"use client"

// Aggregert statistikk på tvers av ALLE fullførte "Egne runder" (ADR-033),
// lenket fra dashbordets "Statistikk"-seksjon (2026-07-28). Egen backend-
// aggregering (GET /rounds/stats/summary) -- ikke bare klientside-utledning
// av round-stats.tsx sin logikk, siden putt/18-hull-regelen (padding av
// uspilte hull til 2 putter, KUN for dette tallet) må kjøre over ALLE
// fullførte runder samlet, ikke én runde om gangen.

import type React from "react"
import { useEffect, useState } from "react"
import { useRouter } from "next/navigation"
import Link from "next/link"
import { ArrowLeft, BarChart3, Flag, Target, Waves, Wind } from "lucide-react"

type ApiStatsSummary = {
  rounds_completed: number
  avg_score_to_par: number | null
  avg_putts_per_18: number | null
  putts_tracked_rounds: number
  fairway_hit_pct: number | null
  fairway_tracked_holes: number
  gir_pct: number | null
  gir_tracked_holes: number
  one_putt_pct: number | null
  scrambling_pct: number | null
  sand_save_pct: number | null
  avg_chip_per_round: number | null
  avg_bunker_per_round: number | null
  avg_penalty_per_round: number | null
  avg_anyway_per_round: number | null
}

function signed(n: number): string {
  const sign = n > 0 ? "+" : n < 0 ? "−" : "±"
  return `${sign}${Math.abs(n).toFixed(1).replace(".", ",")}`
}

function pct(n: number): string {
  return `${Math.round(n)} %`
}

function StatTile({ label, value, hint }: { label: string; value: string; hint?: string }) {
  return (
    <div className="flex flex-col gap-1 rounded-2xl border border-border bg-card p-4 shadow-sm shadow-black/5">
      <span className="text-xs font-semibold uppercase tracking-wide text-muted-foreground">{label}</span>
      <span className="text-2xl font-extrabold tabular-nums text-foreground sm:text-3xl">{value}</span>
      {hint && <span className="text-xs text-muted-foreground">{hint}</span>}
    </div>
  )
}

function Section({
  title,
  icon: Icon,
  children,
}: {
  title: string
  icon: typeof BarChart3
  children: React.ReactNode
}) {
  return (
    <section className="flex flex-col gap-3">
      <h2 className="flex items-center gap-2 text-lg font-extrabold tracking-tight text-foreground">
        <Icon aria-hidden="true" className="size-5 text-primary" />
        {title}
      </h2>
      <div className="grid grid-cols-2 gap-3 sm:grid-cols-3">{children}</div>
    </section>
  )
}

export function RoundsStatsSummary() {
  const router = useRouter()
  const [data, setData] = useState<ApiStatsSummary | null>(null)
  const [error, setError] = useState<string | null>(null)

  useEffect(() => {
    let cancelled = false
    async function load() {
      try {
        const res = await fetch("/rounds/stats/summary", { credentials: "include" })
        if (res.status === 401) {
          router.replace("/")
          return
        }
        if (!res.ok) throw new Error(`stats: ${res.status}`)
        const json: ApiStatsSummary = await res.json()
        if (!cancelled) setData(json)
      } catch {
        if (!cancelled) setError("Klarte ikke å hente statistikken. Prøv igjen om litt.")
      }
    }
    void load()
    return () => {
      cancelled = true
    }
  }, [router])

  return (
    <div className="flex min-h-[100dvh] flex-col bg-background">
      <header className="sticky top-0 z-10 border-b border-border bg-background/95 backdrop-blur">
        <div className="mx-auto flex min-h-14 max-w-xl items-center gap-2 px-4 py-2">
          <Link
            href="/dashboard"
            aria-label="Til dashbord"
            className="flex size-11 shrink-0 items-center justify-center rounded-xl text-muted-foreground transition-colors hover:bg-accent/50 hover:text-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring"
          >
            <ArrowLeft aria-hidden="true" className="size-6" />
          </Link>
          <h1 className="text-lg font-extrabold tracking-tight text-foreground">Statistikk</h1>
        </div>
      </header>

      <main className="mx-auto flex w-full max-w-xl flex-1 flex-col gap-8 px-4 py-6 pb-16">
        {error && (
          <p role="alert" className="text-base font-medium text-destructive">
            {error}
          </p>
        )}

