import { useState, useEffect, useEffectEvent, useCallback } from "react";
import { useNavigate } from "react-router-dom";
import { useAuthStore } from "@/stores/auth-store";
import { apiClient } from "@/api/client";
import type { Particle } from "@/api/types";
import { parseParticlePath, type ParticlePath } from "@/lib/particle-path";
import { ComposeOverlay } from "@/features/compose/compose-overlay";
import { PlaybackPageIndicator } from "@/features/particles/playback-page-indicator";
import { MediaParticleView } from "@/features/particles/media-particle-view";
import { TextParticleView } from "@/features/particles/text-particle-view";
import { FallbackParticleView } from "@/features/particles/fallback-particle-view";
import { Avatar, AvatarFallback, AvatarGroup } from "@/components/ui/avatar";
import ControlsIndicator from "@/features/compose/controls-indicator";
import { Tooltip, TooltipContent, TooltipTrigger } from "@/components/ui/tooltip";
import { useNetwork, useNetworks } from "@/hooks/use-networks";
import { Button } from "@/components/ui/button";
import { Settings } from "lucide-react";
import { Breadcrumb, BreadcrumbItem, BreadcrumbList, BreadcrumbPage, BreadcrumbSeparator } from "@/components/ui/breadcrumb";
import { WindowControls } from "@/components/window-controls";
import { RelativeTimestamp } from "@/components/relative-timestamp";
import { useStreamPlayback } from "@/hooks/use-stream-playback";
import { usePrefetchAdjacentMedia } from "@/hooks/use-prefetch-adjacent-media";

function getParticleDisplayName(particle: Particle): string {
  switch (particle.type) {
    case "stream":
    case "folder":
      return particle.properties.name;
    case "quest":
      return particle.properties.title;
    case "paper":
      return particle.properties.title;
    case "file":
      return particle.properties.filename;
    case "text":
      return particle.properties.content.slice(0, 30);
    case "media":
      return particle.type;
  }
}

// --- Exit countdown hook ---

const EXIT_DELAY_MS = 5000;
const EXIT_TICK_MS = 100;

type PlaybackStatus = "idle" | "playing" | "ended";

function useExitCountdown(
  status: PlaybackStatus,
  composeActive: boolean,
  onExit: () => void,
) {
  const [remainingMs, setRemainingMs] = useState<number | null>(null);

  const handleExit = useEffectEvent(() => {
    onExit();
  });

  // Start/cancel countdown based on playback status
  useEffect(() => {
    if (status === "ended") {
      setRemainingMs(EXIT_DELAY_MS);
    } else {
      setRemainingMs(null);
    }
  }, [status]);

  // Tick the countdown down (pauses when compose is active)
  useEffect(() => {
    if (remainingMs === null || remainingMs <= 0 || composeActive) return;

    const interval = setInterval(() => {
      setRemainingMs((prev) => {
        if (prev === null) return null;
        const next = prev - EXIT_TICK_MS;
        return next <= 0 ? 0 : next;
      });
    }, EXIT_TICK_MS);

    return () => clearInterval(interval);
  }, [remainingMs !== null && remainingMs > 0, composeActive]);

  // Navigate once countdown hits zero
  useEffect(() => {
    if (remainingMs !== null && remainingMs <= 0) {
      handleExit();
    }
  }, [remainingMs]);

  return remainingMs;
}

// --- StreamView ---

interface StreamViewProps {
  streamParticle: Particle & { type: "stream" };
  path: ParticlePath;
}

export function StreamView({ path, streamParticle }: StreamViewProps) {
  const { networkId } = parseParticlePath(path);
  const navigate = useNavigate();

  const {
    children,
    currentParticle,
    currentIndex,
    status,
    paused,
    next,
    prev,
    goTo,
    goToParticle,
    pause,
    resume,
  } = useStreamPlayback(streamParticle, path);

  usePrefetchAdjacentMedia(children, currentIndex);

  const [composeActive, setComposeActive] = useState(false);
  const [progress, setProgress] = useState(0);

  const handleExitNavigate = useCallback(() => {
    navigate(`/${networkId}`);
  }, [navigate, networkId]);

  const exitRemainingMs = useExitCountdown(
    status,
    composeActive,
    handleExitNavigate,
  );

  // Reset progress when particle changes
  useEffect(() => {
    setProgress(0);
  }, [currentParticle?.id]);

  // Pause/resume playback when compose overlay opens/closes
  useEffect(() => {
    if (composeActive) pause();
    else resume();
  }, [composeActive, pause, resume]);

