"use client";

import { useId, useState, type CSSProperties, type ElementType, type PointerEvent } from "react";
import { AnimatePresence, motion, useReducedMotion } from "motion/react";

export type PricingPrismPlan = {
  name: string;
  text?: string;
  /** Price text, so any currency works: "₹499", "Free". */
  monthly: string;
  /** Leave out if the plan costs the same either way. */
  yearly?: string;
  features: string[];
  /** Button text. */
  cta?: string;
  /** Makes the button a link. */
  href?: string;
  /** Keeps the spectrum edge on all the time. */
  featured?: boolean;
  /** Small label on the card, such as "Popular". */
  badge?: string;
};

type Period = "monthly" | "yearly";

type PricingPrismProps = {
  plans: PricingPrismPlan[];
  title?: string;
  /** Small line above the title. */
  eyebrow?: string;
  subtitle?: string;
  /** Called when a plan button without href is pressed. */
  onSelect?: (plan: PricingPrismPlan, period: Period) => void;
  /** Words for the switch and the price ending. */
  labels?: { monthly: string; yearly: string; perMonth: string; perYear: string };
  /** Small note beside the yearly switch, such as "Save 20%". */
  saving?: string;
  /** Card colour. */
  tile?: string;
  /** Spectrum colours. Repeat the first at the end for a smooth ring. */
  colors?: string[];
  /** h2 by default. */
  headingAs?: ElementType;
  /** Set padding and colours here. */
  className?: string;
};

const LABELS = { monthly: "Monthly", yearly: "Yearly", perMonth: "/mo", perYear: "/yr" };
const COLORS = ["#ff6b6b", "#ffc857", "#5eead4", "#38bdf8", "#a78bfa", "#f472b6", "#ff6b6b"];
const RING = "linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0)";
const SPOT = "radial-gradient(15rem at var(--pp-x) var(--pp-y), #000, transparent)";

/* PricingPrism: pricing cards with a monthly / yearly switch. A spectrum splits around the pointer and runs along the card edge, like light through glass. */
export function PricingPrism({
  plans,
  title,
  eyebrow,
  subtitle,
  onSelect,
  labels = LABELS,
  saving,
  tile = "#15122a",
  colors = COLORS,
  headingAs: Heading = "h2",
  className = "bg-[#0b0a14] px-5 py-16 text-white",
}: PricingPrismProps) {
  const reduce = useReducedMotion();
  const id = useId();
  const [period, setPeriod] = useState<Period>("monthly");
  const hasYearly = plans.some((plan) => plan.yearly);
  const spectrum = `conic-gradient(from var(--pp-a) at var(--pp-x) var(--pp-y), ${colors.join(", ")})`;

  const track = (e: PointerEvent<HTMLLIElement>) => {
    const box = e.currentTarget.getBoundingClientRect();
    const x = (e.clientX - box.left) / box.width;
    e.currentTarget.style.setProperty("--pp-x", `${x * 100}%`);
    e.currentTarget.style.setProperty("--pp-y", `${((e.clientY - box.top) / box.height) * 100}%`);
    e.currentTarget.style.setProperty("--pp-a", `${x * 200}deg`);
  };

  return (
    <section aria-labelledby={title ? id : undefined} className={`@container ${className}`}>
      {title && (
        <header className="mx-auto mb-8 max-w-2xl text-center">
          {eyebrow && <p className="mb-2 text-xs font-medium tracking-[0.2em] uppercase opacity-70">{eyebrow}</p>}
          <Heading id={id} className="text-[clamp(1.5rem,6cqw,2.5rem)] leading-tight font-semibold tracking-tight text-balance">
            {title}
          </Heading>
          {subtitle && <p className="mt-3 text-pretty opacity-70">{subtitle}</p>}
        </header>
      )}

      {hasYearly && (
        <div className="mb-8 flex flex-wrap items-center justify-center gap-3">
          <div role="group" aria-label="Billing period" className="inline-flex rounded-full border border-current/15 p-1 text-sm">
            {(["monthly", "yearly"] as const).map((option) => (
              <button
                key={option}
                type="button"
                aria-pressed={period === option}
                onClick={() => setPeriod(option)}
                className={`relative rounded-full px-4 py-1.5 font-medium transition-opacity ${period === option ? "" : "opacity-60 hover:opacity-100"}`}
              >
                {period === option && (
                  <motion.span
                    layoutId={`${id}-pill`}
                    className="absolute inset-0 rounded-full bg-current/15"
                    transition={reduce ? { duration: 0 } : { type: "spring", stiffness: 420, damping: 34 }}
                  />
                )}
                <span className="relative">{labels[option]}</span>
              </button>
            ))}
          </div>
          {saving && (
            <span className="text-sm font-medium" style={{ color: colors[2] }}>
              {saving}
            </span>
          )}
        </div>
      )}

