import React, { useState, useRef, useEffect } from "react";
import { toast } from "react-toastify";
import { API_URL } from "@/config";

function getCookie(name) {
    const value = `; ${document.cookie}`;
    const parts = value.split(`; ${name}=`);
    if (parts.length === 2) return decodeURIComponent(parts.pop().split(';').shift());
    return null;
}

function clearCookie(name) {
    document.cookie = `${name}=; Max-Age=0; path=/;`;
}

export default function LoginPage() {
    const [username, setUsername] = useState("");
    const [password, setPassword] = useState("");
    const [loading, setLoading] = useState(false);

    const passwordRef = useRef();

    useEffect(() => {
        if (passwordRef.current && password === "") {
            passwordRef.current.value = "";
        }
    }, []);

    async function handleSubmit(e) {
        e.preventDefault();
        setLoading(true);

        try {
            if (!username || !password) {
                setLoading(false);
                if (!toast.isActive("login-missing-data-toast")) {
                    toast.error("Username and password are required", {
                        toastId: "login-missing-data-toast",
                    });
                }
                return;
            }

            const formData = new URLSearchParams({
                username,
                password,
                grant_type: "password",
                scope: "",
                client_id: "",
                client_secret: "",
            });

            const resp = await fetch(`${API_URL}/auth/login`, {
                method: "POST",
                headers: { "Content-Type": "application/x-www-form-urlencoded" },
                credentials: "include",
                body: formData.toString(),
            });

            if (resp.status === 401) {
                toast.error("Invalid username or password", {
                    toastId: "login-error-invalid-toast",
                });
                setLoading(false);
                return;
            }

            if (!resp.ok) {
                const data = await resp.json().catch(() => ({}));
                toast.error(data.detail ? `Login failed: ${data.detail}` : "Login failed", {
                    toastId: "login-error-failed-toast",
                });
                setLoading(false);
                return;
            }

            const data = await resp.json();
            if (data.access_token) {
                toast.success("Login successful!", {
                    toastId: "login-success-toast",
                });
                const returnTo = getCookie("returnTo") || "/TRip";
                clearCookie("returnTo");
                window.location.href = returnTo;
            } else {
                toast.error("Login failed: no access token received", {
                    toastId: "login-error-no-token-toast",
                });
                setLoading(false);
            }
        } catch (error) {
            toast.error("Network error during login", {
                toastId: "login-error-network-toast",
            });
            console.error("Login error:", error);
            setLoading(false);
        }
    }

    return (
        <div className="flex items-start justify-center bg-gray-50 dark:bg-[#121212] px-4 pt-20 py-10">
            <div className="max-w-md w-full bg-white dark:bg-[#1E1E1E] rounded-2xl shadow-xl px-10 pb-6">
                <h2 className="flex flex-col items-center text-3xl font-semibold text-gray-900 dark:text-white mb-8 font-sans">
                    <img className="logo-auth mb-4" src="/images/zim.png" alt="Logo" />
                    Log In
                </h2>

                <form className="space-y-6 relative" onSubmit={handleSubmit} noValidate>
                    {/* Username */}
                    <div className="relative">
                        <input
                            type="text"
                            id="username"
                            name="username"
                            autoComplete="off"
                            value={username}
                            onChange={(e) => setUsername(e.target.value)}
                            required
                            disabled={loading}
                            className="peer block w-full px-4 pt-5 pb-2 border border-gray-300 dark:border-gray-700 rounded-lg bg-transparent text-gray-900 dark:text-white placeholder-transparent focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                        />
                        <label
                            htmlFor="username"
                            className="absolute left-4 top-2 text-gray-500 dark:text-gray-400 text-sm transition-all
              peer-placeholder-shown:top-5 peer-placeholder-shown:text-gray-400 peer-placeholder-shown:text-base
              peer-focus:top-2 peer-focus:text-sm peer-focus:text-blue-500 dark:peer-focus:text-blue-400"
                        >
                            Username
                        </label>
                    </div>

                    {/* Password */}
                    <div className="relative">
                        <input
                            type="password"
                            id="password"
                            name="password"
                            autoComplete="new-password"
                            spellCheck="false"
                            ref={passwordRef}
                            value={password}
                            onChange={(e) => setPassword(e.target.value)}
                            required
                            disabled={loading}
                            className="peer block w-full px-4 pt-5 pb-2 border border-gray-300 dark:border-gray-700 rounded-lg bg-transparent text-gray-900 dark:text-white placeholder-transparent focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                        />
                        <label
                            htmlFor="password"
                            className="absolute left-4 top-2 text-gray-500 dark:text-gray-400 text-sm transition-all
              peer-placeholder-shown:top-5 peer-placeholder-shown:text-gray-400 peer-placeholder-shown:text-base
              peer-focus:top-2 peer-focus:text-sm peer-focus:text-blue-500 dark:peer-focus:text-blue-400"
                        >
                            Password
                        </label>
                    </div>

                    <button
                        type="submit"
                        disabled={loading}
                        className={`w-full py-3 bg-blue-600 hover:bg-blue-700 focus:ring-4 focus:ring-blue-300 text-white rounded-lg font-semibold shadow-md transition-colors ${loading ? "opacity-60 cursor-not-allowed" : ""
                            }`}
                    >
                        {loading ? "Signing In..." : "Sign In"}
                    </button>
                </form>
            </div>
        </div>
    );
}