"use client";

import { useState, useMemo, useEffect } from "react";
import { Search, TrendingUp, TrendingDown, LineChart as LineChartIcon, BarChart3, Scale, SlidersHorizontal, Check } from "lucide-react";
import { ZAR2 } from "@/lib/utils";
import { MachineLineChart, type ChartView, type SeriesVisible } from "@/components/MachineLineChart";

// /charts reads profit INCLUDING running cost, so the line, the card badge and the
// Profit view all sit on one basis. lib/profit.ts keeps its workbook default.
const CHART_PROFIT_INCLUDE_RUNNING = true;

type Item = {
  id: string;
  code: string;
  name: string;
  bucket: { income: (number | null)[]; fixed: (number | null)[]; running: (number | null)[] };
  totalIncome: number;
  totalProfit: number;
};

const VIEW_KEY = "mp:chartsView";
const SERIES_KEY = "mp:chartsSeries";

// Combined charts compare income and costs. Profit has its own line or bars view.
const ALL_SERIES: SeriesVisible = { income: true, fixed: true, running: true, profit: false };
const SERIES_LIST: { key: keyof SeriesVisible; label: string; color: string }[] = [
  { key: "income", label: "Income", color: "var(--color-chart-income)" },
  { key: "fixed", label: "Fixed", color: "var(--color-chart-fixed)" },
  { key: "running", label: "Running", color: "var(--color-chart-running)" },
];

export function ChartsGrid({ items }: { items: Item[] }) {
  const [query, setQuery] = useState("");
  const [filter, setFilter] = useState<"all" | "profitable" | "loss">("all");
  const [view, setViewState] = useState<ChartView>("lines");

  // Persist view in localStorage (Part A.5)
  useEffect(() => {
    try {
      const stored = localStorage.getItem(VIEW_KEY);
      if (stored === "lines" || stored === "stack" || stored === "profit" || stored === "profit-line") setViewState(stored);
    } catch {}
  }, []);
  const setView = (v: ChartView) => {
    setViewState(v);
    setSeriesOpen(false);
    try { localStorage.setItem(VIEW_KEY, v); } catch {}
  };

  const [series, setSeries] = useState<SeriesVisible>(ALL_SERIES);
  const [seriesOpen, setSeriesOpen] = useState(false);

  useEffect(() => {
    try {
      const stored = localStorage.getItem(SERIES_KEY);
      if (stored) {
        const parsed = JSON.parse(stored) as Partial<SeriesVisible>;
        if (parsed && typeof parsed === "object") {
          const restored = { ...ALL_SERIES, ...parsed, profit: false };
          setSeries(restored.income || restored.fixed || restored.running ? restored : ALL_SERIES);
        }
      }
    } catch {}
  }, []);

  const toggleSeries = (k: keyof SeriesVisible) => {
    setSeries((prev) => {
      const next = { ...prev, [k]: !prev[k] };
      // An empty chart reads as broken, so the last visible line stays on.
      if (Object.values(next).every((v) => !v)) return prev;
      try { localStorage.setItem(SERIES_KEY, JSON.stringify(next)); } catch {}
      return next;
    });
  };

  const resetSeries = () => {
    setSeries(ALL_SERIES);
    try { localStorage.setItem(SERIES_KEY, JSON.stringify(ALL_SERIES)); } catch {}
  };

  // Close the popover on Escape or an outside click.
  useEffect(() => {
    if (!seriesOpen) return;
    const onKey = (e: KeyboardEvent) => { if (e.key === "Escape") setSeriesOpen(false); };
    const onDown = (e: MouseEvent) => {
      if (!(e.target as HTMLElement)?.closest?.("[data-series-popover]")) setSeriesOpen(false);
    };
    document.addEventListener("keydown", onKey);
    document.addEventListener("mousedown", onDown);
    return () => {
      document.removeEventListener("keydown", onKey);
      document.removeEventListener("mousedown", onDown);
    };
  }, [seriesOpen]);

  const seriesOn = SERIES_LIST.filter((s) => series[s.key]).length;

  const filtered = useMemo(() => {
    let list = items;
    if (query.trim()) {
      const q = query.toLowerCase();
      list = list.filter((i) => i.code.toLowerCase().includes(q) || i.name.toLowerCase().includes(q));
    }
    if (filter === "profitable") list = list.filter((i) => i.totalProfit > 0);
    if (filter === "loss") list = list.filter((i) => i.totalProfit < 0);
    list = [...list].sort((a, b) => b.totalIncome - a.totalIncome);
    return list;
  }, [items, query, filter]);

  const stats = useMemo(() => {
    const profitable = items.filter((i) => i.totalProfit > 0).length;
    const totalIncome = items.reduce((s, i) => s + i.totalIncome, 0);
    return { profitable, total: items.length, totalIncome };
  }, [items]);

