"use client";

import { AnimatePresence, motion, useReducedMotion } from "motion/react";
import {
  ArrowDownUp,
  Check,
  ChevronDown,
  Loader2,
  Search,
  Send,
  Settings,
  Wallet,
  X,
} from "lucide-react";
import { useEffect, useId, useMemo, useRef, useState } from "react";
import { cn } from "@/lib/utils";

/* ============================================================
 * Types + mock data
 * ============================================================ */

export type Chain = { id: string; name: string; color: string; symbol: string };
export type Token = {
  id: string;
  symbol: string;
  name: string;
  chainId: string;
  address?: string;
  balance?: number;
  usd?: number;
  trending?: boolean;
  popular?: boolean;
};

const CHAINS: Chain[] = [
  { id: "eth", name: "Ethereum", color: "#627EEA", symbol: "Ξ" },
  { id: "sol", name: "Solana", color: "#9945FF", symbol: "◎" },
  { id: "base", name: "Base", color: "#0052FF", symbol: "B" },
  { id: "arb", name: "Arbitrum", color: "#28A0F0", symbol: "A" },
  { id: "op", name: "Optimism", color: "#FF0420", symbol: "O" },
  { id: "poly", name: "Polygon", color: "#8247E5", symbol: "P" },
  { id: "bnb", name: "BNB", color: "#F0B90B", symbol: "B" },
  { id: "avax", name: "Avalanche", color: "#E84142", symbol: "A" },
];

const TOKENS: Token[] = [
  {
    id: "eth-eth",
    symbol: "ETH",
    name: "Ether",
    chainId: "eth",
    balance: 1.245,
    usd: 3142,
    popular: true,
  },
  {
    id: "eth-weth",
    symbol: "WETH",
    name: "Wrapped Ether",
    chainId: "eth",
    balance: 0.5,
    usd: 3142,
    popular: true,
  },
  {
    id: "eth-usdc",
    symbol: "USDC",
    name: "USD Coin",
    chainId: "eth",
    balance: 4521,
    usd: 1,
    popular: true,
  },
  {
    id: "eth-usdt",
    symbol: "USDT",
    name: "Tether",
    chainId: "eth",
    balance: 2100,
    usd: 1,
    popular: true,
  },
  {
    id: "eth-dai",
    symbol: "DAI",
    name: "Dai Stablecoin",
    chainId: "eth",
    balance: 800,
    usd: 1,
    popular: true,
  },
  {
    id: "eth-wbtc",
    symbol: "WBTC",
    name: "Wrapped Bitcoin",
    chainId: "eth",
    balance: 0.04,
    usd: 96000,
    popular: true,
  },
  {
    id: "eth-link",
    symbol: "LINK",
    name: "ChainLink Token",
    chainId: "eth",
    balance: 120,
    usd: 22,
    address: "0x51...86ca",
    trending: true,
  },
  {
    id: "eth-aztec",
    symbol: "AZTEC",
    name: "AZTEC",
    chainId: "eth",
    balance: 0,
    address: "0xa2...62d2",
    trending: true,
  },
  {
    id: "eth-cfg",
    symbol: "CFG",
    name: "Centrifuge",
    chainId: "eth",
    balance: 0,
    address: "0xcc...8a94",
    trending: true,
  },
  {
    id: "eth-ondo",
    symbol: "ONDO",
    name: "Ondo",
    chainId: "eth",
    balance: 0,
    address: "0xfa...9be3",
    trending: true,
  },
  {
    id: "sol-sol",
    symbol: "SOL",
    name: "Solana",
    chainId: "sol",
    balance: 12.4,
    usd: 168,
  },
  {
    id: "sol-usdc",
    symbol: "USDC",
    name: "USD Coin",
    chainId: "sol",
    balance: 985.32,
    usd: 1,
  },
  {
    id: "base-eth",
    symbol: "ETH",
    name: "Ether",
    chainId: "base",
    balance: 0.65,
    usd: 3142,
  },
  {
    id: "base-usdc",
    symbol: "USDC",
    name: "USD Coin",
    chainId: "base",
    balance: 1200,
    usd: 1,
  },
  {
    id: "arb-arb",
    symbol: "ARB",
    name: "Arbitrum",
    chainId: "arb",
    balance: 800,
    usd: 0.95,
  },
  {
    id: "arb-eth",
    symbol: "ETH",
    name: "Ether",
    chainId: "arb",
    balance: 0.32,
    usd: 3142,
  },
  {
    id: "op-op",
    symbol: "OP",
    name: "Optimism",
    chainId: "op",
    balance: 450,
    usd: 2.8,
  },
  {
    id: "poly-matic",
    symbol: "MATIC",
    name: "Polygon",
    chainId: "poly",
    balance: 1500,
    usd: 0.75,
  },
  {
    id: "bnb-bnb",
    symbol: "BNB",
    name: "BNB",
    chainId: "bnb",
    balance: 0,
    usd: 620,
  },
  {
    id: "avax-avax",
    symbol: "AVAX",
    name: "Avalanche",
    chainId: "avax",
    balance: 0,
    usd: 38,
  },
];

