import { useEffect, useState, useCallback, lazy, Suspense } from "react"
import { Command as CommandIcon, ChevronLeft, ChevronRight, Loader2, Menu, X } from "lucide-react"
import { NAV, type ViewId } from "@/nav"
import { CommandPalette } from "@/components/CommandPalette"
import { ExpertToggle } from "@/components/ExpertToggle"
import { SystemDrawer } from "@/components/SystemDrawer"
import { useHealth, useSystemStatus } from "@/lib/queries"
import type { Health, SystemStatus } from "@/lib/api"
import { useMetricsFeeder } from "@/lib/metricsStore"
import { useEventStream } from "@/lib/events"
import { cn } from "@/lib/utils"
import { CockpitView } from "@/views/cockpit/CockpitView"

// Code-Splitting: nur das Cockpit (Startseite) lädt sofort, jede weitere View
// kommt als eigenes Chunk erst beim ersten Aufruf — kleineres Start-Bundle.
const ModelsView = lazy(() => import("@/views/ModelsView").then((m) => ({ default: m.ModelsView })))
const ConnectView = lazy(() => import("@/views/ConnectView").then((m) => ({ default: m.ConnectView })))
const MemoryView = lazy(() => import("@/views/MemoryView").then((m) => ({ default: m.MemoryView })))
const AgentView = lazy(() => import("@/views/AgentView").then((m) => ({ default: m.AgentView })))
const KonsoleView = lazy(() => import("@/views/KonsoleView").then((m) => ({ default: m.KonsoleView })))
const GuideView = lazy(() => import("@/views/GuideView").then((m) => ({ default: m.GuideView })))
const AuftragsbuchView = lazy(() => import("@/views/AuftragsbuchView").then((m) => ({ default: m.AuftragsbuchView })))
const IdeenView = lazy(() => import("@/views/IdeenView").then((m) => ({ default: m.IdeenView })))
const ChronikView = lazy(() => import("@/views/ChronikView").then((m) => ({ default: m.ChronikView })))
const EigenlebenView = lazy(() => import("@/views/EigenlebenView").then((m) => ({ default: m.EigenlebenView })))
const WissenView = lazy(() => import("@/views/WissenView").then((m) => ({ default: m.WissenView })))

// Dezenter Lade-Zustand während eine View nachgeladen wird (lokales Netz: kaum sichtbar).
function ViewLoading() {
  return (
    <div className="flex h-64 items-center justify-center text-muted-foreground">
      <Loader2 className="h-5 w-5 animate-spin" aria-label="Lädt …" />
    </div>
  )
}

// Tastatur-Hinweis passend zum Betriebssystem (Palette hört auf Ctrl UND Cmd).
const IS_MAC = /Mac|iPhone|iPad/.test(navigator.platform)

export default function App() {
  useMetricsFeeder()   // sammelt Live-Verlauf global, unabhängig vom aktiven Tab
  useEventStream()     // SSE-Invalidation-Bus (P3a): sofortige Updates, Poller nur Netz
  // View ist im URL-Hash (#models) verankert → Reload/Teilen/Cmd-Klick funktionieren.
  const [view, setView] = useState<ViewId>(() => {
    const h = window.location.hash.slice(1) as ViewId
    return NAV.some((n) => n.id === h) ? h : "dashboard"
  })
  const navigate = useCallback((v: ViewId) => {
    if (window.location.hash.slice(1) === v) setView(v)
    else window.location.hash = v
  }, [])
  const [sidebarCollapsed, setSidebarCollapsed] = useState(() => localStorage.getItem("mc_sidebar_collapsed") === "true")
  const [mobileNavOpen, setMobileNavOpen] = useState(false)
  const [drawerOpen, setDrawerOpen] = useState(false)
  const [drawerTab, setDrawerTab] = useState<"maintenance" | "logs">("maintenance")

  // isError mitnehmen: React Query behält bei Fehlern die letzten Daten — ohne den
  // Fehler-Blick zeigte die Sidebar bei totem Backend ewig den letzten grünen Stand.
  const { data: health, isError: backendDown } = useHealth()
  const { data: sysStatus } = useSystemStatus()

  useEffect(() => {
    document.documentElement.classList.add("dark")
  }, [])

  useEffect(() => {
    const handleOpen = (e: Event) => {
      const customEvent = e as CustomEvent
      setDrawerTab(customEvent.detail?.tab || "maintenance")
      setDrawerOpen(true)
    }
    window.addEventListener("open-system-drawer", handleOpen)
    return () => window.removeEventListener("open-system-drawer", handleOpen)
  }, [])

  useEffect(() => {
    const handleNav = (e: Event) => {
      const v = (e as CustomEvent).detail?.view as ViewId | undefined
      if (v) navigate(v)
    }
    window.addEventListener("mc-navigate", handleNav)
    return () => window.removeEventListener("mc-navigate", handleNav)
  }, [navigate])

  useEffect(() => {
    const onHash = () => {
      const h = window.location.hash.slice(1) as ViewId
      if (NAV.some((n) => n.id === h)) setView(h)
    }
    window.addEventListener("hashchange", onHash)
    return () => window.removeEventListener("hashchange", onHash)
  }, [])