  // The legend follows the global view, and hidden combined series leave it too.
  const legend: { color: string; label: string }[] = (
    view === "profit" || view === "profit-line"
      ? [
          { color: "var(--color-chart-profit)", label: "Profit" },
          { color: "var(--color-chart-loss)", label: "Loss" },
        ]
      : view === "lines"
        ? [
            series.income ? { color: "var(--color-chart-income)", label: "Income" } : null,
            series.fixed ? { color: "var(--color-chart-fixed)", label: "Fixed" } : null,
            series.running ? { color: "var(--color-chart-running)", label: "Running" } : null,
          ]
        : [
            series.income ? { color: "var(--color-chart-income)", label: "Income" } : null,
            series.fixed ? { color: "var(--color-chart-fixed)", label: "Fixed" } : null,
            series.running ? { color: "var(--color-chart-running)", label: "Running" } : null,
          ]
  ).filter((x): x is { color: string; label: string } => x !== null);

  return (
    <>
      {/* Round 4 Part B.1/B.6: title + subtitle stack above legend on mobile; legend wraps below */}
      <div className="flex flex-col gap-3 mb-6">
        <div className="flex items-center justify-between gap-3">
          <div>
            <div className="flex items-center gap-3 mb-1">
              <div className="w-10 h-10 rounded-xl bg-gradient-to-br from-[#30638E]/15 to-[#003D5B]/15 grid place-items-center text-[#30638E]">
                <LineChartIcon className="w-5 h-5" />
              </div>
              <h1 className="text-2xl font-semibold text-[#003D5B] dark:text-white">Machine Charts</h1>
            </div>
            <p className="text-gray-500 dark:text-gray-400 text-sm">
              {stats.total} machines · {stats.profitable} profitable · {ZAR2(stats.totalIncome)} total income
            </p>
          </div>
        </div>
        <div className="flex items-center gap-3 flex-wrap text-xs">
          {legend.map((l) => (
            <div key={l.label} className="flex items-center gap-1.5">
              <div className="w-2 h-2 rounded-full" style={{ background: l.color }} />
              <span className="text-gray-500 dark:text-gray-400">{l.label}</span>
            </div>
          ))}
          {view === "profit-line" && (
            <div className="flex items-center gap-1.5">
              <div className="w-2 h-2 rounded-full bg-white border-2 border-[#7A9E06]" />
              <span className="text-gray-500 dark:text-gray-400">hollow = no running-cost data</span>
            </div>
          )}
        </div>
      </div>