const EASE = [0.16, 1, 0.3, 1] as const;
const DRAWER_EASE = [0.32, 0.72, 0, 1] as const;

/* ============================================================
 * MultiChainSwap
 * ============================================================ */

export interface MultiChainSwapProps {
  chains?: Chain[];
  tokens?: Token[];
  defaultFromId?: string;
  defaultToId?: string;
  className?: string;
}

export function MultiChainSwap({
  chains = CHAINS,
  tokens = TOKENS,
  defaultFromId = "eth-eth",
  defaultToId = "sol-sol",
  className,
}: MultiChainSwapProps) {
  const reduce = useReducedMotion();
  const [fromId, setFromId] = useState(defaultFromId);
  const [toId, setToId] = useState(defaultToId);
  const [amount, setAmount] = useState("1");
  const [flipRot, setFlipRot] = useState(0);
  const [quoting, setQuoting] = useState(false);
  const [picking, setPicking] = useState<"from" | "to" | null>(null);
  const [showDest, setShowDest] = useState(false);
  const [destAddress, setDestAddress] = useState("");

  const from = tokens.find((t) => t.id === fromId)!;
  const to = tokens.find((t) => t.id === toId)!;
  const fromChain = chains.find((c) => c.id === from.chainId)!;
  const toChain = chains.find((c) => c.id === to.chainId)!;

  const numericAmount = Number(amount) || 0;
  const rate = useMemo(() => {
    if (!from.usd || !to.usd) return 1;
    return from.usd / to.usd;
  }, [from.usd, to.usd]);
  const toAmount = numericAmount * rate;
  const networkFee = 0.42;
  const eta = "≈ 24s";

  useEffect(() => {
    if (numericAmount === 0) return;
    setQuoting(true);
    const id = setTimeout(() => setQuoting(false), 450);
    return () => clearTimeout(id);
  }, [numericAmount, fromId, toId]);

  const flip = () => {
    setFlipRot((r) => r + 180);
    setFromId(toId);
    setToId(fromId);
  };

  const pickToken = (id: string) => {
    if (!picking) return;
    if (picking === "from") {
      if (id === toId) setToId(fromId);
      setFromId(id);
    } else {
      if (id === fromId) setFromId(toId);
      setToId(id);
    }
    setPicking(null);
  };

  return (
    <div
      className={cn(
        "relative isolate w-full max-w-[420px] overflow-hidden rounded-3xl",
        "border border-(--color-border-strong)/20 bg-(--color-bg-elev)",
        className,
      )}
    >
      {/* Header */}
      <div className="flex h-12 items-center justify-between border-b border-(--color-border)/50 px-3">
        <span className="px-2 text-sm font-semibold tracking-tight text-(--color-fg)">
          Swap
        </span>
        <button
          type="button"
          aria-label="Settings"
          className="inline-flex h-8 w-8 items-center justify-center rounded-full text-(--color-fg-muted) hover:bg-(--color-fg)/5 hover:text-(--color-fg) press"
        >
          <Settings className="h-4 w-4" />
        </button>
      </div>

