import { existsSync, readFileSync } from "node:fs";
import { resolve } from "node:path";
import { fileURLToPath } from "node:url";
import { spawn } from "node:child_process";
import { parse } from "dotenv";

const projectRoot = fileURLToPath(new URL("../", import.meta.url));
const directories = {
  development: ".next-dev",
  test: ".next-test",
  production: ".next",
};
const commands = new Set(["dev", "build", "start"]);
const readConfig = (file) =>
  existsSync(file) ? parse(readFileSync(file)) : {};
// Normalize each layer before merging so a legacy process override still wins over a profile.
const apiConfig = (values) => ({
  ...values,
  ...(!Object.hasOwn(values, "UPSTREAM_API_URL") &&
  Object.hasOwn(values, "API_BASE_URL")
    ? { UPSTREAM_API_URL: values.API_BASE_URL }
    : {}),
});

/** APP_ENV selects the deployment; NODE_ENV keeps Next's development/production semantics. */
export function nextCommand(
  environment = "development",
  command = "dev",
  args = [],
  { root = projectRoot, variables = process.env } = {},
) {
  if (!Object.hasOwn(directories, environment) || !commands.has(command))
    throw new Error(
      "Usage: node scripts/next-env.mjs development|test|production dev|build|start",
    );
  const base = resolve(root, "config", environment + ".env");
  if (!existsSync(base))
    throw new Error(`缺少环境配置：config/${environment}.env`);
  const env = {
    ...apiConfig(readConfig(base)),
    // Preserve the old local-development setup without leaking it into test/production.
    ...(environment === "development"
      ? apiConfig(readConfig(resolve(root, ".env.local")))
      : {}),
    ...apiConfig(
      readConfig(resolve(root, "config", environment + ".local.env")),
    ),
    ...apiConfig(
      Object.fromEntries(
        Object.entries(variables).filter(([, value]) => value !== undefined),
      ),
    ),
    APP_ENV: environment,
    APP_DIST_DIR: directories[environment],
    NODE_ENV: command === "dev" ? "development" : "production",
  };
  try {
    const value = (env.UPSTREAM_API_URL || "").trim();
    if (value === "current") env.UPSTREAM_API_URL = value;
    else {
      const api = new URL(value);
      if (
        !["http:", "https:"].includes(api.protocol) ||
        api.username ||
        api.password ||
        api.search ||
        api.hash
      )
        throw new Error();
      env.UPSTREAM_API_URL = api.href.replace(/\/+$/, "");
    }
    env.API_BASE_URL = env.UPSTREAM_API_URL;
  } catch {
    throw new Error(
      `config/${environment}.env 的 UPSTREAM_API_URL（兼容 API_BASE_URL）必须为 current 或有效的 HTTP(S) 接口地址`,
    );
  }
  const port = String(env.PORT || "21030");
  if (!/^\d+$/.test(port) || Number(port) < 1 || Number(port) > 65535)
    throw new Error("PORT 必须在 1–65535 之间");
  env.PORT = port;
  const hasOption = (names) =>
    args.some((arg) =>
      names.some((name) => arg === name || arg.startsWith(name + "=")),
    );
  const options =
    command === "build"
      ? []
      : [
          ...(hasOption(["--hostname", "-H"]) ? [] : ["--hostname", "0.0.0.0"]),
          ...(hasOption(["--port", "-p"]) ? [] : ["--port", port]),
        ];
  return {
    executable: process.execPath,
    args: [
      resolve(root, "node_modules/next/dist/bin/next"),
      command,
      ...options,
      ...args,
    ],
    cwd: root,
    env,
  };
}

export async function runNext(environment, command, args, options) {
  const spec = nextCommand(environment, command, args, options);
  const child = spawn(spec.executable, spec.args, {
    cwd: spec.cwd,
    env: spec.env,
    stdio: "inherit",
  });
  const interrupt = () => child.kill("SIGINT"),
    terminate = () => child.kill("SIGTERM");
  process.on("SIGINT", interrupt);
  process.on("SIGTERM", terminate);
  try {
    return await new Promise((resolve, reject) => {
      child.once("error", reject);
      child.once("exit", (code, signal) =>
        resolve(code ?? (signal === "SIGINT" ? 130 : 143)),
      );
    });
  } finally {
    process.off("SIGINT", interrupt);
    process.off("SIGTERM", terminate);
  }
}

if (
  process.argv[1] &&
  resolve(process.argv[1]) === fileURLToPath(import.meta.url)
) {
  try {
    const [environment = "development", command = "dev", ...args] =
      process.argv.slice(2);
    process.exitCode = await runNext(environment, command, args);
  } catch (error) {
    console.error(error instanceof Error ? error.message : "启动 Next.js 失败");
    process.exitCode = 1;
  }
}