"use client";

import { useState, useEffect } from "react";
import { 
  Table, 
  TableBody, 
  TableCell, 
  TableHead, 
  TableHeader, 
  TableRow 
} from "@/components/ui/table";
import { Button } from "@/components/ui/button";
import { Input } from "@/components/ui/input";
import { 
  Dialog, 
  DialogContent, 
  DialogHeader, 
  DialogTitle, 
  DialogFooter,
  DialogClose
} from "@/components/ui/dialog";
import { 
  Select, 
  SelectContent, 
  SelectItem, 
  SelectTrigger, 
  SelectValue 
} from "@/components/ui/select";
import {
  Pagination,
  PaginationContent,
  PaginationEllipsis,
  PaginationItem,
  PaginationLink,
  PaginationNext,
  PaginationPrevious,
} from "@/components/ui/pagination";
import { 
  PlusCircle, 
  Pencil, 
  Trash2, 
  Search, 
  X, 
  Loader2
} from "lucide-react";
import UploadExcelDosen from "@/components/datatable/upload-file-dosen";
import { useToast } from "@/components/ui/toast-provider";

// Define the Dosen type
interface Dosen {
  id_dosen: number;
  nama_dosen: string;
  nip: string;
}

export default function DataTableDosen() {
  const { showSuccess, showError } = useToast();

  // State for data
  const [dosen, setDosen] = useState<Dosen[]>([]);
  const [filteredData, setFilteredData] = useState<Dosen[]>([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  
  // State for filtering
  const [searchTerm, setSearchTerm] = useState("");
  
  // State for pagination
  const [currentPage, setCurrentPage] = useState(1);
  const [pageSize, setPageSize] = useState(10);
  const [paginatedData, setPaginatedData] = useState<Dosen[]>([]);
  
  // State for form
  const [formMode, setFormMode] = useState<"add" | "edit">("add");
  const [formData, setFormData] = useState<Partial<Dosen>>({});
  const [isSubmitting, setIsSubmitting] = useState(false);
  const [isDialogOpen, setIsDialogOpen] = useState(false);
  
  // State for delete confirmation
  const [deleteId, setDeleteId] = useState<number | null>(null);
  const [isDeleting, setIsDeleting] = useState(false);
  const [isDeleteDialogOpen, setIsDeleteDialogOpen] = useState(false);

  // Fetch data on component mount
  useEffect(() => {
    fetchDosen();
  }, []);

  // Filter data when search term changes
  useEffect(() => {
    filterData();
  }, [searchTerm, dosen]);

  // Update paginated data when filtered data or pagination settings change
  useEffect(() => {
    paginateData();
  }, [filteredData, currentPage, pageSize]);

  // Fetch dosen data from API
  const fetchDosen = async () => {
    try {
      setLoading(true);
      let url = "/api/keloladata/data-dosen";
      
      // Add search to URL if it exists
      const params = new URLSearchParams();
      if (searchTerm) {
        params.append("search", searchTerm);
      }
      
      if (params.toString()) {
        url += `?${params.toString()}`;
      }
      
      const response = await fetch(url);
      
      if (!response.ok) {
        throw new Error("Failed to fetch data");
      }
      
      const data = await response.json();
      setDosen(data);
      setFilteredData(data);
      setError(null);
    } catch (err) {
      setError("Error fetching data. Please try again later.");
      console.error("Error fetching data:", err);
    } finally {
      setLoading(false);
    }
  };

  // Filter data based on search term
  const filterData = () => {
    let filtered = [...dosen];
    
    // Filter by search term
    if (searchTerm) {
      filtered = filtered.filter(
        (item) =>
          (item.nama_dosen?.toLowerCase() || "").includes(searchTerm.toLowerCase()) ||
          (item.nip?.toLowerCase() || "").includes(searchTerm.toLowerCase())
      );
    }
    
    setFilteredData(filtered);
    // Reset to first page when filters change
    setCurrentPage(1);
  };

  // Paginate data
  const paginateData = () => {
    const startIndex = (currentPage - 1) * pageSize;
    const endIndex = startIndex + pageSize;
    setPaginatedData(filteredData.slice(startIndex, endIndex));
  };

  // Get total number of pages
  const getTotalPages = () => {
    return Math.ceil(filteredData.length / pageSize);
  };

  // Handle page change
  const handlePageChange = (page: number) => {
    setCurrentPage(page);
  };

