"use client";

import { useState } from "react";

import { BACKEND } from "../config";

export default function LoginPage() {
  const [username, setUsername] = useState("");
  const [password, setPassword] = useState("");
  const [error, setError] = useState<string | null>(null);
  const [loading, setLoading] = useState(false);

  async function handleSubmit(e: React.FormEvent) {
    e.preventDefault();
    setError(null);
    setLoading(true);
    try {
      const res = await fetch(`${BACKEND}/auth/login`, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        credentials: "include",
        body: JSON.stringify({ username, password }),
      });
      const data = await res.json().catch(() => ({}));
      if (res.ok && data.ok) {
        window.location.href = "/";
        return;
      }
      setError(data.error === "invalid_credentials" ? "Invalid username or password." : "Login failed.");
    } catch {
      setError("Could not reach the server.");
    } finally {
      setLoading(false);
    }
  }

  return (
    <div className="min-h-screen bg-gradient-to-br from-black via-gray-900 to-black flex items-center justify-center p-4">
      <div className="w-full max-w-sm rounded-2xl border border-white/10 bg-white/5 p-8">
        <h1 className="text-2xl font-bold text-white text-center">Sign in</h1>
        <p className="mt-2 text-sm text-white/60 text-center">Social Analytics</p>
        <form onSubmit={handleSubmit} className="mt-6 space-y-4">
          <div>
            <label htmlFor="username" className="block text-sm font-medium text-white/80">
              Username
            </label>
            <input
              id="username"
              type="text"
              autoComplete="username"
              value={username}
              onChange={(e) => setUsername(e.target.value)}
              className="mt-1 w-full rounded-lg border border-white/15 bg-black/40 px-3 py-2 text-white outline-none focus:border-white/30"
              required
            />
          </div>
          <div>
            <label htmlFor="password" className="block text-sm font-medium text-white/80">
              Password
            </label>
            <input
              id="password"
              type="password"
              autoComplete="current-password"
              value={password}
              onChange={(e) => setPassword(e.target.value)}
              className="mt-1 w-full rounded-lg border border-white/15 bg-black/40 px-3 py-2 text-white outline-none focus:border-white/30"
              required
            />
          </div>
          {error && (
            <div className="rounded-lg border border-red-500/30 bg-red-500/10 px-3 py-2 text-sm text-red-200">
              {error}
            </div>
          )}
          <button
            type="submit"
            disabled={loading}
            className="w-full rounded-xl bg-white py-2.5 text-sm font-semibold text-black disabled:opacity-50"
          >
            {loading ? "Signing in…" : "Sign in"}
          </button>
        </form>
      </div>
    </div>
  );
}