'use client'

import { useEffect, useState } from 'react'
import Link from 'next/link'
import { Loader2 } from 'lucide-react'
import { formatClock, formatEventDate, formatMoney } from '@/lib/event-types'

interface Entry {
  registration: string
  registration_status: string
  payment_status: string
  amount_due: number
  amount_paid: number
  currency: string
  can_pay: boolean
  next_action?: string
  runner: { first_name?: string; full_name?: string }
  edition: { edition_name?: string; event_date?: string | null; venue?: string; county?: string }
  race: { category_name?: string; distance_label?: string; start_time?: string | null }
  bib_number: string | null
  race_pack_status: string
  check_in_status: string
  result: { finish_status: string; chip_time: number | null; gun_time: number | null; overall_rank?: number } | null
  payments: { date: string; method: string | null; amount: number; status: string; reference: string }[]
}

const STORE = 'lukenya-my-race-token'

function duration(seconds: number | null) {
  if (!seconds) return null
  const s = Math.round(seconds)
  return `${Math.floor(s / 3600)}:${String(Math.floor((s % 3600) / 60)).padStart(2, '0')}:${String(s % 60).padStart(2, '0')}`
}

async function post<T>(url: string, body: unknown): Promise<T> {
  const res = await fetch(url, { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify(body) })
  const data = await res.json().catch(() => ({}))
  if (!res.ok) throw new Error(data.error || 'Something went wrong. Please try again.')
  return data as T
}

export function MyRaceView() {
  const [token, setToken] = useState<string | null>(null)
  const [entry, setEntry] = useState<Entry | null>(null)
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState<string | null>(null)
  const [email, setEmail] = useState('')
  const [sent, setSent] = useState<string | null>(null)
  const [paying, setPaying] = useState(false)

  useEffect(() => {
    // Take the token out of the address bar so it isn't shared by accident, and keep it for this tab.
    const url = new URL(window.location.href)
    const fromUrl = url.searchParams.get('token')
    if (fromUrl) {
      try { sessionStorage.setItem(STORE, fromUrl) } catch { /* private mode */ }
      url.searchParams.delete('token')
      window.history.replaceState(null, '', url.pathname + url.search)
    }
    let saved: string | null = fromUrl
    if (!saved) {
      try { saved = sessionStorage.getItem(STORE) } catch { saved = null }
    }
    setToken(saved)
    if (!saved) {
      setLoading(false)
      return
    }
    post<Entry>('/api/my-race', { token: saved })
      .then(setEntry)
      .catch((err) => {
        setError((err as Error).message)
        try { sessionStorage.removeItem(STORE) } catch { /* ignore */ }
      })
      .finally(() => setLoading(false))
  }, [])

  const requestLink = async () => {
    setError(null)
    try {
      const res = await post<{ message: string }>('/api/my-race', { email })
      setSent(res.message)
    } catch (err) {
      setError((err as Error).message)
    }
  }

  const pay = async () => {
    if (!entry || !token) return
    setPaying(true)
    setError(null)
    try {
      const res = await post<{ authorization_url: string }>('/api/payment/start', {
        registration: entry.registration,
        payment_token: token,
        channel: 'mpesa',
      })
      window.location.assign(res.authorization_url)
    } catch (err) {
      setError((err as Error).message)
      setPaying(false)
    }
  }

  const card = 'max-w-[560px] mx-auto bg-white rounded-xl shadow-[0_2px_16px_rgba(0,0,0,0.08)] p-6 md:p-10'

  if (loading) {
    return (
      <div className={`${card} text-center`}>
        <Loader2 className="w-10 h-10 text-[#006838] mx-auto animate-spin" />
        <p className="font-sans text-[#687279] mt-4">Loading your entry…</p>
      </div>
    )
  }

  if (!entry) {
    return (
      <div className={card}>
        <h1 className="font-heading font-bold text-[#111518] text-[26px] mb-2">My Race</h1>
        <p className="font-sans text-[#687279] text-[15px] mb-6">
          Enter the email you registered with and we&apos;ll send you a private link to your entry.
        </p>
        {error && <p role="alert" className="mb-4 font-sans text-[13px] text-[#c0392b]">{error}</p>}
        {sent ? (
          <p className="font-sans text-[#006838] text-[15px]">{sent}</p>
        ) : (
          <div className="flex flex-col sm:flex-row gap-3">
            <label htmlFor="my-race-email" className="sr-only">Email</label>
            <input
              id="my-race-email"
              type="email"
              value={email}
              onChange={(e) => setEmail(e.target.value)}
              placeholder="you@example.com"
              className="flex-1 px-4 h-12 rounded-lg border border-[#D1D5DB] font-sans text-[15px] focus:border-[#006838] focus:ring-2 focus:ring-[rgba(0,104,56,0.12)] outline-none"
            />
            <button
              onClick={requestLink}
              disabled={!email.includes('@')}
              className="h-12 px-6 rounded-lg bg-[#006838] text-white font-heading font-bold text-sm disabled:bg-[#E5E7EB] disabled:text-[#687279]"
            >
              Email my link
            </button>
          </div>
        )}
      </div>
    )
  }

