import { useState, useEffect, useCallback } from 'react';

import { getAppointmentsApi, deleteAppointmentApi } from '@/api/appointment';
import { exportToExcel } from '@/utils/exportToExcel';

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

import { Loader2, Trash, RefreshCw, Download, ChevronLeft, ChevronRight, Eye, CalendarDays } from 'lucide-react';

export default function AppointmentPage() {
	const [appointments, setAppointments] = useState<any[]>([]);
	const [loading, setLoading] = useState(true);

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

	const [dateMode, setDateMode] = useState<'scheduled' | 'booked'>('scheduled');

	const [filterDate, setFilterDate] = useState('');
	const [startDate, setStartDate] = useState('');
	const [endDate, setEndDate] = useState('');

	const [createdDate, setCreatedDate] = useState('');
	const [createdStartDate, setCreatedStartDate] = useState('');
	const [createdEndDate, setCreatedEndDate] = useState('');

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

	const [currentPage, setCurrentPage] = useState(1);
	const [totalPages, setTotalPages] = useState(1);
	const [totalItems, setTotalItems] = useState(0);
	const [itemsPerPage, setItemsPerPage] = useState(10);

	const fetchAll = useCallback(async () => {
		setLoading(true);
		try {
			const res = await getAppointmentsApi(
				currentPage,
				itemsPerPage,
				filterDate,
				startDate,
				endDate,
				createdDate,
				createdStartDate,
				createdEndDate,
				searchText
			);
			setAppointments(res?.data || []);
			setTotalPages(res?.pagination?.totalPages || 1);
			setTotalItems(res?.pagination?.total || 0);
		} catch (err) {
			console.error(err);
		} finally {
			setLoading(false);
		}
	}, [
		currentPage,
		itemsPerPage,
		filterDate,
		startDate,
		endDate,
		createdDate,
		createdStartDate,
		createdEndDate,
		searchText,
	]);

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

	const filteredAppointments = appointments.filter((item) => {
		const matchesDoctor = filterDoctor ? item.doctor?.name?.toLowerCase().includes(filterDoctor.toLowerCase()) : true;

		return matchesDoctor;
	});

	const handleModeChange = (newMode: 'scheduled' | 'booked') => {
		setDateMode(newMode);
		setFilterDate('');
		setStartDate('');
		setEndDate('');
		setCreatedDate('');
		setCreatedStartDate('');
		setCreatedEndDate('');
		setCurrentPage(1);
	};

	useEffect(() => {
		setCurrentPage(1);
	}, [searchText, filterDoctor, filterDate, startDate, endDate, createdDate, createdStartDate, createdEndDate]);

	const indexOfFirstItem = (currentPage - 1) * itemsPerPage;

	function openView(item: any) {
		setViewData(item);
		setViewOpen(true);
	}

	async function handleDelete(id: number) {
		if (!confirm('Delete appointment?')) return;
		await deleteAppointmentApi(id);
		fetchAll();
	}

	const handleExport = () => {
		const exportData = filteredAppointments.map((item) => ({
			ID: item.id,
			Name: item.name,
			Phone: item.mobileNumber,
			Email: item.email,
			Doctor: item.doctor?.name,
			Department: item.department?.name,
			ScheduledDate: new Date(item.date).toLocaleDateString(),
			BookedDate: new Date(item.createdAt).toLocaleDateString(),
			Message: item.message,
		}));
		exportToExcel(exportData, 'appointments');
	};

	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 tracking-tight">Appointments</h1>
				<div className="flex items-center gap-3">
					<Button variant="outline" onClick={fetchAll} disabled={loading} className="text-base">
						<RefreshCw className="mr-2 h-5 w-5" />
						Refresh
					</Button>
					<Button onClick={handleExport} className="text-base">
						<Download className="mr-2 h-5 w-5" />
						Export
					</Button>
				</div>
			</div>

			<Card className="shadow-sm">
				<CardContent className="p-4 flex flex-wrap xl:flex-nowrap items-end gap-4">
					<div className="flex flex-col gap-1.5 flex-1 min-w-[240px]">
						<label className="text-xs font-semibold text-muted-foreground uppercase tracking-wider">
							Search Target
						</label>
						<Input
							placeholder="Search patient name, phone, or email..."
							value={searchText}
							onChange={(e) => setSearchText(e.target.value)}
							className="text-base h-10"
						/>
					</div>

					<div className="flex flex-col gap-1.5 w-[180px]">
						<label className="text-xs font-semibold text-muted-foreground uppercase tracking-wider flex items-center gap-1">
							<CalendarDays className="h-3.5 w-3.5 text-primary" /> Filter Date By
						</label>
						<select
							value={dateMode}
							onChange={(e) => handleModeChange(e.target.value as 'scheduled' | 'booked')}
							className="flex h-10 w-full rounded-md border border-input bg-background px-3 py-2 text-sm font-medium focus:ring-2 focus:ring-primary focus:outline-none"
						>
							<option value="scheduled">🗓️ Scheduled Date</option>
							<option value="booked">✍️ Booked (Created At)</option>
						</select>
					</div>

