"use client"

// Aggregert statistikk på tvers av "Egne runder" (ADR-033), lenket fra
// dashbordets "Statistikk"-seksjon (2026-07-28, utvidet samme dag med
// tidsvindu + miss-retning + forrige-periode-sammenligning). 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) og "forrige periode"-
// vinduet må regnes over ALLE fullførte runder samlet, ikke én 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, TrendingDown, TrendingUp, 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_left_pct: number | null
  fairway_right_pct: number | null
  fairway_tracked_holes: number
  gir_pct: number | null
  gir_tracked_holes: number
  green_miss_long_pct: number | null
  green_miss_short_pct: number | null
  green_miss_left_pct: number | null
  green_miss_right_pct: number | null
  green_miss_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
}

type ApiWindowSummary = {
  window: string
  current: ApiStatsSummary
  previous: ApiStatsSummary
}

type WindowKey = "last_round" | "last_5" | "last_10" | "month" | "year" | "last_year" | "all"

const WINDOW_OPTIONS: { key: WindowKey; label: string }[] = [
  { key: "last_round", label: "Siste runde" },
  { key: "last_5", label: "Siste 5" },
  { key: "last_10", label: "Siste 10" },
  { key: "month", label: "Denne måneden" },
  { key: "year", label: "I år" },
  { key: "last_year", label: "Siste år" },
  { key: "all", label: "Alltid" },
]

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)} %`
}

// Prosentpoeng-differanse mellom to andeler (ikke "N % endring", men "N pp").
function signedPoints(n: number): string {
  const rounded = Math.round(n)
  const sign = rounded > 0 ? "+" : rounded < 0 ? "−" : "±"
  return `${sign}${Math.abs(rounded)} pp`
}

// "up" = høyere tall er bedre (fairwaytreff, GIR, ...), "down" = lavere
// tall er bedre (snitt til par, putt/runde, ...). Utelatt = ren beskrivende
// retning (miss-retning venstre/høyre osv.) -- ingen "bedre/verre" der.
function Delta({
  current,
  previous,
  format,
  goodDirection,
}: {
  current: number | null
  previous: number | null
  format: (diff: number) => string
  goodDirection?: "up" | "down"
}) {
  if (current === null || previous === null) return null
  const diff = current - previous
  if (diff === 0) return <span className="text-xs font-semibold text-muted-foreground">Uendret</span>
  const improved = goodDirection === "up" ? diff > 0 : goodDirection === "down" ? diff < 0 : null
  const Icon = diff > 0 ? TrendingUp : TrendingDown
  const colorClass = improved === true ? "text-primary" : improved === false ? "text-brand-orange" : "text-muted-foreground"
  return (
    <span className={`inline-flex items-center gap-1 text-xs font-bold ${colorClass}`}>
      <Icon aria-hidden="true" className="size-3.5" />
      <span className="tabular-nums">{format(diff)}</span>
      <span className="sr-only">vs. forrige periode</span>
    </span>
  )
}

function StatTile({
  label,
  value,
  hint,
  delta,
}: {
  label: string
  value: string
  hint?: string
  delta?: React.ReactNode
}) {
  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>
      {delta}
      {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>
  )
}

// Horisontal fordelingsbar med retningsandeler (venstre/høyre eller
// lang/kort/venstre/høyre) -- pooler kun faktisk registrerte bom.
function MissBar({
  tracked,
  segments,
}: {
  tracked: number
  segments: { label: string; value: number | null; color: string }[]
}) {
  if (tracked === 0) return <p className="text-sm text-muted-foreground">Ingen retning registrert ennå.</p>
  return (
    <div className="flex flex-col gap-2">
      <div className="flex h-3 w-full overflow-hidden rounded-full bg-muted">
        {segments.map((s) =>
          s.value && s.value > 0 ? (
            <div key={s.label} style={{ width: `${s.value}%`, backgroundColor: s.color }} title={`${s.label}: ${Math.round(s.value)} %`} />
          ) : null,
        )}
      </div>
      <div className="flex flex-wrap gap-x-4 gap-y-1 text-sm text-muted-foreground">
        {segments.map((s) => (
          <span key={s.label} className="inline-flex items-center gap-1.5">
            <span aria-hidden="true" className="size-2.5 rounded-full" style={{ backgroundColor: s.color }} />
            {s.label}: <span className="font-semibold tabular-nums text-foreground">{s.value !== null ? pct(s.value) : "–"}</span>
          </span>
        ))}
      </div>
    </div>
  )
}

