Buddy 宠物系统

// companion.ts

// Mulberry32 — 小型种子 PRNG，用于确定性抽卡
function mulberry32(seed: number): () => number {
  let a = seed >>> 0
  return function () {
    a |= 0
    a = (a + 0x6d2b79f5) | 0
    let t = Math.imul(a ^ (a >>> 15), 1 | a)
    t = (t + Math.imul(t ^ (t >>> 7), 61 | t)) ^ t
    return ((t ^ (t >>> 14)) >>> 0) / 4294967296
  }
}

function hashString(s: string): number {
  // Bun 环境使用 Bun.hash()，其他环境用 FNV-1a
  if (typeof Bun !== 'undefined') {
    return Number(BigInt(Bun.hash(s)) & 0xffffffffn)
  }
  let h = 2166136261  // FNV offset basis
  for (let i = 0; i < s.length; i++) {
    h ^= s.charCodeAt(i)
    h = Math.imul(h, 16777619)  // FNV prime
  }
  return h >>> 0
}

const SALT = 'friend-2026-401'

export function roll(userId: string): Roll {
  const key = userId + SALT
  // 缓存：500ms tick / 每次按键 / 每轮 observer 都会调用
  if (rollCache?.key === key) return rollCache.value
  const value = rollFrom(mulberry32(hashString(key)))
  rollCache = { key, value }
  return value
}

// types.ts — 确定性生成的"骨骼"数据
type CompanionBones = {
  rarity: Rarity        // 5 档稀有度
  species: Species      // 18 种物种
  eye: Eye              // '·' | '✦' | '×' | '◉' | '@' | '°'
  hat: Hat              // common 固定 'none'，其他随机
  shiny: boolean        // 1% 概率闪光
  stats: Record<StatName, number>  // 5 维属性
}

// 持久化的"灵魂"数据 — 由模型生成
type CompanionSoul = {
  name: string          // AI 起的名字
  personality: string   // AI 生成的性格描述
}

// 最终宠物 = Bones + Soul + hatchedAt
type Companion = CompanionBones & CompanionSoul & { hatchedAt: number }

// 但 config 中只存储 Soul + hatchedAt
// Bones 每次从 hash(userId + salt) 重新计算

// CompanionSprite.tsx

const TICK_MS = 500       // 500ms 一帧
const BUBBLE_SHOW = 20    // 气泡显示 ~10 秒（20 ticks）
const FADE_WINDOW = 6     // 最后 ~3 秒气泡淡出
const PET_BURST_MS = 2500 // /buddy pet 飘心持续 2.5 秒

// Idle 序列：大部分时间休息（帧 0），偶尔抖动（帧 1-2），罕见眨眼
// -1 表示"在帧 0 上眨眼"
const IDLE_SEQUENCE = [0, 0, 0, 0, 1, 0, 0, 0, -1, 0, 0, 2, 0, 0, 0]

// 飘心动画：5 帧上升消失
const H = '♥'  // figures.heart
const PET_HEARTS = [
  '   ♥    ♥   ',
  '  ♥  ♥   ♥  ',
  ' ♥   ♥  ♥   ',
  '♥  ♥      ♥ ',
  '·    ·   ·  '
]

// sprites.ts — Duck 精灵定义
[duck]: [
  // 帧 0 — 静止
  [
    '            ',    // 帽子槽（帧 0-1 为空）
    '    __      ',
    '   ( ·)>    ',    // 眼睛用 {E} 占位符，运行时替换
    '   /    ',
    '    ~~      ',
  ],
  // 帧 1 — 抖动
  [ ... ],
  // 帧 2 — 帽子帧（第 0 行可渲染帽子）
  [ ... ],
]

// 帽子渲染（独立于物种）
const HAT_SPRITES: Record<Hat, string[]> = {
  crown:     ['   ╔══╗   ', '   ║██║   '],
  tophat:    ['  ╔════╗  ', '  ║    ║  '],
  propeller: ['  ╱╲╱╲   ', '  ╲╱╲╱   '],
  halo:      ['  ╭────╮  ', '  ╰────╯  '],
  wizard:    ['   ╱╲    ', '  ╱  ╲   '],
  beanie:    ['  ╭──╮   ', '  ╰──╯   '],
  tinyduck:  ['   __     ', '  (·)>   '],
}

// prompt.ts

export function companionIntroText(name: string, species: string): string {
  return `# Companion

A small ${species} named ${name} sits beside the user's input box
and occasionally comments in a speech bubble. You're not ${name} —
it's a separate watcher.

When the user addresses ${name} directly (by name), its bubble will
answer. Your job in that moment is to stay out of the way: respond
in ONE line or less, or just answer any part of the message meant
for you. Don't explain that you're not ${name} — they know.
Don't narrate what ${name} might say — the bubble handles that.`
}

// 作为 attachment 注入到消息流中
// 首次孵化时注入一次，后续每轮检查是否已告知
export function getCompanionIntroAttachment(messages: Message[]): Attachment[] {
  if (!feature('BUDDY')) return []
  const companion = getCompanion()
  if (!companion || getGlobalConfig().companionMuted) return []
  // 跳过已经告知过的消息
  for (const msg of messages) {
    if (msg.attachment?.type === 'companion_intro'
        && msg.attachment.name === companion.name) return []
  }
  return [{ type: 'companion_intro', name: companion.name, species: companion.species }]
}

// types.ts — 物种名混淆

const c = String.fromCharCode

export const duck = c(0x64, 0x75, 0x63, 0x6b) as 'duck'
//          'd'     'u'     'c'     'k'

export const capybara = c(
  0x63, 0x61, 0x70, 0x79, 0x62, 0x61, 0x72, 0x61
) as 'capybara'
//  'c'   'a'   'p'   'y'   'b'   'a'   'r'   'a'

export const penguin = c(0x70, 0x65, 0x6e, 0x67, 0x75, 0x69, 0x6e) as 'penguin'

// 注释原文：
// "One species name collides with a model-codename canary in
//  excluded-strings.txt. The check greps build output (not source),
//  so runtime-constructing the value keeps the literal out of the
//  bundle while the check stays armed for the actual codename."