import { useEffect, useState } from 'react'
import { Link, useNavigate, useParams } from 'react-router-dom'
import { api } from '../../api/client.js'
import PlayerShell from './PlayerShell.jsx'

// Public, token-gated reset page (/account/reset/:token). Validates the link, lets
// the user choose a new password, then sends them to sign in fresh. Setting the
// password revokes every existing session (web + mobile) server-side and does NOT
// log them in here — so a 2FA account still passes TOTP on the next sign-in.
export default function ResetPassword() {
  const { token } = useParams()
  const navigate = useNavigate()

  const [username, setUsername] = useState(null) // whose account this link is for
  const [loadErr, setLoadErr] = useState('')

  const [password, setPassword] = useState('')
  const [confirm, setConfirm] = useState('')
  const [error, setError] = useState('')
  const [busy, setBusy] = useState(false)
  const [done, setDone] = useState(false)

  useEffect(() => {
    let active = true
    api.getPasswordReset(token)
      .then((r) => active && setUsername(r?.username || ''))
      .catch((err) => active && setLoadErr(
        err.status === 404 ? 'This reset link is invalid or has expired.' : 'Could not load this reset link.',
      ))
    return () => { active = false }
  }, [token])

  async function onSubmit(e) {
    e.preventDefault()
    setError('')
    if (password.length < 8) return setError('Password must be at least 8 characters.')
    if (password !== confirm) return setError('The passwords do not match.')
    setBusy(true)
    try {
      await api.resetPassword(token, password)
      setDone(true)
    } catch (err) {
      if (err.status === 404) setError('This reset link is invalid or has already been used.')
      else if (err.status === 429) setError('Too many attempts. Please try again in a little while.')
      else if (err.status === 400) setError(err.message || 'Please check your password and try again.')
      else setError('Could not reset your password right now. Please try again later.')
      setBusy(false)
    }
  }

  // ── Invalid link ───────────────────────────────────────────────────────────
  if (loadErr) {
    return (
      <PlayerShell subtitle="Reset your password">
        <p className="sans" style={{ margin: 0, color: 'var(--muted)', textAlign: 'center', lineHeight: 1.6 }}>{loadErr}</p>
        <p className="sans" style={{ textAlign: 'center', margin: '16px 0 0' }}>
          <Link to="/account/forgot" style={{ color: 'var(--accent)', textDecoration: 'none' }}>Request a new link</Link>
        </p>
      </PlayerShell>
    )
  }
  if (username === null) {
    return (
      <PlayerShell subtitle="Reset your password">
        <div style={{ display: 'grid', placeItems: 'center', padding: 20 }}><span className="spin" /></div>
      </PlayerShell>
    )
  }

  // ── Done ───────────────────────────────────────────────────────────────────
  if (done) {
    return (
      <PlayerShell subtitle="Password updated">
        <p className="sans" style={{ margin: 0, color: 'var(--muted)', textAlign: 'center', lineHeight: 1.6 }}>
          Your password has been reset. For your security, every existing session has been signed out.
        </p>
        <button
          type="button"
          onClick={() => navigate('/account/login', { replace: true })}
          className="btn btn-primary"
          style={{ display: 'block', width: '100%', borderRadius: 8, padding: 12, textAlign: 'center', marginTop: 20 }}
        >
          Sign in
        </button>
      </PlayerShell>
    )
  }

  // ── Reset form ─────────────────────────────────────────────────────────────
  return (
    <PlayerShell subtitle="Reset your password">
      <p className="sans" style={{ marginTop: 0, marginBottom: 18, color: 'var(--muted)', fontSize: '0.88rem', lineHeight: 1.6 }}>
        Choose a new password{username ? <> for <strong style={{ color: 'var(--head)' }}>{username}</strong></> : null}.
      </p>
      <form onSubmit={onSubmit}>
        {/* A hidden username field helps password managers associate the credential. */}
        {username ? <input type="text" name="username" autoComplete="username" value={username} readOnly hidden /> : null}
        <label style={{ display: 'block', marginBottom: 16 }}>
          <span className="field-label">New password</span>
          <input type="password" autoComplete="new-password" autoFocus value={password} onChange={(e) => setPassword(e.target.value)} className="input" />
        </label>
        <label style={{ display: 'block', marginBottom: 22 }}>
          <span className="field-label">Confirm new password</span>
          <input type="password" autoComplete="new-password" value={confirm} onChange={(e) => setConfirm(e.target.value)} className="input" />
        </label>

        {error && <p className="sans" style={{ margin: '0 0 14px', color: '#d98b84', fontSize: '0.85rem', textAlign: 'center' }}>{error}</p>}

        <button type="submit" disabled={busy} className="btn btn-primary" style={{ display: 'block', width: '100%', borderRadius: 8, padding: 12, textAlign: 'center' }}>
          {busy ? 'Saving…' : 'Set new password'}
        </button>
      </form>
    </PlayerShell>
  )
}