/**
 * @file PetSprite.tsx
 * @description The mascot wearing a custom pet (`/api/pets`). A Codex pet is
 * a 1536×1872 spritesheet — 8 columns × 9 rows of 192×208 frames, one row per
 * animation state (idle, run right, run left, waving, jumping, failed,
 * waiting, running, review) — played one row at a time by Sagi's mood; an
 * uploaded image is shown still and bobs with the same `data-mood` CSS as
 * Sagi. An `action` (dragged left/right, hovered) plays the run-left/run-right
 * or waving row over the mood's, like Codex's own pet. Each row steps at its
 * own pace and holds its last frame longer, so a loop breathes instead of
 * spinning. Reduced motion holds the row's first frame. A sprite that fails to
 * load (deleted from another browser) calls `onBroken`, so the mascot falls
 * back to Sagi instead of an empty box.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

import { useEffect, useState } from "react";
import { api } from "../../lib/api";
import type { Mood } from "./brain";

const CELL = { w: 192, h: 208 };
const SHEET = { cols: 8, rows: 9 };
/** Frames in each row of the Codex atlas. */
const FRAMES = [6, 8, 8, 4, 5, 8, 6, 6, 6];
/** Which row plays for each mood. */
const ROW: Record<Mood, number> = {
  idle: 0,
  sleeping: 0,
  thinking: 7, // running — an agent is working
  watching: 8, // review
  happy: 4, // jumping
  stuck: 6, // waiting — for the user
  worried: 5, // failed
  disconnected: 5,
};
/** What the user is doing to the pet, which outranks its mood. */
export type PetAction = "run-left" | "run-right" | "wave";
const ACTION_ROW: Record<PetAction, number> = { "run-right": 1, "run-left": 2, wave: 3 };
/** Per row: ms per frame, and ms the last frame is held before the loop restarts. */
const PACE: [number, number][] = [
  [220, 1400], // idle: a breath, then a pause
  [120, 120], // run right — keeps up with the drag
  [120, 120], // run left
  [180, 400], // waving
  [160, 700], // jumping
  [200, 1200], // failed
  [220, 900], // waiting
  [170, 400], // running (working)
  [220, 900], // review
];
const SLEEP_PACE: [number, number] = [450, 2000];

export function PetSprite({
  id,
  kind,
  mood,
  action,
  size,
  reducedMotion,
  onBroken,
}: {
  id: string;
  kind: "codex" | "image";
  mood: Mood;
  action?: PetAction | null;
  size: number;
  reducedMotion: boolean;
  onBroken: () => void;
}) {
  const url = api.pets.spriteUrl(id);
  const row = action ? ACTION_ROW[action] : (ROW[mood] ?? 0);
  const sleeping = !action && mood === "sleeping";
  const [frame, setFrame] = useState(0);

  useEffect(() => {
    setFrame(0);
    if (kind !== "codex" || reducedMotion) return;
    const count = FRAMES[row] ?? 1;
    const [step, hold] = sleeping ? SLEEP_PACE : (PACE[row] ?? [200, 200]);
    let f = 0;
    let timer = 0;
    const tick = () => {
      timer = window.setTimeout(
        () => {
          f = (f + 1) % count;
          setFrame(f);
          tick();
        },
        f === count - 1 ? hold : step
      );
    };
    tick();
    return () => window.clearTimeout(timer);
  }, [kind, row, sleeping, reducedMotion]);

  // A background image reports no error of its own: probe it once.
  useEffect(() => {
    if (kind !== "codex") return;
    const probe = new Image();
    probe.onerror = onBroken;
    probe.src = url;
    return () => {
      probe.onerror = null;
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [url, kind]);

  if (kind === "image") {
    return (
      <img
        src={url}
        alt=""
        data-mood={mood}
        className="sagi-pet-image"
        width={size}
        height={size}
        draggable={false}
        onError={onBroken}
        style={{ width: size, height: size, objectFit: "contain" }}
      />
    );
  }
  const scale = size / CELL.h;
  return (
    <div
      data-testid="pet-sprite"
      data-row={row}
      aria-hidden
      style={{
        width: Math.round(CELL.w * scale),
        height: size,
        margin: "0 auto",
        backgroundImage: `url("${url}")`,
        backgroundRepeat: "no-repeat",
        backgroundSize: `${SHEET.cols * CELL.w * scale}px ${SHEET.rows * CELL.h * scale}px`,
        backgroundPosition: `${-frame * CELL.w * scale}px ${-row * CELL.h * scale}px`,
      }}
    />
  );
}