import { defineCommand } from "citty";
import Enquirer from "enquirer";
import { stdin } from "node:process";
import { apiRequest } from "../lib/api";
import {
  readSession,
  removeSessions,
  writeSession,
  type KuberSession,
} from "../lib/session";

type LoginResponse = KuberSession;

type Credentials = { username: string; password: string };
type AuthChoice = {
  name: string;
  input: string;
  value: string;
  initial?: string;
  cursor?: number;
};
export interface LoginPrompt {
  choices: AuthChoice[];
  values: Credentials;
  state: { submitted: boolean; cancelled: boolean; closed: boolean };
  initialize(): Promise<void>;
  render(): Promise<void>;
  submit(): Promise<void>;
  cancel(): Promise<void>;
  run(): Promise<LoginResponse>;
}

// Enquirer's declarations omit its runtime BasicAuth factory.
const BasicAuth = (
  Enquirer as typeof Enquirer & {
    BasicAuth: {
      create(
        authenticate: (values: Credentials) => Promise<LoginResponse | false>,
      ): new (options: Record<string, unknown>) => LoginPrompt;
    };
  }
).BasicAuth;

/** Actual BasicAuth prompt; injectable authentication keeps tests offline. */
export function createLoginPrompt(
  username = "",
  persistent = false,
  authenticate: typeof loginUser = loginUser,
  options: { show?: boolean; stdout?: NodeJS.WriteStream } = {},
): LoginPrompt {
  let failure: unknown;
  let authentication: Promise<LoginResponse | false> | undefined;
  const Auth = BasicAuth.create((values) => {
    // Repeated Enter presses must never issue a second login or session write.
    authentication ??= (async () => {
      try {
        const name = values.username.trim();
        if (!name) throw new Error("Username is required");
        return await authenticate(name, values.password, persistent);
      } catch (error) {
        // BasicAuth doesn't forward rejected authenticate callbacks to run().
        failure = error;
        return false as const;
      }
    })();
    return authentication;
  });
  class KuberBasicAuth extends Auth {
    private submitting = false;

    override async initialize() {
      await super.initialize();
      const choice = this.choices.find((item) => item.name === "username");
      if (choice) {
        choice.input = choice.value = username;
        choice.cursor = username.length;
      }
      await this.render();
    }

    override async submit() {
      if (this.submitting || this.state.closed) return;
      this.submitting = true;
      await super.submit();
    }

    override async render() {
      if (this.state.submitted) {
        // FormPrompt skips choice.format on submission and cancellation.
        const password = this.choices.find(
          (choice) => choice.name === "password",
        );
        if (password) password.input = password.value = password.initial = "";
        this.values.password = "";
      }
      await super.render();
    }

    override async run(): Promise<LoginResponse> {
      let session: LoginResponse;
      try {
        session = await super.run();
      } catch {
        throw new Error("Login cancelled");
      }
      if (failure !== undefined) throw failure;
      return session;
    }
  }
  return new KuberBasicAuth({
    name: "login",
    message: "Log in to kuber.astrxl.dev",
    initial: { username },
    showPassword: false,
    ...options,
  });
}

export async function loginUser(
  username: string,
  password: string,
  persistent: boolean,
): Promise<LoginResponse> {
  const session = await apiRequest<LoginResponse>(
    "/login",
    {
      method: "POST",
      body: JSON.stringify({ username, password, persistent }),
    },
    { authenticated: false },
  );
  await writeSession(session, persistent);
  return session;
}

/** Share the CLI's credential prompt with onboarding without exposing passwords. */
export async function interactiveLogin(
  username = "",
  persistent = false,
  dependencies: {
    isTTY?: boolean;
    prompt?: typeof createLoginPrompt;
  } = {},
): Promise<LoginResponse> {
  if (!(dependencies.isTTY ?? stdin.isTTY))
    throw new Error(
      "Login requires an interactive terminal; run kuber login first",
    );
  const session = await (dependencies.prompt ?? createLoginPrompt)(
    username.trim(),
    persistent,
  ).run();
  console.log(`Logged in as ${session.user.username}`);
  return session;
}

export const login = defineCommand({
  meta: {
    name: "login",
    description: "Log in to kuber.astrxl.dev",
  },
  args: {
    persist: {
      type: "boolean",
      description: "Keep the login across reboots",
    },
  },
  async run({ args }) {
    await interactiveLogin(String(args._[0] ?? ""), Boolean(args.persist));
  },
});

export const logout = defineCommand({
  meta: {
    name: "logout",
    description: "Log out of kuber.astrxl.dev",
  },
  async run() {
    const session = await readSession();
    if (session) {
      try {
        await apiRequest<void>(
          "/logout",
          {
            method: "POST",
          },
          { session },
        );
      } finally {
        await removeSessions();
      }
    } else {
      await removeSessions();
    }
    console.log("Logged out");
  },
});

export const whoami = defineCommand({
  meta: {
    name: "whoami",
    description: "Show the current kuber user",
  },
  async run() {
    const result = await apiRequest<KuberSession["user"]>("/me");
    console.log(`${result.username} (${result.roles.join(", ")})`);
  },
});