      {/* Swap form (always mounted, fixed height) */}
      <div className="flex flex-col gap-1.5 p-4">
        <Field
          side="from"
          token={from}
          chain={fromChain}
          amount={amount}
          onAmount={setAmount}
          editable
          quoting={false}
          onOpenPicker={() => setPicking("from")}
        />

        <FlipButton rotation={flipRot} reduce={!!reduce} onClick={flip} />

        <Field
          side="to"
          token={to}
          chain={toChain}
          amount={toAmount > 0 ? formatAmount(toAmount) : ""}
          editable={false}
          quoting={quoting}
          onOpenPicker={() => setPicking("to")}
        />

        <QuoteRow
          from={from}
          to={to}
          rate={rate}
          fee={networkFee}
          slippage={0.5}
          eta={eta}
          quoting={quoting}
        />

        <DestinationRow
          show={showDest}
          onToggle={() => {
            if (showDest) setDestAddress("");
            setShowDest((v) => !v);
          }}
          address={destAddress}
          onAddress={setDestAddress}
          reduce={!!reduce}
        />

        <ActionButton
          from={from}
          to={to}
          amount={numericAmount}
          destAddress={destAddress}
        />
      </div>

      {/* Token picker — bottom sheet anchored to this card */}
      <TokenPicker
        open={picking !== null}
        side={picking}
        chains={chains}
        tokens={tokens}
        selectedId={picking === "from" ? fromId : toId}
        onPick={pickToken}
        onClose={() => setPicking(null)}
        reduce={!!reduce}
      />
    </div>
  );
}

/* ============================================================
 * Field
 * ============================================================ */

function Field({
  side,
  token,
  chain,
  amount,
  onAmount,
  editable,
  quoting,
  onOpenPicker,
}: {
  side: "from" | "to";
  token: Token;
  chain: Chain;
  amount: string;
  onAmount?: (v: string) => void;
  editable: boolean;
  quoting: boolean;
  onOpenPicker: () => void;
}) {
  const id = useId();
  const usdValue = (Number(amount) || 0) * (token.usd ?? 0);
  return (
    <div className="relative rounded-2xl border border-(--color-border)/50 bg-(--color-bg)/40 p-3.5">
      <label
        htmlFor={id}
        className="mb-2 block text-[11px] font-medium uppercase tracking-wider text-(--color-fg-muted)"
      >
        {side === "from" ? "You pay" : "You get"}
      </label>

      <div className="flex items-center justify-between gap-3">
        <div className="min-w-0 flex-1">
          {editable ? (
            <input
              id={id}
              inputMode="decimal"
              value={amount}
              onChange={(e) => onAmount?.(sanitizeAmount(e.target.value))}
              placeholder="0"
              className="w-full bg-transparent text-2xl font-semibold tracking-tight text-(--color-fg) tabular-nums outline-none placeholder:text-(--color-fg-muted)/60"
            />
          ) : (
            <div className="flex h-9 items-center gap-2 text-2xl font-semibold tracking-tight tabular-nums">
              <motion.span
                animate={{
                  opacity: quoting ? 0.55 : 1,
                  filter: quoting ? "blur(2px)" : "blur(0px)",
                }}
                transition={{ duration: 0.18, ease: EASE }}
                className="text-(--color-fg)"
              >
                {amount || "0"}
              </motion.span>
              <AnimatePresence>
                {quoting ? (
                  <motion.span
                    initial={{ opacity: 0, scale: 0.85 }}
                    animate={{ opacity: 1, scale: 1 }}
                    exit={{ opacity: 0, scale: 0.85 }}
                    transition={{ duration: 0.14, ease: EASE }}
                  >
                    <Loader2 className="h-4 w-4 animate-spin text-(--color-fg-muted)" />
                  </motion.span>
                ) : null}
              </AnimatePresence>
            </div>
          )}
          <p className="mt-1 text-[11px] text-(--color-fg-muted) tabular-nums">
            ≈ ${formatAmount(usdValue, 2)}
          </p>
        </div>

