import { useState, useEffect, useCallback } from 'react'
import { createPortal } from 'react-dom'
import { X, RefreshCw, Calendar, Power } from 'lucide-react'
import { SubscribeLinks } from './SubscribeLinks'

interface IcsSubscribeModalProps {
  /** Token endpoint base, e.g. `/api/trips/123/feed` or `/api/feed/user`. */
  endpoint: string
  title: string
  description: string
  onClose: () => void
}

// A server that has no APP_URL configured hands back a host-relative path; the
// webcal:// handoff and Google deep link need an absolute URL, so resolve it
// against the current origin as a fallback.
function absolutize(url: string): string {
  if (!url) return ''
  if (/^https?:\/\//i.test(url)) return url
  if (url.startsWith('/')) return window.location.origin + url
  return url
}

/**
 * Shared subscribe dialog for the per-trip and all-trips ICS feeds. Opening it
 * only *reads* the current token — it never mints one silently. The user
 * explicitly enables the public link, and can rotate or fully turn it off.
 */
export function IcsSubscribeModal({ endpoint, title, description, onClose }: IcsSubscribeModalProps) {
  const tokenUrl = `${endpoint}/token`
  const [feedUrl, setFeedUrl] = useState<string | null>(null)
  const [loading, setLoading] = useState(true)
  const [busy, setBusy] = useState(false)

  const httpsUrl = feedUrl ? absolutize(feedUrl) : ''
  const webcalUrl = httpsUrl ? httpsUrl.replace(/^https?:\/\//, 'webcal://') : ''

  const load = useCallback(async () => {
    setLoading(true)
    try {
      const res = await fetch(tokenUrl, { credentials: 'include' })
      if (res.ok) {
        const data = await res.json() as { feed_url: string | null }
        setFeedUrl(data.feed_url)
      }
    } catch { /* ignore */ }
    setLoading(false)
  }, [tokenUrl])

  useEffect(() => { load() }, [load])

  const mutate = async (method: 'POST' | 'PUT' | 'DELETE') => {
    setBusy(true)
    try {
      const res = await fetch(tokenUrl, { method, credentials: 'include' })
      if (res.ok) {
        const data = await res.json() as { feed_url: string | null }
        setFeedUrl(data.feed_url)
      }
    } catch { /* ignore */ }
    setBusy(false)
  }

  return createPortal(
    <div
      role="presentation"
      style={{
        position: 'fixed', inset: 0, zIndex: 9999,
        background: 'rgba(0,0,0,0.5)',
        display: 'flex', alignItems: 'center', justifyContent: 'center',
        padding: '16px',
      }}
      onClick={e => { if (e.target === e.currentTarget) onClose() }}
    >
      <div style={{
        background: 'var(--bg-card, white)',
        borderRadius: 14,
        padding: '22px 24px',
        width: '100%',
        maxWidth: 420,
        boxShadow: '0 16px 48px rgba(0,0,0,0.22)',
        border: '1px solid var(--border-faint)',
        color: 'var(--text-primary)',
        fontFamily: 'inherit',
        position: 'relative',
      }}>
        {/* Header */}
        <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', marginBottom: 14 }}>
          <div style={{ display: 'flex', alignItems: 'center', gap: 8 }}>
            <Calendar size={16} strokeWidth={2} style={{ color: 'var(--accent, #6366f1)' }} />
            <span style={{ fontWeight: 600, fontSize: 14 }}>{title}</span>
          </div>
          <button type="button"
            onClick={onClose}
            style={{
              background: 'none', border: 'none', cursor: 'pointer', padding: 4,
              color: 'var(--text-muted)', borderRadius: 6, display: 'flex',
            }}
          >
            <X size={15} strokeWidth={2} />
          </button>
        </div>

        <p style={{ fontSize: 12, color: 'var(--text-muted)', marginBottom: 16, lineHeight: 1.5 }}>
          {description}
        </p>

        {loading ? (
          <div style={{ textAlign: 'center', padding: '16px 0', color: 'var(--text-muted)', fontSize: 12 }}>
            Loading…
          </div>
        ) : !feedUrl ? (
          <>
            <button type="button"
              onClick={() => mutate('POST')}
              disabled={busy}
              style={{
                display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 8,
                width: '100%', padding: '9px 14px', borderRadius: 9, border: 'none',
                background: 'var(--accent, #6366f1)', color: 'var(--accent-text, #fff)',
                fontSize: 12, fontWeight: 600, fontFamily: 'inherit',
                cursor: busy ? 'default' : 'pointer', opacity: busy ? 0.6 : 1,
              }}
            >
              <Calendar size={14} strokeWidth={2} />
              Enable calendar subscription
            </button>
            <p style={{ fontSize: 10, color: 'var(--text-muted)', marginTop: 8, lineHeight: 1.4 }}>
              Creates a secret link anyone with it can read without logging in. You can turn it off anytime.
            </p>
          </>
        ) : (
          <>
            <SubscribeLinks httpsUrl={httpsUrl} webcalUrl={webcalUrl} />

            <div style={{ marginTop: 16, paddingTop: 12, borderTop: '1px solid var(--border-faint)', display: 'flex', gap: 8 }}>
              <button type="button"
                onClick={() => mutate('PUT')}
                disabled={busy}
                style={{
                  display: 'flex', alignItems: 'center', gap: 6,
                  background: 'none', border: '1px solid var(--border-primary)',
                  borderRadius: 7, padding: '5px 10px',
                  fontSize: 11, color: 'var(--text-muted)',
                  cursor: busy ? 'default' : 'pointer',
                  fontFamily: 'inherit', opacity: busy ? 0.6 : 1,
                }}
              >
                <RefreshCw size={11} strokeWidth={2} style={{ animation: busy ? 'spin 0.8s linear infinite' : 'none' }} />
                Regenerate
              </button>
              <button type="button"
                onClick={() => mutate('DELETE')}
                disabled={busy}
                style={{
                  display: 'flex', alignItems: 'center', gap: 6,
                  background: 'none', border: '1px solid var(--border-primary)',
                  borderRadius: 7, padding: '5px 10px',
                  fontSize: 11, color: 'var(--danger, #dc2626)',
                  cursor: busy ? 'default' : 'pointer',
                  fontFamily: 'inherit', opacity: busy ? 0.6 : 1,
                }}
              >
                <Power size={11} strokeWidth={2} />
                Turn off
              </button>
            </div>
            <p style={{ fontSize: 10, color: 'var(--text-muted)', marginTop: 6, lineHeight: 1.4 }}>
              Regenerating creates a new link and invalidates the old one. Turning off disables the link entirely.
            </p>
          </>
        )}
      </div>

      <style>{`@keyframes spin { to { transform: rotate(360deg); } }`}</style>
    </div>,
  document.body
  )
}