  // Handle page size change
  const handlePageSizeChange = (size: string) => {
    setPageSize(Number(size));
    setCurrentPage(1); // Reset to first page when changing page size
  };

  // Reset form data
  const resetForm = () => {
    setFormData({});
  };

  // Handle form input changes
  const handleInputChange = (e: React.ChangeEvent<HTMLInputElement>) => {
    const { name, value } = e.target;
    setFormData((prev) => ({ ...prev, [name]: value }));
  };

  // Open form dialog for adding new dosen
  const handleAdd = () => {
    setFormMode("add");
    resetForm();
    setIsDialogOpen(true);
  };

  // Open form dialog for editing dosen
  const handleEdit = (data: Dosen) => {
    setFormMode("edit");
    setFormData(data);
    setIsDialogOpen(true);
  };

  // Open delete confirmation dialog
  const handleDeleteConfirm = (id: number) => {
    setDeleteId(id);
    setIsDeleteDialogOpen(true);
  };

  // Submit form for add/edit
  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault();
    
    try {
      setIsSubmitting(true);
      
      if (formMode === "add") {
        // Add new dosen
        const response = await fetch("/api/keloladata/data-dosen", {
          method: "POST",
          headers: {
            "Content-Type": "application/json",
          },
          body: JSON.stringify(formData),
        });
        
        const responseData = await response.json();
        
        if (!response.ok) {
          // Handle specific errors
          if (response.status === 409) {
            showError("Gagal!", responseData.message);
            throw new Error(responseData.message);
          }
          if (response.status === 400) {
            showError("Gagal!", responseData.message);
            throw new Error(responseData.message);
          }
          showError("Gagal!", "Gagal menambahkan dosen");
          throw new Error(responseData.message || "Failed to add dosen");
        }
        
        showSuccess("Berhasil!", "Dosen berhasil ditambahkan");
      } else {
        // Edit existing dosen
        const response = await fetch(`/api/keloladata/data-dosen?id=${formData.id_dosen}`, {
          method: "PUT",
          headers: {
            "Content-Type": "application/json",
          },
          body: JSON.stringify(formData),
        });
        
        const responseData = await response.json();
        
        if (!response.ok) {
          // Handle specific errors
          if (response.status === 409) {
            showError("Gagal!", responseData.message);
            throw new Error(responseData.message);
          }
          if (response.status === 400) {
            showError("Gagal!", responseData.message);
            throw new Error(responseData.message);
          }
          showError("Gagal!", responseData.message || "Failed to update dosen");
          throw new Error(responseData.message || "Failed to update dosen");
        }
        
        showSuccess("Berhasil!", "Dosen berhasil diperbarui");
      }
      
      // Refresh data after successful operation
      await fetchDosen();
      setIsDialogOpen(false);
      resetForm();
    } catch (err) {
      console.error("Error submitting form:", err);
    } finally {
      setIsSubmitting(false);
    }
  };

  // Delete dosen
  const handleDelete = async () => {
    if (!deleteId) return;
    
    try {
      setIsDeleting(true);
      
      const response = await fetch(`/api/keloladata/data-dosen?id=${deleteId}`, {
        method: "DELETE",
      });
      
      const responseData = await response.json();
      
      if (!response.ok) {
        if (response.status === 409) {
          showError("Gagal!", responseData.message);
          throw new Error(responseData.message);
        }
        showError("Gagal!", responseData.message || "Failed to delete dosen");
        throw new Error(responseData.message || "Failed to delete dosen");
      }
      
      // Refresh data after successful deletion
      await fetchDosen();
      setIsDeleteDialogOpen(false);
      setDeleteId(null);
      showSuccess("Berhasil!", "Dosen berhasil dihapus");
      } catch (err) {
      console.error("Error deleting dosen:", err);
    } finally {
      setIsDeleting(false);
    }
  };

  // Generate pagination items
  const renderPaginationItems = () => {
    const totalPages = getTotalPages();
    const items = [];
    
    // Always show first page
    items.push(
      <PaginationItem key="first">
        <PaginationLink 
          isActive={currentPage === 1} 
          onClick={() => handlePageChange(1)}
        >
          1
        </PaginationLink>
      </PaginationItem>
    );
    
    // Show ellipsis if needed
    if (currentPage > 3) {
      items.push(
        <PaginationItem key="ellipsis-start">
          <PaginationEllipsis />
        </PaginationItem>
      );
    }
    
