"use client";
import { useCallback, useEffect, useState } from "react";
import { api, type PortfolioHolding } from "@/lib/trpc";
import { UI_STRINGS } from "@/lib/strings";
import { Card, CardHeader, Button, Input } from "@/components/ui";

export interface PortfolioPanelProps {
  onChange?: (holdings: PortfolioHolding[]) => void;
  bare?: boolean;
}

export function PortfolioPanel({ onChange, bare = false }: PortfolioPanelProps) {
  const [holdings, setHoldings] = useState<PortfolioHolding[]>([]);
  const [draftSymbol, setDraftSymbol] = useState("");
  const [draftShares, setDraftShares] = useState("");
  const [draftCost, setDraftCost] = useState("");
  const [loading, setLoading] = useState(true);
  const [busy, setBusy] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [editing, setEditing] = useState<string | null>(null);
  const [editShares, setEditShares] = useState("");
  const [editCost, setEditCost] = useState("");

  const load = useCallback(async (): Promise<PortfolioHolding[] | null> => {
    try {
      const next = await api.portfolio.holdings();
      setHoldings(next);
      setError(null);
      return next;
    } catch (e) {
      setError(e instanceof Error ? e.message : "Could not load holdings.");
      return null;
    } finally {
      setLoading(false);
    }
  }, []);

  useEffect(() => {
    void load();
  }, [load]);

  const notifyChange = (next: PortfolioHolding[]) => {
    onChange?.(next);
  };

  const add = async () => {
    const symbol = draftSymbol.trim().toUpperCase();
    const shares = parseFloat(draftShares);
    const avgCost = parseFloat(draftCost);
    if (!symbol || !Number.isFinite(shares) || shares <= 0 || !Number.isFinite(avgCost) || avgCost < 0) {
      setError("Symbol, positive share count, and average cost are required.");
      return;
    }
    setBusy(true);
    setError(null);
    try {
      await api.portfolio.addHolding(symbol, shares, avgCost);
      setDraftSymbol("");
      setDraftShares("");
      setDraftCost("");
      const next = await load();
      if (next) notifyChange(next);
    } catch (e) {
      setError(e instanceof Error ? e.message : "Could not record holding.");
    } finally {
      setBusy(false);
    }
  };

  const remove = async (symbol: string) => {
    setBusy(true);
    setError(null);
    try {
      await api.portfolio.removeHolding(symbol);
      const next = await load();
      if (next) notifyChange(next);
    } catch (e) {
      setError(e instanceof Error ? e.message : "Could not remove holding.");
    } finally {
      setBusy(false);
    }
  };

  const startEdit = (h: PortfolioHolding) => {
    setEditing(h.symbol);
    setEditShares(String(h.shares));
    setEditCost(String(h.avg_cost));
    setError(null);
  };

  const cancelEdit = () => {
    setEditing(null);
    setEditShares("");
    setEditCost("");
  };

  const saveEdit = async (symbol: string) => {
    const shares = parseFloat(editShares);
    const avgCost = parseFloat(editCost);
    if (!Number.isFinite(shares) || shares <= 0 || !Number.isFinite(avgCost) || avgCost < 0) {
      setError("Shares must be positive and avg cost must be 0 or more.");
      return;
    }
    setBusy(true);
    setError(null);
    try {
      await api.portfolio.updateHolding(symbol, { shares, avgCost });
      setEditing(null);
      const next = await load();
      if (next) notifyChange(next);
    } catch (e) {
      setError(e instanceof Error ? e.message : "Could not update holding.");
    } finally {
      setBusy(false);
    }
  };

  const totalValue = holdings.reduce((sum, h) => sum + h.shares * h.avg_cost, 0);

  const body = (
    <>
      {UI_STRINGS.portfolioCaption ? (
        <p className="text-xs text-fg-muted mb-3">{UI_STRINGS.portfolioCaption}</p>
      ) : null}

