import {
  memo,
  useMemo,
  useState,
  type CSSProperties,
  type ReactNode,
  type Ref,
  type RefObject
} from "react";
import { GitFork } from "lucide-react";
import { ScrollArea } from "@tutti-os/ui-system/components";
import type { AgentActivitySessionForkLineage } from "@tutti-os/agent-activity-core";
import type { AgentMessageMarkdownWorkspaceAppIcon } from "../../../shared/AgentMessageMarkdown";
import type { AgentConversationVM } from "../../../shared/agentConversation/contracts/agentConversationVM";
import type { AgentGUIProviderSkillOption } from "../model/agentGuiNodeTypes";
import type { WorkspaceLinkAction } from "../../../actions/workspaceLinkActions";
import { AgentGUIConversationTimelinePane } from "./AgentGUIConversationTimelinePane";
import styles from "../AgentGUINode.styles";
import type { AgentTranscriptVirtualScrollController } from "../../../shared/agentConversation/components/AgentTranscriptView";
import type { AgentConversationFollowEndMode } from "../../../shared/agentConversation/agentConversationFollowEndController";
import type { AgentTranscriptEditRetryControl } from "../../../shared/agentConversation/components/useAgentTranscriptEditRetryProjection";
import type { AgentActivityEditRetryRecoveryAction } from "@tutti-os/agent-activity-core";
import type { AgentGUIEditRetryPresentation } from "../model/agentGUIEditRetryModel";
import { AgentGUIEditRetryStatus } from "./AgentGUIEditRetryStatus";
import {
  AgentGUITextSelectionActions,
  readAgentGUITextSelection,
  type AgentGUITextSelectionSnapshot
} from "./AgentGUITextSelectionActions";

const TIMELINE_CONTENT_STYLE: CSSProperties = {
  width: "100%",
  minWidth: "100%",
  display: "grid",
  gridTemplateColumns: "minmax(0, 1fr)",
  gap: "24px"
};

interface AgentGUIDetailTimelineProps {
  availableSkills: readonly AgentGUIProviderSkillOption[];
  conversation: AgentConversationVM | null;
  editRetry?: {
    control?: AgentTranscriptEditRetryControl;
    presentation: AgentGUIEditRetryPresentation;
    recover: (action: AgentActivityEditRetryRecoveryAction) => Promise<void>;
  };
  conversationFlowEmpty: React.JSX.Element;
  conversationFlowLabels: {
    thinkingLabel: string;
    toolCallsLabel: (count: number) => string;
    processing: string;
    turnSummary: string;
    userMessageLocator: string;
  };
  hasActiveConversation: boolean;
  followEndMode: AgentConversationFollowEndMode;
  forkedFrom?: AgentActivitySessionForkLineage | null;
  forkThroughTurnPendingTurnIds?: readonly string[];
  homeContent: ReactNode;
  isLoadingOlderMessages: boolean;
  isVisible: boolean;
  isTimelineScrolledToTop: boolean;
  labels: {
    loadingConversation: string;
    continuedFromTask: string;
    selectionAddToConversation: string;
    selectionAskInSide: string;
  };
  onAuthLogin?: (provider?: string | null) => void;
  onForkThroughTurn?: (turnId: string) => void;
  onOpenForkSourceSession?: (agentSessionId: string) => void;
  onLinkAction?: (action: WorkspaceLinkAction) => void;
  onAddSelectionToConversation: (text: string) => void;
  onAskSelectionInSide?: (text: string) => void;
  textSelectionActionsEnabled?: boolean;
  showTimelineSkeleton: boolean;
  showUnavailableChatEmpty: boolean;
  timelineContentRef: RefObject<HTMLDivElement | null>;
  timelineRef: RefObject<HTMLDivElement | null>;
  virtualScrollControllerRef: Ref<AgentTranscriptVirtualScrollController>;
  workspaceAppIcons: readonly AgentMessageMarkdownWorkspaceAppIcon[];
}

