"use client";

import { useState, useCallback } from "react";
import useSWR from "swr";
import Link from "next/link";
import { Button } from "@/components/ui/button";
import { Badge } from "@/components/ui/badge";
import {
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableHeader,
  TableRow,
} from "@/components/ui/table";
import {
  AlertDialog,
  AlertDialogAction,
  AlertDialogCancel,
  AlertDialogContent,
  AlertDialogDescription,
  AlertDialogFooter,
  AlertDialogHeader,
  AlertDialogTitle,
} from "@/components/ui/alert-dialog";
import { Plus, Pencil, Trash2, ClipboardList } from "lucide-react";
import { useTableSort } from "@/hooks/use-table-sort";
import { SortableTableHead } from "@/components/sortable-table-head";
import { ProductDialog } from "@/components/product-dialog";
import { toast } from "sonner";
import { formatCurrency } from "@/lib/format";
import type { Product } from "@/lib/types";

const fetcher = (url: string) => fetch(url).then((r) => r.json());

const statusStyles: Record<string, string> = {
  draft: "bg-muted text-muted-foreground",
  active: "bg-accent/15 text-accent border-accent/30",
  deprecated: "bg-warning/15 text-warning border-warning/30",
  archived: "bg-muted text-muted-foreground",
};

export default function ProductsPage() {
  const [dialogOpen, setDialogOpen] = useState(false);
  const [editingProduct, setEditingProduct] = useState<Product | null>(null);
  const [deleteTarget, setDeleteTarget] = useState<Product | null>(null);

  const { data: products = [], mutate } = useSWR<Product[]>(
    "/api/products",
    fetcher
  );

  const { sorted: sortedProducts, sort, toggleSort } = useTableSort(products);

  const handleSave = useCallback(
    async (data: Partial<Product>) => {
      const url = editingProduct
        ? `/api/products/${editingProduct.id}`
        : "/api/products";
      const method = editingProduct ? "PUT" : "POST";

      const res = await fetch(url, {
        method,
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(data),
      });

      if (!res.ok) {
        const err = await res.json();
        throw new Error(err.error || "Failed to save");
      }

      toast.success(
        editingProduct ? "Product updated" : "Product created"
      );
      mutate();
    },
    [editingProduct, mutate]
  );

  const handleDelete = useCallback(async () => {
    if (!deleteTarget) return;
    await fetch(`/api/products/${deleteTarget.id}`, { method: "DELETE" });
    toast.success("Product deleted");
    setDeleteTarget(null);
    mutate();
  }, [deleteTarget, mutate]);

  function openCreate() {
    setEditingProduct(null);
    setDialogOpen(true);
  }

  function openEdit(prod: Product) {
    setEditingProduct(prod);
    setDialogOpen(true);
  }

  return (
    <div className="flex flex-col gap-6 p-6 lg:p-8">
      <div className="flex items-center justify-between">
        <div>
          <h1 className="text-2xl font-bold tracking-tight text-foreground">
            Products
          </h1>
          <p className="text-sm text-muted-foreground">
            Manage your products and their bill of materials
          </p>
        </div>
        <Button onClick={openCreate}>
          <Plus className="mr-2 h-4 w-4" />
          Add Product
        </Button>
      </div>

      <div className="rounded-lg border bg-card">
        <Table>
          <TableHeader>
            <TableRow>
              <SortableTableHead column="sku" label="SKU" sort={sort} onToggle={toggleSort} className="w-[120px]" />
              <SortableTableHead column="name" label="Name" sort={sort} onToggle={toggleSort} />
              <SortableTableHead column="version" label="Version" sort={sort} onToggle={toggleSort} />
              <SortableTableHead column="status" label="Status" sort={sort} onToggle={toggleSort} />
              <SortableTableHead column="bom_count" label="BOM Items" sort={sort} onToggle={toggleSort} className="text-right" />
              <SortableTableHead column="total_cost" label="BOM Cost" sort={sort} onToggle={toggleSort} className="text-right" />
              <TableHead className="w-[130px]">Actions</TableHead>
            </TableRow>
          </TableHeader>
          <TableBody>
            {sortedProducts.length === 0 ? (
              <TableRow>
                <TableCell
                  colSpan={7}
                  className="text-center py-12 text-muted-foreground"
                >
                  No products yet. Click &quot;Add Product&quot; to get started.
                </TableCell>
              </TableRow>
            ) : (
              sortedProducts.map((prod) => (
                <TableRow key={prod.id}>
                  <TableCell className="font-mono text-xs font-medium">
                    {prod.sku}
                  </TableCell>
                  <TableCell className="font-medium">{prod.name}</TableCell>
                  <TableCell className="text-muted-foreground">
                    v{prod.version}
                  </TableCell>
                  <TableCell>
                    <Badge
                      variant="outline"
                      className={statusStyles[prod.status] || ""}
                    >
                      {prod.status}
                    </Badge>
                  </TableCell>
                  <TableCell className="text-right">
                    {prod.bom_count || 0}
                  </TableCell>
                  <TableCell className="text-right font-mono text-sm">
                    {formatCurrency(Number(prod.total_cost || 0))}
                  </TableCell>
                  <TableCell>
                    <div className="flex items-center gap-1">
                      <Button
                        variant="ghost"
                        size="icon"
                        className="h-8 w-8"
                        asChild
                      >
                        <Link href={`/bom/${prod.id}`}>
                          <ClipboardList className="h-3.5 w-3.5" />
                          <span className="sr-only">View BOM</span>
                        </Link>
                      </Button>
                      <Button
                        variant="ghost"
                        size="icon"
                        className="h-8 w-8"
                        onClick={() => openEdit(prod)}
                      >
                        <Pencil className="h-3.5 w-3.5" />
                        <span className="sr-only">Edit</span>
                      </Button>
                      <Button
                        variant="ghost"
                        size="icon"
                        className="h-8 w-8 text-destructive hover:text-destructive"
                        onClick={() => setDeleteTarget(prod)}
                      >
                        <Trash2 className="h-3.5 w-3.5" />
                        <span className="sr-only">Delete</span>
                      </Button>
                    </div>
                  </TableCell>
                </TableRow>
              ))
            )}
          </TableBody>
        </Table>
      </div>

      <ProductDialog
        open={dialogOpen}
        onOpenChange={setDialogOpen}
        product={editingProduct}
        onSave={handleSave}
      />

      <AlertDialog
        open={!!deleteTarget}
        onOpenChange={() => setDeleteTarget(null)}
      >
        <AlertDialogContent>
          <AlertDialogHeader>
            <AlertDialogTitle>Delete Product</AlertDialogTitle>
            <AlertDialogDescription>
              Are you sure you want to delete{" "}
              <strong>{deleteTarget?.name}</strong> ({deleteTarget?.sku})? This
              will also delete all associated BOM items.
            </AlertDialogDescription>
          </AlertDialogHeader>
          <AlertDialogFooter>
            <AlertDialogCancel>Cancel</AlertDialogCancel>
            <AlertDialogAction
              onClick={handleDelete}
              className="bg-destructive text-destructive-foreground hover:bg-destructive/90"
            >
              Delete
            </AlertDialogAction>
          </AlertDialogFooter>
        </AlertDialogContent>
      </AlertDialog>
    </div>
  );
}