import { useState, useMemo } from "react";
import { ZoomIn, RotateCcw, Minus } from "lucide-react";
import { useCurveStore } from "../../store/curveStore.js";
import type { VFPoint } from "../../types.js";

interface Props {
  /** All curve points — used by global offset slider */
  activePts: VFPoint[];
  /** Called to reset the x-axis zoom to default */
  onResetZoom: () => void;
  /** True if the chart is currently zoomed in */
  isZoomed: boolean;
  /** True when viewing a read-only domain (memory) */
  readOnly?: boolean;
  /** Current zoom factor (1 = no zoom) */
  zoomFactor: number;
  /** Called when user changes zoom via slider */
  onZoomChange: (factor: number) => void;
}

export function CurveToolbar({
  activePts,
  onResetZoom,
  isZoomed,
  readOnly,
  zoomFactor,
  onZoomChange,
}: Props) {
  const {
    pendingDeltas,
    selectedPoints,
    anchorPoint,
    curve,
    stageRangeEdit,
    flattenToAnchor,
  } = useCurveStore();

  const [offsetMhz, setOffsetMhz] = useState(0);

  const uniformDeltaMhz = useMemo(() => {
    if (activePts.length === 0) return 0;
    const firstD =
      pendingDeltas.get(activePts[0].index) ?? activePts[0].delta_khz;
    const uniform = activePts.every(
      (p) => (pendingDeltas.get(p.index) ?? p.delta_khz) === firstD,
    );
    return uniform ? firstD / 1000 : null;
  }, [activePts, pendingDeltas]);

  // Sync the slider to the uniform delta when it changes (adjust state during
  // render instead of an effect; undefined sentinel so the first render syncs).
  const [lastUniformDelta, setLastUniformDelta] = useState<
    number | null | undefined
  >();
  if (uniformDeltaMhz !== null && lastUniformDelta !== uniformDeltaMhz) {
    setLastUniformDelta(uniformDeltaMhz);
    setOffsetMhz(uniformDeltaMhz);
  }

  function handleOffsetChange(mhz: number) {
    setOffsetMhz(mhz);
    stageRangeEdit(activePts, Math.round(mhz * 1000));
  }

  return (
    <div className="flex flex-wrap items-center gap-2 px-1 pb-2">
      {/* Zoom control */}
      <div
        className="flex items-center gap-1.5 px-2 py-1 rounded bg-zinc-800/60 border border-zinc-700/40"
        title="Zoom x-axis (Alt+scroll also works)"
      >
        <ZoomIn size={11} className="text-zinc-500 shrink-0" />
        <input
          type="range"
          min={1}
          max={10}
          step={0.1}
          value={zoomFactor}
          onChange={(e) => onZoomChange(Number(e.target.value))}
          className="w-20 h-1 cursor-pointer accent-cyan-400"
        />
        <span
          className={`text-xs font-mono w-8 tabular-nums ${isZoomed ? "text-cyan-400" : "text-zinc-600"}`}
        >
          {zoomFactor.toFixed(1)}×
        </span>
        {isZoomed && (
          <button
            onClick={onResetZoom}
            title="Reset zoom"
            className="text-zinc-500 hover:text-zinc-300 transition-colors ml-0.5"
          >
            <RotateCcw size={11} />
          </button>
        )}
      </div>

      {/* Divider */}
      <span className="w-px h-6 bg-zinc-800 mx-1" />

      {/* Global offset slider — GPU only */}
      {!readOnly && uniformDeltaMhz !== null && (
        <div className="flex items-center gap-1.5 min-w-[260px]">
          <span className="text-zinc-500 text-xs whitespace-nowrap">
            Global Offset
          </span>
          <input
            type="range"
            min={-1000}
            max={1000}
            step={5}
            value={offsetMhz}
            onChange={(e) => handleOffsetChange(Number(e.target.value))}
            className="w-32 accent-cyan-400"
            title={`${offsetMhz > 0 ? "+" : ""}${offsetMhz} MHz`}
          />
          <span
            className={[
              "text-xs font-mono w-16",
              offsetMhz > 0
                ? "text-cyan-400"
                : offsetMhz < 0
                  ? "text-orange-400"
                  : "text-zinc-500",
            ].join(" ")}
          >
            {offsetMhz > 0 ? "+" : ""}
            {offsetMhz} MHz
          </span>
        </div>
      )}

      {/* Flatten — visible when 2+ points are selected */}
      {!readOnly &&
        selectedPoints.size >= 2 &&
        (() => {
          const anchor =
            anchorPoint !== null && selectedPoints.has(anchorPoint)
              ? anchorPoint
              : Math.min(...selectedPoints);
          const anchorDelta =
            pendingDeltas.get(anchor) ??
            curve?.points.find((p) => p.index === anchor)?.delta_khz ??
            0;
          const label = `·${anchor}  ${anchorDelta >= 0 ? "+" : ""}${anchorDelta / 1000} MHz`;
          return (
            <button
              onClick={flattenToAnchor}
              className="flex items-center gap-1.5 px-2 py-1 rounded text-xs font-medium text-amber-400 hover:text-amber-300 hover:bg-zinc-800 border border-zinc-700/40 transition"
              title={`Flatten all selected points to anchor point ${anchor} (${anchorDelta >= 0 ? "+" : ""}${anchorDelta / 1000} MHz)`}
            >
              <Minus size={11} />
              Flatten to {label}
            </button>
          );
        })()}

      {/* Legend — right-aligned */}
      <div className="flex items-center gap-3 text-xs text-zinc-500 ml-auto">
        <span className="flex items-center gap-1">
          <span className="inline-block w-3 h-0.5 bg-emerald-400 rounded" />{" "}
          effective
        </span>
        <span className="flex items-center gap-1">
          <span className="inline-block w-3 h-px border-t-2 border-dashed border-cyan-400" />{" "}
          pending
        </span>
        <span className="flex items-center gap-1">
          <span className="inline-block w-2 h-2 rounded-full bg-yellow-400" />{" "}
          current
        </span>
      </div>
    </div>
  );
}