        <button
          type="button"
          onClick={onOpenPicker}
          className="group inline-flex h-10 items-center gap-2 rounded-full border border-(--color-border) bg-(--color-bg-elev) pl-1 pr-2.5 text-sm font-semibold text-(--color-fg) press hover:border-(--color-border-strong)"
        >
          <TokenDot token={token} chain={chain} />
          <span>{token.symbol}</span>
          <ChevronDown className="h-3.5 w-3.5 text-(--color-fg-muted)" />
        </button>
      </div>

      <div className="mt-2 flex items-center justify-between text-[11px] text-(--color-fg-muted)">
        <span className="inline-flex items-center gap-1">
          <Wallet className="h-3 w-3" />
          <span className="tabular-nums">
            {token.balance ? formatAmount(token.balance) : "0.00"}
          </span>
          <span>· {chain.name}</span>
        </span>
        {side === "from" && token.balance ? (
          <button
            type="button"
            onClick={() => onAmount?.(String(token.balance))}
            className="rounded px-1.5 py-0.5 text-[10px] font-semibold uppercase tracking-wider text-(--color-fg-muted) hover:bg-(--color-fg)/5 hover:text-(--color-fg)"
          >
            Max
          </button>
        ) : null}
      </div>
    </div>
  );
}

/* ============================================================
 * Flip button
 * ============================================================ */

function FlipButton({
  rotation,
  reduce,
  onClick,
}: {
  rotation: number;
  reduce: boolean;
  onClick: () => void;
}) {
  return (
    <div className="relative -my-4 flex justify-center" style={{ zIndex: 1 }}>
      <motion.button
        type="button"
        onClick={onClick}
        aria-label="Reverse direction"
        whileTap={reduce ? undefined : { scale: 0.9 }}
        animate={reduce ? undefined : { rotate: rotation }}
        transition={{ type: "spring", stiffness: 380, damping: 26, mass: 0.6 }}
        className="inline-flex h-9 w-9 items-center justify-center rounded-full border-[3px] border-(--color-bg-elev) bg-(--color-fg)/10 text-(--color-fg) backdrop-blur"
      >
        <ArrowDownUp className="h-3.5 w-3.5" />
      </motion.button>
    </div>
  );
}

/* ============================================================
 * Quote row
 * ============================================================ */

function QuoteRow({
  from,
  to,
  rate,
  fee,
  slippage,
  eta,
  quoting,
}: {
  from: Token;
  to: Token;
  rate: number;
  fee: number;
  slippage: number;
  eta: string;
  quoting: boolean;
}) {
  return (
    <div className="mt-3 grid grid-cols-2 gap-x-4 gap-y-1.5 rounded-xl border border-(--color-border)/50 bg-(--color-bg)/40 px-3.5 py-2.5 text-[11px]">
      <span className="text-(--color-fg-muted)">Rate</span>
      <span className="text-right tabular-nums text-(--color-fg)">
        {quoting ? (
          <Loader2 className="ml-auto inline h-3 w-3 animate-spin text-(--color-fg-muted)" />
        ) : (
          <>
            1 {from.symbol} ≈ {formatAmount(rate)} {to.symbol}
          </>
        )}
      </span>
      <span className="text-(--color-fg-muted)">Network fee</span>
      <span className="text-right tabular-nums text-(--color-fg)">
        ${fee.toFixed(2)}
      </span>
      <span className="text-(--color-fg-muted)">Slippage</span>
      <span className="text-right tabular-nums text-(--color-fg)">
        {slippage.toFixed(2)}%
      </span>
      <span className="text-(--color-fg-muted)">ETA</span>
      <span className="text-right text-(--color-fg)">{eta}</span>
    </div>
  );
}

