import { useEffect, useState } from 'react';
import {
  Show,
  SignUp,
  SignInButton,
  SignUpButton,
  UserButton,
  useAuth,
  useUser,
} from '@clerk/react';
import type { Room } from 'livekit-client';
import {
  AlertCircleIcon,
  RefreshCwIcon,
  SparklesIcon,
} from 'lucide-react';
import type { Pod, PodInput } from '@podman/shared';
import { joinPod } from './lib/pod.js';
import * as api from './lib/api.js';
import { PodCard } from './components/PodCard.js';
import { CreatePodForm } from './components/CreatePodForm.js';
import { PodView } from './components/PodView.js';
import { GraphView } from './components/GraphView.js';
import { Alert, AlertDescription, AlertTitle } from '@/components/ui/alert';
import { Button } from '@/components/ui/button';
import {
  Card,
  CardAction,
  CardContent,
  CardDescription,
  CardHeader,
  CardTitle,
} from '@/components/ui/card';
import {
  Empty,
  EmptyContent,
  EmptyDescription,
  EmptyHeader,
  EmptyMedia,
  EmptyTitle,
} from '@/components/ui/empty';
import { Skeleton } from '@/components/ui/skeleton';

const SESSION_KEY = 'podman.session';

function pathPodId(): string | null {
  const [segment] = window.location.pathname.split('/').filter(Boolean);
  return segment ? decodeURIComponent(segment) : null;
}

function setPodPath(podId: string, replace = false): void {
  const next = `/${encodeURIComponent(podId)}`;
  if (window.location.pathname === next) return;
  window.history[replace ? 'replaceState' : 'pushState']({}, '', next);
}

function setHomePath(): void {
  if (window.location.pathname === '/') return;
  window.history.pushState({}, '', '/');
}

function replacePath(path: string): void {
  window.history.replaceState({}, '', path || '/');
}

function firstNameFrom(value: string | null | undefined): string {
  return value?.trim().split(/\s+/).filter(Boolean)[0] ?? '';
}

export default function App() {
  const { getToken, isLoaded, isSignedIn } = useAuth();
  const { user } = useUser();
  const [pods, setPods] = useState<Pod[]>([]);
  const [loading, setLoading] = useState(true);
  const [pending, setPending] = useState<Set<string>>(new Set());
  const [error, setError] = useState<string | null>(null);
  const [presence, setPresence] = useState<Record<string, string[]>>({});
  const [joinedPodId, setJoinedPodId] = useState<string | null>(null);
  const [member, setMember] = useState('');
  const [devMode, setDevMode] = useState(false);
  const [room, setRoom] = useState<Room | null>(null);
  const [restoring, setRestoring] = useState(false);
  const [graphPodId, setGraphPodId] = useState<string | null>(null);

  const joinedPod = joinedPodId ? (pods.find((p) => p.id === joinedPodId) ?? null) : null;
  const userEmail = user?.primaryEmailAddress?.emailAddress;
  const defaultMemberName =
    user?.firstName?.trim() ||
    firstNameFrom(user?.fullName) ||
    firstNameFrom(userEmail?.split('@')[0]);
  const currentUserProfile = {
    displayName: defaultMemberName,
    email: userEmail,
    imageUrl: user?.imageUrl,
  };

  useEffect(() => {
    api.setAuthTokenGetter(isSignedIn ? getToken : null);
    return () => api.setAuthTokenGetter(null);
  }, [getToken, isSignedIn]);

  async function refresh() {
    setLoading(true);
    try {
      const [nextPods, nextPresence] = await Promise.all([
        api.listPods(),
        api.getPresence().catch(() => presence),
      ]);
      setPods(nextPods);
      setPresence(nextPresence);
      setError(null);
    } catch (e) {
      setError((e as Error).message);
    } finally {
      setLoading(false);
    }
  }

  const startPending = (key: string) => setPending((s) => new Set(s).add(key));
  const endPending = (key: string) =>
    setPending((s) => {
      const n = new Set(s);
      n.delete(key);
      return n;
    });

