"use client";

import { useEffect, useState } from "react";
import { useSession } from "next-auth/react";
import { useRouter, useParams } from "next/navigation";
import Link from "next/link";
import { Card, CardHeader, CardContent } from "@/components/ui/Card";
import Button from "@/components/ui/Button";
import { Input } from "@/components/ui/Input";
import PageContainer from "@/components/ui/PageContainer";
import PageHeader from "@/components/ui/PageHeader";
import { LoadingState } from "@/components/ui/States";

export default function EditUserPage() {
	const [user, setUser] = useState(null);
	const [formData, setFormData] = useState({
		name: "",
		username: "",
		role: "user",
		is_active: true,
		initial: "",
		password: ""
	});
	const [loading, setLoading] = useState(true);
	const [saving, setSaving] = useState(false);
	const [error, setError] = useState("");
	const [success, setSuccess] = useState("");
	
	const { data: session, status } = useSession();
	const router = useRouter();
	const params = useParams();

	// Check if user is admin
	useEffect(() => {
		if (status === "loading") return;
		if (!session || session.user.role !== "admin") {
			router.push("/");
			return;
		}
	}, [session, status, router]);

	// Fetch user data
	useEffect(() => {
		if (session?.user?.role === "admin" && params.id) {
			fetchUser();
		}
	}, [session, params.id]);

	const fetchUser = async () => {
		try {
			setLoading(true);
			const response = await fetch(`/api/admin/users/${params.id}`);
			
			if (!response.ok) {
				if (response.status === 404) {
					setError("User not found");
					return;
				}
				throw new Error("Failed to fetch user");
			}
			
			const userData = await response.json();
			setUser(userData);
			setFormData({
				name: userData.name,
				username: userData.username,
				role: userData.role,
				is_active: userData.is_active,
				initial: userData.initial || "",
				password: "" // Never populate password field
			});
		} catch (err) {
			setError(err.message);
		} finally {
			setLoading(false);
		}
	};

	const handleSubmit = async (e) => {
		e.preventDefault();
		setSaving(true);
		setError("");
		setSuccess("");

		try {
			// Prepare update data (exclude empty password)
			const updateData = {
				name: formData.name,
				username: formData.username,
				role: formData.role,
				is_active: formData.is_active,
				initial: formData.initial.trim() || null
			};

			// Only include password if it's provided
			if (formData.password.trim()) {
				if (formData.password.length < 6) {
					throw new Error("Password must be at least 6 characters long");
				}
				updateData.password = formData.password;
			}

			const response = await fetch(`/api/admin/users/${params.id}`, {
				method: "PUT",
				headers: {
					"Content-Type": "application/json",
				},
				body: JSON.stringify(updateData),
			});

			if (!response.ok) {
				const errorData = await response.json();
				throw new Error(errorData.error || "Failed to update user");
			}

			const updatedUser = await response.json();
			setUser(updatedUser);
			setSuccess("User updated successfully");
			
			// Clear password field after successful update
			setFormData(prev => ({ ...prev, password: "" }));

		} catch (err) {
			setError(err.message);
		} finally {
			setSaving(false);
		}
	};

	if (status === "loading" || !session) {
		return <LoadingState />;
	}

	if (session.user.role !== "admin") {
		return (
			<PageContainer>
				<div className="text-center py-12">
					<h2 className="text-2xl font-bold text-gray-900 mb-4">Access Denied</h2>
					<p className="text-gray-600 mb-6">You need admin privileges to access this page.</p>
					<Link href="/">
						<Button>Go Home</Button>
					</Link>
				</div>
			</PageContainer>
		);
	}

	if (loading) {
		return <LoadingState />;
	}

	if (error && !user) {
		return (
			<PageContainer>
				<div className="text-center py-12">
					<h2 className="text-2xl font-bold text-gray-900 mb-4">Error</h2>
					<p className="text-gray-600 mb-6">{error}</p>
					<Link href="/admin/users">
						<Button>Back to Users</Button>
					</Link>
				</div>
			</PageContainer>
		);
	}

	return (
		<PageContainer>
			<PageHeader 
				title={`Edit User: ${user?.name}`} 
				description="Update user information and permissions"
			>
				<Link href="/admin/users">
					<Button variant="outline">
						<svg className="w-5 h-5 mr-2" fill="none" stroke="currentColor" viewBox="0 0 24 24">
							<path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M10 19l-7-7m0 0l7-7m-7 7h18" />
						</svg>
						Back to Users
					</Button>
				</Link>
			</PageHeader>

			{error && (
				<div className="mb-6 p-4 bg-red-50 border border-red-200 rounded-md">
					<p className="text-red-600">{error}</p>
				</div>
			)}

			{success && (
				<div className="mb-6 p-4 bg-green-50 border border-green-200 rounded-md">
					<p className="text-green-600">{success}</p>
				</div>
			)}

