"use client";

import Link from "next/link";
import { useEffect, useMemo, useState } from "react";
import { useI18n } from "@/lib/i18n/useI18n";

type Heartbeat = {
  ts: string;
  tsServer?: string | null;
  status: string;
  message?: string | null;
  ip?: string | null;
  fwVersion?: string | null;
};

type Kpi = {
  ts: string;
  oee?: number | null;
  availability?: number | null;
  performance?: number | null;
  quality?: number | null;
  workOrderId?: string | null;
  sku?: string | null;
  good?: number | null;
  scrap?: number | null;
  target?: number | null;
  cycleTime?: number | null;
};

type MachineRow = {
  id: string;
  name: string;
  code?: string | null;
  location?: string | null;
  latestHeartbeat: Heartbeat | null;
  latestKpi?: Kpi | null;
};

type EventRow = {
  id: string;
  ts: string;
  topic?: string;
  eventType: string;
  severity: string;
  title: string;
  description?: string | null;
  requiresAck: boolean;
  machineId?: string;
  machineName?: string;
  source: "ingested";
};

const OFFLINE_MS = 30000;
const MAX_EVENT_MACHINES = 6;

function secondsAgo(ts: string | undefined, locale: string, fallback: string) {
  if (!ts) return fallback;
  const diff = Math.floor((Date.now() - new Date(ts).getTime()) / 1000);
  const rtf = new Intl.RelativeTimeFormat(locale, { numeric: "auto" });
  if (diff < 60) return rtf.format(-diff, "second");
  if (diff < 3600) return rtf.format(-Math.floor(diff / 60), "minute");
  return rtf.format(-Math.floor(diff / 3600), "hour");
}

function isOffline(ts?: string) {
  if (!ts) return true;
  return Date.now() - new Date(ts).getTime() > OFFLINE_MS;
}

function normalizeStatus(status?: string) {
  const s = (status ?? "").toUpperCase();
  if (s === "ONLINE") return "RUN";
  return s;
}

function heartbeatTime(hb?: Heartbeat | null) {
  return hb?.tsServer ?? hb?.ts;
}

function fmtPct(v?: number | null) {
  if (v === null || v === undefined || Number.isNaN(v)) return "--";
  return `${v.toFixed(1)}%`;
}

function fmtNum(v?: number | null) {
  if (v === null || v === undefined || Number.isNaN(v)) return "--";
  return `${Math.round(v)}`;
}

function severityClass(sev?: string) {
  const s = (sev ?? "").toLowerCase();
  if (s === "critical") return "bg-red-500/15 text-red-300";
  if (s === "warning") return "bg-yellow-500/15 text-yellow-300";
  if (s === "info") return "bg-blue-500/15 text-blue-300";
  return "bg-white/10 text-zinc-200";
}

function sourceClass(src: EventRow["source"]) {
  if (src === "ingested") return "bg-white/10 text-zinc-200";
  return "bg-white/10 text-zinc-200";
}

export default function OverviewClient({
  initialMachines = [],
  initialEvents = [],
}: {
  initialMachines?: MachineRow[];
  initialEvents?: EventRow[];
}) {
  const { t, locale } = useI18n();
  const [machines, setMachines] = useState<MachineRow[]>(() => initialMachines);
  const [events, setEvents] = useState<EventRow[]>(() => initialEvents);
  const [loading, setLoading] = useState(false);
  const [eventsLoading, setEventsLoading] = useState(false);

  useEffect(() => {
    let alive = true;

    async function load() {
      try {
        setEventsLoading(true);
        const res = await fetch(`/api/overview?events=critical&eventMachines=${MAX_EVENT_MACHINES}`, {
          cache: "no-cache",
        });
        if (res.status === 304) {
          if (alive) setLoading(false);
          return;
        }
        const json = await res.json().catch(() => ({}));
        if (!alive) return;
        setMachines(json.machines ?? []);
        setEvents(json.events ?? []);
        setLoading(false);
      } catch {
        if (!alive) return;
        setMachines([]);
        setEvents([]);
        setLoading(false);
      } finally {
        if (alive) setEventsLoading(false);
      }
    }

    load();
    const t = setInterval(load, 30000);
    return () => {
      alive = false;
      clearInterval(t);
    };
  }, []);

