import type {
  ButtonHTMLAttributes,
  InputHTMLAttributes,
  ReactNode,
  SelectHTMLAttributes,
  TextareaHTMLAttributes,
} from "react";

export function cx(...classes: Array<string | false | null | undefined>): string {
  return classes.filter(Boolean).join(" ");
}

/* -------------------------------------------------------------------- Card */

export function Card({
  children,
  className,
}: {
  children: ReactNode;
  className?: string;
}) {
  return (
    <section
      className={cx(
        "rounded-2xl border border-slate-200 bg-surface p-5 shadow-sm sm:p-6",
        className,
      )}
    >
      {children}
    </section>
  );
}

export function CardTitle({
  children,
  hint,
}: {
  children: ReactNode;
  hint?: ReactNode;
}) {
  return (
    <div className="mb-4">
      <h2 className="text-base font-semibold text-slate-900">{children}</h2>
      {hint ? <p className="mt-1 text-sm text-slate-500">{hint}</p> : null}
    </div>
  );
}

/* ------------------------------------------------------------------ Button */

type ButtonProps = ButtonHTMLAttributes<HTMLButtonElement> & {
  variant?: "primary" | "secondary" | "ghost" | "danger";
  size?: "md" | "sm";
};

const BUTTON_VARIANTS: Record<NonNullable<ButtonProps["variant"]>, string> = {
  primary:
    "bg-indigo-600 text-white hover:bg-indigo-700 disabled:hover:bg-indigo-600",
  secondary:
    "border border-slate-300 bg-surface text-slate-700 hover:bg-slate-50 disabled:hover:bg-surface",
  ghost: "text-slate-600 hover:bg-slate-100 disabled:hover:bg-transparent",
  danger: "bg-red-600 text-white hover:bg-red-700 disabled:hover:bg-red-600",
};

export function Button({
  variant = "primary",
  size = "md",
  className,
  ...props
}: ButtonProps) {
  return (
    <button
      className={cx(
        "inline-flex items-center justify-center gap-2 rounded-lg font-medium transition-colors disabled:cursor-not-allowed disabled:opacity-50",
        size === "md" ? "px-4 py-2.5 text-sm" : "px-3 py-1.5 text-sm",
        BUTTON_VARIANTS[variant],
        className,
      )}
      {...props}
    />
  );
}

/* ------------------------------------------------------------------- Field */

export function Field({
  label,
  hint,
  error,
  htmlFor,
  children,
}: {
  label: string;
  hint?: ReactNode;
  error?: string | null;
  htmlFor?: string;
  children: ReactNode;
}) {
  return (
    <div>
      <label
        htmlFor={htmlFor}
        className="mb-1.5 block text-sm font-medium text-slate-700"
      >
        {label}
      </label>
      {children}
      {error ? (
        <p role="alert" className="mt-1.5 text-sm text-red-600">
          {error}
        </p>
      ) : hint ? (
        <p className="mt-1.5 text-sm text-slate-500">{hint}</p>
      ) : null}
    </div>
  );
}

export function TextInput({
  invalid,
  className,
  ...props
}: InputHTMLAttributes<HTMLInputElement> & { invalid?: boolean }) {
  return (
    <input
      className={cx(
        "w-full rounded-lg border bg-surface px-3 py-2.5 text-sm text-slate-900 shadow-sm transition-colors placeholder:text-slate-400",
        invalid
          ? "border-red-400 focus-visible:outline-red-500"
          : "border-slate-300",
        className,
      )}
      {...props}
    />
  );
}