  // Playback keyboard: arrows, escape
  useEffect(() => {
    const handleKeyDown = (e: KeyboardEvent) => {
      if (composeActive) return;

      const target = e.target as HTMLElement;
      if (
        target.tagName === "INPUT" ||
        target.tagName === "TEXTAREA" ||
        target.isContentEditable
      ) {
        return;
      }

      switch (e.key) {
        case "ArrowRight":
        case "ArrowDown":
          e.preventDefault();
          next();
          break;
        case "ArrowLeft":
        case "ArrowUp":
          e.preventDefault();
          prev();
          break;
        case "Escape":
          e.preventDefault();
          navigate(`/${networkId}`);
          break;
        case "h": {
          e.preventDefault();
          const roomId = streamParticle.id;
          apiClient.getLivekitToken(roomId).then(({ token, server_url }) => {
            window.electronWindow.openHuddle({ token, serverUrl: server_url });
          });
          break;
        }
      }
    }
    window.addEventListener("keydown", handleKeyDown);
    return () => window.removeEventListener("keydown", handleKeyDown);
  },
    [composeActive, next, prev, navigate, networkId, streamParticle.id],
  );

  // Click-to-navigate: left 30% = prev, right 70% = next
  // Suppressed when the user has selected text (drag-to-select)
  const handlePlaybackClick = useCallback(
    (e: React.MouseEvent<HTMLDivElement>) => {
      const selection = window.getSelection();
      if (selection && selection.toString().length > 0) return;

      const rect = e.currentTarget.getBoundingClientRect();
      const x = (e.clientX - rect.left) / rect.width;
      if (x < 0.3) prev();
      else if (x > 0.7) next();
    },
    [prev, next],
  );

  const onLocalParticleCreated = useCallback(
    (particleId: string) => {
      goToParticle(particleId);
    }, [goToParticle]);

  if (children.length === 0) {
    return (
      <div className="flex h-full flex-col items-center justify-center gap-4 bg-black text-white">
        <p className="text-muted-foreground text-sm">
          No particles in this stream yet
        </p>
        <ControlsIndicator type="reply" showEscape={true}>
          <span>
            <kbd className="rounded bg-white/10 px-1.5 py-0.5 font-mono text-xs">
              H
            </kbd>{" "}
            huddle
          </span>
        </ControlsIndicator>
        <ComposeOverlay
          networkId={networkId}
          targetPath={path}
          onActiveChange={setComposeActive}
        />
      </div>
    );
  }

  // Render particle content inline
  function renderParticle(particle: Particle) {
    switch (particle.type) {
      case "media":
        return (
          <MediaParticleView
            key={particle.id}
            particle={particle}
            streamPath={path}
            paused={paused}
            onEnded={next}
            onProgress={setProgress}
          />
        );
      case "text":
        return (
          <TextParticleView
            key={particle.id}
            particle={particle}
            streamPath={path}
            paused={paused}
            onEnded={next}
            onProgress={setProgress}
          />
        );
      default:
        return <FallbackParticleView particle={particle} />;
    }
  }

  return (
    <div className="relative flex h-screen flex-col bg-black text-white">
      {/* Top gradient safe zone — keeps progress bar & breadcrumbs readable */}
      <div className="pointer-events-none absolute inset-x-0 top-0 z-[5] h-32 bg-gradient-to-b from-black/60 to-transparent" />

      {/* Bottom gradient safe zone — keeps captions & controls readable */}
      <div className="pointer-events-none absolute inset-x-0 bottom-0 z-[5] h-48 bg-gradient-to-t from-black/60 to-transparent" />

      {/* Progress indicator */}
      <div className="z-10 absolute left-0 right-0">
        <PlaybackPageIndicator
          total={children.length}
          current={currentIndex}
          progress={progress}
          onGoTo={goTo}
        />
      </div>

      <div className="z-10 absolute left-0 right-0 mt-3">
        <TopBar networkId={networkId} particle={currentParticle} streamParticle={streamParticle} />
      </div>

      {/* Main playback area */}
      <div className="flex-1 overflow-hidden">
        {currentParticle && (
          <div
            className="relative flex h-full w-full cursor-pointer items-center justify-center"
            onClick={handlePlaybackClick}
          >
            {renderParticle(currentParticle)}
          </div>
        )}
      </div>

      <ComposeOverlay
        networkId={networkId}
        targetPath={path}
        onActiveChange={setComposeActive}
        onParticleCreated={onLocalParticleCreated}
      />