        {data === null && !error ? (
          <div role="status" aria-live="polite" className="flex flex-col items-center justify-center gap-4 py-20 text-center">
            <div aria-hidden="true" className="size-9 animate-spin rounded-full border-4 border-primary/20 border-t-primary" />
            <span className="text-base font-medium text-muted-foreground">Laster statistikk…</span>
          </div>
        ) : data && data.rounds_completed === 0 ? (
          <div className="flex flex-col items-center gap-5 rounded-3xl border border-dashed border-border bg-card/50 px-6 py-16 text-center">
            <div className="flex size-16 items-center justify-center rounded-2xl bg-primary/15">
              <BarChart3 aria-hidden="true" className="size-8 text-primary" />
            </div>
            <div className="flex max-w-md flex-col gap-2">
              <h2 className="text-xl font-bold text-foreground">Ingen fullførte runder ennå</h2>
              <p className="text-lg leading-relaxed text-muted-foreground text-pretty">
                Statistikken bygger seg opp automatisk etter hvert som du fullfører runder.
              </p>
            </div>
          </div>
        ) : data ? (
          <>
            <p className="text-base leading-relaxed text-muted-foreground text-pretty">
              Aggregert over {data.rounds_completed} {data.rounds_completed === 1 ? "fullført runde" : "fullførte runder"}.
            </p>

            <Section title="Oversikt" icon={BarChart3}>
              <StatTile label="Runder fullført" value={String(data.rounds_completed)} />
              <StatTile label="Snitt til par" value={data.avg_score_to_par !== null ? signed(data.avg_score_to_par) : "–"} />
              <StatTile
                label="Putt / 18 hull"
                value={data.avg_putts_per_18 !== null ? data.avg_putts_per_18.toFixed(1).replace(".", ",") : "–"}
                hint={
                  data.putts_tracked_rounds > 0
                    ? `${data.putts_tracked_rounds} ${data.putts_tracked_rounds === 1 ? "runde med" : "runder med"} puttsporing`
                    : "Ingen runder med puttsporing ennå"
                }
              />
            </Section>

            <Section title="Fairway og green" icon={Flag}>
              <StatTile
                label="Fairwaytreff"
                value={data.fairway_hit_pct !== null ? pct(data.fairway_hit_pct) : "–"}
                hint={data.fairway_tracked_holes > 0 ? `${data.fairway_tracked_holes} hull registrert` : undefined}
              />
              <StatTile
                label="Greentreff (GIR)"
                value={data.gir_pct !== null ? pct(data.gir_pct) : "–"}
                hint={data.gir_tracked_holes > 0 ? `${data.gir_tracked_holes} hull registrert` : undefined}
              />
              <StatTile label="Én-putt" value={data.one_putt_pct !== null ? pct(data.one_putt_pct) : "–"} />
            </Section>

            <Section title="Redning" icon={Target}>
              <StatTile
                label="Scrambling"
                value={data.scrambling_pct !== null ? pct(data.scrambling_pct) : "–"}
                hint="Par eller bedre uten GIR"
              />
              <StatTile
                label="Sand save"
                value={data.sand_save_pct !== null ? pct(data.sand_save_pct) : "–"}
                hint="Par eller bedre fra bunker"
              />
            </Section>

            <Section title="Chip, bunker og straffeslag" icon={Waves}>
              <StatTile label="Chip / runde" value={data.avg_chip_per_round !== null ? data.avg_chip_per_round.toFixed(1).replace(".", ",") : "–"} />
              <StatTile label="Bunkerslag / runde" value={data.avg_bunker_per_round !== null ? data.avg_bunker_per_round.toFixed(1).replace(".", ",") : "–"} />
              <StatTile label="Straffeslag / runde" value={data.avg_penalty_per_round !== null ? data.avg_penalty_per_round.toFixed(1).replace(".", ",") : "–"} />
            </Section>

            {data.avg_anyway_per_round !== null && (
              <Section title="Annet" icon={Wind}>
                <StatTile label="Anywayslag / runde" value={data.avg_anyway_per_round.toFixed(1).replace(".", ",")} />
              </Section>
            )}
          </>
        ) : null}
      </main>
    </div>
  )
}