					<div className="flex items-end gap-2 p-2 bg-muted/40 rounded-md border border-dashed flex-wrap sm:flex-nowrap flex-1 min-w-[320px]">
						<div className="flex flex-col gap-1 flex-1 min-w-[110px]">
							<span className="text-[10px] font-bold text-muted-foreground uppercase">Specific Day</span>
							<Input
								type="date"
								value={dateMode === 'scheduled' ? filterDate : createdDate}
								onChange={(e) =>
									dateMode === 'scheduled' ? setFilterDate(e.target.value) : setCreatedDate(e.target.value)
								}
								className="text-sm h-8 bg-background"
								disabled={dateMode === 'scheduled' ? !!startDate || !!endDate : !!createdStartDate || !!createdEndDate}
							/>
						</div>

						<div className="flex flex-col gap-1 flex-1 min-w-[110px]">
							<span className="text-[10px] font-bold text-muted-foreground uppercase">From Range</span>
							<Input
								type="date"
								value={dateMode === 'scheduled' ? startDate : createdStartDate}
								onChange={(e) =>
									dateMode === 'scheduled' ? setStartDate(e.target.value) : setCreatedStartDate(e.target.value)
								}
								className="text-sm h-8 bg-background"
								disabled={dateMode === 'scheduled' ? !!filterDate : !!createdDate}
							/>
						</div>

						<div className="flex flex-col gap-1 flex-1 min-w-[110px]">
							<span className="text-[10px] font-bold text-muted-foreground uppercase">To Range</span>
							<Input
								type="date"
								value={dateMode === 'scheduled' ? endDate : createdEndDate}
								onChange={(e) =>
									dateMode === 'scheduled' ? setEndDate(e.target.value) : setCreatedEndDate(e.target.value)
								}
								className="text-sm h-8 bg-background"
								disabled={dateMode === 'scheduled' ? !!filterDate : !!createdDate}
							/>
						</div>
					</div>

					<div className="flex flex-col gap-1.5 w-[95px]">
						<label className="text-xs font-semibold text-muted-foreground uppercase tracking-wider">Page Limit</label>
						<select
							value={itemsPerPage}
							onChange={(e) => setItemsPerPage(Number(e.target.value))}
							className="flex h-10 w-full rounded-md border border-input bg-background px-3 py-2 text-sm focus:ring-2 focus:ring-primary focus:outline-none"
						>
							<option value={5}>5 Rows</option>
							<option value={10}>10 Rows</option>
							<option value={20}>20 Rows</option>
						</select>
					</div>
				</CardContent>
			</Card>

			<Card>
				<CardHeader className="px-6 py-4 border-b">
					<CardTitle className="text-xl flex items-center gap-2">
						<span>Appointment Registrations</span>
					</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-[1100px] table-fixed border-separate border-spacing-0">
							<TableHeader className="sticky top-0 z-20 bg-background shadow-sm">
								<TableRow>
									<TableHead className="w-[60px] bg-background font-bold text-sm">ID</TableHead>
									<TableHead className="w-[200px] bg-background font-bold text-sm">Patient</TableHead>
									<TableHead className="w-[180px] bg-background font-bold text-sm">Doctor</TableHead>
									<TableHead className="w-[140px] bg-background font-bold text-sm">Scheduled Date</TableHead>
									<TableHead className="w-[140px] bg-background font-bold text-sm">Booked Date</TableHead>
									<TableHead className="w-[200px] bg-background font-bold text-sm">Message</TableHead>
									<TableHead className="w-[100px] bg-background font-bold text-right text-sm">Actions</TableHead>
								</TableRow>
							</TableHeader>

