import { useState, useEffect, useCallback } from 'react';
import { AxiosError } from 'axios';
import { BytescaleUploader } from '@/components/BytescaleUploader/BytescaleUploader';

import { getDepartmentsApi, createDepartmentApi, updateDepartmentApi } from '@/api/department';

import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from '@/components/ui/table';

import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
import { Button } from '@/components/ui/button';

import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogFooter } from '@/components/ui/dialog';

import { Input } from '@/components/ui/input';
import { Textarea } from '@/components/ui/textarea';
import { Switch } from '@/components/ui/switch';
import { Label } from '@/components/ui/label';
import { Badge } from '@/components/ui/badge';

import { Loader2, RefreshCw, Plus, Pencil, Eye, ChevronLeft, ChevronRight } from 'lucide-react';

interface Department {
	departmentId: string;
	name: string;
	image?: string;
	para1: string;
	para2: string;
	para3: string;
	facilities: string;
	services: string;
	isActive: boolean;
	sortOrder: number;
}

export default function DepartmentPage() {
	const [departments, setDepartments] = useState<Department[]>([]);
	const [loading, setLoading] = useState(true);
	const [error, setError] = useState('');

	const [openModal, setOpenModal] = useState(false);
	const [editing, setEditing] = useState<Department | null>(null);

	const [viewOpen, setViewOpen] = useState(false);
	const [viewData, setViewData] = useState<Department | null>(null);

	const [searchText, setSearchText] = useState('');

	const [currentPage, setCurrentPage] = useState(1);
	const itemsPerPage = 10;

	const [form, setForm] = useState<Department>({
		departmentId: '',
		name: '',
		image: '',
		para1: '',
		para2: '',
		para3: '',
		facilities: '',
		services: '',
		isActive: true,
		sortOrder: 0,
	});

	const fetchDepartments = useCallback(async () => {
		setLoading(true);
		setError('');

		try {
			const res = await getDepartmentsApi();
			setDepartments(res?.data || []);
		} catch (err) {
			if (err instanceof AxiosError) {
				setError(err.response?.data?.message || 'Failed to load departments');
			} else {
				setError('Something went wrong');
			}
		} finally {
			setLoading(false);
		}
	}, []);

	useEffect(() => {
		fetchDepartments();
	}, [fetchDepartments]);

	const filteredDepartments = departments.filter(
		(dep) =>
			dep.name.toLowerCase().includes(searchText.toLowerCase()) ||
			dep.departmentId.toLowerCase().includes(searchText.toLowerCase())
	);

	useEffect(() => {
		setCurrentPage(1);
	}, [searchText]);

	const totalPages = Math.ceil(filteredDepartments.length / itemsPerPage);
	const indexOfLastItem = currentPage * itemsPerPage;
	const indexOfFirstItem = indexOfLastItem - itemsPerPage;
	const currentItems = filteredDepartments.slice(indexOfFirstItem, indexOfLastItem);

	function handleChange(e: any) {
		const value = e.target.type === 'number' ? Number(e.target.value) : e.target.value;
		setForm({ ...form, [e.target.name]: value });
	}

	const handleToggleStatus = async (dep: Department) => {
		try {
			const { departmentId, ...updateData } = dep;
			await updateDepartmentApi(departmentId, {
				...updateData,
				isActive: !dep.isActive,
			} as any);
			fetchDepartments();
		} catch (error) {
			console.error('Failed to toggle status', error);
		}
	};

	function openAdd() {
		setEditing(null);
		setForm({
			departmentId: '',
			name: '',
			image: '',
			para1: '',
			para2: '',
			para3: '',
			facilities: '',
			services: '',
			isActive: true,
			sortOrder: 0,
		});
		setOpenModal(true);
	}

	function openEdit(dep: Department) {
		setEditing(dep);
		setForm({
			...dep,
			isActive: dep.isActive ?? true,
			sortOrder: dep.sortOrder ?? 0,
		});
		setOpenModal(true);
	}

	function openView(dep: Department) {
		setViewData(dep);
		setViewOpen(true);
	}

	async function handleSubmit() {
		try {
			if (editing) {
				const { departmentId, ...updateData } = form;
				await updateDepartmentApi(editing.departmentId, form as any);
			} else {
				await createDepartmentApi(form);
			}

			setOpenModal(false);
			fetchDepartments();
		} catch (error) {
			console.error(error);
		}
	}

	return (
		<div className="p-6 space-y-6">
			<div className="flex flex-col md:flex-row md:justify-between md:items-center gap-4">
				<h1 className="text-3xl font-bold">Departments</h1>