  async function connectToPod(podId: string, who: string, replaceRoute = false) {
    const previousPath = window.location.pathname;
    setPodPath(podId, replaceRoute);
    try {
      const result = await joinPod(
        podId,
        who,
        who,
        isSignedIn ? getToken : undefined,
        currentUserProfile,
      );
      setRoom(result.room);
      setDevMode(result.mode === 'dev');
      setMember(who);
      setJoinedPodId(podId);
      sessionStorage.setItem(SESSION_KEY, JSON.stringify({ podId, member: who }));
    } catch (e) {
      replacePath(previousPath);
      throw e;
    }
  }

  useEffect(() => {
    if (!isSignedIn) {
      setLoading(false);
      return;
    }
    void refresh();
  }, [isSignedIn]);

  useEffect(() => {
    if (!isSignedIn || joinedPodId) return;
    let alive = true;
    const tick = async () => {
      try {
        const p = await api.getPresence();
        if (alive) {
          setPresence(p);
        }
      } catch {
        /* presence is best-effort */
      }
    };
    void tick();
    const id = window.setInterval(() => void tick(), 5000);
    return () => {
      alive = false;
      window.clearInterval(id);
    };
  }, [isSignedIn, joinedPodId]);

  useEffect(() => {
    if (!isSignedIn) return;
    const routedPodId = pathPodId();
    const raw = sessionStorage.getItem(SESSION_KEY);
    if (!raw) {
      return;
    }
    let saved: { podId: string; member: string };
    try {
      saved = JSON.parse(raw);
    } catch {
      sessionStorage.removeItem(SESSION_KEY);
      return;
    }
    const podId = routedPodId ?? saved.podId;
    setRestoring(true);
    void (async () => {
      try {
        await connectToPod(podId, saved.member, !!routedPodId);
      } catch {
        sessionStorage.removeItem(SESSION_KEY);
      } finally {
        setRestoring(false);
      }
    })();
  }, [isSignedIn]);

  useEffect(() => {
    const onPopState = () => {
      if (!isSignedIn) return;
      const routedPodId = pathPodId();
      if (!routedPodId) {
        room?.disconnect();
        setRoom(null);
        setJoinedPodId(null);
        return;
      }
      const raw = sessionStorage.getItem(SESSION_KEY);
      if (!raw) return;
      try {
        const saved = JSON.parse(raw) as { member: string };
        if (saved.member && routedPodId !== joinedPodId) {
          void connectToPod(routedPodId, saved.member, true);
        }
      } catch {
        sessionStorage.removeItem(SESSION_KEY);
      }
    };
    window.addEventListener('popstate', onPopState);
    return () => window.removeEventListener('popstate', onPopState);
  }, [isSignedIn, joinedPodId, room]);

  async function run(key: string, fn: () => Promise<void>) {
    startPending(key);
    setError(null);
    try {
      await fn();
    } catch (e) {
      setError((e as Error).message);
    } finally {
      endPending(key);
    }
  }

  const upsert = (p: Pod) => setPods((cur) => cur.map((x) => (x.id === p.id ? p : x)));

  async function handleCreate(input: PodInput): Promise<void> {
    startPending('new');
    setError(null);
    try {
      const created = await api.createPod(input, currentUserProfile);
      setPods((cur) => [...cur, created]);
    } catch (e) {
      setError((e as Error).message);
      throw e;
    } finally {
      endPending('new');
    }
  }

  const handleUpdate = (id: string, patch: PodInput) =>
    run(id, async () => upsert(await api.updatePod(id, patch)));
  const handleDelete = (id: string) =>
    run(id, async () => {
      await api.deletePod(id);
      setPods((cur) => cur.filter((x) => x.id !== id));
      if (pathPodId() === id) setHomePath();
    });
  const handleAddMember = (id: string, name: string) =>
    run(id, async () => upsert(await api.addMember(id, name, currentUserProfile)));
  const handleRemoveMember = (id: string, name: string) =>
    run(id, async () => upsert(await api.removeMember(id, name)));

