import { useCallback, useEffect, useLayoutEffect, useRef, useState } from "react";
import { createPortal } from "react-dom";
import type { Editor } from "@tiptap/react";
import {
  Sparkles,
  Bold,
  Italic,
  Underline,
  Heading1,
  Copy,
  Check,
} from "lucide-react";
import { cn } from "@/lib/utils";
import { useCanvasUIContext } from "../../contexts/CanvasUIContext";

// ── Types ────────────────────────────────────────────────────────────────────

interface MenuPosition {
  x: number;
  y: number;      // top of selection
  bottom: number; // bottom of selection (used to flip menu below when near top)
}

// ── Sub-components ───────────────────────────────────────────────────────────

interface BubbleButtonProps {
  onClick: () => void;
  active?: boolean;
  className?: string;
  children: React.ReactNode;
}

function BubbleButton({ onClick, active, className, children }: BubbleButtonProps) {
  return (
    <button
      type="button"
      onMouseDown={(e) => {
        e.preventDefault(); // keep editor focused
        onClick();
      }}
      className={cn(
        "inline-flex h-7 items-center gap-1 px-2 text-xs font-medium rounded transition-colors",
        "hover:bg-black/8 dark:hover:bg-white/10",
        active && "bg-black/10 dark:bg-white/15",
        className,
      )}
    >
      {children}
    </button>
  );
}

function BubbleSep() {
  return <div className="w-px h-4 bg-black/15 dark:bg-white/25 mx-0.5 shrink-0" />;
}

// ── Main component ───────────────────────────────────────────────────────────

interface WritingBubbleMenuProps {
  editor: Editor;
  onAiRewrite: () => void;
}

export function WritingBubbleMenu({ editor, onAiRewrite }: WritingBubbleMenuProps) {
  const { setWritingSelection } = useCanvasUIContext();
  const [position, setPosition] = useState<MenuPosition | null>(null);
  const [copied, setCopied] = useState(false);
  const menuRef = useRef<HTMLDivElement>(null);
  const [computedStyle, setComputedStyle] = useState<React.CSSProperties>({
    position: "fixed", left: 0, top: 0, zIndex: 9999, visibility: "hidden",
  });

  useLayoutEffect(() => {
    if (!position || !menuRef.current) return;
    const { width: mw, height: mh } = menuRef.current.getBoundingClientRect();
    // X: center on selection, clamp to viewport
    const rawLeft = position.x - mw / 2;
    const safeLeft = Math.max(8, Math.min(rawLeft, window.innerWidth - mw - 8));
    // Y: prefer above; flip below if too close to top
    let safeTop: number;
    if (position.y - mh - 8 >= 8) {
      safeTop = position.y - mh - 8;
    } else {
      safeTop = Math.min(position.bottom + 8, window.innerHeight - mh - 8);
    }
    setComputedStyle({ position: "fixed", left: safeLeft, top: safeTop, zIndex: 9999, visibility: "visible" });
  }, [position]);

  // Track selection → compute menu position
  useEffect(() => {
    const updatePosition = () => {
      const { from, to, empty } = editor.state.selection;

      if (empty || editor.isActive("codeBlock")) {
        setPosition(null);
        return;
      }

      // Use the native DOM selection for pixel coordinates
      const domSel = window.getSelection();
      if (!domSel || domSel.rangeCount === 0) {
        setPosition(null);
        return;
      }

      const range = domSel.getRangeAt(0);
      const rect = range.getBoundingClientRect();
      if (!rect.width && !rect.height) {
        setPosition(null);
        return;
      }

      // Store selection for AI rewrite
      const text = editor.state.doc.textBetween(from, to, "\n");
      if (text.trim()) {
        setWritingSelection({ from, to, text });
      }

      setPosition({
        x: rect.left + rect.width / 2,
        y: rect.top,
        bottom: rect.bottom,
      });
    };

    editor.on("selectionUpdate", updatePosition);
    editor.on("blur", () => setPosition(null));

    return () => {
      editor.off("selectionUpdate", updatePosition);
      editor.off("blur", () => setPosition(null));
    };
  }, [editor, setWritingSelection]);

  const handleAiRewrite = useCallback(() => {
    const { from, to, empty } = editor.state.selection;
    if (!empty) {
      editor.commands.setAiHighlight(from, to);
    }
    onAiRewrite();
  }, [onAiRewrite, editor]);

  const handleCopy = useCallback(() => {
    const { from, to } = editor.state.selection;
    const text = editor.state.doc.textBetween(from, to, "\n");
    navigator.clipboard.writeText(text).then(() => {
      setCopied(true);
      setTimeout(() => setCopied(false), 1500);
    });
  }, [editor]);

  if (!position) return null;

  return createPortal(
    <div
      ref={menuRef}
      style={computedStyle}
      className="animate-in fade-in zoom-in-95 duration-100"
    >
      <div className="flex items-center gap-0 rounded-lg px-1 py-1 shadow-lg ring-1 ring-black/8 bg-popover text-foreground dark:bg-neutral-900 dark:ring-white/10">
        {/* AI 改写 — primary */}
        <BubbleButton
          onClick={handleAiRewrite}
          className="text-amber-500 hover:text-amber-600 font-semibold"
        >
          <Sparkles className="h-3.5 w-3.5" />
          AI 改写
        </BubbleButton>

        <BubbleSep />

        {/* Inline format */}
        <BubbleButton
          onClick={() => editor.chain().focus().toggleBold().run()}
          active={editor.isActive("bold")}
        >
          <Bold className="h-3.5 w-3.5" />
        </BubbleButton>

        <BubbleButton
          onClick={() => editor.chain().focus().toggleItalic().run()}
          active={editor.isActive("italic")}
        >
          <Italic className="h-3.5 w-3.5" />
        </BubbleButton>

        <BubbleButton
          onClick={() => editor.chain().focus().toggleUnderline().run()}
          active={editor.isActive("underline")}
        >
          <Underline className="h-3.5 w-3.5" />
        </BubbleButton>

        <BubbleSep />

        {/* Heading */}
        <BubbleButton
          onClick={() =>
            editor.chain().focus().toggleHeading({ level: 1 }).run()
          }
          active={editor.isActive("heading", { level: 1 })}
        >
          <Heading1 className="h-3.5 w-3.5" />
        </BubbleButton>

        <BubbleSep />

        {/* Copy */}
        <BubbleButton onClick={handleCopy}>
          {copied ? (
            <Check className="h-3.5 w-3.5 text-green-400" />
          ) : (
            <Copy className="h-3.5 w-3.5" />
          )}
        </BubbleButton>
      </div>
    </div>,
    document.body,
  );
}