"use client";
import { useState, useEffect, useCallback } from "react";
import { useActiveSymbol } from "@/stores/active-symbol-store";
import { api } from "@/lib/trpc";
import { UI_STRINGS } from "@/lib/strings";

/**
 * Persistent top bar showing the active symbol, price, change, and search.
 * This is the "central nervous system" — switching symbols updates everything globally.
 */
export function SymbolHeader() {
  const symbol = useActiveSymbol((s) => s.activeSymbol);
  const setActive = useActiveSymbol((s) => s.setActive);
  const [draft, setDraft] = useState(symbol);
  const [showSearch, setShowSearch] = useState(false);
  const [snap, setSnap] = useState<ReturnType<typeof api.market.snapshot> | null>(null);

  // Fetch current price for display
  useEffect(() => {
    const sym = draft || symbol;
    api.market.snapshot(sym).then(setSnap).catch(() => {});
  }, [draft, symbol]);

  const quote = snap?.quote ?? null;
  const sector = snap?.sector ?? null;

  const up = (quote?.change ?? 0) >= 0;
  const priceLabel = quote ? `$${quote.price?.toFixed(2)}` : "";
  const changeLabel = quote && quote.change !== undefined
    ? `${up ? "▲" : "▼"}${up ? "+" : ""}${quote.change.toFixed(2)} (${up ? "+" : ""}${(quote.changePercent ?? 0).toFixed(2)}%)`
    : "";
  const sectorLabel = sector ? `${sector.sector} · ${sector.tickerKind}` : "";

  const handleSubmit = useCallback((e: React.FormEvent) => {
    e.preventDefault();
    const sym = draft.trim().toUpperCase() || symbol;
    setActive(sym);
    setShowSearch(false);
  }, [draft, symbol, setActive]);

  // Keyboard shortcut: Ctrl+K to toggle search
  useEffect(() => {
    const handler = (e: KeyboardEvent) => {
      if ((e.metaKey || e.ctrlKey) && e.key === "k") {
        e.preventDefault();
        setShowSearch(prev => !prev);
      }
      if (e.key === "Escape" && showSearch) {
        setShowSearch(false);
      }
    };
    window.addEventListener("keydown", handler);
    return () => window.removeEventListener("keydown", handler);
  }, [showSearch]);

  // Sync draft when active symbol changes externally
  useEffect(() => {
    setDraft(symbol);
  }, [symbol]);

  return (
    <header className="sticky top-0 z-50 border-b border-[#2a2b3a] bg-[#121318]/95 backdrop-blur-sm">
      <div className="flex items-center justify-between px-4 py-3">
        {/* Left: Logo mark */}
        <div className="flex items-center gap-2 flex-shrink-0">
          <div className="w-7 h-7 rounded-lg bg-[#4f8cff] flex items-center justify-center">
            <span className="text-xs font-bold text-[#121318]">IF</span>
          </div>
          <h1 className="hidden sm:block text-sm font-semibold text-[#e6e7ec] tracking-tight">
            Investor Flow
          </h1>
        </div>

        {/* Right: Ticker info + Search grouped together */}
        <div className="flex items-center gap-4">
          {/* Active symbol — compact, next to search */}
          <div className="hidden sm:flex items-baseline gap-2 text-xs">
            <span className="font-bold text-[#e6e7ec]">{symbol}</span>
            {priceLabel && (
              <span className="font-mono text-[#8a8b9a]">{priceLabel}</span>
            )}
            {changeLabel && (
              <span className={`font-mono ${up ? "text-[#34d399]" : "text-[#fbbf24]"}`}>
                {changeLabel}
              </span>
            )}
          </div>

          {/* Mobile: just ticker */}
          <div className="sm:hidden flex items-center gap-1.5 text-xs">
            <span className="font-bold text-[#e6e7ec]">{symbol}</span>
            {priceLabel && (
              <span className="font-mono text-[#8a8b9a]">{priceLabel}</span>
            )}
          </div>

          {/* Search */}
          <form onSubmit={handleSubmit} className="flex items-center">
            <label className="sr-only" htmlFor="symbol-search">Search symbol</label>
            <div className={`relative transition-all duration-200 ${showSearch ? "w-56" : "w-40"}`}>
              <input
                id="symbol-search"
                value={draft}
                onChange={(e) => setDraft(e.target.value)}
                onFocus={() => setShowSearch(true)}
                onBlur={() => setTimeout(() => setShowSearch(false), 200)}
                placeholder="Search…"
                className="w-full bg-[#1a1b24] border border-[#2a2b3a] rounded-lg px-3 py-1.5 text-xs text-[#e6e7ec] placeholder:text-[#5a5b6a] focus:outline-none focus:border-[#4f8cff] focus:ring-1 focus:ring-[#4f8cff]"
              />
              <kbd className="absolute right-2 top-1/2 -translate-y-1/2 text-[9px] text-[#5a5b6a] bg-[#0a0b0f] border border-[#2a2b3a] rounded px-1.5">
                ⌘K
              </kbd>
            </div>
          </form>
        </div>
      </div>
    </header>
  );
}