  // Mobile-Navigation schließt nach jedem View-Wechsel (ein Tipp = ein Ziel).
  useEffect(() => { setMobileNavOpen(false) }, [view])

  const active = NAV.find((n) => n.id === view)!

  return (
    <div className="flex h-full relative">
      {/* Ruhiger Ambient-Hintergrund: statische radial-gradients statt animierter
          Fullscreen-Blur-Filter — gleicher Look, praktisch keine GPU-Last. */}
      <div
        className="fixed inset-0 -z-50 pointer-events-none"
        style={{
          backgroundColor: "hsl(224,30%,6%)",
          backgroundImage: [
            "radial-gradient(45% 40% at 12% 8%, hsl(172 72% 50% / 0.10), transparent 70%)",
            "radial-gradient(50% 45% at 88% 92%, hsl(270 70% 60% / 0.10), transparent 70%)",
            "radial-gradient(40% 35% at 75% 30%, hsl(239 70% 62% / 0.07), transparent 70%)",
          ].join(", "),
        }}
      />

      <CommandPalette onNavigate={navigate} />
      <SystemDrawer open={drawerOpen} onClose={() => setDrawerOpen(false)} defaultTab={drawerTab} />

      {/* Sidebar (Desktop, ab md) */}
      <aside className={cn(
        "hidden md:flex shrink-0 flex-col border-r border-border/40 bg-card/45 backdrop-blur-md transition-all duration-300 ease-in-out",
        sidebarCollapsed ? "w-16" : "w-60"
      )}>
        <SidebarContent
          collapsed={sidebarCollapsed}
          onToggleCollapse={() => {
            setSidebarCollapsed((c) => {
              const next = !c
              localStorage.setItem("mc_sidebar_collapsed", next.toString())
              return next
            })
          }}
          view={view}
          health={health}
          backendDown={backendDown}
          sysStatus={sysStatus}
        />
      </aside>

      {/* Sidebar (Mobile, Off-Canvas mit Backdrop) */}
      <div
        className={cn(
          "md:hidden fixed inset-0 z-50 transition-opacity duration-200",
          mobileNavOpen ? "opacity-100" : "pointer-events-none opacity-0"
        )}
        aria-hidden={!mobileNavOpen}
      >
        <div className="absolute inset-0 bg-black/60" onClick={() => setMobileNavOpen(false)} />
        <aside className={cn(
          "absolute inset-y-0 left-0 flex w-72 max-w-[85vw] flex-col border-r border-border/40 bg-[hsl(224,28%,8%)] transition-transform duration-300 ease-in-out",
          mobileNavOpen ? "translate-x-0" : "-translate-x-full"
        )}>
          <SidebarContent
            collapsed={false}
            onClose={() => setMobileNavOpen(false)}
            view={view}
            health={health}
            backendDown={backendDown}
            sysStatus={sysStatus}
          />
        </aside>
      </div>

      {/* Main */}
      <div className="flex min-w-0 flex-1 flex-col">
        <header className="flex h-14 shrink-0 items-center justify-between gap-3 border-b border-border/40 px-4 md:px-6 bg-card/20 backdrop-blur-sm">
          <div className="flex min-w-0 items-center gap-3">
            <button
              onClick={() => setMobileNavOpen(true)}
              className="md:hidden p-1.5 -ml-1 rounded-md hover:bg-accent text-muted-foreground transition-colors cursor-pointer"
              aria-label="Navigation öffnen"
            >
              <Menu className="h-5 w-5" aria-hidden="true" />
            </button>
            <div className="truncate text-xs font-medium text-muted-foreground tracking-wide uppercase font-sans">{active.hint}</div>
          </div>
          <div className="flex shrink-0 items-center gap-2">
            <ExpertToggle />
            <a
              href="https://git.tobisniceshomelab.ddnsfree.com/Hitonabi/mission-control-v2/src/branch/main/docs/BEDIENUNG.md"
              target="_blank"
              rel="noopener"
              className="hidden sm:flex h-8 items-center rounded-md border border-border/40 bg-background/40 px-2.5 text-xs text-muted-foreground hover:bg-accent hover:text-accent-foreground transition-all cursor-pointer font-semibold"
              title="Bedien-Anleitung"
            >
              Hilfe
            </a>