  const stats = useMemo(() => {
    const total = machines.length;
    let online = 0;
    let running = 0;
    let idle = 0;
    let stopped = 0;
    let oeeSum = 0;
    let oeeCount = 0;
    let availSum = 0;
    let availCount = 0;
    let perfSum = 0;
    let perfCount = 0;
    let qualSum = 0;
    let qualCount = 0;
    let goodSum = 0;
    let scrapSum = 0;
    let targetSum = 0;

    for (const m of machines) {
      const hb = m.latestHeartbeat;
      const offline = isOffline(heartbeatTime(hb));
      if (!offline) online += 1;

      const status = normalizeStatus(hb?.status);
      if (!offline) {
        if (status === "RUN") running += 1;
        else if (status === "IDLE") idle += 1;
        else if (status === "STOP" || status === "DOWN") stopped += 1;
      }

      const k = m.latestKpi;
      if (k?.oee != null) {
        oeeSum += Number(k.oee);
        oeeCount += 1;
      }
      if (k?.availability != null) {
        availSum += Number(k.availability);
        availCount += 1;
      }
      if (k?.performance != null) {
        perfSum += Number(k.performance);
        perfCount += 1;
      }
      if (k?.quality != null) {
        qualSum += Number(k.quality);
        qualCount += 1;
      }
      if (k?.good != null) goodSum += Number(k.good);
      if (k?.scrap != null) scrapSum += Number(k.scrap);
      if (k?.target != null) targetSum += Number(k.target);
    }

    return {
      total,
      online,
      offline: total - online,
      running,
      idle,
      stopped,
      oee: oeeCount ? oeeSum / oeeCount : null,
      availability: availCount ? availSum / availCount : null,
      performance: perfCount ? perfSum / perfCount : null,
      quality: qualCount ? qualSum / qualCount : null,
      goodSum,
      scrapSum,
      targetSum,
    };
  }, [machines]);

  const attention = useMemo(() => {
    const list = machines
      .map((m) => {
        const hb = m.latestHeartbeat;
        const offline = isOffline(heartbeatTime(hb));
        const k = m.latestKpi;
        const oee = k?.oee ?? null;
        let score = 0;
        if (offline) score += 100;
        if (oee != null && oee < 75) score += 50;
        if (oee != null && oee < 85) score += 25;
        return { machine: m, offline, oee, score };
      })
      .filter((x) => x.score > 0)
      .sort((a, b) => b.score - a.score)
      .slice(0, 6);

    return list;
  }, [machines]);

  const formatEventType = (eventType?: string) => {
    if (!eventType) return "";
    const key = `overview.event.${eventType}`;
    const label = t(key);
    return label === key ? eventType : label;
  };

  const formatSource = (source?: string) => {
    if (!source) return "";
    const key = `overview.source.${source}`;
    const label = t(key);
    return label === key ? source : label;
  };

  const formatSeverity = (severity?: string) => {
    if (!severity) return "";
    const key = `overview.severity.${severity}`;
    const label = t(key);
    return label === key ? severity.toUpperCase() : label;
  };

  return (
    <div className="p-4 sm:p-6">
      <div className="mb-6 flex flex-col gap-4 sm:flex-row sm:items-start sm:justify-between">
        <div>
          <h1 className="text-2xl font-semibold text-white">{t("overview.title")}</h1>
          <p className="text-sm text-zinc-400">{t("overview.subtitle")}</p>
        </div>

        <Link
          href="/machines"
          className="w-full rounded-xl border border-white/10 bg-white/5 px-4 py-2 text-center text-sm text-white hover:bg-white/10 sm:w-auto"
        >
          {t("overview.viewMachines")}
        </Link>
      </div>

      {loading && <div className="mb-4 text-sm text-zinc-400">{t("overview.loading")}</div>}

