import { useState } from 'react';
import { useMutation, useQueryClient } from '@tanstack/react-query';
import { Button } from '@astryxdesign/core/Button';
import { Card } from '@astryxdesign/core/Card';
import { HStack } from '@astryxdesign/core/HStack';
import { Text } from '@astryxdesign/core/Text';
import { VStack } from '@astryxdesign/core/VStack';
import { Minus, Plus, X } from 'lucide-react';
import { errorMessage } from '@/api/client';
import { stockApi } from '@/api/stock';
import type { Product } from '@/api/types';
import { Drawer } from '@/features/store-admin/Drawer';
import { queryKeys } from '@/queries/keys';

/**
 * Asking for several products at once.
 *
 * Restocking after a delivery is one errand. Doing it a product at a time means
 * a dialog per line, and the branch either gives up halfway or raises twenty
 * separate requests the admin then has to decide twenty times.
 *
 * ── Why the quantities are still per product ────────────────────────────────
 *
 * The obvious shortcut is one quantity for the whole batch. It is wrong: a shop
 * asks for two crates of oil and twenty packets of biscuits, and a single box
 * would either be ignored or produce a request nobody meant. So every line
 * keeps its own number, defaulted to 1 and adjustable in place.
 *
 * A line can be dropped here too. Picking eight and realising one was a mistake
 * should not mean closing this and starting the selection again.
 */
export interface BulkRequestDialogProps {
  products: Product[];
  tenantid: number;
  locationid: number;
  locationname: string;
  onClose: () => void;
  /** Called when at least one request was raised, so the caller can clear its selection. */
  onDone: () => void;
}

export function BulkRequestDialog({
  products,
  tenantid,
  locationid,
  locationname,
  onClose,
  onDone,
}: BulkRequestDialogProps) {
  const client = useQueryClient();
  const [qty, setQty] = useState<Record<number, number>>(() =>
    Object.fromEntries(products.map((product) => [product.productid, 1])),
  );
  const [dropped, setDropped] = useState<ReadonlySet<number>>(() => new Set());
  const [problem, setProblem] = useState<string | null>(null);

  const lines = products.filter((product) => !dropped.has(product.productid));

  const send = useMutation({
    mutationFn: () =>
      stockApi.createMany(
        lines.map((product) => ({
          tenantid,
          locationid,
          productid: product.productid,
          qty: qty[product.productid] ?? 1,
          locationname,
          productname: product.productname ?? '',
        })),
      ),
    onSuccess: async (result) => {
      const failed = result?.failed?.length ?? 0;
      await client.invalidateQueries({ queryKey: queryKeys.stock.all });
      if (failed > 0) {
        // Some landed. Saying so beats a bare success that hides the gap, and
        // beats an error that implies none of them were raised.
        setProblem(
          `${lines.length - failed} of ${lines.length} raised. The rest could not be — try them again.`,
        );
        return;
      }
      onDone();
      onClose();
    },
    onError: (cause) => setProblem(errorMessage(cause)),
  });

  const setLine = (productid: number, next: number) =>
    setQty((prev) => ({ ...prev, [productid]: Math.max(1, Math.min(9999, next)) }));

  return (
    <Drawer
      title="Ask for stock"
      subtitle={`${lines.length} product${lines.length === 1 ? '' : 's'}`}
      width={520}
      onClose={onClose}
    >
      <VStack gap={3}>
        <Text type="body" size="sm" color="secondary">
          Set how much of each you need. Your admin decides each one, and nothing reaches the shelf
          until they approve it.
        </Text>

          <div className="bulkreq-list">
            {lines.map((product) => (
              <div key={product.productid} className="bulkreq-line">
                <VStack gap={0} style={{ minWidth: 0 }}>
                  <Text type="label" size="sm" weight="semibold" maxLines={1}>
                    {product.productname ?? `Product ${product.productid}`}
                  </Text>
                  <Text type="body" size="xsm" color="secondary">
                    {[product.unitvalue, product.productunit].filter(Boolean).join(' ') || '—'}
                  </Text>
                </VStack>

                <HStack gap={0.5} align="center">
                  <button
                    type="button"
                    className="qty-step"
                    aria-label={`One fewer ${product.productname ?? 'unit'}`}
                    onClick={() => setLine(product.productid, (qty[product.productid] ?? 1) - 1)}
                  >
                    <Minus size={13} />
                  </button>
                  <input
                    className="qty-input"
                    inputMode="numeric"
                    value={String(qty[product.productid] ?? 1)}
                    aria-label={`Quantity of ${product.productname ?? 'product'}`}
                    onChange={(event) =>
                      setLine(product.productid, Number(event.target.value.replace(/\D/g, '')) || 1)
                    }
                  />
                  <button
                    type="button"
                    className="qty-step"
                    aria-label={`One more ${product.productname ?? 'unit'}`}
                    onClick={() => setLine(product.productid, (qty[product.productid] ?? 1) + 1)}
                  >
                    <Plus size={13} />
                  </button>
                  <button
                    type="button"
                    className="qty-step"
                    aria-label={`Remove ${product.productname ?? 'product'} from this request`}
                    onClick={() =>
                      setDropped((prev) => new Set(prev).add(product.productid))
                    }
                  >
                    <X size={13} />
                  </button>
                </HStack>
              </div>
            ))}
          </div>

          {problem ? (
            <Card padding={2} variant="transparent">
              <Text type="body" size="sm" role="alert" style={{ color: 'var(--color-error, #d64545)' }}>
                {problem}
              </Text>
            </Card>
          ) : null}

          <HStack justify="between" align="center" gap={2} wrap="wrap">
            <Button label="Cancel" variant="ghost" isDisabled={send.isPending} onClick={onClose} />
            <Button
              label={send.isPending ? 'Sending…' : `Send ${lines.length} request${lines.length === 1 ? '' : 's'}`}
              variant="primary"
              isLoading={send.isPending}
              isDisabled={send.isPending || lines.length === 0}
              onClick={() => {
                setProblem(null);
                send.mutate();
              }}
            />
        </HStack>
      </VStack>
    </Drawer>
  );
}