"use client";

import { useCallback, useEffect, useState } from "react";
import { DockviewDefaultTab, type IDockviewPanelHeaderProps } from "dockview-react";
import { IconStar } from "@tabler/icons-react";
import { AgentLogo } from "@/components/agent-logo";
import {
  ContextMenu,
  ContextMenuContent,
  ContextMenuItem,
  ContextMenuSeparator,
  ContextMenuTrigger,
} from "@kandev/ui/context-menu";
import {
  AlertDialog,
  AlertDialogAction,
  AlertDialogCancel,
  AlertDialogContent,
  AlertDialogDescription,
  AlertDialogFooter,
  AlertDialogHeader,
  AlertDialogTitle,
} from "@kandev/ui/alert-dialog";
import { useAppStore } from "@/components/state-provider";
import { useToast } from "@/components/toast-provider";
import { getWebSocketClient } from "@/lib/ws/connection";
import type { TaskSessionState } from "@/lib/types/http";

function isStoppable(s: TaskSessionState) {
  return s === "RUNNING" || s === "STARTING" || s === "WAITING_FOR_INPUT";
}
function isDeletable(s: TaskSessionState) {
  return s !== "RUNNING" && s !== "STARTING";
}
function isResumable(s: TaskSessionState) {
  return s === "COMPLETED" || s === "FAILED" || s === "CANCELLED";
}

function useSessionTabState(sessionId: string | undefined) {
  const isPrimary = useAppStore((state) => {
    const activeTaskId = state.tasks.activeTaskId;
    if (!activeTaskId || !sessionId) return false;
    const task = state.kanban.tasks.find((t: { id: string }) => t.id === activeTaskId);
    if (task?.primarySessionId) return task.primarySessionId === sessionId;
    return state.taskSessions.items[sessionId]?.is_primary === true;
  });
  const sessionState = useAppStore((state) => {
    if (!sessionId) return null;
    return state.taskSessions.items[sessionId]?.state ?? null;
  }) as TaskSessionState | null;
  const taskId = useAppStore((state) => state.tasks.activeTaskId);
  const agentLabel = useAppStore((state) => {
    if (!sessionId) return null;
    const session = state.taskSessions.items[sessionId];
    if (!session?.agent_profile_id) return null;
    const profile = state.agentProfiles.items.find(
      (p: { id: string }) => p.id === session.agent_profile_id,
    );
    if (!profile) return null;
    const parts = profile.label.split(" \u2022 ");
    return parts[1] || parts[0] || profile.label;
  });
  const agentName = useAppStore((state) => {
    if (!sessionId) return null;
    const session = state.taskSessions.items[sessionId];
    if (!session?.agent_profile_id) return null;
    return (
      state.agentProfiles.items.find((p: { id: string }) => p.id === session.agent_profile_id)
        ?.agent_name ?? null
    );
  });
  const sessionNumber = useAppStore((state) => {
    if (!sessionId) return null;
    const activeTaskId = state.tasks.activeTaskId;
    const sessions = activeTaskId ? state.taskSessionsByTask.itemsByTaskId[activeTaskId] : null;
    if (!sessions) return null;
    // Sort chronologically (oldest first) so indexes are stable regardless of
    // which session is primary or the backend's default DESC ordering.
    const sorted = [...sessions].sort(
      (a: { started_at: string }, b: { started_at: string }) =>
        new Date(a.started_at).getTime() - new Date(b.started_at).getTime(),
    );
    const idx = sorted.findIndex((s: { id: string }) => s.id === sessionId);
    return idx >= 0 ? idx + 1 : null;
  });
  const sessionCount = useAppStore((state) => {
    const activeTaskId = state.tasks.activeTaskId;
    if (!activeTaskId) return 0;
    return state.taskSessionsByTask.itemsByTaskId[activeTaskId]?.length ?? 0;
  });
  return { isPrimary, sessionState, taskId, agentLabel, agentName, sessionNumber, sessionCount };
}

