/**
 * [INPUT]: 无运行时依赖（纯数据：Framer Motion 的 Apple 级 spring 配置与 variant 预设）
 * [OUTPUT]: 对外提供 SPRING 预设、APPLE_EASE* 曲线、VIEWPORT，及 variant：
 *   fadeInUp / scaleIn / staggerContainer / staggerItem / slideInLeft / slideInRight /
 *   hoverLift / tapScale / modalOverlay / modalContent / pageTransition
 * [POS]: lib 的动效契约层（单一真相源），被 components/landing/*、pages/*、App 路由过渡共用
 * [PROTOCOL]: 变更时更新此头部，然后检查 CLAUDE.md
 */

// ───────────────────────────────────────────────────────────────────────────
// Apple 风格 spring 预设：弹簧起势 + 阻尼落定 + 质量惯性（禁 linear、禁无阻尼弹跳）
// ───────────────────────────────────────────────────────────────────────────
export const SPRING = {
  snappy: { type: 'spring', stiffness: 400, damping: 30 },              // 微交互（按钮/卡片 hover）~200ms
  gentle: { type: 'spring', stiffness: 300, damping: 35 },              // 柔和过渡（面板/模态）~350ms
  bouncy: { type: 'spring', stiffness: 500, damping: 25, mass: 0.8 },   // 弹性强调（成功反馈）~300ms
  smooth: { type: 'spring', stiffness: 200, damping: 40, mass: 1.2 },   // 优雅落定（页面/大元素）~500ms
  inertia: { type: 'spring', stiffness: 150, damping: 20, mass: 0.5 },  // 惯性滑动（列表/轮播）
}

// 非 spring 场景的 Apple 缓动曲线（退场、透明度等）
export const APPLE_EASE = [0.25, 0.1, 0.25, 1.0]      // iOS 标准
export const APPLE_EASE_OUT = [0.22, 1, 0.36, 1]      // iOS 弹出
export const APPLE_DECELERATE = [0, 0, 0.2, 1]        // iOS 减速

// whileInView 触发：进入视口一次、提前 100px 预触发
export const VIEWPORT = { once: true, margin: '-100px' }

// ───────────────────────────────────────────────────────────────────────────
// 进场 variant（spring 物理，自然起势 + 阻尼落定）
// ───────────────────────────────────────────────────────────────────────────
export const fadeInUp = {
  hidden: { opacity: 0, y: 24 },
  visible: { opacity: 1, y: 0, transition: SPRING.gentle },
}

export const scaleIn = {
  hidden: { opacity: 0, scale: 0.9 },
  visible: { opacity: 1, scale: 1, transition: { type: 'spring', stiffness: 400, damping: 25 } },
}

export const staggerContainer = {
  hidden: { opacity: 0 },
  visible: { opacity: 1, transition: { staggerChildren: 0.06, delayChildren: 0.1 } },
}

export const staggerItem = {
  hidden: { opacity: 0, y: 20 },
  visible: { opacity: 1, y: 0, transition: { type: 'spring', stiffness: 350, damping: 30 } },
}

export const slideInLeft = {
  hidden: { opacity: 0, x: -30 },
  visible: { opacity: 1, x: 0, transition: SPRING.gentle },
}

export const slideInRight = {
  hidden: { opacity: 0, x: 30 },
  visible: { opacity: 1, x: 0, transition: SPRING.gentle },
}

// ───────────────────────────────────────────────────────────────────────────
// 交互 variant（hover / tap）——只动 transform，阴影交给 index.css 微拟物体系
// ───────────────────────────────────────────────────────────────────────────
export const hoverLift = {
  rest: { scale: 1, y: 0 },
  hover: { scale: 1.02, y: -4, transition: SPRING.snappy },
}

export const tapScale = {
  rest: { scale: 1 },
  pressed: { scale: 0.96, transition: { type: 'spring', stiffness: 500, damping: 30 } },
}

// ───────────────────────────────────────────────────────────────────────────
// 模态 / 路由（进场 spring，退场短 duration）
// ───────────────────────────────────────────────────────────────────────────
export const modalOverlay = {
  hidden: { opacity: 0 },
  visible: { opacity: 1, transition: { duration: 0.2 } },
  exit: { opacity: 0, transition: { duration: 0.15 } },
}

export const modalContent = {
  hidden: { opacity: 0, scale: 0.95, y: 20 },
  visible: { opacity: 1, scale: 1, y: 0, transition: SPRING.gentle },
  exit: { opacity: 0, scale: 0.95, transition: { duration: 0.15 } },
}

// 页面路由过渡：用 y 位移（避免整页 x 横移触发水平滚动条 / 破坏 sticky 页头）
export const pageTransition = {
  initial: { opacity: 0, y: 12 },
  animate: { opacity: 1, y: 0, transition: { type: 'spring', stiffness: 260, damping: 40 } },
  exit: { opacity: 0, y: -8, transition: { duration: 0.2, ease: APPLE_EASE } },
}