import React, { useCallback, useEffect, useRef, useState } from "react";
import { useNavigate, useParams } from "react-router-dom";
import type { TerminalRef } from "../components/features/terminal/terminal";
import type { TerminalSessionInfo } from "../components/features/terminal/terminal-session-tabs";
import { useMobileViewport } from "./use-mobile-viewport";
import { useAutoHide } from "./use-auto-hide";
import { useVirtualKeyboard } from "./use-virtual-keyboard";
import { useTerminalSessions } from "./use-terminal-sessions";
import type { TerminalSession } from "../api/terminal";
import type { ModifierKey } from "./use-special-keys";

const SESSIONS_TO_INFO = (sessions: TerminalSession[]): TerminalSessionInfo[] =>
  sessions.map((s) => ({
    id: s.id,
    name: s.name,
    status: s.status as TerminalSessionInfo["status"],
  }));

type TerminalStatus =
  | "connecting"
  | "connected"
  | "disconnected"
  | "error"
  | "resetting";

export const useTerminalPage = () => {
  const { instanceId } = useParams<{ instanceId: string }>();
  const navigate = useNavigate();
  const isMobile = useMobileViewport();
  const [isFullscreen, setIsFullscreen] = useState(false);
  const terminalRefs = useRef<Record<string, React.RefObject<TerminalRef>>>({});
  const headerAutoHide = useAutoHide({ timeout: 3000, enabled: isMobile });

  const [terminalStatuses, setTerminalStatuses] = useState<
    Record<string, TerminalStatus>
  >({});
  const changeFontSizeRefs = useRef<
    Record<string, ((delta: number) => void) | null>
  >({});
  const sendDataRefs = useRef<Record<string, ((data: string) => void) | null>>(
    {},
  );
  const focusInputRefs = useRef<Record<string, (() => void) | null>>({});
  const [showResetConfirm, setShowResetConfirm] = useState(false);
  const [showSpecialKeysPanel, setShowSpecialKeysPanel] = useState(false);
  const [activeModifier, setActiveModifier] = useState<ModifierKey | null>(
    null,
  );
  const { isOpen: isKeyboardOpen, height: keyboardHeight } =
    useVirtualKeyboard();

  const [instanceInfo, setInstanceInfo] = useState<{
    display_name: string;
    workspace_name?: string | null;
    tool_type_name: string;
  } | null>(null);

  const {
    sessions,
    activeSessionId,
    setActiveSessionId,
    createSession,
    closeSession,
    renameSession,
    resetSession,
    loading,
    error,
  } = useTerminalSessions(instanceId ?? "");

  // Fetch instance details for tab title
  useEffect(() => {
    if (!instanceId) return;
    const load = async () => {
      try {
        const { getUserSessions } = await import("../api/sessions");
        const allSessions = await getUserSessions();
        const match = allSessions.find((s) => s.id === instanceId);
        if (match) {
          setInstanceInfo({
            display_name: match.display_name,
            workspace_name: match.workspace_name,
            tool_type_name: match.tool_type_name,
          });
        }
      } catch {
        // ignore
      }
    };
    void load();
  }, [instanceId]);

  // Auto-create default session
  useEffect(() => {
    if (!loading && sessions.length === 0 && !error && instanceId) {
      void createSession("Session 1");
    }
  }, [loading, sessions.length, error, instanceId, createSession]);

  // Update document title based on active terminal session
  useEffect(() => {
    if (!instanceId) {
      document.title = "Terminal";
      return;
    }
    const active = sessions.find((s) => s.id === activeSessionId);
    const baseName = instanceInfo
      ? `${instanceInfo.workspace_name ?? instanceInfo.display_name} · ${instanceInfo.tool_type_name}`
      : `Instance ${instanceId.slice(0, 8)}`;
    if (sessions.length <= 1) {
      document.title = baseName;
    } else {
      const sessionName = active?.name ?? "Session";
      document.title = `${baseName} ${sessionName}`;
    }
    return () => {
      document.title = "Headquarter";
    };
  }, [instanceId, activeSessionId, sessions, instanceInfo]);

  // Sync refs with sessions
  useEffect(() => {
    for (const session of sessions) {
      if (!terminalRefs.current[session.id]) {
        terminalRefs.current[session.id] = React.createRef<TerminalRef>();
      }
    }
    const currentIds = new Set(sessions.map((s) => s.id));
    for (const id of Object.keys(terminalRefs.current)) {
      if (!currentIds.has(id)) {
        delete terminalRefs.current[id];
        delete sendDataRefs.current[id];
        delete focusInputRefs.current[id];
        delete changeFontSizeRefs.current[id];
      }
    }
    setTerminalStatuses((prev) => {
      const next: Record<string, TerminalStatus> = {};
      for (const id of currentIds) {
        if (prev[id]) {
          next[id] = prev[id];
        }
      }
      return next;
    });
  }, [sessions]);

  // Fit and focus active terminal
  useEffect(() => {
    if (activeSessionId && terminalRefs.current[activeSessionId]) {
      const ref = terminalRefs.current[activeSessionId];
      let raf1 = 0;
      let raf2 = 0;
      raf1 = requestAnimationFrame(() => {
        raf2 = requestAnimationFrame(() => {
          ref.current?.fit();
          ref.current?.focus();
        });
      });
      return () => {
        cancelAnimationFrame(raf1);
        cancelAnimationFrame(raf2);
      };
    }
  }, [activeSessionId]);