				<div className="flex flex-wrap gap-3">
					<Input
						placeholder="Search department..."
						value={searchText}
						onChange={(e) => setSearchText(e.target.value)}
						className="w-[250px] text-base"
					/>

					<Button variant="outline" onClick={fetchDepartments} disabled={loading} className="text-base">
						<RefreshCw className="mr-2 h-5 w-5" />
						Refresh
					</Button>

					<Button onClick={openAdd} className="text-base">
						<Plus className="mr-2 h-5 w-5" />
						Add Department
					</Button>
				</div>
			</div>

			{error && <div className="p-4 text-red-600 bg-red-50 border rounded-md text-base">{error}</div>}

			<Card>
				<CardHeader>
					<CardTitle className="text-xl">Department List</CardTitle>
				</CardHeader>

				<CardContent className="p-0 sm:p-6 space-y-4">
					<div className="rounded-md border overflow-x-auto overflow-y-auto max-h-[650px] relative">
						<Table className="w-full min-w-[700px] table-fixed border-separate border-spacing-0">
							<TableHeader className="sticky top-0 z-20 bg-background shadow-sm">
								<TableRow>
									<TableHead className="w-[100px] bg-background text-sm font-bold">Priority</TableHead>
									<TableHead className="w-[300px] bg-background text-sm font-bold">Name</TableHead>
									<TableHead className="w-[80px] bg-background text-sm font-bold">Status (Active)</TableHead>
									<TableHead className="w-[80px] bg-background text-right text-sm font-bold">Actions</TableHead>
								</TableRow>
							</TableHeader>

							<TableBody>
								{loading ? (
									<TableRow>
										<TableCell colSpan={4} className="text-center py-10">
											<Loader2 className="h-8 w-8 animate-spin mx-auto" />
										</TableCell>
									</TableRow>
								) : currentItems.length === 0 ? (
									<TableRow>
										<TableCell colSpan={4} className="text-center text-muted-foreground py-10 text-base">
											No departments found
										</TableCell>
									</TableRow>
								) : (
									currentItems.map((dep) => (
										<TableRow key={dep.departmentId} className="hover:bg-muted/50">
											<TableCell className="font-mono text-sm">{dep.sortOrder}</TableCell>

											<TableCell>
												<div className="font-semibold text-base truncate" title={dep.name}>
													{dep.name}
												</div>
												<div className="text-xs text-muted-foreground">{dep.departmentId}</div>
											</TableCell>
											<TableCell>
												<div className="flex items-center gap-2">
													<Switch checked={dep.isActive} onCheckedChange={() => handleToggleStatus(dep)} />
													<Badge variant={dep.isActive ? 'default' : 'secondary'}>
														{dep.isActive ? 'Active' : 'Hidden'}
													</Badge>
												</div>
											</TableCell>

											<TableCell className="text-right">
												<div className="flex justify-end gap-2">
													<Button size="icon" variant="ghost" className="h-9 w-9" onClick={() => openView(dep)}>
														<Eye className="h-4 w-4" />
													</Button>

													<Button size="icon" variant="ghost" className="h-9 w-9" onClick={() => openEdit(dep)}>
														<Pencil className="h-4 w-4" />
													</Button>
												</div>
											</TableCell>
										</TableRow>
									))
								)}
							</TableBody>
						</Table>
					</div>

					{!loading && filteredDepartments.length > 0 && (
						<div className="flex items-center justify-between px-2 py-6 border-t">
							<div className="text-base text-muted-foreground">
								Showing <span className="font-semibold">{indexOfFirstItem + 1}</span> to{' '}
								<span className="font-semibold">{Math.min(indexOfLastItem, filteredDepartments.length)}</span> of{' '}
								<span className="font-semibold">{filteredDepartments.length}</span> departments
							</div>
							<div className="flex items-center gap-6">
								<div className="text-base font-semibold">
									Page {currentPage} of {totalPages}
								</div>
								<div className="flex gap-2">
									<Button
										variant="outline"
										size="icon"
										className="h-10 w-10"
										onClick={() => setCurrentPage((prev) => Math.max(prev - 1, 1))}
										disabled={currentPage === 1}
									>
										<ChevronLeft className="h-5 w-5" />
									</Button>
									<Button
										variant="outline"
										size="icon"
										className="h-10 w-10"
										onClick={() => setCurrentPage((prev) => Math.min(prev + 1, totalPages))}
										disabled={currentPage === totalPages || totalPages === 0}
									>
										<ChevronRight className="h-5 w-5" />
									</Button>
								</div>
							</div>
						</div>
					)}
				</CardContent>
			</Card>

