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 ASTRO_CONFIG_FILENAMES = [
  "astro.config.js",
  "astro.config.mjs",
  "astro.config.cjs",
  "astro.config.ts",
  "astro.config.mts",
];

/**
 * Build strategy for Astro applications using the @astrojs/node adapter
 * in standalone mode. Runs `astro build` and produces an artifact from `dist/`.
 */
export class AstroBuild 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, ASTRO_CONFIG_FILENAMES, signal)) ||
      (await hasPackageDependency(this.#appPath, ["astro"], signal))
    );
  }

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

    const distDir = path.join(this.#appPath, "dist");
    const entryPath = path.join(distDir, "server", "entry.mjs");
    const entryStat = await stat(entryPath).catch(() => null);
    if (!entryStat?.isFile()) {
      throw new Error(
        'Astro build did not produce a standalone server entrypoint. Install @astrojs/node and configure it with adapter: node({ mode: "standalone" }) in your astro.config file.',
      );
    }

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

    try {
      const artifactDir = path.join(outDir, "app");
      await cp(distDir, 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/entry.mjs",
        defaultPortMapping: { http: defaultHttpPortForBuildType("astro") },
        cleanup: () => rm(outDir, { recursive: true, force: true }),
      };
    } catch (error) {
      await rm(outDir, { recursive: true, force: true });
      throw error;
    }
  }
}