/* ============================================================
 * Action button
 * ============================================================ */

function ActionButton({
  from,
  to,
  amount,
  destAddress,
}: {
  from: Token;
  to: Token;
  amount: number;
  destAddress: string;
}) {
  const noAmount = amount <= 0;
  const overBalance = from.balance !== undefined && amount > from.balance;
  const validDest = destAddress && isValidAddress(destAddress);
  const label = noAmount
    ? "Enter an amount"
    : overBalance
      ? `Insufficient ${from.symbol}`
      : validDest
        ? `Swap + Send to ${truncateAddress(destAddress)}`
        : `Swap ${from.symbol} → ${to.symbol}`;
  const disabled = noAmount || overBalance;

  return (
    <motion.button
      type="button"
      whileTap={disabled ? undefined : { scale: 0.97 }}
      transition={{ type: "spring", stiffness: 500, damping: 30, mass: 0.6 }}
      disabled={disabled}
      className={cn(
        "mt-3 inline-flex h-12 w-full items-center justify-center rounded-2xl text-sm font-semibold transition-colors",
        disabled
          ? "cursor-not-allowed bg-(--color-fg)/10 text-(--color-fg-muted)"
          : "bg-(--color-fg) text-(--color-bg) hover:bg-(--color-fg)/90",
      )}
    >
      <AnimatePresence mode="wait" initial={false}>
        <motion.span
          key={label}
          initial={{ opacity: 0 }}
          animate={{ opacity: 1 }}
          exit={{ opacity: 0 }}
          transition={{ duration: 0.14, ease: EASE }}
        >
          {label}
        </motion.span>
      </AnimatePresence>
    </motion.button>
  );
}

/* ============================================================
 * Destination address row
 * ============================================================ */

function DestinationRow({
  show,
  onToggle,
  address,
  onAddress,
  reduce,
}: {
  show: boolean;
  onToggle: () => void;
  address: string;
  onAddress: (v: string) => void;
  reduce: boolean;
}) {
  const inputRef = useRef<HTMLInputElement>(null);
  const hasAddress = address.length > 0;
  const valid = isValidAddress(address);

  useEffect(() => {
    if (!show) return;
    requestAnimationFrame(() =>
      inputRef.current?.focus({ preventScroll: true }),
    );
  }, [show]);

  return (
    <div className="mt-1 overflow-hidden rounded-xl border border-(--color-border)/50 bg-(--color-bg)/40">
      <button
        type="button"
        onClick={onToggle}
        className="flex w-full items-center justify-between gap-2 px-3.5 py-2.5 text-[12px] text-(--color-fg-muted) hover:text-(--color-fg)"
      >
        <span className="flex items-center gap-2">
          <Send className="h-3.5 w-3.5 shrink-0" />
          <span>
            {show && hasAddress && valid
              ? `To: ${truncateAddress(address)}`
              : "Send to different address"}
          </span>
        </span>
        <motion.span
          animate={reduce ? {} : { rotate: show ? 180 : 0 }}
          transition={{ duration: 0.2, ease: EASE }}
          style={{ display: "inline-flex" }}
        >
          <ChevronDown className="h-3.5 w-3.5" />
        </motion.span>
      </button>

