"use client";

import { useMemo, useState } from "react";
import ToolShell from "@/components/toolkit/ToolShell";
import { Card, CardHeader, CardTitle, CardContent } from "@/components/ui/card";
import { Input } from "@/components/ui/input";

function num(v: string) {
  const n = parseFloat(v);
  return Number.isFinite(n) ? n : 0;
}

const UM_PER_INCH = 25400;

export default function Page() {
  const [spotUm, setSpotUm] = useState("60");
  const [gapUm, setGapUm] = useState("40");
  const [lpi, setLpi] = useState("635"); // 635 LPI ≈ 40 µm gap

  // Keep gap and LPI linked both ways
  function onGapChange(v: string) {
    setGapUm(v);
    const g = num(v);
    setLpi(g > 0 ? (UM_PER_INCH / g).toFixed(2) : "");
  }
  function onLpiChange(v: string) {
    setLpi(v);
    const L = num(v);
    setGapUm(L > 0 ? (UM_PER_INCH / L).toFixed(2) : "");
  }

  const coverage = useMemo(() => {
    const d = num(spotUm);
    const g = num(gapUm);
    if (d <= 0 || g <= 0) return { overlap: 0, uncovered: 0 };
    const signed = 100 * (1 - g / d);
    return { overlap: Math.max(0, signed), uncovered: Math.max(0, -signed) };
  }, [spotUm, gapUm]);

  const gapMm = (num(gapUm) / 1000) || 0;
  const spotMm = (num(spotUm) / 1000) || 0;

  return (
    <ToolShell title="Hatch Overlap">
      <Card>
        <CardHeader>
          <CardTitle className="text-base">Inputs</CardTitle>
        </CardHeader>
        <CardContent className="grid gap-3 sm:grid-cols-3">
          <label className="text-[11px] sm:text-xs">
            <div className="mb-1 text-muted-foreground">Spot size (µm)</div>
            <Input inputMode="decimal" value={spotUm} onChange={(e) => setSpotUm(e.target.value)} />
          </label>
          <label className="text-[11px] sm:text-xs">
            <div className="mb-1 text-muted-foreground">Hatch gap (µm)</div>
            <Input inputMode="decimal" value={gapUm} onChange={(e) => onGapChange(e.target.value)} />
          </label>
          <label className="text-[11px] sm:text-xs">
            <div className="mb-1 text-muted-foreground">Hatch LPI</div>
            <Input inputMode="decimal" value={lpi} onChange={(e) => onLpiChange(e.target.value)} />
          </label>
        </CardContent>
      </Card>

      <Card className="mt-4">
        <CardHeader>
          <CardTitle className="text-base">Result</CardTitle>
        </CardHeader>
        <CardContent className="grid gap-3 sm:grid-cols-4">
          <div>
            <div className="text-sm text-muted-foreground">Overlap</div>
            <div className="text-lg">{coverage.overlap.toFixed(1)}%</div>
            {coverage.uncovered > 0 && (
              <div className="text-xs text-amber-600">{coverage.uncovered.toFixed(1)}% uncovered gap</div>
            )}
          </div>
          <div>
            <div className="text-sm text-muted-foreground">Gap</div>
            <div className="text-lg">{gapMm.toFixed(4)} mm</div>
            <div className="text-xs text-muted-foreground">{num(gapUm).toFixed(1)} µm</div>
          </div>
          <div>
            <div className="text-sm text-muted-foreground">Spot Ø</div>
            <div className="text-lg">{spotMm.toFixed(4)} mm</div>
            <div className="text-xs text-muted-foreground">{num(spotUm).toFixed(1)} µm</div>
          </div>
          <div>
            <div className="text-sm text-muted-foreground">From LPI</div>
            <div className="text-lg">
              {num(lpi) > 0 ? (UM_PER_INCH / num(lpi) / 1000).toFixed(4) : "0.0000"} mm
            </div>
            <div className="text-xs text-muted-foreground">
              {num(lpi) > 0 ? (UM_PER_INCH / num(lpi)).toFixed(1) : "0.0"} µm
            </div>
          </div>
        </CardContent>
      </Card>
    </ToolShell>
  );
}