							<TableBody>
								{loading ? (
									<TableRow>
										<TableCell colSpan={7} className="text-center py-10">
											<Loader2 className="h-8 w-8 animate-spin mx-auto text-primary" />
										</TableCell>
									</TableRow>
								) : filteredAppointments.length === 0 ? (
									<TableRow>
										<TableCell colSpan={7} className="text-center text-muted-foreground py-10 text-base">
											No appointments found matching your selected criteria.
										</TableCell>
									</TableRow>
								) : (
									filteredAppointments.map((item) => (
										<TableRow key={item.id} className="hover:bg-muted/50 transition-colors">
											<TableCell className="font-mono text-xs">{item.id}</TableCell>
											<TableCell>
												<div className="font-semibold text-base truncate">{item.name}</div>
												<div className="text-xs text-muted-foreground">{item.mobileNumber}</div>
											</TableCell>
											<TableCell>
												<div className="text-sm font-medium">{item.doctor?.name || '-'}</div>
												<div className="text-[10px] text-muted-foreground truncate">{item.department?.name}</div>
											</TableCell>
											<TableCell>
												<div
													className={`text-sm font-semibold rounded px-1.5 py-0.5 inline-block ${dateMode === 'scheduled' ? 'bg-primary/10 text-primary' : 'bg-muted'}`}
												>
													{new Date(item.date).toLocaleDateString()}
												</div>
											</TableCell>
											<TableCell>
												<div
													className={`text-sm rounded px-1.5 py-0.5 inline-block ${dateMode === 'booked' ? 'bg-sky-500/10 text-sky-600 font-semibold' : 'text-muted-foreground'}`}
												>
													{new Date(item.createdAt).toLocaleDateString()}
												</div>
											</TableCell>
											<TableCell>
												<div className="text-sm line-clamp-2 text-muted-foreground italic">{item.message || '-'}</div>
											</TableCell>
											<TableCell className="text-right">
												<div className="flex justify-end gap-1">
													<Button size="icon" variant="ghost" className="h-9 w-9" onClick={() => openView(item)}>
														<Eye className="h-4 w-4" />
													</Button>
													<Button
														size="icon"
														variant="ghost"
														className="h-9 w-9 text-destructive hover:text-destructive hover:bg-destructive/10"
														onClick={() => handleDelete(item.id)}
													>
														<Trash className="h-4 w-4" />
													</Button>
												</div>
											</TableCell>
										</TableRow>
									))
								)}
							</TableBody>
						</Table>
					</div>

					{!loading && totalItems > 0 && (
						<div className="flex items-center justify-between px-2 py-4 border-t">
							<div className="text-sm text-muted-foreground">
								Showing <span className="font-semibold">{indexOfFirstItem + 1}</span> to{' '}
								<span className="font-semibold">{Math.min(currentPage * itemsPerPage, totalItems)}</span> of{' '}
								<span className="font-semibold">{totalItems}</span> entries
							</div>
							<div className="flex items-center gap-6">
								<div className="text-sm font-medium">
									Page {currentPage} of {totalPages}
								</div>
								<div className="flex gap-1">
									<Button
										variant="outline"
										size="icon"
										className="h-9 w-9"
										onClick={() => setCurrentPage((prev) => Math.max(prev - 1, 1))}
										disabled={currentPage === 1}
									>
										<ChevronLeft className="h-4 w-4" />
									</Button>
									<Button
										variant="outline"
										size="icon"
										className="h-9 w-9"
										onClick={() => setCurrentPage((prev) => Math.min(prev + 1, totalPages))}
										disabled={currentPage === totalPages || totalPages === 0}
									>
										<ChevronRight className="h-4 w-4" />
									</Button>
								</div>
							</div>
						</div>
					)}
				</CardContent>
			</Card>

			<Dialog open={viewOpen} onOpenChange={setViewOpen}>
				<DialogContent className="w-full !max-w-3xl max-h-[85vh] overflow-y-auto">
					<DialogHeader>
						<DialogTitle className="text-2xl border-b pb-2">Appointment Details</DialogTitle>
					</DialogHeader>
					{viewData && (
						<div className="space-y-6 py-4">
							<div className="grid grid-cols-1 md:grid-cols-2 gap-6">
								<div className="space-y-4">
									<div>
										<p className="text-xs uppercase font-bold text-muted-foreground">Patient Information</p>
										<p className="text-lg font-bold text-primary">{viewData.name}</p>
										<p className="text-sm">{viewData.mobileNumber}</p>
										<p className="text-sm">{viewData.email || 'No email provided'}</p>
									</div>
									<div>
										<p className="text-xs uppercase font-bold text-muted-foreground">Key Datestamps</p>
										<p className="text-base font-semibold text-primary">
											Scheduled: {new Date(viewData.date).toLocaleDateString()}
										</p>
										<p className="text-xs text-muted-foreground">
											Record Created: {new Date(viewData.createdAt).toLocaleString()}
										</p>
									</div>
								</div>
								<div className="space-y-4">
									<div>
										<p className="text-xs uppercase font-bold text-muted-foreground">Doctor / Department</p>
										<p className="text-base font-bold">{viewData.doctor?.name || 'Not Assigned'}</p>
										<p className="text-sm text-muted-foreground">{viewData.department?.name || 'General'}</p>
									</div>
									<div className="p-4 bg-muted/30 rounded-lg">
										<p className="text-xs uppercase font-bold text-muted-foreground mb-2">Message from Patient</p>
										<p className="text-sm italic leading-relaxed whitespace-pre-wrap">
											{viewData.message || 'No message provided.'}
										</p>
									</div>
								</div>
							</div>
						</div>
					)}
					<DialogFooter>
						<Button onClick={() => setViewOpen(false)} className="w-full md:w-auto">
							Close
						</Button>
					</DialogFooter>
				</DialogContent>
			</Dialog>
		</div>
	);
}