			<Card>
				<CardHeader>
					<h3 className="text-lg font-semibold">User Information</h3>
				</CardHeader>
				<CardContent>
					<form onSubmit={handleSubmit} className="space-y-6">
						<div className="grid grid-cols-1 md:grid-cols-2 gap-6">
							<div>
								<label className="block text-sm font-medium text-gray-700 mb-2">
									Name *
								</label>
								<Input
									type="text"
									value={formData.name}
									onChange={(e) => setFormData({ ...formData, name: e.target.value })}
									required
								/>
							</div>

							<div>
								<label className="block text-sm font-medium text-gray-700 mb-2">
									Username *
								</label>
								<Input
									type="text"
									value={formData.username}
									onChange={(e) => setFormData({ ...formData, username: e.target.value })}
									required
								/>
							</div>

							<div>
								<label className="block text-sm font-medium text-gray-700 mb-2">
									Role *
								</label>
								<select
									value={formData.role}
									onChange={(e) => setFormData({ ...formData, role: e.target.value })}
									className="w-full px-3 py-2 border border-gray-300 rounded-md focus:outline-none focus:ring-2 focus:ring-blue-500"
									required
								>
									<option value="read_only">Read Only</option>
									<option value="user">User</option>
									<option value="project_manager">Project Manager</option>
									<option value="team_lead">Team Lead</option>
									<option value="admin">Admin</option>
								</select>
							</div>

							<div>
								<label className="block text-sm font-medium text-gray-700 mb-2">
									New Password
								</label>
								<Input
									type="password"
									value={formData.password}
									onChange={(e) => setFormData({ ...formData, password: e.target.value })}
									placeholder="Leave blank to keep current password"
									minLength={6}
								/>
								<p className="text-xs text-gray-500 mt-1">
									Leave blank to keep the current password
								</p>
							</div>
						</div>

						<div>
							<label className="block text-sm font-medium text-gray-700 mb-2">
								Initial
							</label>
							<Input
								type="text"
								value={formData.initial}
								onChange={(e) => setFormData({ ...formData, initial: e.target.value })}
								placeholder="1-2 letter identifier"
								maxLength={2}
								className="w-full md:w-1/2"
							/>
							<p className="text-xs text-gray-500 mt-1">
								Optional 1-2 letter identifier for the user
							</p>
						</div>

						<div className="flex items-center">
							<input
								type="checkbox"
								id="is_active"
								checked={formData.is_active}
								onChange={(e) => setFormData({ ...formData, is_active: e.target.checked })}
								className="h-4 w-4 text-blue-600 focus:ring-blue-500 border-gray-300 rounded"
								disabled={user?.id === session?.user?.id}
							/>
							<label htmlFor="is_active" className="ml-2 block text-sm text-gray-900">
								Active User
								{user?.id === session?.user?.id && (
									<span className="text-gray-500 ml-1">(Cannot deactivate your own account)</span>
								)}
							</label>
						</div>

						<div className="flex space-x-4 pt-6 border-t border-gray-200">
							<Button type="submit" disabled={saving}>
								{saving ? "Saving..." : "Save Changes"}
							</Button>
							<Link href="/admin/users">
								<Button type="button" variant="outline">
									Cancel
								</Button>
							</Link>
						</div>
					</form>
				</CardContent>
			</Card>

			{/* User Details Card */}
			{user && (
				<Card className="mt-6">
					<CardHeader>
						<h3 className="text-lg font-semibold">Account Details</h3>
					</CardHeader>
					<CardContent>
						<div className="grid grid-cols-1 md:grid-cols-3 gap-6">
							<div>
								<p className="text-sm font-medium text-gray-500">Created</p>
								<p className="text-sm text-gray-900">{new Date(user.created_at).toLocaleDateString()}</p>
							</div>
							<div>
								<p className="text-sm font-medium text-gray-500">Last Updated</p>
								<p className="text-sm text-gray-900">
									{user.updated_at ? new Date(user.updated_at).toLocaleDateString() : "Never"}
								</p>
							</div>
							<div>
								<p className="text-sm font-medium text-gray-500">Last Login</p>
								<p className="text-sm text-gray-900">
									{user.last_login ? new Date(user.last_login).toLocaleDateString() : "Never"}
								</p>
							</div>
							<div>
								<p className="text-sm font-medium text-gray-500">Failed Login Attempts</p>
								<p className="text-sm text-gray-900">{user.failed_login_attempts || 0}</p>
							</div>
							<div>
								<p className="text-sm font-medium text-gray-500">Account Status</p>
								<p className="text-sm text-gray-900">
									{user.is_active ? "Active" : "Inactive"}
								</p>
							</div>
							<div>
								<p className="text-sm font-medium text-gray-500">Account Locked</p>
								<p className="text-sm text-gray-900">
									{user.locked_until && new Date(user.locked_until) > new Date() 
										? `Until ${new Date(user.locked_until).toLocaleDateString()}`
										: "No"
									}
								</p>
							</div>
						</div>
					</CardContent>
				</Card>
			)}
		</PageContainer>
	);
}