"use client";

import { useEffect, useId, useRef, useState } from "react";
import { defaultCycle } from "@/lib/bloub-official/cycles";
import { NOTIF_BLUE } from "@/lib/bloub-official/decor";
import { type BotFrame, BotEngine } from "@/lib/bloub-official/engine";
import {
  DEFAULT_EXPRESSION,
  EXPRESSION_BY_ID,
} from "@/lib/bloub-official/expressions";
import { DEMI_VIEWBOX, RAYON } from "@/lib/bloub-official/repere";
import { SHAPE_BY_ID } from "@/lib/bloub-official/skins";
import type { StateId } from "@/lib/bloub-official/states";
import { cn } from "@/lib/utils";

export type BloubAvatarProps = {
  animated?: boolean;
  className?: string;
  label?: string;
  playSequence?: boolean;
  size?: number;
  state?: StateId;
  surface?: "chat" | "page";
};

export function BloubAvatar({
  animated = true,
  className,
  label = "AI 助手",
  playSequence = false,
  size = 32,
  state = "idle",
  surface = "chat",
}: BloubAvatarProps) {
  const rawId = useId();
  const uid = rawId.replace(/[^a-zA-Z0-9_-]/g, "");
  const maskId = `bloub-mask-${uid}`;
  const engineRef = useRef<BotEngine | null>(null);
  const clockRef = useRef(0);

  if (!engineRef.current) {
    engineRef.current = new BotEngine(
      RAYON,
      state,
      SHAPE_BY_ID.get("squircle")?.radii ?? null,
      EXPRESSION_BY_ID.get(DEFAULT_EXPRESSION) ?? null
    );
  }

  const [frame, setFrame] = useState<BotFrame>(() =>
    engineRef.current!.sample(0)
  );

  useEffect(() => {
    if (playSequence) return;
    const engine = engineRef.current;
    if (!engine || engine.state === state) return;
    engine.setState(state, clockRef.current);
    setFrame(engine.sample(clockRef.current));
  }, [playSequence, state]);

  useEffect(() => {
    const engine = engineRef.current;
    if (!engine) return;

    const cycle = defaultCycle().blocks;
    const firstState = playSequence
      ? cycle[0]?.state ?? "idle"
      : engine.state;
    engine.reset(firstState, 0);
    clockRef.current = 0;
    setFrame(engine.sample(0));

    const reducedMotion = window.matchMedia(
      "(prefers-reduced-motion: reduce)"
    ).matches;
    if (!animated || reducedMotion) return;

    let animationFrame = 0;
    let lastFrameAt = 0;
    let blockIndex = 0;
    let nextBlockAt = cycle[0]?.duration ?? Number.POSITIVE_INFINITY;

    const tick = (timestamp: number) => {
      const delta = lastFrameAt
        ? Math.min((timestamp - lastFrameAt) / 1000, 0.064)
        : 0;
      lastFrameAt = timestamp;
      clockRef.current += delta;

      if (playSequence && cycle.length > 0) {
        while (clockRef.current >= nextBlockAt) {
          blockIndex = (blockIndex + 1) % cycle.length;
          const nextBlock = cycle[blockIndex]!;
          engine.setState(nextBlock.state, nextBlockAt);
          nextBlockAt += nextBlock.duration;
        }
      }

      setFrame(engine.sample(clockRef.current));
      animationFrame = window.requestAnimationFrame(tick);
    };

    animationFrame = window.requestAnimationFrame(tick);
    return () => window.cancelAnimationFrame(animationFrame);
  }, [animated, playSequence]);

  const renderDot = (
    dot: BotFrame["dots"][number],
    index: number,
    layer: "back" | "front"
  ) => {
    const fill = dot.color ?? "currentColor";
    const common = {
      fill,
      opacity:
        dot.color || dot.depth === undefined
          ? dot.opacity
          : dot.opacity * dot.depth,
    };
    const key = `${layer}-${index}`;

