import { randomUUID } from 'crypto';

export type OAuthState = {
  providerName: string;
  redirectUri: string;
  createdAt: number;
  userId?: number;
  isBinding: boolean;
};

const STATE_TTL_MS = 5 * 60 * 1000; // 5 minutes

export class OAuthStateStore {
  private store = new Map<string, OAuthState>();

  private cleanupInterval: NodeJS.Timeout | null = null;

  constructor() {
    this.startCleanup();
  }

  generate(
    providerName: string,
    redirectUri: string,
    userId?: number
  ): { state: string; oauthState: OAuthState } {
    const state = randomUUID();
    const oauthState: OAuthState = {
      providerName,
      redirectUri,
      createdAt: Date.now(),
      userId,
      isBinding: userId !== undefined,
    };
    this.store.set(state, oauthState);
    return { state, oauthState };
  }

  validate(state: string): OAuthState | null {
    const oauthState = this.store.get(state);
    if (!oauthState) {
      return null;
    }

    if (Date.now() - oauthState.createdAt > STATE_TTL_MS) {
      this.store.delete(state);
      return null;
    }

    return oauthState;
  }

  consume(state: string): OAuthState | null {
    const oauthState = this.validate(state);
    if (oauthState) {
      this.store.delete(state);
    }
    return oauthState;
  }

  private startCleanup() {
    this.cleanupInterval = setInterval(() => {
      const now = Date.now();
      for (const [state, data] of this.store.entries()) {
        if (now - data.createdAt > STATE_TTL_MS) {
          this.store.delete(state);
        }
      }
    }, 60_000);
  }

  destroy() {
    if (this.cleanupInterval) {
      clearInterval(this.cleanupInterval);
    }
  }
}

export const oauthStateStore = new OAuthStateStore();