'use client'
import { useQuery, gql } from '@/lib/graphql/hooks'
import { useEffect } from 'react'
import Link from 'next/link'
import { TeamFlag } from '@/components/team-flag'

const GROUPS_QUERY = gql`
  query Groups {
    groupStandings(year: 2026) {
      groupName pos played won drawn lost goalsFor goalsAgainst goalDiff pts
      team { id name iso2 slug }
    }
    matches(year: 2026, isQuali: false) {
      id group date time isLive scoreFt
      team1 { name iso2 slug } team2 { name iso2 slug }
    }
  }
`

interface Standing {
  groupName: string; pos?: number | null
  played: number; won: number; drawn: number; lost: number
  goalsFor: number; goalsAgainst: number; goalDiff: number; pts: number
  team: { id: number; name: string; iso2?: string | null; slug: string }
}

interface MatchRow {
  id: number; group?: string | null; date?: string | null; time?: string | null
  isLive: boolean; scoreFt?: number[] | null
  team1: { name: string; iso2?: string | null; slug: string }
  team2: { name: string; iso2?: string | null; slug: string }
}

function utcKickoff(date: string, time: string): number {
  const m = time.match(/^(\d{2}):(\d{2})(?:\s+UTC([+-]\d+(?:\.\d+)?))?/)
  if (!m) return new Date(date).getTime()
  const [y, mo, d] = date.split('-').map(Number)
  const offsetH = m[3] ? parseFloat(m[3]) : 0
  return Date.UTC(y, mo - 1, d, parseInt(m[1]) - offsetH, parseInt(m[2]))
}

function formatKickoff(date: string, time: string | null | undefined): string {
  if (!time) return new Date(date + 'T00:00:00').toLocaleDateString('en-GB', { weekday: 'short', day: 'numeric', month: 'short' })
  const ms = utcKickoff(date, time)
  const local = new Date(ms)
  const today = new Date()
  const tomorrow = new Date(today); tomorrow.setDate(today.getDate() + 1)
  const isToday = local.toDateString() === today.toDateString()
  const isTomorrow = local.toDateString() === tomorrow.toDateString()
  const day = isToday ? 'Today' : isTomorrow ? 'Tomorrow'
    : local.toLocaleDateString('en-GB', { weekday: 'short', day: 'numeric', month: 'short' })
  return `${day} · ${local.toLocaleTimeString('en-GB', { hour: '2-digit', minute: '2-digit' })}`
}

export default function GroupsPage() {
  const { data, loading } = useQuery(GROUPS_QUERY, { pollInterval: 60_000 })

  useEffect(() => { document.title = 'Group Stage · World Cup' }, [])

  const standings: Standing[] = data?.groupStandings ?? []
  const allMatches: MatchRow[] = data?.matches ?? []

  const byGroup = standings.reduce<Record<string, Standing[]>>((acc, s) => {
    acc[s.groupName] = [...(acc[s.groupName] ?? []), s]
    return acc
  }, {})

  const matchesByGroup = allMatches
    .filter(m => m.group)
    .reduce<Record<string, MatchRow[]>>((acc, m) => {
      acc[m.group!] = [...(acc[m.group!] ?? []), m]
      return acc
    }, {})

  const groups = Object.entries(byGroup).sort(([a], [b]) => a.localeCompare(b))

  return (
    <div className="max-w-[1200px] mx-auto px-7 py-10 pb-16">
      <div className="mb-9">
        <h1 className="font-['Bebas_Neue'] text-[52px] tracking-[0.04em] text-green leading-none">2026 Groups</h1>
        <p className="text-green-muted text-sm mt-1.5">48 teams · 12 groups · Top 2 + 8 best 3rd-place advance</p>
      </div>

      {loading && !data && (
        <div className="grid grid-cols-[repeat(auto-fill,minmax(300px,1fr))] gap-3.5">
          {Array.from({ length: 12 }).map((_, i) => (
            <div key={i} className="h-72 rounded-2xl animate-pulse bg-card" />
          ))}
        </div>
      )}

      <div className="grid grid-cols-[repeat(auto-fill,minmax(300px,1fr))] gap-3.5">
        {groups.map(([groupName, rows]) => {
          const sorted = [...rows].sort((a, b) => {
            if (b.pts !== a.pts) return b.pts - a.pts
            if (b.goalDiff !== a.goalDiff) return b.goalDiff - a.goalDiff
            return b.goalsFor - a.goalsFor
          })
          const letter = groupName.replace('Group ', '')

          const groupMatches = (matchesByGroup[groupName] ?? [])
            .sort((a, b) => {
              if (!a.date) return 1
              if (!b.date) return -1
              const ta = a.time ? utcKickoff(a.date, a.time) : new Date(a.date).getTime()
              const tb = b.time ? utcKickoff(b.date!, b.time) : new Date(b.date!).getTime()
              return ta - tb
            })
          const played = groupMatches.filter(m => m.scoreFt)
          const upcoming = groupMatches.filter(m => !m.scoreFt && !m.isLive)
          const live = groupMatches.filter(m => m.isLive)

          return (
            <div key={groupName} className="glass-card">
              {/* Header */}
              <div className="px-4 py-3 border-b border-green/10"
                style={{ background: 'linear-gradient(90deg,color-mix(in srgb,var(--color-green) 12%,transparent) 0%,color-mix(in srgb,var(--color-green) 4%,transparent) 100%)' }}>
                <span className="font-['Bebas_Neue'] text-[28px] text-green tracking-[0.05em]">GROUP {letter}</span>
              </div>