      {/* Toolbar — wraps to multiple rows on mobile. Round 4 Part B.1/B.3/B.5. */}
      <div className="relative bg-white dark:bg-surface rounded-2xl border border-gray-100 dark:border-border p-4 shadow-sm mb-5 flex flex-wrap items-center gap-3">
        <div className="relative flex-1 min-w-[160px]">
          <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-gray-400" />
          <input
            value={query}
            onChange={(e) => setQuery(e.target.value)}
            placeholder="Search by code or name…"
            className="w-full min-h-[44px] pl-9 pr-3 bg-gray-50 dark:bg-white/5 border border-transparent rounded-lg text-sm placeholder:text-gray-400 focus:bg-white dark:focus:bg-white/10 focus:border-[#30638E] focus:outline-none"
          />
        </div>
        <select
          aria-label="Filter machines"
          value={filter}
          onChange={(e) => setFilter(e.target.value as typeof filter)}
          className="lg:hidden min-h-[44px] max-w-full px-3 rounded-lg bg-gray-50 dark:bg-white/5 text-sm text-gray-600 dark:text-gray-300 border border-gray-200 dark:border-border"
        >
          <option value="all">All machines</option>
          <option value="profitable">Profitable</option>
          <option value="loss">Loss-making</option>
        </select>
        <div className="hidden lg:flex items-center gap-1">
          {[
            { id: "all", label: "All" },
            { id: "profitable", label: "Profitable" },
            { id: "loss", label: "Loss-making" },
          ].map((f) => (
            <button
              key={f.id}
              onClick={() => setFilter(f.id as typeof filter)}
              className={`min-h-[44px] min-w-[44px] px-3 text-xs font-medium rounded-lg transition ${
                filter === f.id
                  ? "bg-[#30638E] text-white"
                  : "text-gray-600 dark:text-gray-400 hover:bg-gray-100 dark:hover:bg-white/5"
              }`}
            >
              {f.label}
            </button>
          ))}
        </div>
        <div className="flex items-center gap-1 sm:pl-3 sm:border-l sm:border-gray-200 sm:dark:border-white/10">
          <span className="text-[10px] uppercase tracking-wider text-gray-400 dark:text-text-soft mr-1 hidden sm:inline">View</span>
          {[
            { id: "lines", label: "Lines", icon: LineChartIcon },
            { id: "stack", label: "Cost stack", icon: BarChart3 },
            { id: "profit-line", label: "Profit only", icon: TrendingUp },
            { id: "profit", label: "Profit bars", icon: Scale },
          ].map((v) => (
            <button
              key={v.id}
              type="button"
              onClick={() => setView(v.id as ChartView)}
              aria-pressed={view === v.id}
              className={`min-h-[44px] px-3 text-xs font-medium rounded transition flex items-center gap-1 ${
                view === v.id
                  ? "bg-[#003D5B] text-white"
                  : "text-gray-500 dark:text-gray-400 hover:bg-gray-100 dark:hover:bg-white/5"
              }`}
            >
              <v.icon className="w-3 h-3" />
              {v.label}
            </button>
          ))}
        </div>

        {/* Series filter for the combined Income / Fixed / Running views. */}
        {(view === "lines" || view === "stack") && <div className="relative" data-series-popover>
          <button
            onClick={() => setSeriesOpen((o) => !o)}
            aria-expanded={seriesOpen}
            aria-haspopup="true"
            className={`min-h-[44px] min-w-[44px] px-3 text-xs font-medium rounded-lg transition flex items-center gap-1.5 ${
              seriesOn === SERIES_LIST.length
                ? "text-gray-500 dark:text-gray-400 hover:bg-gray-100 dark:hover:bg-white/5"
                : "bg-[#30638E]/10 text-[#30638E] dark:text-[#7FB3D5]"
            }`}
          >
            <SlidersHorizontal className="w-3.5 h-3.5" />
            <span>Series</span>
            <span className="tabular-nums">
              {seriesOn}/{SERIES_LIST.length}
            </span>
          </button>

          {seriesOpen && (
            <div className="absolute left-0 sm:left-auto sm:right-0 mt-2 z-30 w-60 max-w-[calc(100vw-2rem)] rounded-2xl border border-gray-100 dark:border-border bg-white dark:bg-surface shadow-lg p-2">
              <div className="px-2 pt-1 pb-2 text-xs uppercase tracking-wider text-gray-400 dark:text-text-soft">
                Show on chart
              </div>
              {SERIES_LIST.map((s) => {
                // Only the LAST remaining series is locked — the guard exists to stop
                // an empty chart, not to trap the reader on one series. Disabling every
                // box here meant the only way to add a line back was "Show all".
                const locked = seriesOn === 1 && series[s.key];
                return (
                  <label
                    key={s.key}
                    className={`relative flex items-center gap-3 min-h-[44px] px-2 rounded-lg text-sm ${
                      locked ? "opacity-50" : "cursor-pointer hover:bg-gray-50 dark:hover:bg-white/5"
                    }`}
                  >
                    <input
                      type="checkbox"
                      checked={series[s.key]}
                      disabled={locked}
                      onChange={() => toggleSeries(s.key)}
                      className="absolute inset-0 w-full h-full opacity-0 cursor-pointer disabled:cursor-not-allowed peer"
                    />
                    <span aria-hidden="true" className={`w-4 h-4 shrink-0 rounded border grid place-items-center peer-focus-visible:outline-2 peer-focus-visible:outline-offset-2 peer-focus-visible:outline-[#30638E] ${series[s.key] ? "bg-[#30638E] border-[#30638E] text-white" : "border-gray-300 dark:border-gray-500"}`}>
                      {series[s.key] && <Check className="w-3 h-3" />}
                    </span>
                    <span className="w-2.5 h-2.5 rounded-full" style={{ background: s.color }} />
                    <span className="text-gray-700 dark:text-gray-200">{s.label}</span>
                  </label>
                );
              })}
              <button
                onClick={resetSeries}
                disabled={seriesOn === SERIES_LIST.length}
                className="w-full min-h-[44px] mt-1 rounded-lg text-xs text-gray-500 dark:text-gray-400 hover:bg-gray-50 dark:hover:bg-white/5 disabled:opacity-40 disabled:hover:bg-transparent"
              >
                Show all
              </button>
            </div>
          )}
        </div>}
      </div>