    // Show pages around current page
    for (let i = Math.max(2, currentPage - 1); i <= Math.min(totalPages - 1, currentPage + 1); i++) {
      if (i === 1 || i === totalPages) continue; // Skip first and last pages as they're always shown
      items.push(
        <PaginationItem key={i}>
          <PaginationLink 
            isActive={currentPage === i} 
            onClick={() => handlePageChange(i)}
          >
            {i}
          </PaginationLink>
        </PaginationItem>
      );
    }
    
    // Show ellipsis if needed
    if (currentPage < totalPages - 2) {
      items.push(
        <PaginationItem key="ellipsis-end">
          <PaginationEllipsis />
        </PaginationItem>
      );
    }
    
    // Always show last page if there's more than one page
    if (totalPages > 1) {
      items.push(
        <PaginationItem key="last">
          <PaginationLink 
            isActive={currentPage === totalPages} 
            onClick={() => handlePageChange(totalPages)}
          >
            {totalPages}
          </PaginationLink>
        </PaginationItem>
      );
    }
    
    return items;
  };

  // Calculate the range of entries being displayed
  const getDisplayRange = () => {
    if (filteredData.length === 0) return { start: 0, end: 0 };
    
    const start = (currentPage - 1) * pageSize + 1;
    const end = Math.min(currentPage * pageSize, filteredData.length);
    
    return { start, end };
  };

  return (
    <div className="space-y-4">
      <div className="flex flex-col sm:flex-row justify-between items-start sm:items-center gap-4">
        <h2 className="text-2xl font-bold">Data Dosen</h2>
        <div className="flex flex-col sm:flex-row gap-2">
          <Button onClick={handleAdd}>
            <PlusCircle className="mr-2 h-4 w-4" />
            Tambah Dosen
          </Button>
        </div>
      </div>

      {/* Search */}
      <div className="flex flex-col sm:flex-row gap-4">
        <div className="relative flex-1">
          <Search className="absolute left-2.5 top-2.5 h-4 w-4 text-muted-foreground" />
          <Input
            placeholder="Cari berdasarkan nama dosen atau NIP..."
            className="pl-8"
            value={searchTerm}
            onChange={(e) => setSearchTerm(e.target.value)}
          />
          {searchTerm && (
            <X
              className="absolute right-2.5 top-2.5 h-4 w-4 text-muted-foreground cursor-pointer"
              onClick={() => setSearchTerm("")}
            />
          )}
        </div>
      </div>

      {/* Show entries selector */}
      <div className="flex items-center gap-2">
        <span className="text-sm">Show</span>
        <Select
          value={pageSize.toString()}
          onValueChange={handlePageSizeChange}
        >
          <SelectTrigger className="w-[80px]">
            <SelectValue placeholder={pageSize.toString()} />
          </SelectTrigger>
          <SelectContent>
            <SelectItem value="5">5</SelectItem>
            <SelectItem value="10">10</SelectItem>
            <SelectItem value="25">25</SelectItem>
            <SelectItem value="50">50</SelectItem>
            <SelectItem value="100">100</SelectItem>
          </SelectContent>
        </Select>
        <span className="text-sm">entries</span>
      </div>

      {/* Table */}
      {loading ? (
        <div className="flex justify-center items-center py-8">
          <Loader2 className="h-8 w-8 animate-spin text-primary" />
        </div>
      ) : error ? (
        <div className="bg-destructive/10 p-4 rounded-md text-destructive text-center">
          {error}
        </div>
      ) : (
        <div className="border rounded-md">
          <Table>
            <TableHeader>
              <TableRow>
                {/* <TableHead className="w-[80px]">ID</TableHead> */}
                <TableHead>Nama Dosen</TableHead>
                <TableHead>NIP</TableHead>
                <TableHead className="text-right">Aksi</TableHead>
              </TableRow>
            </TableHeader>
            <TableBody>
              {paginatedData.length === 0 ? (
                <TableRow>
                  <TableCell colSpan={4} className="text-center py-8">
                    Tidak ada data yang sesuai dengan pencarian
                  </TableCell>
                </TableRow>
              ) : (
                paginatedData.map((dosenItem) => (
                  <TableRow key={dosenItem.id_dosen}>
                    {/* <TableCell>{dosenItem.id_dosen}</TableCell> */}
                    <TableCell className="font-medium">{dosenItem.nama_dosen}</TableCell>
                    <TableCell>{dosenItem.nip}</TableCell>
                    <TableCell className="text-right">
                      <div className="flex justify-end gap-2">
                        <Button
                          size="sm"
                          variant="outline"
                          onClick={() => handleEdit(dosenItem)}
                        >
                          <Pencil className="h-4 w-4" />
                        </Button>
                        <Button
                          size="sm"
                          variant="outline"
                          className="text-destructive hover:bg-destructive/10"
                          onClick={() => handleDeleteConfirm(dosenItem.id_dosen)}
                        >
                          <Trash2 className="h-4 w-4" />
                        </Button>
                      </div>
                    </TableCell>
                  </TableRow>
                ))
              )}
            </TableBody>
          </Table>
        </div>
      )}