      <div className="grid grid-cols-1 gap-4 xl:grid-cols-3">
        <div className="rounded-2xl border border-white/10 bg-white/5 p-5">
          <div className="text-xs text-zinc-400">{t("overview.fleetHealth")}</div>
          <div className="mt-2 text-3xl font-semibold text-white">{stats.total}</div>
          <div className="mt-2 text-xs text-zinc-400">{t("overview.machinesTotal")}</div>
          <div className="mt-4 flex flex-wrap gap-2 text-xs">
            <span className="rounded-full bg-emerald-500/15 px-2 py-0.5 text-emerald-300">
              {t("overview.online")} {stats.online}
            </span>
            <span className="rounded-full bg-white/10 px-2 py-0.5 text-zinc-300">
              {t("overview.offline")} {stats.offline}
            </span>
            <span className="rounded-full bg-emerald-500/10 px-2 py-0.5 text-emerald-200">
              {t("overview.run")} {stats.running}
            </span>
            <span className="rounded-full bg-yellow-500/15 px-2 py-0.5 text-yellow-300">
              {t("overview.idle")} {stats.idle}
            </span>
            <span className="rounded-full bg-red-500/15 px-2 py-0.5 text-red-300">
              {t("overview.stop")} {stats.stopped}
            </span>
          </div>
        </div>

        <div className="rounded-2xl border border-white/10 bg-white/5 p-5">
          <div className="text-xs text-zinc-400">{t("overview.productionTotals")}</div>
          <div className="mt-2 grid grid-cols-1 gap-3 sm:grid-cols-3">
            <div className="rounded-xl border border-white/10 bg-black/20 p-3">
              <div className="text-[11px] text-zinc-400">{t("overview.good")}</div>
              <div className="mt-1 text-sm font-semibold text-white">{fmtNum(stats.goodSum)}</div>
            </div>
            <div className="rounded-xl border border-white/10 bg-black/20 p-3">
              <div className="text-[11px] text-zinc-400">{t("overview.scrap")}</div>
              <div className="mt-1 text-sm font-semibold text-white">{fmtNum(stats.scrapSum)}</div>
            </div>
            <div className="rounded-xl border border-white/10 bg-black/20 p-3">
              <div className="text-[11px] text-zinc-400">{t("overview.target")}</div>
              <div className="mt-1 text-sm font-semibold text-white">{fmtNum(stats.targetSum)}</div>
            </div>
          </div>
          <div className="mt-3 text-xs text-zinc-400">{t("overview.kpiSumNote")}</div>
        </div>

        <div className="rounded-2xl border border-white/10 bg-white/5 p-5">
          <div className="text-xs text-zinc-400">{t("overview.activityFeed")}</div>
          <div className="mt-2 text-3xl font-semibold text-white">{events.length}</div>
          <div className="mt-2 text-xs text-zinc-400">
            {eventsLoading ? t("overview.eventsRefreshing") : t("overview.eventsLast30")}
          </div>
          <div className="mt-4 space-y-2">
            {events.slice(0, 3).map((e) => (
              <div key={e.id} className="flex items-center justify-between text-xs text-zinc-300">
                <div className="truncate">
                  {e.machineName ? `${e.machineName}: ` : ""}
                  {e.title}
                </div>
                <div className="shrink-0 text-zinc-500">
                  {secondsAgo(e.ts, locale, t("common.never"))}
                </div>
              </div>
            ))}
            {events.length === 0 && !eventsLoading ? (
              <div className="text-xs text-zinc-500">{t("overview.eventsNone")}</div>
            ) : null}
          </div>
        </div>
      </div>

      <div className="mt-6 grid grid-cols-1 gap-4 md:grid-cols-2 xl:grid-cols-4">
        <div className="rounded-2xl border border-white/10 bg-white/5 p-5">
          <div className="text-xs text-zinc-400">{t("overview.oeeAvg")}</div>
          <div className="mt-2 text-3xl font-semibold text-emerald-300">{fmtPct(stats.oee)}</div>
        </div>
        <div className="rounded-2xl border border-white/10 bg-white/5 p-5">
          <div className="text-xs text-zinc-400">{t("overview.availabilityAvg")}</div>
          <div className="mt-2 text-2xl font-semibold text-white">{fmtPct(stats.availability)}</div>
        </div>
        <div className="rounded-2xl border border-white/10 bg-white/5 p-5">
          <div className="text-xs text-zinc-400">{t("overview.performanceAvg")}</div>
          <div className="mt-2 text-2xl font-semibold text-white">{fmtPct(stats.performance)}</div>
        </div>
        <div className="rounded-2xl border border-white/10 bg-white/5 p-5">
          <div className="text-xs text-zinc-400">{t("overview.qualityAvg")}</div>
          <div className="mt-2 text-2xl font-semibold text-white">{fmtPct(stats.quality)}</div>
        </div>
      </div>

