import {
  chmodSync,
  existsSync,
  linkSync,
  lstatSync,
  mkdirSync,
  opendirSync,
  readFileSync,
  renameSync,
  unlinkSync,
  writeFileSync,
} from "node:fs";
import { join } from "node:path";
import type {
  WindowsAuthStorageBridge,
  WindowsAuthStorageDirectory,
} from "../../src/auth/windows-auth-storage.js";

// Test-process fixture only. The production POSIX implementation is the Go auth-storage bridge;
// the Go package covers retained-descriptor adversarial races separately.
export function createFixturePosixAuthStorageBridge(): WindowsAuthStorageBridge {
  const ensure = async (root: string): Promise<void> => {
    if (!existsSync(root)) {
      mkdirSync(root, { mode: 0o700 });
      chmodSync(root, 0o700);
    }
    for (const name of ["sessions", "oidc"]) {
      const path = join(root, name);
      if (!existsSync(path)) {
        mkdirSync(path, { mode: 0o700 });
        chmodSync(path, 0o700);
      }
    }
  };
  const path = async (root: string, directory: WindowsAuthStorageDirectory, filename: string): Promise<string> => {
    await ensure(root);
    return join(root, directory, filename);
  };
  const names = async (root: string, directory: WindowsAuthStorageDirectory): Promise<string[]> => {
    await ensure(root);
    const handle = opendirSync(join(root, directory));
    const result: string[] = [];
    try {
      for (;;) {
        const entry = handle.readSync();
        if (entry === null) break;
        result.push(entry.name);
      }
    } finally {
      handle.closeSync();
    }
    return result.sort();
  };
  const missing = (error: unknown): boolean => (error as { code?: unknown })?.code === "ENOENT";
  return {
    validateRoot: ensure,
    ensureLayout: ensure,
    readAuthConfig: (value) => readFileSync(value),
    readLocalUsers: async (value) => readFileSync(value),
    create: async (root, directory, filename, contents) => {
      try {
        const value = await path(root, directory, filename);
        writeFileSync(value, contents, { flag: "wx", mode: 0o600 });
        chmodSync(value, 0o600);
        return true;
      } catch (error) {
        if (missing(error) || (error as { code?: unknown })?.code === "EEXIST") return false;
        throw error;
      }
    },
    read: async (root, directory, filename) => {
      try { return readFileSync(await path(root, directory, filename)); } catch (error) {
        if (missing(error)) return undefined;
        throw error;
      }
    },
    replace: async (root, directory, filename, contents) => {
      const value = await path(root, directory, filename);
      const temporary = `${value}.fixture-replacement`;
      writeFileSync(temporary, contents, { flag: "wx", mode: 0o600 });
      renameSync(temporary, value);
    },
    remove: async (root, directory, filename) => {
      try {
        unlinkSync(await path(root, directory, filename));
        return true;
      } catch (error) {
        if (missing(error)) return false;
        throw error;
      }
    },
    list: async (root, directory, maximumEntries = 256) => {
      const result = await names(root, directory);
      if (result.length > maximumEntries) throw new Error("fixture list overflow");
      return result.map((name) => ({ name, modifiedUnixMs: lstatSync(join(root, directory, name)).mtimeMs }));
    },
    listPage: async (root, directory, afterName, maximumEntries) => {
      if (directory !== "sessions") throw new Error("fixture directory invalid");
      const selected = (await names(root, directory)).filter((name) => afterName === undefined || name > afterName);
      return {
        entries: selected.slice(0, maximumEntries).map((name) => ({
          name, modifiedUnixMs: lstatSync(join(root, directory, name)).mtimeMs,
        })),
        more: selected.length > maximumEntries,
      };
    },
    claimConsume: async (root, filename) => {
      const source = await path(root, "oidc", filename);
      const claim = source.replace(/\.json$/, ".claim");
      try {
        linkSync(source, claim);
      } catch (error) {
        if (missing(error) || (error as { code?: unknown })?.code === "EEXIST") return undefined;
        throw error;
      }
      const contents = readFileSync(source);
      unlinkSync(source);
      unlinkSync(claim);
      return contents;
    },
    readClaim: async (root, filename) => {
      const source = await path(root, "oidc", filename);
      const claim = source.replace(/\.json$/, ".claim");
      try {
        const left = lstatSync(source);
        const right = lstatSync(claim);
        if (left.ino !== right.ino || left.dev !== right.dev || left.nlink !== 2 || right.nlink !== 2) return undefined;
        return readFileSync(source);
      } catch (error) {
        if (missing(error)) return undefined;
        throw error;
      }
    },
    removeClaim: async (root, filename) => {
      const source = await path(root, "oidc", filename);
      const claim = source.replace(/\.json$/, ".claim");
      try {
        const left = lstatSync(source);
        const right = lstatSync(claim);
        if (left.ino !== right.ino || left.dev !== right.dev || left.nlink !== 2 || right.nlink !== 2) return false;
        unlinkSync(source);
        unlinkSync(claim);
        return true;
      } catch (error) {
        if (missing(error)) return false;
        throw error;
      }
    },
  };
}