      <ul className="mx-auto grid max-w-6xl grid-cols-[repeat(auto-fit,minmax(min(100%,15rem),1fr))] gap-4">
        {plans.map((plan, i) => {
          const yearly = period === "yearly" && !!plan.yearly;
          const price = yearly ? plan.yearly! : plan.monthly;
          const unit = yearly ? labels.perYear : labels.perMonth;
          const button = "block w-full rounded-xl px-4 py-2.5 text-center text-sm font-semibold transition-opacity hover:opacity-85";
          const look = plan.featured ? { backgroundColor: "#fff", color: "#0b0a14" } : { boxShadow: "inset 0 0 0 1px color-mix(in srgb, currentColor 25%, transparent)" };
          return (
            <motion.li
              key={plan.name}
              onPointerMove={track}
              className="group/plan relative isolate flex flex-col overflow-hidden rounded-3xl p-6"
              style={{ backgroundColor: tile, "--pp-x": "50%", "--pp-y": "0%", "--pp-a": "0deg" } as CSSProperties}
              initial={reduce ? { opacity: 0 } : { opacity: 0, y: 20 }}
              whileInView={reduce ? { opacity: 1 } : { opacity: 1, y: 0 }}
              viewport={{ once: true, amount: 0.15 }}
              transition={{ duration: 0.6, delay: Math.min(i, 6) * 0.07, ease: [0.16, 1, 0.3, 1] }}
            >
              <span
                aria-hidden
                className="absolute inset-0 -z-10 opacity-0 transition-opacity duration-500 group-hover/plan:opacity-20 motion-reduce:transition-none"
                style={{ backgroundImage: spectrum, maskImage: SPOT, WebkitMaskImage: SPOT }}
              />
              <span
                aria-hidden
                className={`pointer-events-none absolute inset-0 rounded-[inherit] p-[1.5px] transition-opacity duration-500 group-focus-within/plan:opacity-100 group-hover/plan:opacity-100 motion-reduce:transition-none ${plan.featured ? "opacity-100" : "opacity-15"}`}
                style={{ backgroundImage: spectrum, mask: RING, WebkitMask: RING, maskComposite: "exclude", WebkitMaskComposite: "xor" }}
              />

              <div className="flex items-center justify-between gap-2">
                <p className="font-semibold">{plan.name}</p>
                {plan.badge && <span className="rounded-full bg-current/10 px-2.5 py-0.5 text-xs font-medium">{plan.badge}</span>}
              </div>
              {plan.text && <p className="mt-1 text-sm text-pretty opacity-70">{plan.text}</p>}

              <p className="mt-5 flex items-baseline gap-1">
                <AnimatePresence mode="popLayout" initial={false}>
                  <motion.span
                    key={price}
                    className="text-4xl font-semibold tracking-tight"
                    initial={reduce ? false : { opacity: 0, y: 14, filter: "blur(4px)" }}
                    animate={{ opacity: 1, y: 0, filter: "blur(0px)" }}
                    exit={reduce ? { opacity: 0, transition: { duration: 0 } } : { opacity: 0, y: -14, filter: "blur(4px)" }}
                    transition={{ duration: 0.3, ease: [0.16, 1, 0.3, 1] }}
                  >
                    {price}
                  </motion.span>
                </AnimatePresence>
                {/\d/.test(price) && <span className="text-sm opacity-60">{unit}</span>}
              </p>

              <ul className="mt-5 mb-6 grid gap-2 text-sm">
                {plan.features.map((feature) => (
                  <li key={feature} className="flex gap-2">
                    <span aria-hidden style={{ color: colors[3] }}>
                      ✓
                    </span>
                    <span className="opacity-85">{feature}</span>
                  </li>
                ))}
              </ul>

              <div className="mt-auto">
                {plan.href ? (
                  <a href={plan.href} className={button} style={look}>
                    {plan.cta ?? "Choose plan"}
                  </a>
                ) : (
                  <button type="button" onClick={() => onSelect?.(plan, yearly ? "yearly" : "monthly")} className={button} style={look}>
                    {plan.cta ?? "Choose plan"}
                  </button>
                )}
              </div>
            </motion.li>
          );
        })}
      </ul>
    </section>
  );
}