      <div className="mt-6 grid grid-cols-1 gap-4 xl:grid-cols-3">
        <div className="rounded-2xl border border-white/10 bg-white/5 p-5 xl:col-span-1">
          <div className="mb-3 flex items-center justify-between">
            <div className="text-sm font-semibold text-white">{t("overview.attentionList")}</div>
            <div className="text-xs text-zinc-400">
              {attention.length} {t("overview.shown")}
            </div>
          </div>
          {attention.length === 0 ? (
            <div className="text-sm text-zinc-400">{t("overview.noUrgent")}</div>
          ) : (
            <div className="space-y-3">
              {attention.map(({ machine, offline, oee }) => (
                <div key={machine.id} className="rounded-xl border border-white/10 bg-black/20 p-3">
                  <div className="flex items-center justify-between gap-3">
                    <div className="min-w-0">
                      <div className="truncate text-sm font-semibold text-white">{machine.name}</div>
                      <div className="mt-1 text-xs text-zinc-400">
                        {machine.code ?? ""} {machine.location ? `- ${machine.location}` : ""}
                      </div>
                    </div>
                    <div className="text-xs text-zinc-400">
                      {secondsAgo(heartbeatTime(machine.latestHeartbeat), locale, t("common.never"))}
                    </div>
                  </div>
                  <div className="mt-2 flex items-center gap-2 text-xs">
                    <span
                      className={`rounded-full px-2 py-0.5 ${
                        offline ? "bg-white/10 text-zinc-300" : "bg-emerald-500/15 text-emerald-300"
                      }`}
                    >
                      {offline ? t("overview.status.offline") : t("overview.status.online")}
                    </span>
                    {oee != null && (
                      <span className="rounded-full bg-yellow-500/15 px-2 py-0.5 text-yellow-300">
                        OEE {fmtPct(oee)}
                      </span>
                    )}
                  </div>
                </div>
              ))}
            </div>
          )}
        </div>

        <div className="rounded-2xl border border-white/10 bg-white/5 p-5 xl:col-span-2">
          <div className="mb-3 flex items-center justify-between">
            <div className="text-sm font-semibold text-white">{t("overview.timeline")}</div>
            <div className="text-xs text-zinc-400">
              {events.length} {t("overview.items")}
            </div>
          </div>

          {events.length === 0 && !eventsLoading ? (
            <div className="text-sm text-zinc-400">{t("overview.noEvents")}</div>
          ) : (
            <div className="h-[360px] space-y-3 overflow-y-auto no-scrollbar">
              {events.map((e) => (
                <div key={`${e.id}-${e.source}`} className="rounded-xl border border-white/10 bg-black/20 p-4">
                  <div className="flex items-start justify-between gap-3">
                    <div className="min-w-0">
                      <div className="flex flex-wrap items-center gap-2">
                        <span className={`rounded-full px-2 py-0.5 text-xs ${severityClass(e.severity)}`}>
                          {formatSeverity(e.severity)}
                        </span>
                        <span className="rounded-full bg-white/10 px-2 py-0.5 text-xs text-zinc-200">
                          {formatEventType(e.eventType)}
                        </span>
                        <span className={`rounded-full px-2 py-0.5 text-xs ${sourceClass(e.source)}`}>
                          {formatSource(e.source)}
                        </span>
                        {e.requiresAck ? (
                          <span className="rounded-full bg-white/10 px-2 py-0.5 text-xs text-white">
                            {t("overview.ack")}
                          </span>
                        ) : null}
                      </div>

                      <div className="mt-2 truncate text-sm font-semibold text-white">
                        {e.machineName ? `${e.machineName}: ` : ""}
                        {e.title}
                      </div>
                      {e.description ? (
                        <div className="mt-1 text-sm text-zinc-300">{e.description}</div>
                      ) : null}
                    </div>
                    <div className="shrink-0 text-xs text-zinc-400">
                      {secondsAgo(e.ts, locale, t("common.never"))}
                    </div>
                  </div>
                </div>
              ))}
            </div>
          )}
        </div>
      </div>
    </div>
  );
}