"use client";

/**
 * The emoji row at the top of a message's long-press menu.
 *
 * Five quick reactions plus a "+" that opens the full set — a drawer on
 * mobile, a popover anchored to the "+" on desktop. A modal would take over
 * the screen and hide the message being reacted to, which is the one thing
 * that needs to stay visible while choosing.
 *
 * It sits inside the context menu rather than being its own popover: long
 * press is one gesture, and two surfaces competing for it would mean neither
 * felt reliable.
 */

import { useEffect, useState } from "react";
import { createPortal } from "react-dom";
import { Plus } from "lucide-react";
import { EMOJI_GROUPS } from "@/components/ui/emoji-picker";
import { useMediaQuery } from "@/components/selection-toolbar/shared";
import {
  Drawer,
  DrawerContent,
  DrawerDescription,
  DrawerHeader,
  DrawerTitle,
} from "@/components/ui/drawer";
import { cn } from "@/lib/utils";

const POPOVER_W = 320;
const POPOVER_H = 320;
const EDGE_PAD = 8;

/** What a double-tap sends. Matches the server's own default. */
export const HEART_EMOJI = "❤️";

/** The five offered without opening the full set. */
export const QUICK_REACTIONS = [HEART_EMOJI, "😂", "🙏", "😮", "😢"];

export function ReactionRow({
  current,
  onPick,
}: {
  /** The viewer's existing reaction, so it can be shown as selected. */
  current?: string;
  /** Picking the current emoji again clears it — the caller decides. */
  onPick: (emoji: string) => void;
}) {
  // Non-null both opens the full set and positions it: the popover hangs off
  // the "+" button's rect, which only exists at click time.
  const [browsing, setBrowsing] = useState<{ x: number; y: number } | null>(
    null,
  );
  const close = () => setBrowsing(null);

  return (
    <>
      <div className="flex items-center gap-1 border-b border-border px-2 py-2">
        {QUICK_REACTIONS.map((emoji) => (
          <button
            key={emoji}
            type="button"
            onClick={() => onPick(emoji)}
            aria-label={`React ${emoji}`}
            aria-pressed={current === emoji}
            className={cn(
              "inline-flex size-9 items-center justify-center rounded-full text-lg transition-colors",
              current === emoji ? "bg-primary/15" : "hover:bg-muted",
            )}
          >
            {emoji}
          </button>
        ))}
        <button
          type="button"
          onClick={(e) => {
            const r = e.currentTarget.getBoundingClientRect();
            // Top-centre of the "+": the popover opens upward from here.
            setBrowsing({ x: r.left + r.width / 2, y: r.top });
          }}
          aria-label="More reactions"
          className="inline-flex size-9 items-center justify-center rounded-full text-muted-foreground hover:bg-muted hover:text-foreground"
        >
          <Plus className="size-4" />
        </button>
      </div>

      {browsing && <FullSet anchor={browsing} onPick={onPick} onClose={close} />}
    </>
  );
}

/** The whole emoji set: popover on desktop, drawer on touch. */
function FullSet({
  anchor,
  onPick,
  onClose,
}: {
  anchor: { x: number; y: number };
  onPick: (emoji: string) => void;
  onClose: () => void;
}) {
  const isMobile = useMediaQuery("(max-width: 767px)");

  // Desktop only: Escape closes. The drawer handles its own dismissal, and a
  // popover deliberately doesn't lock scrolling behind it.
  useEffect(() => {
    if (isMobile) return;
    const onKey = (e: KeyboardEvent) => e.key === "Escape" && onClose();
    document.addEventListener("keydown", onKey);
    return () => document.removeEventListener("keydown", onKey);
  }, [isMobile, onClose]);

  const grid = (
    <div className="space-y-4 p-3">
      {EMOJI_GROUPS.map((group) => (
        <section key={group.label}>
          <h3 className="mb-2 text-xs font-medium uppercase tracking-wide text-muted-foreground">
            {group.label}
          </h3>
          <div className="grid grid-cols-8 gap-1">
            {group.emojis.map((emoji) => (
              <button
                key={emoji}
                type="button"
                onClick={() => {
                  onClose();
                  onPick(emoji);
                }}
                aria-label={`React ${emoji}`}
                className="inline-flex size-9 items-center justify-center rounded-md text-lg hover:bg-muted"
              >
                {emoji}
              </button>
            ))}
          </div>
        </section>
      ))}
    </div>
  );

  if (isMobile) {
    return (
      <Drawer open onOpenChange={(o) => !o && onClose()}>
        <DrawerContent className="bg-card">
          <DrawerHeader className="text-left">
            <DrawerTitle>Pick a reaction</DrawerTitle>
            <DrawerDescription>
              Choose any emoji to react with.
            </DrawerDescription>
          </DrawerHeader>
          <div className="max-h-[45vh] overflow-y-auto overscroll-contain">
            {grid}
          </div>
        </DrawerContent>
      </Drawer>
    );
  }

  if (typeof document === "undefined") return null;

  // Opens upward: the "+" sits in a menu raised over a message, so there is
  // usually more room above it than below. Flips down only if that would clip.
  let left = anchor.x - POPOVER_W / 2;
  if (left + POPOVER_W > window.innerWidth - EDGE_PAD) {
    left = window.innerWidth - POPOVER_W - EDGE_PAD;
  }
  if (left < EDGE_PAD) left = EDGE_PAD;

  // Room above the button, less a small gap and the viewport edge.
  const roomAbove = anchor.y - 8 - EDGE_PAD;
  // Open upward when there is any reasonable room, which by the composer
  // there almost always is.
  const openUp = roomAbove > 160;
  // Anchored by whichever edge faces the button, so the panel hugs it
  // regardless of how tall its contents actually are. Positioning by top
  // minus a MAX height floats it away whenever the content is shorter.
  const vertical = openUp
    ? { bottom: window.innerHeight - anchor.y + 8 }
    : { top: anchor.y + 8 };
  // Never taller than the space it has.
  const maxH = Math.min(
    POPOVER_H,
    openUp ? roomAbove : window.innerHeight - anchor.y - 8 - EDGE_PAD,
  );

  return createPortal(
    <>
      {/* Catches the outside click. Transparent — a popover dims nothing. */}
      <div className="fixed inset-0 z-[60]" onClick={onClose} aria-hidden />
      <div
        role="dialog"
        aria-label="Pick a reaction"
        style={{ left, ...vertical, width: POPOVER_W, maxHeight: maxH }}
        className="fixed z-[61] flex flex-col overflow-hidden rounded-xl border border-border bg-card shadow-lg"
      >
        <div className="flex-1 overflow-y-auto">{grid}</div>
      </div>
    </>,
    document.body,
  );
}