  async function handleJoin(pod: Pod, who: string) {
    startPending(pod.id);
    setError(null);
    try {
      await connectToPod(pod.id, who);
    } catch (e) {
      setError((e as Error).message);
    } finally {
      endPending(pod.id);
    }
  }

  async function handleAddAndJoin(pod: Pod) {
    startPending(pod.id);
    setError(null);
    try {
      if (!defaultMemberName) {
        throw new Error('Sign in with Clerk before joining a pod.');
      }
      upsert(await api.addMember(pod.id, defaultMemberName, currentUserProfile));
      await connectToPod(pod.id, defaultMemberName);
    } catch (e) {
      setError((e as Error).message);
    } finally {
      endPending(pod.id);
    }
  }

  function handleLeave() {
    room?.disconnect();
    setRoom(null);
    setJoinedPodId(null);
    sessionStorage.removeItem(SESSION_KEY);
    setHomePath();
    void refresh();
  }

  const showReconnecting = restoring || (joinedPodId !== null && joinedPod === null);

  if (!isLoaded) {
    return (
      <div className="grid min-h-screen place-items-center bg-background text-foreground">
        <Skeleton className="h-12 w-64" />
      </div>
    );
  }

  if (!isSignedIn) {
    return <AuthGate />;
  }

  if (joinedPod) {
    return (
      <PodView
        team={joinedPod}
        me={member}
        room={room}
        devMode={devMode}
        currentUserProfile={currentUserProfile}
        onLeave={handleLeave}
      />
    );
  }

  if (graphPodId) {
    return <GraphView podId={graphPodId} onClose={() => setGraphPodId(null)} />;
  }

  return (
    <div className="min-h-screen bg-background text-foreground">
      <div className="mx-auto flex min-h-screen w-full max-w-[1440px] flex-col gap-6 px-4 py-4 sm:px-6 lg:px-8">
        <header className="sticky top-0 z-10 -mx-4 border-b bg-background/86 px-4 pb-4 pt-2 backdrop-blur-xl sm:-mx-6 sm:px-6 lg:-mx-8 lg:px-8">
          <div className="flex flex-col gap-4 sm:flex-row sm:items-center sm:justify-between">
            <div className="flex min-w-0 items-center gap-3">
              <div className="grid size-10 place-items-center rounded-lg bg-primary text-sm font-semibold text-primary-foreground shadow-sm">
                PM
              </div>
              <div className="min-w-0">
                <h1 className="text-[1.95rem] font-semibold leading-none tracking-tight">PodMan</h1>
              </div>
            </div>

            <div className="flex items-center gap-2">
              <Show when="signed-out">
                <SignInButton mode="modal">
                  <Button variant="outline">Sign in</Button>
                </SignInButton>
                <SignUpButton mode="modal">
                  <Button>Sign up</Button>
                </SignUpButton>
              </Show>
              <Show when="signed-in">
                <UserButton />
              </Show>
              <Button variant="outline" onClick={() => void refresh()} disabled={loading}>
                <RefreshCwIcon data-icon="inline-start" />
                Refresh
              </Button>
            </div>
          </div>
        </header>

        {error && (
          <Alert variant="destructive">
            <AlertCircleIcon />
            <AlertTitle>PodMan could not complete that action</AlertTitle>
            <AlertDescription>{error}</AlertDescription>
          </Alert>
        )}

        {showReconnecting ? (
          <Card>
            <CardHeader>
              <CardTitle>Reconnecting to your pod</CardTitle>
              <CardDescription>Restoring the saved LiveKit session.</CardDescription>
              <CardAction>
                <Button variant="outline" size="sm" onClick={handleLeave}>
                  Cancel
                </Button>
              </CardAction>
            </CardHeader>
            <CardContent>
              <Skeleton className="h-2 w-full" />
            </CardContent>
          </Card>
        ) : (
          <main className="grid min-w-0 flex-1 gap-5 lg:grid-cols-[minmax(0,1fr)_360px]">
            <section className="flex min-w-0 flex-col gap-4">
              <div className="flex flex-col gap-2 sm:flex-row sm:items-end sm:justify-between">
                <div className="min-w-0">
                  <p className="text-xs font-medium uppercase text-muted-foreground">Workspaces</p>
                  <h2 className="text-xl font-semibold tracking-tight">Active pods</h2>
                </div>
              </div>

