import type { Message } from "@langchain/langgraph-sdk";

import type { AgentThread, AgentThreadContext } from "./types";

type ThreadAgentRef = Pick<AgentThreadContext, "agent_id" | "agent_name">;

type ThreadRouteTarget =
  | string
  | {
      thread_id: string;
      context?: ThreadAgentRef | null;
      metadata?: Record<string, unknown> | null;
    };

function pickAgentRef(
  context: ThreadAgentRef | null | undefined,
  metadata: Record<string, unknown> | null | undefined,
): string | undefined {
  if (context?.agent_id) return context.agent_id;
  if (context?.agent_name) return context.agent_name;
  const metaId = metadata?.agent_id;
  if (typeof metaId === "string" && metaId) return metaId;
  const metaName = metadata?.agent_name;
  if (typeof metaName === "string" && metaName) return metaName;
  return undefined;
}

export function pathOfThread(
  thread: ThreadRouteTarget,
  context?: ThreadAgentRef | null,
) {
  const threadId = typeof thread === "string" ? thread : thread.thread_id;
  const agentRef =
    typeof thread === "string"
      ? pickAgentRef(context, null)
      : pickAgentRef(thread.context, thread.metadata);

  return agentRef
    ? `/workspace/agents/${encodeURIComponent(agentRef)}/chats/${threadId}`
    : `/workspace/chats/${threadId}`;
}

export function textOfMessage(message: Message) {
  if (typeof message.content === "string") {
    return message.content;
  } else if (Array.isArray(message.content)) {
    for (const part of message.content) {
      if (part.type === "text") {
        return part.text;
      }
    }
  }
  return null;
}

export function titleOfThread(thread: AgentThread) {
  return thread.values?.title ?? "Untitled";
}