frontend/src/pages/AuthPage.jsx

import { useState } from 'react'
import { useNavigate, useSearchParams } from 'react-router-dom'
import { useAuth } from '../context/AuthContext'

export default function AuthPage() {
  const [searchParams]             = useSearchParams()
  const [tab,      setTab]         = useState(searchParams.get('tab') === 'signup' ? 'signup' : 'login')
  const [error,    setError]       = useState('')
  const [loading,  setLoading]     = useState(false)

  // Login fields
  const [identity, setIdentity] = useState('')
  const [loginPw,  setLoginPw]  = useState('')

  // Signup fields
  const [uname,    setUname]    = useState('')
  const [email,    setEmail]    = useState('')
  const [signupPw, setSignupPw] = useState('')

  const { login, signup } = useAuth()
  const navigate           = useNavigate()

  async function handleLogin(e) {
    e.preventDefault()
    setError(''); setLoading(true)
    try {
      await login(identity, loginPw)
      navigate('/app/dashboard')
    } catch (err) { setError(err.message) }
    finally { setLoading(false) }
  }

  async function handleSignup(e) {
    e.preventDefault()
    setError(''); setLoading(true)
    try {
      await signup(uname, email, signupPw)
      navigate('/app/dashboard')
    } catch (err) { setError(err.message) }
    finally { setLoading(false) }
  }

  return (
    <div className="auth-screen">
      {/* Breathing rings */}
      <div className="breath-rings">
        {[1,2,3,4].map(i => <div key={i} className={`ring ring-${i}`} />)}
      </div>

      <div className="auth-card">
        {/* Brand */}
        <div className="auth-brand">
          <img src="/logo.svg" alt="BREATHE" className="auth-logo" />
          <p className="auth-subtitle">Stress Intelligence Platform</p>
        </div>

        {/* Tabs */}
        <div className="auth-tabs">
          <button className={`auth-tab ${tab==='login'  ? 'auth-tab--active' : ''}`} onClick={() => { setTab('login');  setError('') }}>Log In</button>
          <button className={`auth-tab ${tab==='signup' ? 'auth-tab--active' : ''}`} onClick={() => { setTab('signup'); setError('') }}>Sign Up</button>
        </div>

        {error && <div className="form-error">{error}</div>}

        {/* Login form */}
        {tab === 'login' && (
          <form className="auth-form" onSubmit={handleLogin}>
            <div className="field">
              <label>Email or Username</label>
              <input type="text" placeholder="you@example.com" value={identity}
                onChange={e => setIdentity(e.target.value)} autoComplete="username" required />
            </div>
            <div className="field">
              <label>Password</label>
              <input type="password" placeholder="••••••••" value={loginPw}
                onChange={e => setLoginPw(e.target.value)} autoComplete="current-password" required />
            </div>
            <button type="submit" className="btn-primary btn--full" disabled={loading}>
              {loading ? <span className="btn-spinner" /> : 'Log In →'}
            </button>
          </form>
        )}

        {/* Signup form */}
        {tab === 'signup' && (
          <form className="auth-form" onSubmit={handleSignup}>
            <div className="field">
              <label>Username</label>
              <input type="text" placeholder="breatheuser" value={uname}
                onChange={e => setUname(e.target.value)} autoComplete="username" required />
            </div>
            <div className="field">
              <label>Email</label>
              <input type="email" placeholder="you@example.com" value={email}
                onChange={e => setEmail(e.target.value)} autoComplete="email" required />
            </div>
            <div className="field">
              <label>Password <small>(min 8 characters)</small></label>
              <input type="password" placeholder="••••••••" value={signupPw}
                onChange={e => setSignupPw(e.target.value)} autoComplete="new-password" required />
            </div>
            <button type="submit" className="btn-primary btn--full" disabled={loading}>
              {loading ? <span className="btn-spinner" /> : 'Create Account →'}
            </button>
          </form>
        )}
      </div>
    </div>
  )
}