      <div className="grid grid-cols-1 sm:grid-cols-4 gap-2">
        <label className="block text-xs text-fg-muted sm:col-span-1">
          Symbol
          <Input
            value={draftSymbol}
            onChange={(e) => { setDraftSymbol(e.target.value); setError(null); }}
            placeholder="e.g. AAPL"
            className="mt-1"
            disabled={busy}
          />
        </label>
        <label className="block text-xs text-fg-muted">
          Shares
          <Input
            value={draftShares}
            onChange={(e) => { setDraftShares(e.target.value); setError(null); }}
            placeholder="100"
            type="number"
            className="mt-1"
            disabled={busy}
          />
        </label>
        <label className="block text-xs text-fg-muted">
          Avg cost ($)
          <Input
            value={draftCost}
            onChange={(e) => { setDraftCost(e.target.value); setError(null); }}
            placeholder="150.00"
            type="number"
            step="0.01"
            className="mt-1"
            disabled={busy}
          />
        </label>
        <div className="flex items-end">
          <Button onClick={add} disabled={busy} className="w-full">
            {busy ? "Saving…" : "Record holding"}
          </Button>
        </div>
      </div>

      {error && <p className="mt-3 text-sm text-danger">{error}</p>}

      {loading ? (
        <p className="mt-4 text-sm text-fg-faint">Loading holdings…</p>
      ) : holdings.length === 0 ? (
        <p className="mt-4 text-sm text-fg-faint">{UI_STRINGS.emptyPortfolio}</p>
      ) : (
        <div className="mt-4 space-y-2 max-h-72 overflow-y-auto">
          <div className="grid grid-cols-[minmax(0,1fr)_4.5rem_5rem_5rem_4rem] gap-2 text-xs text-fg-faint pb-1 border-b border-line">
            <span>Symbol</span>
            <span className="text-right">Shares</span>
            <span className="text-right">Avg cost</span>
            <span className="text-right">Cost basis</span>
            <span className="text-right" />
          </div>
          {holdings.map((h) => (
            editing === h.symbol ? (
              <div key={h.symbol} className="grid grid-cols-[minmax(0,1fr)_4.5rem_5rem_5rem_4rem] gap-2 items-center py-1.5 text-sm rounded bg-surface-sunken">
                <span className="font-mono text-fg truncate">{h.symbol}</span>
                <Input
                  value={editShares}
                  onChange={(e) => setEditShares(e.target.value)}
                  type="number"
                  className="text-right"
                  disabled={busy}
                />
                <Input
                  value={editCost}
                  onChange={(e) => setEditCost(e.target.value)}
                  type="number"
                  step="0.01"
                  className="text-right"
                  disabled={busy}
                />
                <span className="text-right tnum text-fg">
                  ${(parseFloat(editShares || "0") * parseFloat(editCost || "0")).toFixed(0)}
                </span>
                <div className="flex gap-1 justify-end">
                  <Button size="sm" variant="ghost" onClick={() => saveEdit(h.symbol)} disabled={busy}>
                    Save
                  </Button>
                  <Button size="sm" variant="ghost" onClick={cancelEdit} disabled={busy}>
                    Cancel
                  </Button>
                </div>
              </div>
            ) : (
              <div
                key={h.symbol}
                className="grid grid-cols-[minmax(0,1fr)_4.5rem_5rem_5rem_4rem] gap-2 items-center py-1.5 text-sm rounded hover:bg-surface-sunken transition-colors cursor-pointer"
                onClick={() => startEdit(h)}
              >
                <span className="font-mono text-fg truncate">{h.symbol}</span>
                <span className="text-right tnum text-fg-muted">{h.shares}</span>
                <span className="text-right tnum text-fg-muted">${h.avg_cost.toFixed(2)}</span>
                <span className="text-right tnum text-fg">${(h.shares * h.avg_cost).toFixed(0)}</span>
                <button
                  type="button"
                  onClick={(e) => { e.stopPropagation(); remove(h.symbol); }}
                  disabled={busy}
                  className="text-xs text-fg-faint hover:text-danger text-right disabled:opacity-50"
                >
                  Remove
                </button>
              </div>
            )
          ))}
          <div className="flex justify-between pt-2 border-t border-line text-sm font-semibold text-fg">
            <span>Cost-basis total</span>
            <span className="tnum">${totalValue.toFixed(0)}</span>
          </div>
        </div>
      )}
    </>
  );

  if (bare) return <div className="space-y-1">{body}</div>;

  return (
    <Card>
      <CardHeader title={UI_STRINGS.portfolioTitle} />
      {body}
    </Card>
  );
}