      {filtered.length === 0 ? (
        <div className="bg-white dark:bg-surface rounded-2xl border border-gray-100 dark:border-border p-12 text-center">
          <Search className="w-8 h-8 text-gray-300 dark:text-text-soft mx-auto mb-3" />
          <div className="text-sm text-gray-500 dark:text-gray-400">No machines match "{query}"</div>
          <button onClick={() => setQuery("")} className="mt-3 min-h-[44px] min-w-[44px] px-3 text-xs text-accent-ink hover:underline">
            Clear search
          </button>
        </div>
      ) : (
        <div className="grid grid-cols-1 lg:grid-cols-2 gap-4">
          {filtered.map((item) => {
            // Was computeProfit({ income: totalIncome, fixed: 0, running: 0 }) — which is
            // just totalIncome, so every card showed a green "profit" equal to its income.
            // totalProfit is the real YTD figure from buildIncomeRows, on the same basis
            // the profit line uses below.
            const profit = item.totalProfit;
            const positiveProfit = profit >= 0;
            const profitOnly = view === "profit-line";
            return (
              <div key={item.id} data-machine-code={item.code} className="bg-white dark:bg-surface rounded-2xl border border-gray-100 dark:border-border p-5 shadow-sm hover:shadow-md transition">
                <div className="flex items-start justify-between mb-3">
                  <div>
                    <span className="font-mono text-xs px-1.5 py-0.5 rounded bg-[#00798C]/10 text-[#00798C] font-semibold">
                      {item.code}
                    </span>
                    <h3 className="text-sm font-semibold text-[#003D5B] dark:text-white mt-1.5">{item.name}</h3>
                  </div>
                  <div className={`flex items-center gap-1 px-2 py-1 rounded-lg text-xs font-medium ${
                    positiveProfit ? "bg-[#00798C]/10 text-[#00798C]" : "bg-[#D1495B]/10 text-[#D1495B]"
                  }`}>
                    {positiveProfit ? <TrendingUp className="w-3 h-3" /> : <TrendingDown className="w-3 h-3" />}
                    {positiveProfit ? "+" : ""}{ZAR2(profit)}
                  </div>
                </div>
                <div className="flex items-center justify-between text-xs text-gray-500 dark:text-gray-400 mb-3">
                  <span>YTD income</span>
                  <span className="text-[#003D5B] dark:text-white font-semibold">{ZAR2(item.totalIncome)}</span>
                </div>
                <div className="text-xs text-gray-500 dark:text-gray-400 mb-3">
                  {profitOnly ? "Monthly profit" : view === "profit" ? "Monthly profit bars" : view === "stack" ? "Monthly costs" : "Monthly trend"}
                </div>
                {profitOnly && (
                  <div className="flex flex-wrap items-center gap-x-3 gap-y-1 mb-3 text-xs text-gray-500 dark:text-gray-400">
                    <span className="inline-flex items-center gap-1.5">
                      <span className="w-2 h-2 rounded-full bg-[var(--color-chart-profit)]" />Profit
                    </span>
                    <span className="inline-flex items-center gap-1.5">
                      <span className="w-2 h-2 rounded-full bg-[var(--color-chart-loss)]" />Loss
                    </span>
                    <span>Hollow dot = no running-cost data</span>
                  </div>
                )}
                <MachineLineChart
                  income={item.bucket.income}
                  fixed={item.bucket.fixed}
                  running={item.bucket.running}
                  view={view}
                  includeRunningCost={CHART_PROFIT_INCLUDE_RUNNING}
                  series={series}
                />
              </div>
            );
          })}
        </div>
      )}
    </>
  );
}