    if (dot.d) {
      return (
        <path
          {...common}
          d={dot.d}
          key={key}
          transform={`translate(${dot.x} ${dot.y}) rotate(${dot.rot ?? 0}) scale(${RAYON})`}
        />
      );
    }

    return (
      <circle {...common} cx={dot.x} cy={dot.y} key={key} r={dot.r} />
    );
  };

  return (
    <svg
      aria-label={label}
      className={cn(
        "block shrink-0 text-[#0a0a0c] dark:text-[#3ecf8e]",
        surface === "page"
          ? "[--bloub-paper:#f4f4f5] dark:[--bloub-paper:#08090b]"
          : "[--bloub-paper:#ffffff] dark:[--bloub-paper:#09090b]",
        className
      )}
      height={size}
      role="img"
      viewBox={`${-DEMI_VIEWBOX} ${-DEMI_VIEWBOX} ${DEMI_VIEWBOX * 2} ${DEMI_VIEWBOX * 2}`}
      width={size}
    >
      <defs>
        <mask
          height={DEMI_VIEWBOX * 2}
          id={maskId}
          maskUnits="userSpaceOnUse"
          width={DEMI_VIEWBOX * 2}
          x={-DEMI_VIEWBOX}
          y={-DEMI_VIEWBOX}
        >
          <path d={frame.bodyPath} fill="#fff" />
          {frame.eyes.map((eye, index) => (
            <path
              d={eye.d}
              fill="#000"
              key={`eye-${index}`}
              opacity={eye.alpha}
              transform={eye.matrix}
            />
          ))}
          {frame.notch ? (
            <circle
              cx={frame.notch.x}
              cy={frame.notch.y}
              fill="#000"
              r={frame.notch.r}
            />
          ) : null}
        </mask>

        {frame.arcs.map((arc) => (
          <linearGradient
            gradientUnits="userSpaceOnUse"
            id={`${uid}-${arc.id}`}
            key={`gradient-${arc.id}`}
            x1={arc.grad.x1}
            x2={arc.grad.x2}
            y1={arc.grad.y1}
            y2={arc.grad.y2}
          >
            {arc.grad.stops.map((color, index) => (
              <stop
                key={`${arc.id}-${color}-${index}`}
                offset={index / (arc.grad.stops.length - 1)}
                stopColor={color}
              />
            ))}
          </linearGradient>
        ))}
      </defs>

      <g fill="none" strokeLinecap="round">
        {frame.arcs.map((arc) => (
          <path
            d={arc.back}
            key={`arc-back-${arc.id}`}
            opacity={arc.opacity}
            stroke={`url(#${uid}-${arc.id})`}
            strokeWidth={arc.width}
          />
        ))}
      </g>

      {frame.dotsBehind ? (
        <g>{frame.dots.map((dot, index) => renderDot(dot, index, "back"))}</g>
      ) : null}

      <g opacity={frame.bodyAlpha}>
        <path d={frame.bodyPath} fill="var(--bloub-paper)" />
        <g mask={`url(#${maskId})`}>
          <rect
            fill="currentColor"
            height={DEMI_VIEWBOX * 2}
            width={DEMI_VIEWBOX * 2}
            x={-DEMI_VIEWBOX}
            y={-DEMI_VIEWBOX}
          />
        </g>
      </g>

      {!frame.dotsBehind ? (
        <g>{frame.dots.map((dot, index) => renderDot(dot, index, "front"))}</g>
      ) : null}

      {frame.notif ? (
        <circle
          cx={frame.notif.x}
          cy={frame.notif.y}
          fill={NOTIF_BLUE}
          r={frame.notif.r}
        />
      ) : null}

      <g fill="none" strokeLinecap="round">
        {frame.arcs.map((arc) => (
          <path
            d={arc.front}
            key={`arc-front-${arc.id}`}
            opacity={arc.opacity}
            stroke={`url(#${uid}-${arc.id})`}
            strokeWidth={arc.width}
          />
        ))}
      </g>
    </svg>
  );
}