      {/* Bottom-left: metadata */}
      <div className="absolute bottom-0 left-0 z-10 flex items-center gap-2 px-2 pb-2 text-xs text-white/70">
        {currentParticle && (
          <SeenIndicator stream={streamParticle} currentParticle={currentParticle} networkId={networkId} />
        )}
        {exitRemainingMs !== null && (
          <span className="rounded-full bg-black/30 px-2 py-1 backdrop-blur-sm">
            Closing in {Math.ceil(exitRemainingMs / 1000)}s
          </span>
        )}
      </div>

      {/* Bottom-center: controls */}
      <div className="absolute inset-x-0 bottom-0 z-10 flex justify-center pb-3">
        <ControlsIndicator type="reply" showEscape={true}>
          <span>
            <kbd className="rounded bg-white/10 px-1.5 py-0.5 font-mono text-xs">
              H
            </kbd>{" "}
            huddle
          </span>
        </ControlsIndicator>
      </div>
    </div>
  );
}

function TopBar({ networkId, particle, streamParticle }: { networkId: string; particle: Particle | null; streamParticle: Particle & { type: "stream" } }) {
  const navigate = useNavigate();

  return (
    <div className="drag-region flex flex-row px-4 gap-5 items-center">
      <WindowControls />

      <Breadcrumb className="no-drag rounded-full bg-black/30 backdrop-blur-sm px-3 py-1 mx-auto">
        <BreadcrumbList>
          {streamParticle && (
            <>
              <BreadcrumbItem className="text-xs">
                <BreadcrumbPage>{getParticleDisplayName(streamParticle)}</BreadcrumbPage>
              </BreadcrumbItem>
            </>
          )}

          {particle && (
            <>
              <BreadcrumbSeparator />
              <BreadcrumbItem className="text-xs">
                <BreadcrumbPage><ParticleBreadcrumbContent particle={particle} networkId={networkId} /></BreadcrumbPage>
              </BreadcrumbItem>
            </>
          )}
        </BreadcrumbList>
      </Breadcrumb>

      <Button
        variant="ghost"
        size="sm"
        className="no-drag text-muted-foreground"
        onClick={() => navigate("/settings")}
      >
        <Settings className="size-3.5" />
      </Button>
    </div>
  );
}

function NetworkBreadcrumbContent({ networkId }: { networkId: string }) {
  const { data: networks } = useNetworks();
  const network = networks?.find((n) => n.id === networkId);
  const name = network?.name ?? networkId;
  const initials = name.slice(0, 2).toUpperCase();

  return (
    <span className="flex items-center gap-1.5">
      <Avatar size="sm">
        <AvatarFallback>
          {initials}
        </AvatarFallback>
      </Avatar>
      {name}
    </span>
  );
}

function ParticleBreadcrumbContent({ particle, networkId }: { particle: Particle; networkId: string }) {
  const network = useNetwork(networkId);
  const creator = network?.humans?.find((h) => h.id === particle.created_by_human_id);
  const prefix = creator?.email_prefix ?? particle.created_by_human_id;
  const initials = prefix.slice(0, 2).toUpperCase();

  return (
    <span className="flex
        items-center gap-1.5">
      <Avatar size="sm">
        <AvatarFallback>
          {initials}
        </AvatarFallback>
      </Avatar>
      {prefix} - <RelativeTimestamp date={particle.created_at} />
    </span>
  )
}

// Shows a list of avatars of users who have seen the current particle, based on playback markers in the stream particle.
const SeenIndicator = ({ stream, currentParticle, networkId }: { stream: Particle & { type: "stream" }, currentParticle: Particle, networkId: string }) => {
  const authedUser = useAuthStore((s) => s.user);
  const network = useNetwork(networkId);
  const playbackMarkers = stream.playback_markers ?? {};

  const seenUserIds = Object.entries(playbackMarkers)
    .filter(([userId, timestamp]) => timestamp.getTime() >= currentParticle.created_at.getTime() && userId !== authedUser?.id)
    .map(([userId, _]) => userId);

  const seenHumans = seenUserIds
    .map((userId) => network?.humans?.find((h) => h.id === userId))
    .filter((h): h is NonNullable<typeof h> => !!h && h.id !== currentParticle.created_by_human_id);

  if (seenHumans.length === 0) return null;

  return (
    <>
      {"Seen by"}
      <AvatarGroup>
        {seenHumans.map((human) => (
          <Tooltip key={human.id}>
            <TooltipTrigger asChild>
              <Avatar size="sm">
                <AvatarFallback>
                  {human.email_prefix.slice(0, 2)}
                </AvatarFallback>
              </Avatar>
            </TooltipTrigger>
            <TooltipContent>
              <p>Seen by {human.email_prefix}</p>
            </TooltipContent>
          </Tooltip>
        ))}
      </AvatarGroup>
    </>
  );
}