import type { FastifyInstance } from 'fastify';
import { v4 as uuid } from 'uuid';
import { db } from '../../db/client.js';
import { users } from '../../db/schema.js';
import { eq, and } from 'drizzle-orm';
import type { JwtPayload, LoginResponse, AuthType } from '../../types/auth.js';

export function signTokens(app: FastifyInstance, userId: string, authType: AuthType, tier: string) {
  const payload: JwtPayload = { userId, authType, tier };
  const accessToken = app.jwt.sign(payload, { expiresIn: '1h' });
  const refreshToken = app.jwt.sign(payload, { expiresIn: '30d' });
  return { accessToken, refreshToken };
}

export function buildLoginResponse(
  user: typeof users.$inferSelect,
  accessToken: string,
  refreshToken: string,
): LoginResponse {
  return {
    accessToken,
    refreshToken,
    user: {
      id: user.id,
      nickname: user.nickname ?? null,
      avatarUrl: user.avatarUrl ?? null,
      tier: user.tier ?? 'free',
      xpTotal: user.xpTotal ?? 0,
      streakDays: user.streakDays ?? 0,
    },
  };
}

export async function findOrCreateGuest(deviceId: string, app: FastifyInstance): Promise<LoginResponse> {
  const [existing] = await db
    .select()
    .from(users)
    .where(and(eq(users.authType, 'guest'), eq(users.authId, deviceId)))
    .limit(1);

  let user = existing;

  if (!user) {
    const newId = uuid();
    await db.insert(users).values({
      id: newId,
      authType: 'guest',
      authId: deviceId,
    });
    const [created] = await db.select().from(users).where(eq(users.id, newId)).limit(1);
    user = created;
  }

  if (!user) throw new Error('Failed to create user');

  const tokens = signTokens(app, user.id, 'guest', user.tier ?? 'free');
  return buildLoginResponse(user, tokens.accessToken, tokens.refreshToken);
}

export async function findOrCreateHuawei(
  openId: string,
  nickname: string | null,
  avatarUrl: string | null,
  app: FastifyInstance,
): Promise<LoginResponse> {
  const [existing] = await db
    .select()
    .from(users)
    .where(and(eq(users.authType, 'huawei'), eq(users.authId, openId)))
    .limit(1);

  let user = existing;

  if (!user) {
    const newId = uuid();
    await db.insert(users).values({
      id: newId,
      authType: 'huawei',
      authId: openId,
      nickname,
      avatarUrl,
    });
    const [created] = await db.select().from(users).where(eq(users.id, newId)).limit(1);
    user = created;
  }

  if (!user) throw new Error('Failed to create user');

  const tokens = signTokens(app, user.id, 'huawei', user.tier ?? 'free');
  return buildLoginResponse(user, tokens.accessToken, tokens.refreshToken);
}

export async function refreshJwt(app: FastifyInstance, refreshToken: string): Promise<{ accessToken: string }> {
  const decoded = app.jwt.verify<JwtPayload>(refreshToken);
  const payload: JwtPayload = {
    userId: decoded.userId,
    authType: decoded.authType,
    tier: decoded.tier,
  };
  const accessToken = app.jwt.sign(payload, { expiresIn: '1h' });
  return { accessToken };
}