  // Keyboard shortcuts
  useEffect(() => {
    const handleKeyDown = (e: KeyboardEvent) => {
      const isAltShift = e.altKey && e.shiftKey && !e.ctrlKey && !e.metaKey;
      if (!isAltShift) return;

      const activeSessionIndex = activeSessionId
        ? sessions.findIndex((session) => session.id === activeSessionId)
        : -1;

      switch (e.key.toLowerCase()) {
        case "n":
          e.preventDefault();
          if (sessions.length < 5) {
            void createSession(`Session ${sessions.length + 1}`);
          }
          break;
        case "w":
          e.preventDefault();
          if (
            activeSessionId &&
            window.confirm("Close this terminal session?")
          ) {
            void closeSession(activeSessionId);
          }
          break;
        case "arrowleft":
          e.preventDefault();
          if (activeSessionIndex > 0) {
            setActiveSessionId(sessions[activeSessionIndex - 1].id);
          }
          break;
        case "arrowright":
          e.preventDefault();
          if (activeSessionIndex >= 0 && activeSessionIndex < sessions.length - 1) {
            setActiveSessionId(sessions[activeSessionIndex + 1].id);
          }
          break;
        case "r":
          e.preventDefault();
          if (activeSessionId) void resetSession(activeSessionId);
          break;
        case "f":
          e.preventDefault();
          setIsFullscreen((prev) => !prev);
          break;
        default:
          break;
      }
    };

    window.addEventListener("keydown", handleKeyDown);
    return () => window.removeEventListener("keydown", handleKeyDown);
  }, [
    sessions,
    activeSessionId,
    createSession,
    closeSession,
    resetSession,
    setActiveSessionId,
  ]);

  // Keep screen awake
  useEffect(() => {
    let wakeLock: WakeLockSentinel | null = null;
    const requestWakeLock = async () => {
      try {
        if ("wakeLock" in navigator) {
          wakeLock = await navigator.wakeLock.request("screen");
        }
      } catch {
        // ignore
      }
    };
    void requestWakeLock();
    const handleVisibilityChange = () => {
      if (document.visibilityState === "visible") void requestWakeLock();
    };
    document.addEventListener("visibilitychange", handleVisibilityChange);
    return () => {
      document.removeEventListener("visibilitychange", handleVisibilityChange);
      wakeLock?.release().catch(() => {});
    };
  }, []);

  // Lock page scroll on mobile
  useEffect(() => {
    if (!isMobile) return;
    document.documentElement.classList.add("terminal-page-open");
    document.body.classList.add("terminal-page-open");
    return () => {
      document.documentElement.classList.remove("terminal-page-open");
      document.body.classList.remove("terminal-page-open");
    };
  }, [isMobile]);

  const handleFullscreenClick = useCallback(
    (e: React.MouseEvent<HTMLElement>) => {
      if (!isFullscreen) return;
      const target = e.target as Node;
      const current = e.currentTarget as HTMLElement;
      const content = current.querySelector(".terminal-page-content");
      const header = current.querySelector(".terminal-fullscreen-header");
      if (content?.contains(target) || header?.contains(target)) return;
      setIsFullscreen(false);
    },
    [isFullscreen],
  );

  const handleSelect = useCallback(
    (sessionId: string) => setActiveSessionId(sessionId),
    [setActiveSessionId],
  );

  const handleClose = useCallback(
    async (sessionId: string) => closeSession(sessionId),
    [closeSession],
  );

  const handleCreate = useCallback(() => {
    void createSession(`Session ${sessions.length + 1}`);
  }, [createSession, sessions.length]);

  const handleRename = useCallback(
    (sessionId: string, newName: string) => {
      void renameSession(sessionId, newName);
    },
    [renameSession],
  );

  const handleTerminalReady = useCallback(
    (
      sessionId: string | undefined,
      sendData: (data: string) => void,
      status: TerminalStatus,
      focusInput: () => void,
      changeFontSize: (delta: number) => void,
    ) => {
      const key = sessionId ?? "default";
      setTerminalStatuses((prev) => ({
        ...prev,
        [key]: status,
      }));
      sendDataRefs.current[key] = sendData;
      focusInputRefs.current[key] = focusInput;
      changeFontSizeRefs.current[key] = changeFontSize;
    },
    [],
  );

  const handleFontSizeChange = useCallback(
    (delta: number) => {
      const key = activeSessionId ?? "default";
      changeFontSizeRefs.current[key]?.(delta);
    },
    [activeSessionId],
  );

  const handleSendKey = useCallback(
    (data: string) => {
      const key = activeSessionId ?? "default";
      sendDataRefs.current[key]?.(data);
    },
    [activeSessionId],
  );

  const handleReset = useCallback(() => {
    if (activeSessionId && terminalRefs.current[activeSessionId]) {
      terminalRefs.current[activeSessionId].current?.reset();
    }
  }, [activeSessionId]);

  return {
    instanceId,
    navigate,
    isMobile,
    isFullscreen,
    setIsFullscreen,
    terminalRefs,
    headerAutoHide,
    terminalStatuses,
    showResetConfirm,
    setShowResetConfirm,
    showSpecialKeysPanel,
    setShowSpecialKeysPanel,
    activeModifier,
    setActiveModifier,
    isKeyboardOpen,
    keyboardHeight,
    sessions,
    activeSessionId,
    setActiveSessionId,
    loading,
    error,
    handleFullscreenClick,
    handleSelect,
    handleClose,
    handleCreate,
    handleRename,
    handleTerminalReady,
    handleFontSizeChange,
    handleSendKey,
    handleReset,
    sessionInfos: SESSIONS_TO_INFO(sessions),
  };
};