function useSessionTabActions(
  sessionId: string | undefined,
  taskId: string | null,
  api: IDockviewPanelHeaderProps["api"],
  containerApi: IDockviewPanelHeaderProps["containerApi"],
) {
  const { toast, updateToast } = useToast();
  const removeTaskSession = useAppStore((state) => state.removeTaskSession);

  const wsAction = useCallback(
    async (action: string, label: string, payload: Record<string, unknown>, timeout = 15000) => {
      const client = getWebSocketClient();
      if (!client) return;
      const toastId = toast({ title: `${label}...`, variant: "loading" });
      try {
        await client.request(action, payload, timeout);
        updateToast(toastId, { title: `${label} successful`, variant: "success" });
      } catch (error) {
        const msg = error instanceof Error ? error.message : "Unknown error";
        updateToast(toastId, { title: `${label} failed`, description: msg, variant: "error" });
      }
    },
    [toast, updateToast],
  );

  const handleSetPrimary = useCallback(
    () => sessionId && wsAction("session.set_primary", "Set primary", { session_id: sessionId }),
    [sessionId, wsAction],
  );
  const handleStop = useCallback(
    () => sessionId && wsAction("session.stop", "Stopping session", { session_id: sessionId }),
    [sessionId, wsAction],
  );
  const handleResume = useCallback(
    () =>
      sessionId &&
      taskId &&
      wsAction(
        "session.launch",
        "Resuming session",
        { task_id: taskId, intent: "resume", session_id: sessionId },
        30000,
      ),
    [sessionId, taskId, wsAction],
  );
  const handleDelete = useCallback(async () => {
    if (!sessionId || !taskId) return;
    await wsAction("session.delete", "Deleting session", { session_id: sessionId });
    removeTaskSession(taskId, sessionId);
    const panel = containerApi.getPanel(api.id);
    if (panel) containerApi.removePanel(panel);
  }, [sessionId, taskId, wsAction, removeTaskSession, api.id, containerApi]);
  const handleCloseOthers = useCallback(() => {
    const toClose = api.group.panels.filter((p) => p.id !== api.id);
    for (const panel of toClose) containerApi.removePanel(panel);
  }, [api, containerApi]);

  return { handleSetPrimary, handleStop, handleResume, handleDelete, handleCloseOthers };
}

function DeleteSessionDialog({
  open,
  onOpenChange,
  isPrimary,
  sessionCount,
  onConfirm,
}: {
  open: boolean;
  onOpenChange: (open: boolean) => void;
  isPrimary: boolean;
  sessionCount: number;
  onConfirm: () => void;
}) {
  return (
    <AlertDialog open={open} onOpenChange={onOpenChange}>
      <AlertDialogContent>
        <AlertDialogHeader>
          <AlertDialogTitle>Delete session?</AlertDialogTitle>
          <AlertDialogDescription asChild>
            <div>
              <p>This will permanently delete the conversation history with this session.</p>
              {isPrimary && sessionCount > 1 && (
                <p className="mt-2 font-medium">
                  This is the primary session. Another session will be set as primary.
                </p>
              )}
              {sessionCount === 1 && (
                <p className="mt-2 font-medium">This is the only session for this task.</p>
              )}
            </div>
          </AlertDialogDescription>
        </AlertDialogHeader>
        <AlertDialogFooter>
          <AlertDialogCancel className="cursor-pointer">Cancel</AlertDialogCancel>
          <AlertDialogAction
            onClick={() => {
              onOpenChange(false);
              onConfirm();
            }}
            className="cursor-pointer bg-destructive text-destructive-foreground hover:bg-destructive/90"
          >
            Delete
          </AlertDialogAction>
        </AlertDialogFooter>
      </AlertDialogContent>
    </AlertDialog>
  );
}

