import { resolve } from "node:path";
import { tmpdir } from "node:os";

import {
  createTestWorkspace,
  removeTestWorkspace,
} from "../workspace/workspaceFixture.js";
import {
  processTest,
  type ProcessResult,
  type TestProcesses,
} from "../process/processFixture.js";

/** Caller-controlled values for one compiled REA CLI invocation. */
export interface CliInvocation {
  readonly arguments: readonly string[];
  readonly cwd?: string;
  readonly environment?: NodeJS.ProcessEnv;
  readonly input?: string | Uint8Array;
  readonly timeoutMs?: number;
}

/** Normalized result from the compiled REA CLI. */
export interface CliResult extends ProcessResult {
  readonly json: unknown | undefined;
}

/** Compiled REA CLI driver owned by one test. */
export interface TestCli {
  run(invocation: CliInvocation): Promise<CliResult>;
}

const parseJson = (stdout: string): unknown | undefined => {
  const document = stdout.trim();
  if (document.length === 0) return undefined;
  try {
    return JSON.parse(document) as unknown;
  } catch {
    return undefined;
  }
};

/** Create a compiled CLI driver backed by the supplied process registry. */
export const createTestCli = (
  processes: TestProcesses,
  compileCache?: string,
): TestCli => ({
  run: async ({
    arguments: arguments_,
    cwd,
    environment,
    input,
    timeoutMs,
  }) => {
    const result = await processes.run(
      process.execPath,
      [resolve("scripts/rea.mjs"), ...arguments_],
      {
        cwd: cwd ?? process.cwd(),
        env: {
          PATH: process.env.PATH ?? "",
          // Native Windows APIs need the system root and a writable temporary
          // directory even when the command's application environment is empty.
          ...(process.platform === "win32"
            ? {
                SystemRoot: process.env.SystemRoot,
                TEMP: tmpdir(),
                TMP: tmpdir(),
              }
            : {}),
          ...(compileCache === undefined ||
          environment?.NODE_V8_COVERAGE !== undefined
            ? {}
            : { NODE_COMPILE_CACHE: compileCache }),
          ...environment,
        },
        ...(input === undefined ? {} : { input }),
        ...(timeoutMs === undefined ? {} : { timeoutMs }),
      },
    );
    return { ...result, json: parseJson(result.stdout) };
  },
});

/** Vitest API extended with an owned process registry and compiled CLI driver. */
export const cliTest = processTest.extend<{
  $test: { cli: TestCli };
  $worker: { cliCompileCache: string };
}>({
  cliCompileCache: [
    // oxlint-disable-next-line no-empty-pattern -- Vitest parses fixture dependencies from object destructuring.
    async ({}, use) => {
      const workspace = await createTestWorkspace("rea-cli-compile-cache-");
      try {
        await use(workspace.path("node-compile"));
      } finally {
        await removeTestWorkspace(workspace.root);
      }
    },
    { scope: "worker" },
  ],
  cli: async ({ processes, cliCompileCache }, use) => {
    await use(createTestCli(processes, cliCompileCache));
  },
});