import type {
  CanvasOperationKind,
  CanvasViewOperationPlan,
} from "@/types/canvas/agent-protocol";

function normalizeNodeIds(nodeIds?: string[]) {
  return Array.from(
    new Set(
      (nodeIds || [])
        .map((nodeId) => String(nodeId || "").trim())
        .filter(Boolean)
    )
  );
}

export function buildCanvasAgentResultViewOperation(params: {
  projectId?: string | null;
  operationId: string;
  mutationOperation?: CanvasOperationKind;
  sourceNodeIds?: string[];
  createdNodeIds?: string[];
  updatedNodeIds?: string[];
  anchorNodeId?: string | null;
  padding?: number;
  durationMs?: number;
  reason?: string;
}): CanvasViewOperationPlan | null {
  const projectId = String(params.projectId || "").trim();
  const operationId = String(params.operationId || "").trim();
  if (!projectId || !operationId) return null;

  const createdNodeIds = normalizeNodeIds(params.createdNodeIds);
  const sourceNodeIds = normalizeNodeIds(params.sourceNodeIds).filter(
    (nodeId) => !createdNodeIds.includes(nodeId)
  );
  const updatedNodeIds = normalizeNodeIds(params.updatedNodeIds).filter(
    (nodeId) => !createdNodeIds.includes(nodeId) && !sourceNodeIds.includes(nodeId)
  );
  const hasCreatedResult = createdNodeIds.length > 0;
  const comparisonNodeIds =
    hasCreatedResult && sourceNodeIds.length > 0
      ? [...sourceNodeIds, ...createdNodeIds]
      : [];
  const nodeIds =
    comparisonNodeIds.length > 0
      ? comparisonNodeIds
      : createdNodeIds.length > 0
        ? createdNodeIds
        : updatedNodeIds;
  if (nodeIds.length === 0) return null;

  const requestedAnchorNodeId = String(params.anchorNodeId || "").trim();
  const anchorNodeId =
    comparisonNodeIds.length > 0
      ? sourceNodeIds.includes(requestedAnchorNodeId)
        ? requestedAnchorNodeId
        : sourceNodeIds[0]
      : nodeIds.includes(requestedAnchorNodeId)
        ? requestedAnchorNodeId
        : nodeIds[0];
  const operation =
    nodeIds.length > 1
      ? "focus_nodes"
      : hasCreatedResult
        ? "focus_latest_result"
        : "focus_node";

  return {
    version: 1,
    viewOperationId: `${operationId}:view`,
    operation,
    projectId,
    nodeIds,
    anchorNodeId,
    padding: params.padding ?? 120,
    durationMs: params.durationMs ?? 360,
    persist: false,
    reason:
      params.reason ||
      (params.mutationOperation === "replace_node_media"
        ? "focus_canvas_agent_replaced_nodes"
        : comparisonNodeIds.length > 0
          ? "focus_canvas_agent_writeback_comparison"
        : hasCreatedResult
          ? "focus_canvas_agent_writeback_result"
          : "focus_canvas_agent_updated_nodes"),
  };
}