              {/* Standings */}
              <div className="grid px-4 py-2 text-[9px] text-green-muted tracking-[0.1em] uppercase"
                style={{ gridTemplateColumns: '1fr 22px 22px 22px 22px 22px 30px', gap: '3px' }}>
                <span>Team</span>
                <span className="text-center">P</span><span className="text-center">W</span>
                <span className="text-center">D</span><span className="text-center">L</span>
                <span className="text-center">GD</span><span className="text-center">Pts</span>
              </div>
              {sorted.map((t, idx) => (
                <Link key={t.team.id} href={`/teams/${t.team.slug}`}>
                  <div className={`grid px-4 py-2.5 items-center border-t border-green/[6%] hover:bg-green/[3%] transition-colors cursor-pointer ${idx < 2 ? 'bg-green/[2.5%]' : ''}`}
                    style={{ gridTemplateColumns: '1fr 22px 22px 22px 22px 22px 30px', gap: '3px' }}>
                    <div className="flex items-center gap-2 overflow-hidden">
                      <TeamFlag name={t.team.name} iso2={t.team.iso2} size="sm" />
                      <span className={`text-sm truncate font-medium ${idx < 2 ? 'text-text' : 'text-green-sec'}`}>{t.team.name}</span>
                    </div>
                    {[t.played, t.won, t.drawn, t.lost].map((v, i) => (
                      <span key={i} className="text-center text-[13px] text-green-mid">{v}</span>
                    ))}
                    <span className="text-center text-[13px] text-green-mid">
                      {t.goalDiff > 0 ? `+${t.goalDiff}` : t.goalDiff}
                    </span>
                    <span className="text-center text-[13px] font-bold text-green">{t.pts}</span>
                  </div>
                </Link>
              ))}

              {/* Live matches */}
              {live.length > 0 && (
                <div className="border-t border-green/10 px-4 py-2.5 space-y-1.5">
                  {live.map(m => (
                    <Link key={m.id} href={`/tournaments/2026#match-${m.id}`}>
                      <div className="flex items-center gap-2 py-1 hover:opacity-80">
                        <span className="text-[9px] font-bold text-green-light tracking-wider animate-pulse">LIVE</span>
                        <TeamFlag name={m.team1.name} iso2={m.team1.iso2} size="sm" />
                        <span className="text-[12px] text-text font-medium">{m.team1.name}</span>
                        <span className="text-[11px] text-green-muted mx-0.5">vs</span>
                        <span className="text-[12px] text-text font-medium">{m.team2.name}</span>
                        <TeamFlag name={m.team2.name} iso2={m.team2.iso2} size="sm" />
                      </div>
                    </Link>
                  ))}
                </div>
              )}

              {/* Results */}
              {played.length > 0 && (
                <div className="border-t border-green/10 px-4 py-2.5 space-y-1">
                  {played.map(m => (
                    <Link key={m.id} href={`/tournaments/2026#match-${m.id}`}>
                      <div className="flex items-center gap-2 py-1 text-[12px] hover:opacity-80">
                        <TeamFlag name={m.team1.name} iso2={m.team1.iso2} size="sm" />
                        <span className="text-green-sec truncate flex-1">{m.team1.name}</span>
                        <span className="font-['Bebas_Neue'] text-[15px] text-green tabular-nums">
                          {m.scoreFt![0]}–{m.scoreFt![1]}
                        </span>
                        <span className="text-green-sec truncate flex-1 text-right">{m.team2.name}</span>
                        <TeamFlag name={m.team2.name} iso2={m.team2.iso2} size="sm" />
                      </div>
                    </Link>
                  ))}
                </div>
              )}

              {/* Upcoming */}
              {upcoming.length > 0 && (
                <div className="border-t border-green/[6%] px-4 py-2.5 space-y-1">
                  {upcoming.map(m => (
                    <Link key={m.id} href={`/tournaments/2026#match-${m.id}`}>
                      <div className="flex items-center gap-2 py-1 text-[12px] hover:opacity-80">
                        <TeamFlag name={m.team1.name} iso2={m.team1.iso2} size="sm" />
                        <span className="text-green-sec truncate flex-1">{m.team1.name}</span>
                        <span className="text-[10px] text-green-muted whitespace-nowrap tabular-nums">
                          {m.date ? formatKickoff(m.date, m.time) : '–'}
                        </span>
                        <span className="text-green-sec truncate flex-1 text-right">{m.team2.name}</span>
                        <TeamFlag name={m.team2.name} iso2={m.team2.iso2} size="sm" />
                      </div>
                    </Link>
                  ))}
                </div>
              )}
            </div>
          )
        })}
      </div>
    </div>
  )
}