			<Dialog open={openModal} onOpenChange={setOpenModal}>
				<DialogContent className="w-full !max-w-5xl max-h-[90vh] overflow-y-auto">
					<DialogHeader>
						<DialogTitle>{editing ? 'Edit Department' : 'Add Department'}</DialogTitle>
					</DialogHeader>

					<div className="space-y-4">
						<div className="space-y-2">
							<label className="text-sm font-semibold">Department Image</label>
							<BytescaleUploader
								value={form.image}
								folderPath="/departments"
								onChange={(url) => setForm({ ...form, image: url })}
							/>
						</div>
						<Input
							name="departmentId"
							value={form.departmentId}
							onChange={handleChange}
							disabled={!!editing}
							placeholder="Department ID"
						/>

						<Input name="name" value={form.name} onChange={handleChange} placeholder="Department Name" />

						<Textarea name="para1" value={form.para1} onChange={handleChange} placeholder="Para1" />
						<Textarea name="para2" value={form.para2} onChange={handleChange} placeholder="Para2" />
						<Textarea name="para3" value={form.para3} onChange={handleChange} placeholder="Para3" />
						<Textarea name="facilities" value={form.facilities} onChange={handleChange} placeholder="Facilities" />
						<Textarea name="services" value={form.services} onChange={handleChange} placeholder="Services" />

						<div className="grid grid-cols-1 md:grid-cols-2 gap-4 border-t pt-4">
							<div className="flex items-center justify-between p-3 border rounded-md">
								<Label htmlFor="isActive" className="text-base cursor-pointer">
									Active Visibility
								</Label>
								<Switch
									id="isActive"
									checked={form.isActive}
									onCheckedChange={(val) => setForm({ ...form, isActive: val })}
								/>
							</div>
							<div className="space-y-1">
								<Label htmlFor="sortOrder">Sort Priority (Lower numbers show first)</Label>
								<Input
									id="sortOrder"
									name="sortOrder"
									type="number"
									value={form.sortOrder}
									onChange={handleChange}
									placeholder="0"
								/>
							</div>
						</div>
					</div>

					<DialogFooter>
						<Button variant="outline" onClick={() => setOpenModal(false)}>
							Cancel
						</Button>
						<Button onClick={handleSubmit}>{editing ? 'Save Changes' : 'Create'}</Button>
					</DialogFooter>
				</DialogContent>
			</Dialog>

			<Dialog open={viewOpen} onOpenChange={setViewOpen}>
				<DialogContent className="w-full !max-w-5xl max-h-[90vh] overflow-y-auto">
					<DialogHeader>
						<DialogTitle>Department Details</DialogTitle>
					</DialogHeader>
					{viewData && (
						<div className="space-y-4 text-sm">
							<div className="flex gap-4 items-center border-b pb-4">
								<Badge variant={viewData.isActive ? 'default' : 'secondary'}>
									{viewData.isActive ? 'ACTIVE' : 'HIDDEN'}
								</Badge>
								<p>
									<b>Sort Order:</b> {viewData.sortOrder}
								</p>
								<p>
									<b>ID:</b> {viewData.departmentId}
								</p>
							</div>
							<p>
								<b>Name:</b> {viewData.name}
							</p>
							<p>
								<b>Para1:</b>
								<br />
								{viewData.para1}
							</p>
							<p>
								<b>Para2:</b>
								<br />
								{viewData.para2}
							</p>
							<p>
								<b>Para3:</b>
								<br />
								{viewData.para3}
							</p>
							<p>
								<b>Facilities:</b>
								<br />
								{viewData.facilities}
							</p>
							<p>
								<b>Services:</b>
								<br />
								{viewData.services}
							</p>
						</div>
					)}
					<DialogFooter>
						<Button onClick={() => setViewOpen(false)}>Close</Button>
					</DialogFooter>
				</DialogContent>
			</Dialog>
		</div>
	);
}