export const AgentGUIDetailTimeline = memo(function AgentGUIDetailTimeline({
  availableSkills,
  conversation,
  editRetry,
  conversationFlowEmpty,
  conversationFlowLabels,
  hasActiveConversation,
  followEndMode,
  forkedFrom,
  forkThroughTurnPendingTurnIds,
  homeContent,
  isLoadingOlderMessages,
  isVisible,
  isTimelineScrolledToTop,
  labels,
  onAuthLogin,
  onForkThroughTurn,
  onOpenForkSourceSession,
  onLinkAction,
  onAddSelectionToConversation,
  onAskSelectionInSide,
  textSelectionActionsEnabled = true,
  showTimelineSkeleton,
  showUnavailableChatEmpty,
  timelineContentRef,
  timelineRef,
  virtualScrollControllerRef,
  workspaceAppIcons
}: AgentGUIDetailTimelineProps): React.JSX.Element {
  "use memo";
  const [textSelection, setTextSelection] =
    useState<AgentGUITextSelectionSnapshot | null>(null);
  const forkLineageAttachments = useMemo(
    () =>
      forkedFrom?.targetTurnId
        ? [
            {
              id: `fork-lineage:${forkedFrom.operationId}`,
              anchorTurnId: forkedFrom.targetTurnId,
              missingAnchorBehavior: "hide" as const,
              content: (
                <div
                  className="my-3 flex w-full items-center gap-3 text-[14px] font-medium text-[var(--tutti-purple)]"
                  data-testid="agent-gui-fork-lineage"
                >
                  <span
                    className="h-px min-w-0 flex-1 bg-[var(--line-2,var(--tutti-line-2))]"
                    aria-hidden="true"
                  />
                  <button
                    type="button"
                    className="flex shrink-0 cursor-pointer items-center gap-2 rounded-md px-1 py-0.5 transition-opacity hover:opacity-80 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-[var(--tutti-purple)]"
                    onClick={() =>
                      onOpenForkSourceSession?.(forkedFrom.sourceAgentSessionId)
                    }
                  >
                    <GitFork width={16} height={16} aria-hidden="true" />
                    {labels.continuedFromTask}
                  </button>
                  <span
                    className="h-px min-w-0 flex-1 bg-[var(--line-2,var(--tutti-line-2))]"
                    aria-hidden="true"
                  />
                </div>
              )
            }
          ]
        : [],
    [
      forkedFrom?.operationId,
      forkedFrom?.sourceAgentSessionId,
      forkedFrom?.targetTurnId,
      labels.continuedFromTask,
      onOpenForkSourceSession
    ]
  );
  return (
    <>
      <ScrollArea
        scrollbarMode="native"
        className="flex h-full min-h-0 flex-1 flex-col [&_[data-orientation=vertical][data-slot=scroll-area-scrollbar]]:opacity-100"
        viewportRef={timelineRef}
        viewportContentRef={timelineContentRef}
        viewportTestId="agent-gui-timeline"
        viewportClassName={`${styles.timeline} ${
          hasActiveConversation
            ? styles.timelineWithComposer
            : styles.timelineCentered
        } ${
          !isTimelineScrolledToTop ? styles.timelineScrolledFromTop : ""
        } ${showUnavailableChatEmpty ? styles.timelineUnavailableChatEmpty : ""}`.trim()}
        viewportContentStyle={TIMELINE_CONTENT_STYLE}
        viewportProps={{
          onMouseUp: (event) =>
            setTextSelection(readAgentGUITextSelection(event.currentTarget)),
          onPointerDown: () => setTextSelection(null),
          onScroll: () => setTextSelection(null)
        }}
      >
        {hasActiveConversation ? (
          <>
            <AgentGUIConversationTimelinePane
              conversation={conversation}
              turnAttachments={forkLineageAttachments}
              editRetry={editRetry?.control}
              followEndMode={followEndMode}
              isLoading={showTimelineSkeleton}
              isLoadingOlderMessages={isLoadingOlderMessages}
              isVisible={isVisible}
              loadingLabel={labels.loadingConversation}
              empty={conversationFlowEmpty}
              onLinkAction={onLinkAction}
              onAuthLogin={onAuthLogin}
              onForkThroughTurn={onForkThroughTurn}
              forkThroughTurnPendingTurnIds={forkThroughTurnPendingTurnIds}
              availableSkills={availableSkills}
              workspaceAppIcons={workspaceAppIcons}
              labels={conversationFlowLabels}
              virtualScrollControllerRef={virtualScrollControllerRef}
            />
            {editRetry ? (
              <AgentGUIEditRetryStatus
                presentation={editRetry.presentation}
                onRecover={editRetry.recover}
              />
            ) : null}
          </>
        ) : (
          homeContent
        )}
      </ScrollArea>
      {textSelectionActionsEnabled &&
      hasActiveConversation &&
      textSelection &&
      timelineRef.current ? (
        <AgentGUITextSelectionActions
          labels={{
            addToConversation: labels.selectionAddToConversation,
            askInSide: labels.selectionAskInSide
          }}
          snapshot={textSelection}
          portalTarget={timelineRef.current.ownerDocument.body}
          onAddToConversation={onAddSelectionToConversation}
          onAskInSide={onAskSelectionInSide}
          onDismiss={() => setTextSelection(null)}
        />
      ) : null}
    </>
  );
});