import { mkdtemp, rm, writeFile } from "node:fs/promises";
import { tmpdir } from "node:os";
import path from "node:path";
import { afterEach, describe, expect, it } from "vitest";
import {
  discoverModules,
  ModuleDiscoveryError,
  type ModuleDiscoveryIssueCode,
  resolveModulesDirectory,
} from "../src/modules/index.js";

const versions = { moduleSdkVersion: "0.1.0", platformVersion: "0.1.0" } as const;
const repositoryRoot = path.join(path.sep, "opt", "ekklesia");
const temporaryDirectories: string[] = [];

afterEach(async () => {
  await Promise.all(
    temporaryDirectories.splice(0).map((directory) => rm(directory, { recursive: true })),
  );
});

async function temporaryDirectory(): Promise<string> {
  const directory = await mkdtemp(path.join(tmpdir(), "ekklesia-modules-directory-"));
  temporaryDirectories.push(directory);
  return directory;
}

function captureDiscoveryError(operation: () => unknown): ModuleDiscoveryError {
  try {
    operation();
  } catch (error) {
    expect(error).toBeInstanceOf(ModuleDiscoveryError);
    return error as ModuleDiscoveryError;
  }
  throw new Error("Expected a ModuleDiscoveryError.");
}

async function captureAsyncDiscoveryError(
  operation: Promise<unknown>,
): Promise<ModuleDiscoveryError> {
  try {
    await operation;
  } catch (error) {
    expect(error).toBeInstanceOf(ModuleDiscoveryError);
    return error as ModuleDiscoveryError;
  }
  throw new Error("Expected a ModuleDiscoveryError.");
}

function codes(error: ModuleDiscoveryError): readonly ModuleDiscoveryIssueCode[] {
  return error.issues.map((issue) => issue.code);
}

/** Everything an operator, a log, or a test report could ever see from this error. */
function rendered(error: ModuleDiscoveryError): string {
  return JSON.stringify({ issues: error.issues, message: error.message, stack: error.stack });
}

describe("resolveModulesDirectory", () => {
  it("defaults to the repository's own modules directory when nothing is configured", () => {
    expect(resolveModulesDirectory({ configured: undefined, repositoryRoot })).toEqual({
      modulesDirectory: path.join(repositoryRoot, "modules"),
      modulesDirectoryRequired: false,
    });
  });

  it("accepts an explicit absolute path, normalized, and requires it to exist", () => {
    expect(
      resolveModulesDirectory({ configured: "/var/lib/ekklesia/modules/", repositoryRoot }),
    ).toEqual({ modulesDirectory: "/var/lib/ekklesia/modules", modulesDirectoryRequired: true });
    expect(
      resolveModulesDirectory({ configured: "/var/lib/./ekklesia//modules", repositoryRoot }),
    ).toEqual({ modulesDirectory: "/var/lib/ekklesia/modules", modulesDirectoryRequired: true });
  });

  it("never resolves a configured path against the repository or the working directory", () => {
    const resolved = resolveModulesDirectory({ configured: "/srv/modules", repositoryRoot });
    expect(resolved.modulesDirectory).toBe("/srv/modules");
  });

  it.each([
    ["a relative name", "modules"],
    ["a dot-relative path", "./modules"],
    ["a parent-relative path", "../private/modules"],
    ["a home-relative path", "~/modules"],
    ["the empty string", ""],
    ["whitespace only", "   "],
    ["an absolute path with surrounding whitespace", " /var/lib/ekklesia/modules"],
    ["a NUL byte", "/var/lib/ekklesia/\u0000modules"],
  ])("rejects %s with a sanitized MODULES_DIRECTORY_INVALID", (_label, configured) => {
    const error = captureDiscoveryError(() =>
      resolveModulesDirectory({ configured, repositoryRoot }),
    );
    expect(codes(error)).toEqual(["MODULES_DIRECTORY_INVALID"]);
    expect(error.issues[0]?.message).toBe("EKKLESIA_MODULES_DIR must be an absolute path.");
  });

  it("never echoes the supplied value in the error", () => {
    const configured = "relative/secret-token-a1b2c3/postgresql://admin:hunter2@db/modules";
    const error = captureDiscoveryError(() =>
      resolveModulesDirectory({ configured, repositoryRoot }),
    );
    const text = rendered(error);
    expect(text).not.toContain("secret-token-a1b2c3");
    expect(text).not.toContain("hunter2");
    expect(text).not.toContain("relative/");
  });
});

describe("module discovery against a configured modules directory", () => {
  it("fails closed, without the path, when a configured directory does not exist", async () => {
    const parent = await temporaryDirectory();
    const missing = path.join(parent, "private-mount-name-7f3e");
    const error = await captureAsyncDiscoveryError(
      discoverModules({ ...versions, modulesDirectory: missing, modulesDirectoryRequired: true }),
    );
    expect(codes(error)).toEqual(["MODULES_DIRECTORY_UNREADABLE"]);
    expect(rendered(error)).not.toContain("private-mount-name-7f3e");
    expect(rendered(error)).not.toContain(parent);
  });

  it("fails closed when a configured path is a file rather than a directory", async () => {
    const parent = await temporaryDirectory();
    const file = path.join(parent, "modules");
    await writeFile(file, "not a directory");
    const error = await captureAsyncDiscoveryError(
      discoverModules({ ...versions, modulesDirectory: file, modulesDirectoryRequired: true }),
    );
    expect(codes(error)).toEqual(["MODULES_DIRECTORY_UNREADABLE"]);
    expect(rendered(error)).not.toContain(parent);
  });

  it("rejects a relative configured path even when it bypasses the resolver", async () => {
    const error = await captureAsyncDiscoveryError(
      discoverModules({ ...versions, modulesDirectory: "modules", modulesDirectoryRequired: true }),
    );
    expect(codes(error)).toEqual(["MODULES_DIRECTORY_INVALID"]);
  });

  it("treats an existing, empty configured directory as zero installed modules", async () => {
    const directory = await temporaryDirectory();
    await expect(
      discoverModules({ ...versions, modulesDirectory: directory, modulesDirectoryRequired: true }),
    ).resolves.toEqual([]);
  });

  it("keeps the development default lenient: a missing default directory is zero modules", async () => {
    const parent = await temporaryDirectory();
    await expect(
      discoverModules({ ...versions, modulesDirectory: path.join(parent, "modules") }),
    ).resolves.toEqual([]);
  });

  it("discovers through the resolver's own selection unchanged", async () => {
    const directory = await temporaryDirectory();
    const selection = resolveModulesDirectory({ configured: directory, repositoryRoot });
    await expect(discoverModules({ ...versions, ...selection })).resolves.toEqual([]);
  });
});