tsx', '.wasm']
      }
    }
    const rootDir = ctx.nuxt.options.rootDir
    node.shouldExternalize = async (id: string) => {
      const result = await isExternal(id, rootDir, externalOpts)
      if (result?.external) {
        return resolveModule(result.id, { url: rootDir })
      }
      return false
    }

    return async (event) => {
      const moduleId = decodeURI(event.req.url).substring(1)
      if (moduleId === '/') {
        throw createError({ statusCode: 400 })
      }
      const module = await node.fetchModule(moduleId) as any
      return module
    }
  }))

  return app.nodeHandler
}

export async function prepareDevServerEntry (ctx: ViteBuildContext) {
  let entryPath = resolve(ctx.nuxt.options.appDir, 'entry.async.mjs')
  if (!fse.existsSync(entryPath)) {
    entryPath = resolve(ctx.nuxt.options.appDir, 'entry.async')
  }

  // TODO: Update me
  const host = ctx.nuxt.options.server.host || 'localhost'
  const port = ctx.nuxt.options.server.port || '3000'
  const protocol = ctx.nuxt.options.server.https ? 'https' : 'http'

  // Serialize and pass vite-node runtime options
  const viteNodeServerOptions = {
    baseURL: `${protocol}://${host}:${port}/__nuxt_vite_node__`,
    rootDir: ctx.nuxt.options.rootDir,
    entryPath,
    base: ctx.ssrServer.config.base || '/_nuxt/'
  }
  process.env.NUXT_VITE_NODE_OPTIONS = JSON.stringify(viteNodeServerOptions)

  const serverResolvedPath = resolve(distDir, 'runtime/vite-node.mjs')
  const manifestResolvedPath = resolve(distDir, 'runtime/client.manifest.mjs')

  await fse.writeFile(
    resolve(ctx.nuxt.options.buildDir, 'dist/server/server.mjs'),
    `export { default } from ${JSON.stringify(pathToFileURL(serverResolvedPath).href)}`
  )
  await fse.writeFile(
    resolve(ctx.nuxt.options.buildDir, 'dist/server/client.manifest.mjs'),
    `export { default } from ${JSON.stringify(pathToFileURL(manifestResolvedPath).href)}`
  )
}