      <AnimatePresence>
        {show ? (
          <motion.div
            key="dest-input"
            initial={reduce ? { opacity: 0 } : { height: 0, opacity: 0 }}
            animate={reduce ? { opacity: 1 } : { height: "auto", opacity: 1 }}
            exit={reduce ? { opacity: 0 } : { height: 0, opacity: 0 }}
            transition={{ duration: 0.22, ease: EASE }}
            style={{ overflow: "hidden" }}
          >
            <div className="border-t border-(--color-border)/50 px-3.5 pb-3 pt-2.5">
              <div
                className={cn(
                  "flex items-center gap-2 rounded-lg border px-2.5 py-2 transition-colors",
                  hasAddress && !valid
                    ? "border-red-500/40"
                    : "border-(--color-border)",
                )}
              >
                <input
                  ref={inputRef}
                  value={address}
                  onChange={(e) => onAddress(e.target.value.trim())}
                  placeholder="0x... or name.eth"
                  spellCheck={false}
                  className="min-w-0 flex-1 bg-transparent font-mono text-[12px] text-(--color-fg) outline-none placeholder:text-(--color-fg-muted)/60"
                />
                <AnimatePresence mode="wait">
                  {hasAddress ? (
                    valid ? (
                      <motion.span
                        key="check"
                        initial={{ opacity: 0, scale: 0.7 }}
                        animate={{ opacity: 1, scale: 1 }}
                        exit={{ opacity: 0, scale: 0.7 }}
                        transition={{ duration: 0.14, ease: EASE }}
                      >
                        <Check className="h-3.5 w-3.5 shrink-0 text-green-500" />
                      </motion.span>
                    ) : (
                      <motion.button
                        key="clear"
                        type="button"
                        onClick={() => onAddress("")}
                        aria-label="Clear address"
                        initial={{ opacity: 0, scale: 0.7 }}
                        animate={{ opacity: 1, scale: 1 }}
                        exit={{ opacity: 0, scale: 0.7 }}
                        transition={{ duration: 0.14, ease: EASE }}
                        className="shrink-0 text-(--color-fg-muted) hover:text-(--color-fg)"
                      >
                        <X className="h-3.5 w-3.5" />
                      </motion.button>
                    )
                  ) : null}
                </AnimatePresence>
              </div>
            </div>
          </motion.div>
        ) : null}
      </AnimatePresence>
    </div>
  );
}

/* ============================================================
 * TokenPicker — bottom sheet anchored to swap card
 * ============================================================ */

function TokenPicker({
  open,
  side,
  chains,
  tokens,
  selectedId,
  onPick,
  onClose,
  reduce,
}: {
  open: boolean;
  side: "from" | "to" | null;
  chains: Chain[];
  tokens: Token[];
  selectedId: string;
  onPick: (id: string) => void;
  onClose: () => void;
  reduce: boolean;
}) {
  const [chainFilter, setChainFilter] = useState<string>("all"); // "all" or chain.id
  const [q, setQ] = useState("");
  const inputRef = useRef<HTMLInputElement>(null);

  useEffect(() => {
    if (!open) return;
    setQ("");
    // Focus without letting the browser scroll the page to bring the input
    // into view — that's what causes the swap form behind to "shift up".
    requestAnimationFrame(() =>
      inputRef.current?.focus({ preventScroll: true }),
    );
  }, [open]);

  // Esc to close
  useEffect(() => {
    if (!open) return;
    const onKey = (e: KeyboardEvent) => {
      if (e.key === "Escape") onClose();
    };
    window.addEventListener("keydown", onKey);
    return () => window.removeEventListener("keydown", onKey);
  }, [open, onClose]);

  const popular = useMemo(
    () => tokens.filter((t) => t.popular).slice(0, 6),
    [tokens],
  );

  const filtered = useMemo(() => {
    const needle = q.trim().toLowerCase();
    return tokens.filter((t) => {
      if (chainFilter !== "all" && t.chainId !== chainFilter) return false;
      if (!needle) return true;
      const chain = chains.find((c) => c.id === t.chainId);
      return [t.symbol, t.name, chain?.name, t.address].some((h) =>
        h?.toLowerCase().includes(needle),
      );
    });
  }, [q, chainFilter, tokens, chains]);

  return (
    <AnimatePresence>
      {open ? (
        <>
          {/* Backdrop inside the card */}
          <motion.button
            key="backdrop"
            type="button"
            aria-label="Close"
            onClick={onClose}
            initial={{ opacity: 0 }}
            animate={{ opacity: 1 }}
            exit={{ opacity: 0 }}
            transition={{ duration: 0.2, ease: EASE }}
            className="absolute inset-0 z-10 cursor-default bg-(--color-bg)/40 backdrop-blur-sm"
          />

