import { join, resolve } from 'path';
import { workspaceRoot } from '@nx/devkit';
import { existsSync } from 'fs-extra';
import { defineNuxtModule } from '@nuxt/kit';
import { defu } from 'defu';
import { NuxtModule } from '@nuxt/schema';

export const NxNuxtModule: NuxtModule = defineNuxtModule({
  meta: { name: '@nx/nuxt/module', configKey: 'nx' },
  setup(_options, nuxt) {
    nuxt.options.alias = defu(nuxt.options.alias, nxTsPaths());
  },
});

/**
 * read the compilerOptions.paths option from a tsconfig and return as aliases for Nuxt
 **/
function nxTsPaths() {
  const tsConfigPath = getTsConfig(join(workspaceRoot, 'tsconfig.base.json'));
  const tsPaths = require(tsConfigPath)?.compilerOptions?.paths as Record<
    string,
    string[]
  >;

  const alias: Record<string, string> = {};
  if (tsPaths) {
    for (const p in tsPaths) {
      // '@org/something/*': ['libs/something/src/*'] => '@org/something': '{pathToWorkspaceRoot}/libs/something/src'
      alias[p.replace(/\/\*$/, '')] = join(
        workspaceRoot,
        tsPaths[p][0].replace(/\/\*$/, '')
      );
    }
  }

  return alias;
}

function getTsConfig(preferredTsConfigPath: string): string {
  return [
    resolve(preferredTsConfigPath),
    resolve(join(workspaceRoot, 'tsconfig.base.json')),
    resolve(join(workspaceRoot, 'tsconfig.json')),
  ].find((tsPath) => {
    if (existsSync(tsPath)) {
      return tsPath;
    }
  });
}