export function RoundsStatsSummary() {
  const router = useRouter()
  const [window, setWindow] = useState<WindowKey>("all")
  const [data, setData] = useState<ApiWindowSummary | null>(null)
  const [error, setError] = useState<string | null>(null)

  useEffect(() => {
    let cancelled = false
    async function load() {
      try {
        const res = await fetch(`/rounds/stats/summary?window=${window}`, { credentials: "include" })
        if (res.status === 401) {
          router.replace("/")
          return
        }
        if (!res.ok) throw new Error(`stats: ${res.status}`)
        const json: ApiWindowSummary = 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, window])

  const s = data?.current ?? null

  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">
        <div className="flex gap-2 overflow-x-auto pb-1">
          {WINDOW_OPTIONS.map((opt) => (
            <button
              key={opt.key}
              type="button"
              onClick={() => setWindow(opt.key)}
              className={`min-h-11 shrink-0 rounded-full px-4 text-sm font-bold transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring ${
                window === opt.key ? "bg-primary text-primary-foreground" : "bg-muted text-foreground hover:bg-accent"
              }`}
            >
              {opt.label}
            </button>
          ))}
        </div>

        {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>
        ) : s && s.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 i perioden</h2>
              <p className="text-lg leading-relaxed text-muted-foreground text-pretty">
                Prøv et annet tidsvindu, eller kom tilbake etter neste fullførte runde.
              </p>
            </div>
          </div>
        ) : data ? (
          (() => {
            const s = data.current
            const p = data.previous
            return (
          <>
            <p className="text-base leading-relaxed text-muted-foreground text-pretty">
              Aggregert over {s.rounds_completed} {s.rounds_completed === 1 ? "fullført runde" : "fullførte runder"}
              {p.rounds_completed > 0 && (
                <>
                  {" "}
                  · sammenlignet med {p.rounds_completed} {p.rounds_completed === 1 ? "runde" : "runder"} i perioden før
                </>
              )}
              .
            </p>

            <Section title="Oversikt" icon={BarChart3}>
              <StatTile label="Runder fullført" value={String(s.rounds_completed)} />
              <StatTile
                label="Snitt til par"
                value={s.avg_score_to_par !== null ? signed(s.avg_score_to_par) : "–"}
                delta={<Delta current={s.avg_score_to_par} previous={p.avg_score_to_par} format={signed} goodDirection="down" />}
              />
              <StatTile
                label="Putt / 18 hull"
                value={s.avg_putts_per_18 !== null ? s.avg_putts_per_18.toFixed(1).replace(".", ",") : "–"}
                delta={<Delta current={s.avg_putts_per_18} previous={p.avg_putts_per_18} format={signed} goodDirection="down" />}
                hint={
                  s.putts_tracked_rounds > 0
                    ? `${s.putts_tracked_rounds} ${s.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={s.fairway_hit_pct !== null ? pct(s.fairway_hit_pct) : "–"}
                delta={<Delta current={s.fairway_hit_pct} previous={p.fairway_hit_pct} format={signedPoints} goodDirection="up" />}
                hint={s.fairway_tracked_holes > 0 ? `${s.fairway_tracked_holes} hull registrert` : undefined}
              />
              <StatTile
                label="Greentreff (GIR)"
                value={s.gir_pct !== null ? pct(s.gir_pct) : "–"}
                delta={<Delta current={s.gir_pct} previous={p.gir_pct} format={signedPoints} goodDirection="up" />}
                hint={s.gir_tracked_holes > 0 ? `${s.gir_tracked_holes} hull registrert` : undefined}
              />
              <StatTile
                label="Én-putt"
                value={s.one_putt_pct !== null ? pct(s.one_putt_pct) : "–"}
                delta={<Delta current={s.one_putt_pct} previous={p.one_putt_pct} format={signedPoints} goodDirection="up" />}
              />
            </Section>

