import { flowchartUpdateSchema, type FlowchartUpdate } from "@oj2/contract"

import { redis } from "./redis"

export const userEventChannel = "user:events"

/**
 * 站点配置变更广播。旧后端的 `utils/websocket.push_config_update`：
 * 超管改了配置，所有开着页面的人立刻生效，不必刷新。
 * 这是全站广播，不分用户，所以是一个固定 topic 而不是 per-user。
 */
export const configUpdateChannel = "config:updates"
export const configTopic = "events:config"

export async function publishConfigUpdate(key: string, value: unknown) {
  await redis.publish(configUpdateChannel, JSON.stringify({ type: "config_update", key, value }))
}

interface UserEvent {
  userId: number
  data: FlowchartUpdate | Record<string, unknown>
}

interface AchievementNotification {
  id: number
  name: string
  description: string
  icon: string
  rarity: string
  kind: "achievement" | "badge"
}

export function userEventTopic(userId: number) {
  return `events:user:${userId}`
}

export async function publishFlowchartUpdate(userId: number, data: FlowchartUpdate) {
  await redis.publish(userEventChannel, JSON.stringify({ userId, data: flowchartUpdateSchema.parse(data) }))
}

export async function publishAchievementNotification(
  userId: number,
  achievements: AchievementNotification[],
) {
  if (!achievements.length) return
  await redis.publish(userEventChannel, JSON.stringify({
    userId,
    data: { type: "achievement_unlocked", achievements },
  }))
}

export function parseUserEvent(raw: string): UserEvent | null {
  try {
    const value = JSON.parse(raw) as UserEvent
    if (!Number.isInteger(value.userId) || !value.data || typeof value.data !== "object") return null
    return value
  } catch {
    return null
  }
}