"use client";

import { useEffect, useState } from "react";
import {
  Bar,
  BarChart,
  Legend,
  ResponsiveContainer,
  Tooltip,
  XAxis,
  YAxis,
} from "recharts";

type WorkoutDataPoint = {
  label: string;
  date: string;
  name: string;
  volumeKg: number;
};

type Props = {
  data: WorkoutDataPoint[];
};

const COLORS: Record<string, string> = {};
const PALETTE = ["var(--color-accent)", "#5b9bd5", "#70ad47", "#ffc000", "#ed7d31"];

function getColor(name: string): string {
  if (!COLORS[name]) {
    COLORS[name] = PALETTE[Object.keys(COLORS).length % PALETTE.length];
  }
  return COLORS[name];
}

export function VolumeTrendChart({ data }: Props) {
  const [mounted, setMounted] = useState(false);
  useEffect(() => setMounted(true), []);

  if (!mounted) {
    return (
      <div className="w-full rounded-2xl border border-white/10 bg-surface/55 shadow-lg shadow-black/10 backdrop-blur-md p-4">
        <div className="mb-2 h-4 w-56 animate-pulse rounded bg-white/10" />
        <div className="h-[220px] animate-pulse rounded bg-white/5" />
      </div>
    );
  }

  const workoutNames = [...new Set(data.map((d) => d.name))];

  const chartData: Record<string, string | number>[] = [];
  const grouped = new Map<string, Record<string, string | number>>();

  for (const point of data) {
    const key = point.date;
    if (!grouped.has(key)) {
      grouped.set(key, { label: point.label });
    }
    const entry = grouped.get(key)!;
    entry[point.name] = ((entry[point.name] as number) || 0) + point.volumeKg;
  }

  for (const entry of grouped.values()) {
    chartData.push(entry);
  }

  return (
    <div className="w-full rounded-2xl border border-white/10 bg-surface/55 shadow-lg shadow-black/10 backdrop-blur-md p-4">
      <div className="mb-2 text-sm text-fg/60">
        Trend wolumenu treningowego wg typu
      </div>
      <ResponsiveContainer width="100%" height={220}>
        <BarChart data={chartData} margin={{ top: 8, right: 8, left: 0, bottom: 0 }}>
          <XAxis dataKey="label" stroke="var(--color-fg)" opacity={0.5} fontSize={11} />
          <YAxis stroke="var(--color-fg)" opacity={0.5} fontSize={11} width={48} />
          <Tooltip
            cursor={{ fill: "var(--color-bg)" }}
            contentStyle={{
              background: "color-mix(in oklab, var(--color-surface) 92%, transparent)",
              border: "1px solid rgba(255,255,255,0.12)",
              borderRadius: 12,
              fontSize: 12,
              color: "var(--color-fg)",
            }}
            formatter={(value) => [
              `${Math.round(Number(value)).toLocaleString("pl-PL")} kg`,
              "Wolumen",
            ]}
          />
          <Legend
            wrapperStyle={{ fontSize: 12, color: "var(--color-fg)" }}
          />
          {workoutNames.map((name) => (
            <Bar
              key={name}
              dataKey={name}
              fill={getColor(name)}
              radius={[4, 4, 0, 0]}
              stackId="volume"
            />
          ))}
        </BarChart>
      </ResponsiveContainer>
    </div>
  );
}