/** Gemeinsame Grundgestaltung aller Eingabefelder. */
export const CONTROL_BASE =
  "w-full rounded-lg border bg-surface px-3 py-2.5 text-sm text-slate-900 shadow-sm transition-colors placeholder:text-slate-400 disabled:cursor-not-allowed disabled:bg-slate-50 disabled:text-slate-500";

export function TextArea({
  invalid,
  className,
  ...props
}: TextareaHTMLAttributes<HTMLTextAreaElement> & { invalid?: boolean }) {
  return (
    <textarea
      rows={3}
      className={cx(
        CONTROL_BASE,
        "resize-y",
        invalid ? "border-red-400" : "border-slate-300",
        className,
      )}
      {...props}
    />
  );
}

export function Select({
  invalid,
  className,
  children,
  ...props
}: SelectHTMLAttributes<HTMLSelectElement> & { invalid?: boolean }) {
  return (
    <select
      className={cx(
        CONTROL_BASE,
        "cursor-pointer appearance-none bg-[length:1.1rem] bg-[right_0.7rem_center] bg-no-repeat pr-9",
        invalid ? "border-red-400" : "border-slate-300",
        className,
      )}
      style={{
        backgroundImage:
          "url(\"data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='m6 9 6 6 6-6'/%3E%3C/svg%3E\")",
      }}
      {...props}
    >
      {children}
    </select>
  );
}

export function Checkbox({
  label,
  hint,
  id,
  ...props
}: InputHTMLAttributes<HTMLInputElement> & { label: string; hint?: string }) {
  return (
    <div className="flex items-start gap-2.5">
      <input
        id={id}
        type="checkbox"
        className="mt-0.5 size-4 shrink-0 cursor-pointer rounded border-slate-300 accent-indigo-600"
        {...props}
      />
      <label htmlFor={id} className="cursor-pointer text-sm text-slate-700">
        {label}
        {hint ? <span className="block text-slate-500">{hint}</span> : null}
      </label>
    </div>
  );
}

/** Zwei Felder nebeneinander, ab „sm“ — für Paare wie Vor- und Nachname. */
export function FieldRow({ children }: { children: ReactNode }) {
  return (
    <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">{children}</div>
  );
}

/** Abschnitt innerhalb eines Formulars mit eigener Überschrift. */
export function FieldSet({
  legend,
  children,
}: {
  legend: string;
  children: ReactNode;
}) {
  return (
    <fieldset className="border-t border-slate-200 pt-4">
      <legend className="pr-2 text-xs font-semibold tracking-wide text-slate-500 uppercase">
        {legend}
      </legend>
      <div className="mt-3 flex flex-col gap-4">{children}</div>
    </fieldset>
  );
}

/* ------------------------------------------------------------------- Badge */

export function Badge({
  tone = "neutral",
  children,
}: {
  tone?: "neutral" | "accent" | "soon" | "success";
  children: ReactNode;
}) {
  const tones: Record<string, string> = {
    neutral: "bg-slate-100 text-slate-600",
    // Hervorhebung — hieß früher "popular", als sie nur für das Abzeichen
    // „Beliebt" auf der Startseite gedacht war.
    accent: "bg-accent-soft text-accent-soft-fg",
    soon: "bg-slate-100 text-slate-500",
    success: "bg-emerald-100 text-emerald-700",
  };
  return (
    <span
      className={cx(
        "inline-flex items-center rounded-full px-2 py-0.5 text-xs font-medium",
        tones[tone],
      )}
    >
      {children}
    </span>
  );
}

/* ------------------------------------------------------------------ Notice */

export function Notice({
  tone,
  children,
}: {
  tone: "warning" | "error" | "info" | "success";
  children: ReactNode;
}) {
  const tones: Record<string, string> = {
    warning: "border-amber-300 bg-amber-50 text-amber-900",
    error: "border-red-300 bg-red-50 text-red-800",
    info: "border-sky-300 bg-sky-50 text-sky-900",
    success: "border-emerald-300 bg-emerald-50 text-emerald-900",
  };
  return (
    <div
      role={tone === "error" ? "alert" : "status"}
      className={cx("rounded-lg border px-3.5 py-3 text-sm", tones[tone])}
    >
      {children}
    </div>
  );
}