          {/* Sheet panel */}
          <motion.div
            key="sheet"
            initial={reduce ? { opacity: 0 } : { opacity: 0, y: "100%" }}
            animate={reduce ? { opacity: 1 } : { opacity: 1, y: 0 }}
            exit={reduce ? { opacity: 0 } : { opacity: 0, y: "100%" }}
            transition={
              reduce
                ? { duration: 0.18, ease: EASE }
                : { type: "spring", stiffness: 420, damping: 40, mass: 0.5 }
            }
            className="absolute inset-x-0 bottom-0 z-20 flex max-h-[92%] flex-col rounded-t-3xl border-t border-(--color-border-strong) bg-(--color-bg-elev) shadow-[0_-20px_40px_-20px_rgb(0_0_0/0.4)]"
            role="dialog"
            aria-modal="true"
            aria-label={`Select ${side === "from" ? "from" : "to"} token`}
          >
            {/* Drag handle (visual only) */}
            <div className="flex justify-center pt-2.5 pb-1">
              <span className="h-1 w-9 rounded-full bg-(--color-fg)/15" />
            </div>

            {/* Search */}
            <div className="flex items-center gap-2 border-b border-(--color-border) px-4 pb-3">
              <Search className="h-4 w-4 shrink-0 text-(--color-fg-muted)" />
              <input
                ref={inputRef}
                value={q}
                onChange={(e) => setQ(e.target.value)}
                placeholder="Search name or paste address"
                className="w-full bg-transparent text-sm text-(--color-fg) outline-none placeholder:text-(--color-fg-muted)/70"
              />
              <button
                type="button"
                onClick={onClose}
                aria-label="Close"
                className="inline-flex h-7 w-7 items-center justify-center rounded-full text-(--color-fg-muted) hover:bg-(--color-fg)/5 hover:text-(--color-fg)"
              >
                <X className="h-3.5 w-3.5" />
              </button>
            </div>

            {/* Chain chips */}
            <div className="scrollbar-hide flex items-center gap-1.5 overflow-x-auto border-b border-(--color-border) px-3 py-5">
              <ChainChip
                active={chainFilter === "all"}
                onClick={() => setChainFilter("all")}
                label="All"
              />
              {chains.map((c) => (
                <ChainChip
                  key={c.id}
                  active={chainFilter === c.id}
                  onClick={() => setChainFilter(c.id)}
                  chain={c}
                />
              ))}
            </div>

            {/* Scroll area */}
            <div className="flex-1 overflow-y-auto px-3 pb-4 pt-3">
              {/* Popular */}
              {!q && chainFilter === "all" ? (
                <>
                  <p className="px-1 pb-2 text-[11px] font-semibold uppercase tracking-wider text-(--color-fg-muted)">
                    Most popular
                  </p>
                  <div className="scrollbar-hide flex items-center gap-1.5 overflow-x-auto pb-3">
                    {popular.map((t) => {
                      const chain = chains.find((c) => c.id === t.chainId)!;
                      return (
                        <button
                          key={t.id}
                          type="button"
                          onClick={() => onPick(t.id)}
                          className="inline-flex shrink-0 items-center gap-2 rounded-full border border-(--color-border) bg-(--color-bg)/50 py-1 pl-1 pr-3 text-sm font-semibold text-(--color-fg) press hover:border-(--color-border-strong)"
                        >
                          <TokenDot token={t} chain={chain} size={22} />
                          {t.symbol}
                        </button>
                      );
                    })}
                  </div>
                </>
              ) : null}

              {/* Trending / All */}
              <p className="px-1 pb-1.5 text-[11px] font-semibold uppercase tracking-wider text-(--color-fg-muted)">
                {q ? "Results" : chainFilter === "all" ? "Trending" : "Tokens"}
              </p>
              <ul className="flex flex-col gap-0.5">
                {filtered.length === 0 ? (
                  <li className="py-8 text-center text-xs text-(--color-fg-muted)">
                    No tokens found
                  </li>
                ) : null}
                {filtered.map((t) => {
                  const chain = chains.find((c) => c.id === t.chainId)!;
                  const active = t.id === selectedId;
                  return (
                    <li key={t.id}>
                      <button
                        type="button"
                        onClick={() => onPick(t.id)}
                        className={cn(
                          "flex w-full items-center justify-between rounded-xl px-2 py-2 text-left transition-colors press",
                          active
                            ? "bg-(--color-fg)/5"
                            : "hover:bg-(--color-fg)/[0.04]",
                        )}
                      >
                        <span className="flex min-w-0 items-center gap-2.5">
                          <TokenDot token={t} chain={chain} size={32} />
                          <span className="flex min-w-0 flex-col">
                            <span className="truncate text-sm font-semibold text-(--color-fg)">
                              {t.name}
                            </span>
                            <span className="truncate text-[11px] text-(--color-fg-muted)">
                              {t.symbol}
                            </span>
                          </span>
                        </span>
                        <span className="shrink-0 text-right text-[11px] tabular-nums text-(--color-fg-muted)">
                          {t.address ??
                            (t.balance ? formatAmount(t.balance) : "")}
                        </span>
                      </button>
                    </li>
                  );
                })}
              </ul>
            </div>
          </motion.div>
        </>
      ) : null}
    </AnimatePresence>
  );
}