      {/* Pagination info and controls */}
      {!loading && !error && filteredData.length > 0 && (
        <div className="flex flex-col sm:flex-row justify-between items-center gap-4">
          <div className="text-sm text-muted-foreground">
            Showing {getDisplayRange().start} to {getDisplayRange().end} of {filteredData.length} entries
          </div>
          <Pagination>
            <PaginationContent>
              <PaginationItem>
                <PaginationPrevious 
                  onClick={() => handlePageChange(Math.max(1, currentPage - 1))}
                  className={currentPage === 1 ? "pointer-events-none opacity-50" : ""}
                />
              </PaginationItem>
              
              {renderPaginationItems()}
              
              <PaginationItem>
                <PaginationNext 
                  onClick={() => handlePageChange(Math.min(getTotalPages(), currentPage + 1))}
                  className={currentPage === getTotalPages() ? "pointer-events-none opacity-50" : ""}
                />
              </PaginationItem>
            </PaginationContent>
          </Pagination>
        </div>
      )}

      {/* Add/Edit Dialog */}
      <Dialog open={isDialogOpen} onOpenChange={setIsDialogOpen}>
        <DialogContent className="sm:max-w-[500px]">
          <DialogHeader>
            <DialogTitle>
              {formMode === "add" ? "Tambah Dosen" : "Edit Dosen"}
            </DialogTitle>
          </DialogHeader>
          <form onSubmit={handleSubmit}>
            <div className="grid gap-4 py-4">
              <div className="space-y-2">
                <label htmlFor="nama_dosen" className="text-sm font-medium">
                  Nama Dosen <span className="text-destructive">*</span>
                </label>
                <Input
                  id="nama_dosen"
                  name="nama_dosen"
                  value={formData.nama_dosen || ""}
                  onChange={handleInputChange}
                  required
                  maxLength={120}
                />
              </div>
              <div className="space-y-2">
                <label htmlFor="nip" className="text-sm font-medium">
                  NIP <span className="text-destructive">*</span>
                </label>
                <Input
                  id="nip"
                  name="nip"
                  value={formData.nip || ""}
                  onChange={handleInputChange}
                  required
                  maxLength={18}
                  placeholder="18 karakter"
                />
                <p className="text-xs text-muted-foreground">
                  NIP harus terdiri dari 18 karakter
                </p>
              </div>
            </div>
            <DialogFooter>
              <DialogClose asChild>
                <Button type="button" variant="outline">
                  Batal
                </Button>
              </DialogClose>
              <Button type="submit" disabled={isSubmitting}>
                {isSubmitting && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}
                {formMode === "add" ? "Tambah" : "Simpan"}
              </Button>
            </DialogFooter>
          </form>
        </DialogContent>
      </Dialog>

      {/* Delete Confirmation Dialog */}
      <Dialog open={isDeleteDialogOpen} onOpenChange={setIsDeleteDialogOpen}>
        <DialogContent className="sm:max-w-[400px]">
          <DialogHeader>
            <DialogTitle>Konfirmasi Hapus</DialogTitle>
          </DialogHeader>
          <div className="py-4">
            <p>Apakah Anda yakin ingin menghapus data dosen ini?</p>
            <p className="text-sm text-muted-foreground mt-1">
              Tindakan ini tidak dapat dibatalkan.
            </p>
          </div>
          <DialogFooter>
            <DialogClose asChild>
              <Button type="button" variant="outline">
                Batal
              </Button>
            </DialogClose>
            <Button
              variant="destructive"
              onClick={handleDelete}
              disabled={isDeleting}
            >
              {isDeleting && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}
              Hapus
            </Button>
          </DialogFooter>
        </DialogContent>
      </Dialog>
    </div>
  );
}