cabrits-math/components/explorers/step-controls.tsx

"use client";

import { useEffect, useCallback, useRef } from "react";

interface StepControlsProps {
  currentStep: number;
  totalSteps: number;
  isPlaying: boolean;
  onStepForward: () => void;
  onStepBack: () => void;
  onTogglePlay: () => void;
  onReset: () => void;
  canStepForward: boolean;
  canStepBack: boolean;
  playIntervalMs?: number;
}

export function StepControls({
  currentStep,
  totalSteps,
  isPlaying,
  onStepForward,
  onStepBack,
  onTogglePlay,
  onReset,
  canStepForward,
  canStepBack,
  playIntervalMs = 950,
}: StepControlsProps) {
  const timerRef = useRef<ReturnType<typeof setInterval> | null>(null);

  // Auto-play timer
  useEffect(() => {
    if (isPlaying && canStepForward) {
      timerRef.current = setInterval(() => {
        onStepForward();
      }, playIntervalMs);
    }
    return () => {
      if (timerRef.current) clearInterval(timerRef.current);
    };
  }, [isPlaying, canStepForward, onStepForward, playIntervalMs]);

  // Keyboard shortcuts
  const handleKeyDown = useCallback(
    (e: KeyboardEvent) => {
      const el = e.target as HTMLElement;
      const tag = el.tagName;
      if (["INPUT", "TEXTAREA", "SELECT"].includes(tag)) return;
      if (el.closest("button, [role='button'], a")) return;

      if (e.key === "ArrowRight" || e.key === " ") {
        e.preventDefault();
        if (canStepForward) onStepForward();
      }
      if (e.key === "ArrowLeft") {
        e.preventDefault();
        if (canStepBack) onStepBack();
      }
      if (e.key.toLowerCase() === "p") onTogglePlay();
      if (e.key.toLowerCase() === "r") onReset();
    },
    [canStepForward, canStepBack, onStepForward, onStepBack, onTogglePlay, onReset],
  );

  useEffect(() => {
    document.addEventListener("keydown", handleKeyDown);
    return () => document.removeEventListener("keydown", handleKeyDown);
  }, [handleKeyDown]);

  const progress = totalSteps > 0 ? (currentStep / totalSteps) * 100 : 0;

  return (
    <div className="space-y-3">
      {/* Progress bar */}
      {totalSteps > 0 && (
        <div className="mx-auto max-w-md">
          <div className="mb-1.5 flex items-center justify-between text-xs text-muted">
            <span>Step {currentStep} of {totalSteps}</span>
            <span>{Math.round(progress)}%</span>
          </div>
          <div className="h-1.5 overflow-hidden rounded-full bg-border/60">
            <div
              className="h-full rounded-full bg-gradient-to-r from-unit-1 to-unit-4 transition-all duration-300"
              style={{ width: `${progress}%` }}
            />
          </div>
        </div>
      )}

      {/* Controls */}
      <div className="flex flex-wrap items-center justify-center gap-2">
        <button
          onClick={onStepBack}
          disabled={!canStepBack || isPlaying}
          className="rounded-xl border border-border/60 bg-surface px-4 py-2.5 text-sm font-semibold text-foreground shadow-[var(--shadow-sm)] transition-all duration-200 hover:shadow-[var(--shadow-md)] hover:-translate-y-px disabled:cursor-not-allowed disabled:opacity-35 disabled:hover:translate-y-0 disabled:hover:shadow-[var(--shadow-sm)]"
        >
          &#9664; Back
        </button>
        <button
          onClick={onTogglePlay}
          disabled={!canStepForward && !isPlaying}
          className="min-w-[110px] rounded-xl bg-correct px-5 py-2.5 text-sm font-semibold text-white shadow-[var(--shadow-sm)] transition-all duration-200 hover:shadow-[var(--shadow-md)] hover:-translate-y-px disabled:cursor-not-allowed disabled:opacity-35 disabled:hover:translate-y-0 disabled:hover:shadow-[var(--shadow-sm)]"
        >
          {isPlaying ? "⏸ Pause" : "▶ Play"}
        </button>
        <button
          onClick={onStepForward}
          disabled={!canStepForward || isPlaying}
          className="rounded-xl bg-foreground px-5 py-2.5 text-sm font-semibold text-background shadow-[var(--shadow-sm)] transition-all duration-200 hover:shadow-[var(--shadow-md)] hover:-translate-y-px disabled:cursor-not-allowed disabled:opacity-35 disabled:hover:translate-y-0 disabled:hover:shadow-[var(--shadow-sm)]"
        >
          Next Step &#9654;
        </button>
        <button
          onClick={onReset}
          className="rounded-xl border border-incorrect/30 bg-surface px-4 py-2.5 text-sm font-semibold text-incorrect shadow-[var(--shadow-sm)] transition-all duration-200 hover:bg-incorrect hover:text-white hover:shadow-[var(--shadow-md)] hover:-translate-y-px"
        >
          &#8634; Reset
        </button>
      </div>

      {/* Keyboard hint */}
      <p className="text-center text-[0.7rem] text-muted/50">
        <kbd className="rounded border border-border/60 bg-background px-1 py-px font-mono text-[0.6rem]">Space</kbd>{" / "}
        <kbd className="rounded border border-border/60 bg-background px-1 py-px font-mono text-[0.6rem]">&#8594;</kbd>{" "}
        next{" · "}
        <kbd className="rounded border border-border/60 bg-background px-1 py-px font-mono text-[0.6rem]">&#8592;</kbd>{" "}
        back{" · "}
        <kbd className="rounded border border-border/60 bg-background px-1 py-px font-mono text-[0.6rem]">P</kbd>{" "}
        play{" · "}
        <kbd className="rounded border border-border/60 bg-background px-1 py-px font-mono text-[0.6rem]">R</kbd>{" "}
        reset
      </p>
    </div>
  );
}