              {loading ? (
                <div className="grid gap-4 xl:grid-cols-2">
                  <PodSkeleton />
                  <PodSkeleton />
                </div>
              ) : pods.length ? (
                <div className="grid gap-4 xl:grid-cols-2">
                  {pods.map((pod) => (
                    <PodCard
                      key={pod.id}
                      pod={pod}
                      busy={pending.has(pod.id)}
                      presence={presence[pod.id] ?? []}
                      currentUserProfile={currentUserProfile}
                      onJoin={handleJoin}
                      onAddAndJoin={handleAddAndJoin}
                      onAddMember={handleAddMember}
                      onRemoveMember={handleRemoveMember}
                      onUpdate={handleUpdate}
                      onDelete={handleDelete}
                      onOpenGraph={setGraphPodId}
                    />
                  ))}
                </div>
              ) : (
                <Empty className="min-h-[360px] rounded-lg border bg-card">
                  <EmptyHeader>
                    <EmptyMedia variant="icon">
                      <SparklesIcon />
                    </EmptyMedia>
                    <EmptyTitle>No pods yet</EmptyTitle>
                    <EmptyDescription>Create the first room for this team.</EmptyDescription>
                  </EmptyHeader>
                  <EmptyContent>
                    <CreatePodForm
                      busy={pending.has('new')}
                      defaultMemberName={defaultMemberName}
                      onCreate={handleCreate}
                      compact
                    />
                  </EmptyContent>
                </Empty>
              )}
            </section>

            <aside className="flex flex-col gap-4">
              <CreatePodForm
                busy={pending.has('new')}
                defaultMemberName={defaultMemberName}
                onCreate={handleCreate}
              />
            </aside>
          </main>
        )}
      </div>
    </div>
  );
}

function AuthGate() {
  return (
    <div className="min-h-screen bg-background text-foreground">
      <div className="mx-auto flex min-h-screen w-full max-w-[1120px] flex-col px-4 py-4 sm:px-6 lg:px-8">
        <header className="flex items-center justify-between border-b pb-4 pt-2">
          <div className="flex min-w-0 items-center gap-3">
            <div className="grid size-10 place-items-center rounded-lg bg-primary text-sm font-semibold text-primary-foreground shadow-sm">
              PM
            </div>
            <h1 className="text-[1.95rem] font-semibold leading-none tracking-tight">PodMan</h1>
          </div>
          <SignInButton mode="modal">
            <Button variant="outline">Sign in</Button>
          </SignInButton>
        </header>

        <main className="grid flex-1 items-center gap-8 py-8 lg:grid-cols-[minmax(0,1fr)_420px]">
          <section className="max-w-xl">
            <p className="text-xs font-medium uppercase text-muted-foreground">Team memory</p>
            <h2 className="mt-2 text-3xl font-semibold tracking-tight">
              Create your account to enter PodMan
            </h2>
            <p className="mt-3 text-base text-muted-foreground">
              PodMan saves your context across pods so agents can learn from your work in every
              room you join.
            </p>
          </section>

          <div className="flex justify-center lg:justify-end">
            <SignUp routing="hash" />
          </div>
        </main>
      </div>
    </div>
  );
}

function PodSkeleton() {
  return (
    <Card>
      <CardHeader>
        <Skeleton className="h-5 w-40" />
        <Skeleton className="h-4 w-56" />
      </CardHeader>
      <CardContent>
        <div className="flex flex-col gap-3">
          <Skeleton className="h-20 w-full" />
          <Skeleton className="h-8 w-full" />
        </div>
      </CardContent>
    </Card>
  );
}