import { joinURL } from 'ufo'
import { VIRTUAL_MODULES } from '@tanstack/start-server-core'
import { ENTRY_POINTS, START_ENVIRONMENT_NAMES } from '../../constants'
import {
  buildStartManifest,
  serializeStartManifest,
} from '../../start-manifest-plugin/manifestBuilder'
import { createVirtualModule } from '../createVirtualModule'
import type { GetConfigFn, NormalizedClientBuild } from '../../types'
import type { PluginOption } from 'vite'

export function startManifestPlugin(opts: {
  getClientBuild: () => NormalizedClientBuild | undefined
  getConfig: GetConfigFn
}): PluginOption {
  return createVirtualModule({
    name: 'tanstack-start:start-manifest-plugin',
    moduleId: VIRTUAL_MODULES.startManifest,
    enforce: 'pre',
    load() {
      const { resolvedStartConfig } = opts.getConfig()
      if (this.environment.name !== START_ENVIRONMENT_NAMES.server) {
        return 'export default {}'
      }

      if (this.environment.config.command === 'serve') {
        return `export const tsrStartManifest = () => ({
            routes: {},
            clientEntry: '${joinURL(resolvedStartConfig.basePaths.publicBase, '@id', ENTRY_POINTS.client)}',
          })`
      }

      const routeTreeRoutes = globalThis.TSS_ROUTES_MANIFEST
      const clientBuild = opts.getClientBuild()
      // TODO this needs further discussion with vite-rsc, this is a temporary workaround
      // If the client bundle isn't available yet (e.g., during RSC scan builds),
      // return a dummy manifest. The real manifest will be generated in the actual build.
      if (!clientBuild) {
        return `export const tsrStartManifest = () => ({
              routes: {},
              clientEntry: '${joinURL(resolvedStartConfig.basePaths.publicBase, '@id', ENTRY_POINTS.client)}',
              })`
      }
      const startManifest = buildStartManifest({
        clientBuild,
        routeTreeRoutes,
        basePath: resolvedStartConfig.basePaths.publicBase,
      })

      return `export const tsrStartManifest = () => (${serializeStartManifest(startManifest)})`
    },
  })
}