import type { ButtonHTMLAttributes, HTMLAttributes, ReactNode } from "react";

/** Miuix-style primitives: Button / Tag / Switch / Spinner / Surface / Empty.
 *  Springs are applied only to interactive elements (cubic-bezier(0.34,1.56,0.64,1)). */

type ButtonVariant = "primary" | "soft" | "ghost" | "outline" | "danger";

export interface ButtonProps extends ButtonHTMLAttributes<HTMLButtonElement> {
  variant?: ButtonVariant;
  size?: "sm" | "md";
  children: ReactNode;
}

const buttonVariant: Record<ButtonVariant, string> = {
  primary: "bg-[var(--mu-accent)] text-white hover:bg-[var(--mu-accent-hi)] shadow-[var(--mu-shadow-2)]",
  soft: "bg-[var(--mu-surface-4)] text-[var(--mu-text-hi)] hover:bg-[var(--mu-surface-5)]",
  ghost: "text-[var(--mu-text-mid)] hover:bg-[var(--mu-surface-4)]",
  outline:
    "border border-[var(--mu-glass-border)] text-[var(--mu-text-hi)] hover:bg-[var(--mu-surface-4)]",
  danger: "bg-[var(--mu-err)] text-white",
};

export function Button({
  variant = "soft",
  size = "md",
  className = "",
  children,
  ...rest
}: ButtonProps): React.ReactNode {
  const pad = size === "sm" ? "px-2.5 py-1 text-xs" : "px-4 py-2 text-sm";
  return (
    <button
      className={`inline-flex items-center justify-center gap-1.5 font-medium transition-all duration-200 ease-[var(--mu-spring)] active:scale-[0.97] disabled:opacity-50 disabled:pointer-events-none ${pad} ${buttonVariant[variant]} ${className}`}
      {...rest}
    >
      {children}
    </button>
  );
}

export type TagTone = "accent" | "ok" | "warn" | "err" | "neutral";

export interface TagProps {
  tone?: TagTone;
  children: ReactNode;
  className?: string;
  /** 原生 title：给标签补充「为什么」的悬停说明（如无 id 条目的后果）。 */
  title?: string;
}

const tagTone: Record<TagTone, string> = {
  accent: "bg-[var(--mu-accent)]/15 text-[var(--mu-accent-hi)]",
  ok: "bg-[var(--mu-ok)]/15 text-[var(--mu-ok)]",
  warn: "bg-[var(--mu-warn)]/15 text-[var(--mu-warn)]",
  err: "bg-[var(--mu-err)]/15 text-[var(--mu-err)]",
  neutral: "bg-[var(--mu-surface-4)] text-[var(--mu-text-mid)]",
};

export function Tag({ tone = "neutral", children, className = "", title }: TagProps): React.ReactNode {
  return (
    <span
      title={title}
      className={`inline-flex items-center gap-1 rounded-[var(--mu-radius-sm)] px-2 py-0.5 text-xs font-medium ${tagTone[tone]} ${className}`}
    >
      {children}
    </span>
  );
}

export interface SwitchProps {
  checked: boolean;
  onChange: (next: boolean) => void;
  disabled?: boolean;
  label?: string;
}

export function Switch({ checked, onChange, disabled, label }: SwitchProps): React.ReactNode {
  return (
    <label
      className={`flex items-center gap-2 select-none ${disabled ? "opacity-50 pointer-events-none" : ""}`}
    >
      <button
        type="button"
        role="switch"
        aria-checked={checked}
        aria-label={label}
        onClick={() => onChange(!checked)}
        className={`relative h-6 w-11 shrink-0 rounded-[var(--mu-radius-pill)] transition-colors duration-200 ${
          checked ? "bg-[var(--mu-accent)]" : "bg-[var(--mu-surface-5)]"
        }`}
      >
        <span
          className={`absolute top-0.5 h-5 w-5 rounded-full bg-white shadow-md transition-transform duration-300 ease-[var(--mu-spring)] ${
            checked ? "translate-x-[22px]" : "translate-x-0.5"
          }`}
        />
      </button>
      {label ? <span className="text-sm text-[var(--mu-text-mid)]">{label}</span> : null}
    </label>
  );
}

export interface SpinnerProps {
  size?: number;
  label?: string;
}

export function Spinner({ size = 18, label }: SpinnerProps): React.ReactNode {
  return (
    <span className="inline-flex items-center gap-2 text-[var(--mu-text-lo)]">
      <span
        className="inline-block animate-spin rounded-full border-2 border-[var(--mu-surface-5)] border-t-[var(--mu-accent)]"
        style={{ width: size, height: size }}
      />
      {label ? <span className="text-xs">{label}</span> : null}
    </span>
  );
}

export interface SurfaceProps extends HTMLAttributes<HTMLDivElement> {
  glass?: boolean;
  liquid?: boolean;
  gap?: "none" | "sm" | "md";
  children: ReactNode;
}

export function Surface({
  glass = false,
  liquid = false,
  gap = "md",
  className = "",
  children,
  ...rest
}: SurfaceProps): React.ReactNode {
  const pad = gap === "none" ? "" : gap === "sm" ? "p-3" : "p-5";
  const base = glass
    ? "glass"
    : liquid
      ? "liquid-glass"
      : "bg-[var(--mu-surface-3)] border border-[var(--mu-glass-border)] shadow-[var(--mu-shadow-1)]";
  return (
    <div className={`rounded-[var(--mu-radius-lg)] ${base} ${pad} ${className}`} {...rest}>
      {children}
    </div>
  );
}

export interface EmptyStateProps {
  icon?: ReactNode;
  title: string;
  hint?: string;
}

export function EmptyState({ icon, title, hint }: EmptyStateProps): React.ReactNode {
  return (
    <div className="flex flex-col items-center justify-center gap-2 py-16 text-center">
      {icon ? <div className="text-3xl opacity-60">{icon}</div> : null}
      <div className="text-sm font-medium text-[var(--mu-text-mid)]">{title}</div>
      {hint ? <div className="text-xs text-[var(--mu-text-lo)]">{hint}</div> : null}
    </div>
  );
}