import { cp, mkdtemp, rm, stat } from "node:fs/promises";
import os from "node:os";
import path from "node:path";

import { normalizeArtifactSymlinks } from "./artifact-postprocess.ts";
import type { BuildArtifact, BuildStrategy } from "./build-strategy.ts";
import {
  hasPackageDependency,
  hasRootFile,
  runPackageCli,
} from "./build-strategy.ts";
import { defaultHttpPortForBuildType } from "./config/frameworks.ts";
import type { BuildCommandIo } from "./workspace.ts";

const NUXT_CONFIG_FILENAMES = [
  "nuxt.config.js",
  "nuxt.config.mjs",
  "nuxt.config.cjs",
  "nuxt.config.ts",
  "nuxt.config.mts",
];

/**
 * Build strategy for Nuxt applications using the Nitro `node-server` preset
 * (the default). Runs `nuxt build` and produces an artifact from `.output/`.
 */
export class NuxtBuild implements BuildStrategy {
  readonly #appPath: string;
  readonly #io?: BuildCommandIo;

  constructor(options: { appPath: string; io?: BuildCommandIo }) {
    this.#appPath = options.appPath;
    this.#io = options.io;
  }

  async canBuild(signal?: AbortSignal): Promise<boolean> {
    return (
      (await hasRootFile(this.#appPath, NUXT_CONFIG_FILENAMES, signal)) ||
      (await hasPackageDependency(this.#appPath, ["nuxt"], signal))
    );
  }

  async execute(signal?: AbortSignal): Promise<BuildArtifact> {
    signal?.throwIfAborted();
    await runPackageCli({
      appPath: this.#appPath,
      cliName: "nuxt",
      args: ["build"],
      failurePrefix: "Nuxt",
      missingMessage:
        "Could not find the Nuxt CLI. Install it with `npm install nuxt` or ensure npx/bunx is available.",
      env: this.#io?.env,
      onOutput: this.#io?.onOutput,
      signal,
    });

    const outputDir = path.join(this.#appPath, ".output");
    const entryPath = path.join(outputDir, "server", "index.mjs");
    const entryStat = await stat(entryPath).catch(() => null);
    if (!entryStat?.isFile()) {
      throw new Error(
        "Nuxt build did not produce a Nitro node server entrypoint at .output/server/index.mjs. Ensure nitro.preset is 'node-server' (the default) — set NITRO_PRESET=node-server or remove any custom preset from nuxt.config.",
      );
    }

    const outDir = await mkdtemp(path.join(os.tmpdir(), "compute-build-"));

    try {
      const artifactDir = path.join(outDir, "app");
      await cp(outputDir, artifactDir, {
        recursive: true,
        verbatimSymlinks: true,
      });
      // Materialize any symlinks into the app/workspace node_modules so the
      // artifact is self-contained once unpacked elsewhere.
      await normalizeArtifactSymlinks(artifactDir, this.#appPath, signal);

      return {
        directory: artifactDir,
        entrypoint: "server/index.mjs",
        defaultPortMapping: { http: defaultHttpPortForBuildType("nuxt") },
        cleanup: () => rm(outDir, { recursive: true, force: true }),
      };
    } catch (error) {
      await rm(outDir, { recursive: true, force: true });
      throw error;
    }
  }
}