import { useMemo, useState } from "react";
import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import toast from "react-hot-toast";

import {
  ALL_TRADE_DIRECTIONS,
  TRADE_DIRECTION_LABELS,
  userTradeAccessService,
  type TradeDirection,
} from "@/services/userTradeAccess.service";
import {
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableHeader,
  TableRow,
} from "@/components/ui/table";

const QUERY_KEY = ["user-trade-access", "list"] as const;

type EmployeeRow = {
  userId: string;
  name: string;
  email: string;
};

/**
 * Per-user trade-direction access (Import / Export / Intercity checkboxes).
 * All three checked (or never configured) = unrestricted; unchecking limits
 * the user's contracts, bookings, schedules, batch board, payments, invoices
 * and overview to the checked directions. Admins always bypass the scope.
 */
export default function TradeAccessPage() {
  const queryClient = useQueryClient();
  const [search, setSearch] = useState("");

  const { data: usersResponse, isLoading: usersLoading } = useQuery({
    queryKey: ["staff-users", "employees"],
    queryFn: userTradeAccessService.employees,
  });

  const { data: configs, isLoading: configsLoading } = useQuery({
    queryKey: QUERY_KEY,
    queryFn: userTradeAccessService.list,
  });

  const saveMutation = useMutation({
    mutationFn: ({
      userId,
      directions,
    }: {
      userId: string;
      directions: TradeDirection[];
    }) => userTradeAccessService.set(userId, directions),
    onSuccess: () => {
      void queryClient.invalidateQueries({ queryKey: QUERY_KEY });
      void queryClient.invalidateQueries({
        queryKey: ["user-trade-access", "me"],
      });
      toast.success("Trade access updated");
    },
  });

  const configByUser = useMemo(() => {
    const map = new Map<string, TradeDirection[]>();
    for (const row of configs ?? []) map.set(row.userId, row.directions);
    return map;
  }, [configs]);

  const rows: EmployeeRow[] = useMemo(() => {
    const items = usersResponse?.items ?? [];
    const mapped = items
      .map((u) => ({
        userId: u.id ?? "",
        name: u.name?.en ?? u.username ?? "—",
        email: u.email ?? "",
      }))
      .filter((r: EmployeeRow) => r.userId);
    const term = search.trim().toLowerCase();
    if (!term) return mapped;
    return mapped.filter(
      (r: EmployeeRow) =>
        r.name.toLowerCase().includes(term) ||
        r.email.toLowerCase().includes(term),
    );
  }, [usersResponse, search]);

  // No row yet = unrestricted, so render as all three checked.
  const directionsFor = (userId: string): TradeDirection[] =>
    configByUser.get(userId) ?? [...ALL_TRADE_DIRECTIONS];

  const toggle = (userId: string, direction: TradeDirection) => {
    const current = directionsFor(userId);
    const next = current.includes(direction)
      ? current.filter((d) => d !== direction)
      : [...current, direction];
    saveMutation.mutate({ userId, directions: next });
  };

  const loading = usersLoading || configsLoading;

  return (
    <div className="space-y-4 p-4">
      <div>
        <h1 className="text-xl font-bold">Trade direction access</h1>
        <p className="text-sm text-muted-foreground">
          Choose which trade directions each backoffice user can see. This
          filters their contracts, bookings, schedules, batch board, payments,
          invoices and overview. All three checked means full access; super and
          organization admins are never restricted.
        </p>
      </div>

      <input
        type="search"
        value={search}
        onChange={(e) => setSearch(e.target.value)}
        placeholder="Search by name or email…"
        className="w-full max-w-sm rounded-md border px-3 py-2 text-sm"
      />

      {loading ? (
        <p className="text-sm text-muted-foreground">Loading users…</p>
      ) : (
        <Table>
          <TableHeader>
            <TableRow>
              <TableHead>User</TableHead>
              <TableHead>Email</TableHead>
              {ALL_TRADE_DIRECTIONS.map((d) => (
                <TableHead key={d} className="text-center">
                  {TRADE_DIRECTION_LABELS[d]}
                </TableHead>
              ))}
              <TableHead>Access</TableHead>
            </TableRow>
          </TableHeader>
          <TableBody>
            {rows.map((row) => {
              const dirs = directionsFor(row.userId);
              const unrestricted = dirs.length === ALL_TRADE_DIRECTIONS.length;
              return (
                <TableRow key={row.userId}>
                  <TableCell className="font-medium">{row.name}</TableCell>
                  <TableCell>{row.email}</TableCell>
                  {ALL_TRADE_DIRECTIONS.map((d) => (
                    <TableCell key={d} className="text-center">
                      <input
                        type="checkbox"
                        className="h-4 w-4 accent-primary"
                        checked={dirs.includes(d)}
                        disabled={saveMutation.isPending}
                        onChange={() => toggle(row.userId, d)}
                        aria-label={`${row.name} — ${TRADE_DIRECTION_LABELS[d]}`}
                      />
                    </TableCell>
                  ))}
                  <TableCell>
                    {unrestricted ? (
                      <span className="text-xs text-muted-foreground">
                        Full access
                      </span>
                    ) : dirs.length === 0 ? (
                      <span className="text-xs font-medium text-red-600">
                        No data
                      </span>
                    ) : (
                      <span className="text-xs font-medium text-amber-600">
                        {dirs.map((d) => TRADE_DIRECTION_LABELS[d]).join(" + ")}{" "}
                        only
                      </span>
                    )}
                  </TableCell>
                </TableRow>
              );
            })}
            {rows.length === 0 && (
              <TableRow>
                <TableCell
                  colSpan={3 + ALL_TRADE_DIRECTIONS.length}
                  className="text-center text-sm text-muted-foreground"
                >
                  No users found.
                </TableCell>
              </TableRow>
            )}
          </TableBody>
        </Table>
      )}
    </div>
  );
}