  const confirmed = entry.registration_status === 'Confirmed' || entry.registration_status === 'Completed'
  const balance = Math.max(entry.amount_due - entry.amount_paid, 0)
  const rows: [string, string | null | undefined][] = [
    ['Race', [entry.race.distance_label, entry.race.category_name].filter(Boolean).join(' ')],
    ['Race day', [formatEventDate(entry.edition.event_date), formatClock(entry.race.start_time) && `start ${formatClock(entry.race.start_time)}`].filter(Boolean).join(', ')],
    ['Venue', [entry.edition.venue, entry.edition.county].filter(Boolean).join(', ')],
    ['Entry', entry.registration],
    ['Bib', entry.bib_number || 'Not allocated yet'],
    ['Race pack', entry.race_pack_status],
    ['Check-in', entry.check_in_status],
  ]

  return (
    <div className={card}>
      <p className="font-sans text-[#687279] text-[14px]">{entry.edition.edition_name}</p>
      <h1 className="font-heading font-bold text-[#111518] text-[26px] mb-1">
        {entry.runner.first_name ? `${entry.runner.first_name}, ` : ''}
        {confirmed ? "you're in." : 'your entry is not confirmed yet.'}
      </h1>
      <p className="font-sans text-[15px] mb-6 text-[#687279]">
        {confirmed
          ? `Paid ${formatMoney(entry.amount_paid, entry.currency) || ''}.`
          : balance > 0
            ? `${formatMoney(balance, entry.currency)} is still to pay. Your place is confirmed once payment reaches us.`
            : `Status: ${entry.registration_status}.`}
      </p>

      {entry.next_action && (
        <p className="mb-6 rounded-lg bg-[#F2F8F4] border border-[#3BB34A]/30 px-4 py-3 font-sans text-[14px] text-[#111518]">
          <span className="font-heading font-bold text-[#006838]">Next: </span>{entry.next_action}
        </p>
      )}

      {entry.can_pay && (
        <button
          onClick={pay}
          disabled={paying}
          className="w-full h-12 mb-6 rounded-lg bg-[#FFF100] text-[#714508] font-heading font-bold text-sm uppercase tracking-wide hover:bg-[#3BB34A] hover:text-white inline-flex items-center justify-center gap-2"
        >
          {paying && <Loader2 className="w-4 h-4 animate-spin" />}
          {paying ? 'Opening payment…' : `Pay ${formatMoney(balance, entry.currency)}`}
        </button>
      )}
      {error && <p role="alert" className="mb-4 font-sans text-[13px] text-[#c0392b]">{error}</p>}

      <dl className="divide-y divide-[#E5E7EB] border-y border-[#E5E7EB]">
        {rows.map(([label, value]) => (
          <div key={label} className="flex justify-between gap-4 py-3">
            <dt className="font-heading font-semibold text-[13px] text-[#687279]">{label}</dt>
            <dd className="font-sans text-[14px] text-[#111518] text-right">{value || '—'}</dd>
          </div>
        ))}
        {entry.result && (
          <div className="flex justify-between gap-4 py-3">
            <dt className="font-heading font-semibold text-[13px] text-[#687279]">Result</dt>
            <dd className="font-sans text-[14px] text-[#111518] text-right">
              {entry.result.finish_status}
              {duration(entry.result.chip_time || entry.result.gun_time) ? `, ${duration(entry.result.chip_time || entry.result.gun_time)}` : ''}
              {entry.result.overall_rank ? `, position ${entry.result.overall_rank}` : ''}
            </dd>
          </div>
        )}
      </dl>

      {entry.payments.length > 0 && (
        <div className="mt-6">
          <h2 className="font-heading font-bold text-[#111518] text-[15px] mb-2">Payments</h2>
          <ul className="space-y-1">
            {entry.payments.map((p) => (
              <li key={p.reference || p.date} className="flex justify-between font-sans text-[13px] text-[#687279]">
                <span>{formatEventDate(p.date)} · {p.method || 'Online'}</span>
                <span>{formatMoney(p.amount, entry.currency)} · {p.status}</span>
              </li>
            ))}
          </ul>
        </div>
      )}

      <p className="mt-8 font-sans text-[12px] text-[#687279]">
        This page is private to you. Don&apos;t share the link from your email.{' '}
        <Link href="/race-info" className="text-[#006838] underline">Race information</Link>
      </p>
    </div>
  )
}