function ChainChip({
  active,
  onClick,
  chain,
  label,
}: {
  active: boolean;
  onClick: () => void;
  chain?: Chain;
  label?: string;
}) {
  return (
    <button
      type="button"
      onClick={onClick}
      aria-pressed={active}
      className={cn(
        "inline-flex h-9 shrink-0 items-center justify-center rounded-xl border transition-colors press",
        chain ? "w-9" : "px-3",
        active
          ? "border-(--color-fg)/20 bg-(--color-fg)/5 text-(--color-fg)"
          : "border-(--color-border)/60 bg-(--color-bg)/40 text-(--color-fg) hover:border-(--color-border-strong)",
      )}
      title={chain?.name ?? label}
    >
      {chain ? (
        <ChainDot chain={chain} size={20} />
      ) : (
        <span className="text-xs font-semibold">{label}</span>
      )}
    </button>
  );
}

/* ============================================================
 * Bits
 * ============================================================ */

function ChainDot({ chain, size = 16 }: { chain: Chain; size?: number }) {
  return (
    <span
      style={{ width: size, height: size, background: chain.color }}
      className="inline-flex shrink-0 items-center justify-center rounded-full text-[9px] font-bold text-white"
    >
      {chain.symbol}
    </span>
  );
}

function TokenDot({
  token,
  chain,
  size = 28,
}: {
  token: Token;
  chain: Chain;
  size?: number;
}) {
  return (
    <span
      className="relative inline-flex shrink-0"
      style={{ width: size, height: size }}
    >
      <span className="absolute inset-0 inline-flex items-center justify-center rounded-full border border-(--color-border) bg-(--color-bg) text-[11px] font-bold text-(--color-fg)">
        {token.symbol.slice(0, 2)}
      </span>
      <span
        style={{
          background: chain.color,
          width: size * 0.42,
          height: size * 0.42,
        }}
        className="absolute -bottom-0.5 -right-0.5 inline-flex items-center justify-center rounded-full border-2 border-(--color-bg-elev) text-[7px] font-bold text-white"
      >
        {chain.symbol}
      </span>
    </span>
  );
}

function isValidAddress(v: string) {
  if (/^0x[0-9a-fA-F]{40}$/.test(v)) return true;
  if (/\.(eth|sol|bnb)$/.test(v) && v.length > 5) return true;
  return false;
}

function truncateAddress(v: string) {
  if (v.startsWith("0x") && v.length === 42)
    return v.slice(0, 6) + "…" + v.slice(-4);
  return v;
}

function sanitizeAmount(v: string) {
  const cleaned = v.replace(/[^0-9.]/g, "");
  const parts = cleaned.split(".");
  if (parts.length <= 1) return cleaned;
  return parts[0] + "." + parts.slice(1).join("");
}

function formatAmount(n: number, max = 6) {
  if (!isFinite(n)) return "0";
  if (n === 0) return "0";
  if (n >= 1000)
    return n.toLocaleString(undefined, { maximumFractionDigits: 2 });
  return n.toLocaleString(undefined, { maximumFractionDigits: max });
}

// Drawer ease retained for callers that import the curve.
export const SWAP_DRAWER_EASE = DRAWER_EASE;