import { useState } from 'react'
import { useNavigate } from 'react-router-dom'
import { useAuth } from '../../contexts/AuthContext.jsx'
import { useSite } from '../../contexts/SiteContext.jsx'
import { api } from '../../api/client.js'
import { showNotice } from '../../lib/notice.js'
import {
  WHAT_GOES, WHAT_STAYS, STAFF_NAME_NOTE, isStaffRole, usernameMatches, isSharedDemoLogin, refusalMessage,
} from '../../lib/accountDeletion.js'

// "Delete my account" (docs/website/ACCOUNT_DELETION.md §4.2). Last on the
// Account page and set apart from the sections above it.
//
// The account goes at once — there is no grace period (AD4) — so the safeguard
// is the confirm step: the typed username, the password, and a two-factor code
// when two-factor is on. Delete stays off until the username matches.
//
// On success the server has already dropped every session. This screen sends
// the browser home, re-reads the session (which is now gone) and says so.

const DANGER = '#d98b84'

export default function DeleteAccountPanel({ account }) {
  const { refresh } = useAuth()
  const { settings } = useSite()
  const navigate = useNavigate()

  const [open, setOpen] = useState(false)
  const [typed, setTyped] = useState('')
  const [password, setPassword] = useState('')
  const [code, setCode] = useState('')
  const [useRecovery, setUseRecovery] = useState(false)
  const [busy, setBusy] = useState(false)
  const [error, setError] = useState('')

  const demoLocked = isSharedDemoLogin(settings, account.username)
  const noPassword = account.has_password === false
  const needsCode = Boolean(account.totp_enabled)
  const ready = usernameMatches(typed, account.username) && password.length > 0 && (!needsCode || code.trim().length > 0)

  function close() {
    setOpen(false)
    setTyped('')
    setPassword('')
    setCode('')
    setUseRecovery(false)
    setError('')
  }

  async function confirm(e) {
    e.preventDefault()
    if (!ready || busy) return
    setBusy(true)
    setError('')
    try {
      await api.deleteMyAccount({
        username: typed.trim(),
        password,
        ...(needsCode ? (useRecovery ? { recoveryCode: code.trim() } : { code: code.trim() }) : {}),
      })
      navigate('/', { replace: true })
      showNotice('Your account has been deleted.')
      await refresh()
    } catch (err) {
      setError(refusalMessage(err))
      setBusy(false)
    }
  }

  return (
    <section
      aria-labelledby="delete-account-heading"
      style={{ borderTop: `1px solid ${DANGER}`, paddingTop: 26, marginTop: 40 }}
    >
      <h2 id="delete-account-heading" className="display" style={{ marginTop: 0, fontSize: '1.15rem', color: DANGER }}>
        Delete my account
      </h2>
      <div className="sans" style={{ color: 'var(--muted)', fontSize: '0.88rem', lineHeight: 1.6, maxWidth: 640 }}>
        <p style={{ marginTop: 0 }}>
          Your account is deleted straight away and cannot be restored. These go with it:
        </p>
        <ul style={{ margin: '0 0 12px', paddingLeft: 20 }}>
          {WHAT_GOES.map((line) => <li key={line}>{line}</li>)}
        </ul>
        <p style={{ margin: '0 0 6px' }}>What stays:</p>
        <ul style={{ margin: '0 0 12px', paddingLeft: 20 }}>
          {WHAT_STAYS.map((line) => <li key={line}>{line}</li>)}
        </ul>
        {isStaffRole(account.role) && <p style={{ margin: '0 0 12px' }}>{STAFF_NAME_NOTE}</p>}
      </div>

      {noPassword && (
        <p className="sans" style={{ color: DANGER, fontSize: '0.86rem' }}>
          This account has no password yet. Set one in the Password section above first; the password is how you
          confirm a deletion.
        </p>
      )}

      {!open && (
        <div>
          <button
            type="button"
            onClick={() => setOpen(true)}
            disabled={demoLocked || noPassword}
            className="btn btn-sq"
            style={{ borderColor: DANGER, color: DANGER }}
          >
            Delete my account…
          </button>
          {demoLocked && (
            <p className="sans dim" style={{ fontSize: '0.82rem', margin: '8px 0 0' }}>
              This is turned off on the demo site.
            </p>
          )}
        </div>
      )}

      {open && (
        <form
          onSubmit={confirm}
          style={{ display: 'flex', flexDirection: 'column', gap: 12, maxWidth: 360, padding: 16, border: `1px solid ${DANGER}`, borderRadius: 10 }}
        >
          <label>
            <span className="field-label">
              Type <strong style={{ color: 'var(--head)' }}>{account.username}</strong> to confirm
            </span>
            <input
              type="text"
              value={typed}
              onChange={(e) => setTyped(e.target.value)}
              className="input"
              autoComplete="off"
              autoCapitalize="none"
              spellCheck={false}
            />
          </label>
          <label>
            <span className="field-label">Password</span>
            <input type="password" value={password} onChange={(e) => setPassword(e.target.value)} className="input" autoComplete="current-password" />
          </label>
          {needsCode && (
            <label>
              <span className="field-label">{useRecovery ? 'Recovery code' : 'Authenticator code'}</span>
              <input
                type="text"
                inputMode={useRecovery ? 'text' : 'numeric'}
                autoComplete="one-time-code"
                value={code}
                onChange={(e) => setCode(e.target.value)}
                className="input"
              />
              <button
                type="button"
                className="pill"
                style={{ marginTop: 8 }}
                onClick={() => { setUseRecovery((v) => !v); setCode('') }}
              >
                {useRecovery ? 'Use an authenticator code instead' : 'Use a recovery code instead'}
              </button>
            </label>
          )}
          <div style={{ display: 'flex', gap: 10, alignItems: 'center', flexWrap: 'wrap' }}>
            <button
              type="submit"
              disabled={!ready || busy}
              className="btn btn-sq"
              style={{ background: ready ? DANGER : undefined, borderColor: DANGER, color: ready ? '#1a1a1a' : DANGER }}
            >
              {busy ? 'Deleting…' : 'Delete my account'}
            </button>
            <button type="button" onClick={close} disabled={busy} className="pill">Cancel</button>
          </div>
          {error && <p role="alert" className="sans" style={{ margin: 0, color: DANGER, fontSize: '0.85rem' }}>{error}</p>}
        </form>
      )}
    </section>
  )
}