import type { OoAvatar, OoFrame, OoLife, OoMoment, OoPaint, OoShape } from "@rakazo/core";
import {
  buildOoRig,
  createOoLife,
  OO_LIST_MOMENTS,
  OO_RIG_INSET,
  OO_RIG_SIZE,
  OO_STILL_TIME,
  ooFrame,
  ooLodForSize,
  ooSeededRandom,
} from "@rakazo/core";
import type { ReactNode } from "react";
import { useEffect, useId, useMemo, useRef, useState } from "react";
import { useReducedMotion } from "react-native-reanimated";
import Svg, {
  Circle,
  Defs,
  Ellipse,
  G,
  LinearGradient,
  Path,
  RadialGradient,
  Rect,
  Stop,
} from "react-native-svg";

const VIEWBOX = `${OO_RIG_INSET} ${OO_RIG_INSET + 4} ${OO_RIG_SIZE - 2 * OO_RIG_INSET} ${OO_RIG_SIZE - 2 * OO_RIG_INSET}`;
const FACE_VIEWBOX = "47 62 112 112";
/** Native frames redraw the SVG tree, so they run at half the display rate. */
const FRAME_SECONDS = 1 / 30;
/** Above this size an Oo always moves; smaller ones only for list moments. */
const LIVELY_SIZE = 56;

type Tick = (now: number) => void;
const ticks = new Set<Tick>();
let frameRequest = 0;

function loop(now: number) {
  for (const tick of ticks) tick(now / 1000);
  frameRequest = ticks.size ? requestAnimationFrame(loop) : 0;
}

function subscribe(tick: Tick): () => void {
  ticks.add(tick);
  if (!frameRequest) frameRequest = requestAnimationFrame(loop);
  return () => {
    ticks.delete(tick);
  };
}

function paintProps(paint: OoPaint, gradient: string) {
  const fill =
    paint.fill === "$body"
      ? `url(#${gradient}-body)`
      : paint.fill === "$shine"
        ? `url(#${gradient}-shine)`
        : paint.fill;
  return {
    fill: fill ?? (paint.stroke ? "none" : undefined),
    stroke: paint.stroke,
    strokeWidth: paint.strokeWidth,
    opacity: paint.opacity,
    fillOpacity: paint.fillOpacity,
    strokeOpacity: paint.strokeOpacity,
    strokeLinecap: paint.round ? ("round" as const) : undefined,
    strokeLinejoin: paint.round ? ("round" as const) : undefined,
    strokeDasharray: paint.dash,
  };
}

function draw(
  shape: OoShape,
  key: number,
  gradient: string,
  frame: OoFrame,
  mouthColor: string,
): ReactNode {
  switch (shape.type) {
    case "path":
      return <Path key={key} d={shape.d} {...paintProps(shape, gradient)} />;
    case "circle":
      return (
        <Circle
          key={key}
          cx={shape.cx}
          cy={shape.cy}
          r={shape.r}
          {...paintProps(shape, gradient)}
        />
      );
    case "ellipse":
      return (
        <Ellipse
          key={key}
          cx={shape.cx}
          cy={shape.cy}
          rx={shape.rx}
          ry={shape.ry}
          {...paintProps(shape, gradient)}
        />
      );
    case "rect":
      return (
        <Rect
          key={key}
          x={shape.x}
          y={shape.y}
          width={shape.width}
          height={shape.height}
          rx={shape.rx}
          {...paintProps(shape, gradient)}
        />
      );
    case "group": {
      const { part, fx } = shape;
      if (part === "mouth") {
        return (
          <Path
            key={key}
            d={frame.mouth.d}
            fill={frame.mouth.filled ? mouthColor : "none"}
            stroke={mouthColor}
            strokeWidth={3.2}
            strokeLinecap="round"
            strokeLinejoin="round"
          />
        );
      }
      if (part === "tongue") {
        return frame.tongue ? <Path key={key} d={frame.tongue} fill="#FF7FA6" /> : null;
      }
      const state = fx
        ? frame.fx(fx.kind, fx.index)
        : part && part !== "fx"
          ? frame.parts[part]
          : undefined;
      if (state?.hidden ?? shape.hidden) return null;
      return (
        <G key={key} transform={state?.transform ?? shape.transform} opacity={state?.opacity}>
          {shape.children.map((child, index) => draw(child, index, gradient, frame, mouthColor))}
        </G>
      );
    }
  }
}

export function OoFigure({
  avatar,
  color,
  fallbackShape,
  moment,
  size,
  still = false,
  focus = "body",
}: {
  avatar: OoAvatar;
  color: string;
  fallbackShape: number;
  moment: OoMoment;
  size: number;
  still?: boolean;
  /** `face` crops to the eyes, for pickers of eye styles and eyewear. */
  focus?: "body" | "face";
}) {
  const gradient = `oo${useId().replace(/[^a-zA-Z0-9-_]/g, "")}`;
  const lod = ooLodForSize(size);
  const rig = useMemo(
    () => buildOoRig({ avatar, color, fallbackShape, moment, lod }),
    [avatar, color, fallbackShape, moment, lod],
  );
  const reducedMotion = useReducedMotion();
  const lively =
    !still && !reducedMotion && (size > LIVELY_SIZE || OO_LIST_MOMENTS.includes(moment));
  const lifeRef = useRef<OoLife | null>(null);
  const [frame, setFrame] = useState<OoFrame | null>(null);

  useEffect(() => {
    setFrame(null);
    if (!lively) return;
    if (!lifeRef.current) lifeRef.current = createOoLife();
    const life = lifeRef.current;
    const start = performance.now() / 1000 - Math.random() * 10;
    let last = 0;
    return subscribe((now) => {
      if (now - last < FRAME_SECONDS) return;
      last = now;
      setFrame(ooFrame({ rig, avatar, moment, t: now - start, life }));
    });
  }, [rig, avatar, moment, lively]);

  const stillFrame = useMemo(
    () =>
      ooFrame({
        rig,
        avatar,
        moment,
        t: OO_STILL_TIME,
        life: createOoLife(ooSeededRandom(1)),
        still: true,
      }),
    [rig, avatar, moment],
  );
  const shown = frame ?? stillFrame;
  const { colors } = rig;
  return (
    <Svg width={size} height={size} viewBox={focus === "face" ? FACE_VIEWBOX : VIEWBOX}>
      <Defs>
        <LinearGradient id={`${gradient}-body`} x1="0" y1="0" x2="1" y2="1">
          <Stop offset="0" stopColor={colors.light} />
          <Stop offset="0.45" stopColor={colors.base} />
          <Stop offset="1" stopColor={colors.dark} />
        </LinearGradient>
        <RadialGradient id={`${gradient}-shine`} cx="0.3" cy="0.22" r="0.55">
          <Stop offset="0" stopColor="#FFFFFF" stopOpacity="0.55" />
          <Stop offset="1" stopColor="#FFFFFF" stopOpacity="0" />
        </RadialGradient>
      </Defs>
      {rig.shapes.map((shape, index) => draw(shape, index, gradient, shown, rig.mouthColor))}
    </Svg>
  );
}