function SessionContextMenuItems({
  sessionState,
  isPrimary,
  actions,
  onDelete,
}: {
  sessionState: TaskSessionState | null;
  isPrimary: boolean;
  actions: ReturnType<typeof useSessionTabActions>;
  onDelete: () => void;
}) {
  return (
    <ContextMenuContent>
      <ContextMenuItem
        className="cursor-pointer"
        onSelect={actions.handleSetPrimary}
        disabled={isPrimary || !sessionState || !isStoppable(sessionState)}
      >
        Set as Primary
      </ContextMenuItem>
      <ContextMenuSeparator />
      {sessionState && isStoppable(sessionState) && (
        <ContextMenuItem className="cursor-pointer" onSelect={actions.handleStop}>
          Stop
        </ContextMenuItem>
      )}
      {sessionState && isResumable(sessionState) && (
        <ContextMenuItem className="cursor-pointer" onSelect={actions.handleResume}>
          Resume
        </ContextMenuItem>
      )}
      {sessionState && isDeletable(sessionState) && (
        <ContextMenuItem className="cursor-pointer text-destructive" onSelect={onDelete}>
          Delete
        </ContextMenuItem>
      )}
      <ContextMenuSeparator />
      <ContextMenuItem className="cursor-pointer" onSelect={actions.handleCloseOthers}>
        Close Others
      </ContextMenuItem>
    </ContextMenuContent>
  );
}

/**
 * Custom dockview tab for session panels.
 * Shows agent logo, index badge, and star for primary; right-click for lifecycle actions.
 */
export function SessionTab(props: IDockviewPanelHeaderProps) {
  const { api, containerApi } = props;
  const sessionId = api.id.startsWith("session:") ? api.id.slice("session:".length) : undefined;
  const { isPrimary, sessionState, taskId, agentLabel, agentName, sessionNumber, sessionCount } =
    useSessionTabState(sessionId);
  const actions = useSessionTabActions(sessionId, taskId, api, containerApi);
  const [confirmDelete, setConfirmDelete] = useState(false);
  const [isActive, setIsActive] = useState(api.isActive);

  useEffect(() => {
    const disposable = api.onDidActiveChange((e) => setIsActive(e.isActive));
    return () => disposable.dispose();
  }, [api]);

  useEffect(() => {
    if (agentLabel && api.title !== agentLabel) api.setTitle(agentLabel);
  }, [agentLabel, api]);

  const showMultiSessionBadges = sessionCount > 1;

  return (
    <>
      <ContextMenu>
        <ContextMenuTrigger
          className="flex h-full items-center cursor-pointer"
          data-testid={sessionId ? `session-tab-${sessionId}` : undefined}
        >
          <div className="flex items-center">
            {isPrimary && showMultiSessionBadges && (
              <IconStar className="h-3 w-3 fill-foreground/50 stroke-0 shrink-0 ml-2" />
            )}
            {sessionNumber != null && showMultiSessionBadges && (
              <span className="ml-1.5 text-[11px] font-medium leading-none text-muted-foreground bg-foreground/10 rounded px-1.5 py-0.5">
                {sessionNumber}
              </span>
            )}
            {agentName && (
              <AgentLogo
                agentName={agentName}
                size={14}
                className={`ml-1.5 shrink-0${isActive ? "" : " opacity-50"}`}
              />
            )}
            <DockviewDefaultTab {...props} hideClose={sessionCount <= 1} />
          </div>
        </ContextMenuTrigger>
        <SessionContextMenuItems
          sessionState={sessionState}
          isPrimary={isPrimary}
          actions={actions}
          onDelete={() => setConfirmDelete(true)}
        />
      </ContextMenu>
      <DeleteSessionDialog
        open={confirmDelete}
        onOpenChange={setConfirmDelete}
        isPrimary={isPrimary}
        sessionCount={sessionCount}
        onConfirm={actions.handleDelete}
      />
    </>
  );
}