            <button
              onClick={() => {
                const ev = new KeyboardEvent("keydown", { key: "k", metaKey: true })
                document.dispatchEvent(ev)
              }}
              className="flex items-center gap-2 rounded-md border border-border/40 bg-background/40 px-2.5 py-1.5 text-xs text-muted-foreground hover:bg-accent hover:text-accent-foreground transition-all cursor-pointer"
            >
              <CommandIcon className="h-3.5 w-3.5" />
              <span className="hidden sm:inline">Suchen</span>
              <kbd className="hidden sm:inline rounded bg-muted px-1.5 py-0.5 font-mono text-[9px]">{IS_MAC ? "⌘K" : "Strg+K"}</kbd>
            </button>
          </div>
        </header>

        <main className="flex-1 overflow-y-auto p-4 md:p-6 scrollbar-thin">
          <Suspense fallback={<ViewLoading />}>
            {view === "dashboard" && <CockpitView onNavigate={(v) => navigate(v as ViewId)} />}
            {view === "ideen" && <IdeenView />}
            {view === "auftraege" && <AuftragsbuchView />}
            {view === "models" && <ModelsView />}
            {view === "connect" && <ConnectView />}
            {view === "memory" && <MemoryView />}
            {view === "wissen" && <WissenView />}
            {view === "chronik" && <ChronikView />}
            {view === "eigenleben" && <EigenlebenView />}
            {view === "agent" && <AgentView />}
            {view === "konsole" && <KonsoleView />}
            {view === "guide" && <GuideView />}
          </Suspense>
        </main>
      </div>
    </div>
  )
}

// Sidebar-Inhalt (Logo, Navigation, Status-Fuß) — geteilt zwischen Desktop-Leiste
// und Mobile-Off-Canvas, damit beide immer identisch bleiben.
function SidebarContent({
  collapsed, onToggleCollapse, onClose, view, health, backendDown, sysStatus,
}: {
  collapsed: boolean
  onToggleCollapse?: () => void
  onClose?: () => void
  view: ViewId
  health: Health | undefined
  backendDown: boolean
  sysStatus: SystemStatus | undefined
}) {
  return (
    <>
      <div className={cn("flex items-center py-4 border-b border-border/40 shrink-0", collapsed ? "flex-col gap-3 px-2" : "justify-between px-5")}>
        <div className="flex items-center gap-2 overflow-hidden">
          <div className="h-7 w-7 rounded-lg bg-primary shadow-md shadow-primary/20 shrink-0" />
          {!collapsed && (
            <div className="leading-tight">
              <div className="text-sm font-semibold tracking-wide font-space">Mission Control</div>
              <div className="text-xs text-muted-foreground">2.0</div>
            </div>
          )}
        </div>
        {onToggleCollapse && (
          <button
            onClick={onToggleCollapse}
            className="p-1 rounded-md hover:bg-accent text-muted-foreground transition-colors cursor-pointer"
            aria-label={collapsed ? "Seitenleiste ausklappen" : "Seitenleiste einklappen"}
            title={collapsed ? "Maximieren" : "Minimieren"}
          >
            {collapsed ? <ChevronRight className="h-4 w-4" aria-hidden="true" /> : <ChevronLeft className="h-4 w-4" aria-hidden="true" />}
          </button>
        )}
        {onClose && (
          <button
            onClick={onClose}
            className="p-1 rounded-md hover:bg-accent text-muted-foreground transition-colors cursor-pointer"
            aria-label="Navigation schließen"
          >
            <X className="h-4 w-4" aria-hidden="true" />
          </button>
        )}
      </div>

      <nav className="flex-1 space-y-1 px-3 py-4 overflow-y-auto">
        {(() => {
          let lastGroup: string | null = null
          return NAV.map((item) => {
            const showGroupHeader = item.group !== lastGroup
            lastGroup = item.group
            return (
              <div key={item.id} className="space-y-1">
                {showGroupHeader && (
                  collapsed ? (
                    lastGroup !== NAV[0].group && <div className="my-3 border-t border-border/30" />
                  ) : (
                    <div className="mt-5 mb-1.5 px-3 text-[10px] font-bold uppercase tracking-widest text-muted-foreground/40 first:mt-0 select-none">
                      {item.group}
                    </div>
                  )
                )}
                <a
                  href={`#${item.id}`}
                  onClick={onClose}
                  aria-current={view === item.id ? "page" : undefined}
                  className={cn(
                    "flex w-full items-center rounded-md text-sm transition-all cursor-pointer",
                    collapsed ? "justify-center p-2.5" : "gap-3 px-3 py-2",
                    view === item.id
                      ? (collapsed ? "nav-active-collapsed" : "nav-active")
                      : "text-muted-foreground hover:bg-accent hover:text-accent-foreground",
                  )}
                  title={collapsed ? item.label : undefined}
                  aria-label={collapsed ? item.label : undefined}
                >
                  <item.icon className="h-4.5 w-4.5 shrink-0" aria-hidden="true" />
                  {!collapsed && <span className="truncate">{item.label}</span>}
                </a>
              </div>
            )
          })
        })()}
      </nav>

