import { FastifyInstance } from "fastify";
import { JwtPayload, User } from "@library/shared-types";
import { prisma } from "../lib/prisma";

export class AuthService {
  private prisma = prisma;

  constructor(private readonly app: FastifyInstance) {}

  /**
   * Generate JWT token for user.
   */
  async generateToken(user: User): Promise<string> {
    const payload: JwtPayload = {
      sub: user.id,
      email: user.email,
      username: user.username,
      isAdmin: user.isAdmin,
    };

    return this.app.jwt.sign(payload, {
      expiresIn: "7d",
    });
  }

  /**
   * Verify JWT token.
   */
  async verifyToken(token: string): Promise<JwtPayload> {
    return this.app.jwt.verify(token) as JwtPayload;
  }

  /**
   * Get user by ID from database.
   */
  async getUserById(id: string): Promise<User | null> {
    const dbUser = await this.prisma.user.findUnique({
      where: { id },
    });

    if (!dbUser) {
      return null;
    }

    return {
      id: dbUser.id,
      discordId: dbUser.discordId,
      username: dbUser.username,
      email: dbUser.email,
      avatarUrl: dbUser.avatar || undefined,
      isAdmin: dbUser.isAdmin,
      isBanned: dbUser.isBanned,
      inDiscord: dbUser.inDiscord,
      isVip: dbUser.isVip,
      isMod: dbUser.isMod,
      isStaff: dbUser.isStaff,
    };
  }

  /**
   * Create or update user from Discord OAuth data.
   */
  async createOrUpdateUserFromDiscord(discordData: DiscordUser, inDiscord: boolean, isVip: boolean, isMod: boolean, isStaff: boolean): Promise<User> {
    const avatarUrl = discordData.avatar
      ? `https://cdn.discordapp.com/avatars/${discordData.id}/${discordData.avatar}.png`
      : undefined;

    // Upsert user in database
    const dbUser = await this.prisma.user.upsert({
      where: {
        discordId: discordData.id,
      },
      create: {
        discordId: discordData.id,
        username: discordData.username,
        email: discordData.email,
        avatar: avatarUrl,
        isAdmin: discordData.id === process.env.ADMIN_DISCORD_ID,
        inDiscord,
        isVip,
        isMod,
        isStaff,
      },
      update: {
        username: discordData.username,
        email: discordData.email,
        avatar: avatarUrl,
        inDiscord,
        isVip,
        isMod,
        isStaff,
      },
    });

    return {
      id: dbUser.id,
      discordId: dbUser.discordId,
      username: dbUser.username,
      email: dbUser.email,
      avatarUrl: dbUser.avatar || undefined,
      isAdmin: dbUser.isAdmin,
      isBanned: dbUser.isBanned,
      inDiscord: dbUser.inDiscord,
      isVip: dbUser.isVip,
      isMod: dbUser.isMod,
      isStaff: dbUser.isStaff,
    };
  }
}

interface DiscordUser {
  id: string;
  username: string;
  email: string;
  avatar?: string;
}