            <div className="flex flex-col gap-4 rounded-2xl border border-border bg-card p-4 shadow-sm shadow-black/5">
              <div>
                <h3 className="text-sm font-bold text-foreground">Hvor bommer du fra utslaget?</h3>
                <p className="text-xs text-muted-foreground">Kun par 4/5, kun registrerte utslag.</p>
              </div>
              <MissBar
                tracked={s.fairway_tracked_holes}
                segments={[
                  { label: "Venstre", value: s.fairway_left_pct, color: "var(--chart-5)" },
                  { label: "Fairway", value: s.fairway_hit_pct, color: "var(--primary)" },
                  { label: "Høyre", value: s.fairway_right_pct, color: "var(--chart-4)" },
                ]}
              />
              <div>
                <h3 className="text-sm font-bold text-foreground">Hvor bommer du på innspillet?</h3>
                <p className="text-xs text-muted-foreground">Kun hull der greentreff ble bommet og retning registrert.</p>
              </div>
              <MissBar
                tracked={s.green_miss_tracked_holes}
                segments={[
                  { label: "Langt", value: s.green_miss_long_pct, color: "var(--chart-5)" },
                  { label: "Kort", value: s.green_miss_short_pct, color: "var(--chart-4)" },
                  { label: "Venstre", value: s.green_miss_left_pct, color: "var(--chart-6)" },
                  { label: "Høyre", value: s.green_miss_right_pct, color: "var(--info)" },
                ]}
              />
            </div>

            <Section title="Redning" icon={Target}>
              <StatTile
                label="Scrambling"
                value={s.scrambling_pct !== null ? pct(s.scrambling_pct) : "–"}
                delta={<Delta current={s.scrambling_pct} previous={p.scrambling_pct} format={signedPoints} goodDirection="up" />}
                hint="Par eller bedre uten GIR"
              />
              <StatTile
                label="Sand save"
                value={s.sand_save_pct !== null ? pct(s.sand_save_pct) : "–"}
                delta={<Delta current={s.sand_save_pct} previous={p.sand_save_pct} format={signedPoints} goodDirection="up" />}
                hint="Par eller bedre fra bunker"
              />
            </Section>

            <Section title="Chip, bunker og straffeslag" icon={Waves}>
              <StatTile
                label="Chip / runde"
                value={s.avg_chip_per_round !== null ? s.avg_chip_per_round.toFixed(1).replace(".", ",") : "–"}
                delta={<Delta current={s.avg_chip_per_round} previous={p.avg_chip_per_round} format={signed} goodDirection="down" />}
              />
              <StatTile
                label="Bunkerslag / runde"
                value={s.avg_bunker_per_round !== null ? s.avg_bunker_per_round.toFixed(1).replace(".", ",") : "–"}
                delta={<Delta current={s.avg_bunker_per_round} previous={p.avg_bunker_per_round} format={signed} goodDirection="down" />}
              />
              <StatTile
                label="Straffeslag / runde"
                value={s.avg_penalty_per_round !== null ? s.avg_penalty_per_round.toFixed(1).replace(".", ",") : "–"}
                delta={<Delta current={s.avg_penalty_per_round} previous={p.avg_penalty_per_round} format={signed} goodDirection="down" />}
              />
            </Section>

            {s.avg_anyway_per_round !== null && (
              <Section title="Annet" icon={Wind}>
                <StatTile
                  label="Anywayslag / runde"
                  value={s.avg_anyway_per_round.toFixed(1).replace(".", ",")}
                  delta={<Delta current={s.avg_anyway_per_round} previous={p.avg_anyway_per_round} format={signed} goodDirection="down" />}
                />
              </Section>
            )}
          </>
            )
          })()
        ) : null}
      </main>
    </div>
  )
}