      <div className={cn("py-3 text-xs text-muted-foreground border-t border-border/40 shrink-0", collapsed ? "px-2 text-center" : "px-5")}>
        {collapsed ? (
          <div className="flex justify-center">
            <span className={cn(
              "h-2.5 w-2.5 rounded-full ring-2 ring-black/40",
              backendDown || !health
                ? "bg-red-500"
                : (!health.engine_reachable ? "bg-amber-500"
                   : (health.brain && !health.brain.ready ? "bg-amber-500 animate-pulse" : "bg-emerald-500 animate-pulse"))
            )} title={backendDown
              ? "Zentrale antwortet nicht — Anzeigen evtl. veraltet"
              : health
                ? (!health.engine_reachable ? "Engine offline"
                   : (health.brain && !health.brain.ready ? `Hirn offline (${health.brain.model ?? "fast"})` : "Engine + Hirn online"))
                : "Backend offline"} />
          </div>
        ) : (
          <div className="space-y-2 text-left">
            {backendDown ? (
              <span className="flex items-center gap-2 text-red-400">
                <span className="h-2 w-2 rounded-full bg-red-500 animate-pulse" />
                <span className="truncate">Zentrale antwortet nicht</span>
              </span>
            ) : health ? (
              <>
              <span className="flex items-center gap-2">
                <span className={cn("h-2 w-2 rounded-full animate-pulse", health.engine_reachable ? "bg-emerald-500" : "bg-amber-500")} />
                <span className="truncate">Engine {health.engine_reachable ? "online" : "offline"}</span>
              </span>
              {health.brain && !health.brain.ready && (
                <span className="flex items-center gap-2 text-amber-400" title={`Agent-Hirn '${health.brain.model ?? "fast"}' lädt nicht/abgestürzt`}>
                  <span className="h-2 w-2 rounded-full bg-amber-500 animate-pulse" />
                  <span className="truncate">Hirn offline{health.brain.model ? ` (${health.brain.model})` : ""}</span>
                </span>
              )}
              </>
            ) : (
              <span className="flex items-center gap-2">
                <span className="h-2 w-2 rounded-full bg-red-500" /> <span className="truncate">Backend offline</span>
              </span>
            )}

            {sysStatus?.versions && (
              <div className="space-y-1 text-[9px] text-muted-foreground/60 mt-2 pt-2 border-t border-border/30">
                <div className="truncate" title={sysStatus.versions.mc2 ? `${sysStatus.versions.mc2.branch}-${sysStatus.versions.mc2.hash}${sysStatus.versions.mc2.dirty ? "*" : ""} (${sysStatus.versions.mc2.date})` : "nicht gefunden"}>
                  <strong>MC2:</strong> {sysStatus.versions.mc2 ? `${sysStatus.versions.mc2.hash}${sysStatus.versions.mc2.dirty ? "*" : ""}` : "—"}
                </div>
                <div className="truncate" title={sysStatus.versions.engine?.type === "git" ? `${sysStatus.versions.engine.branch}-${sysStatus.versions.engine.hash}${sysStatus.versions.engine.dirty ? "*" : ""} (${sysStatus.versions.engine.date})` : sysStatus.versions.engine?.version_text || "unbekannt"}>
                  <strong>Engine:</strong> {sysStatus.versions.engine?.type === "git" ? `${sysStatus.versions.engine.hash}${sysStatus.versions.engine.dirty ? "*" : ""}` : (sysStatus.versions.engine?.version_text?.split(" ").pop() || "—")}
                </div>
                <div className="truncate" title={sysStatus.versions.hermes_agent ? `${sysStatus.versions.hermes_agent.branch}-${sysStatus.versions.hermes_agent.hash}${sysStatus.versions.hermes_agent.dirty ? "*" : ""} (${sysStatus.versions.hermes_agent.date})` : "nicht gefunden"}>
                  <strong>Hermes Agent:</strong> {sysStatus.versions.hermes_agent ? `${sysStatus.versions.hermes_agent.hash}${sysStatus.versions.hermes_agent.dirty ? "*" : ""}` : "—"}
                </div>
              </div>
            )}
          </div>
        )}
      </div>
    </>
  )
}