import { nanoid } from "nanoid";
import type {
  AssistantConversationItem,
  AssistantDebugPayload,
  AssistantMessageResponsePayload,
  AssistantReplyType
} from "../types/assistant";
import type { CommitAssistantTurnAndLogOutput } from "./assistantTurnCommitRuntimeAdapter";
import { commitAssistantTurnAndLog } from "./assistantTurnCommitRuntimeAdapter";

export interface LivingModeDecisionForFinalize {
  mode?: string | null;
  reason?: string | null;
}

export interface FinalizeAssistantLivingChatTurnInput {
  sessionId: string;
  userMessage: string;
  assistantReply: string;
  replyType: AssistantReplyType;
  debug: AssistantDebugPayload | Record<string, unknown>;
  modeDecision?: LivingModeDecisionForFinalize | null;
  appendItem: Parameters<typeof commitAssistantTurnAndLog>[0]["appendItem"];
  getSession: Parameters<typeof commitAssistantTurnAndLog>[0]["getSession"];
  persistSession: Parameters<typeof commitAssistantTurnAndLog>[0]["persistSession"];
  cloneConversation: Parameters<typeof commitAssistantTurnAndLog>[0]["cloneConversation"];
  logEvent: Parameters<typeof commitAssistantTurnAndLog>[0]["logEvent"];
  messageIdFactory?: () => string;
  nowIso?: () => string;
  commitFn?: typeof commitAssistantTurnAndLog;
}

export interface FinalizeAssistantLivingChatTurnOutput {
  assistantItem: AssistantConversationItem;
  commitResult: CommitAssistantTurnAndLogOutput;
  response: AssistantMessageResponsePayload;
}

function toTraceId(debug: AssistantDebugPayload | Record<string, unknown>): string | null {
  const value = (debug as Record<string, unknown> | null | undefined)?.trace_id;
  if (typeof value !== "string") {
    return null;
  }
  const trimmed = value.trim();
  return trimmed.length > 0 ? trimmed : null;
}

export function finalizeAssistantLivingChatTurn(
  input: FinalizeAssistantLivingChatTurnInput
): FinalizeAssistantLivingChatTurnOutput {
  const nowIso = input.nowIso ?? (() => new Date().toISOString());
  const messageIdFactory = input.messageIdFactory ?? (() => `msg-${nanoid(10)}`);
  const commitSafe = input.commitFn ?? commitAssistantTurnAndLog;
  const assistantItem: AssistantConversationItem = {
    message_id: messageIdFactory(),
    session_id: input.sessionId,
    role: "assistant",
    text: input.assistantReply,
    reply_type: input.replyType,
    created_at: nowIso(),
    trace_id: toTraceId(input.debug),
    debug: input.debug as AssistantDebugPayload
  };
  const logDetails = {
    session_id: input.sessionId,
    message_id: assistantItem.message_id,
    user_message: input.userMessage,
    living_router_mode: input.modeDecision?.mode ?? "chat",
    living_router_reason: input.modeDecision?.reason ?? "living_chat_signal_detected",
    assistant_reply: assistantItem.text,
    reply_type: assistantItem.reply_type,
    trace_id: assistantItem.trace_id
  };
  const commitResult = commitSafe({
    sessionId: input.sessionId,
    assistantItem,
    eventType: "assistant_message_chat",
    logDetails,
    appendItem: input.appendItem,
    getSession: input.getSession,
    persistSession: input.persistSession,
    cloneConversation: input.cloneConversation,
    logEvent: input.logEvent
  });
  const response: AssistantMessageResponsePayload = {
    ok: true,
    session_id: input.sessionId,
    assistant_reply: assistantItem.text,
    reply_type: assistantItem.reply_type as AssistantReplyType,
    conversation_item: assistantItem,
    debug: input.debug as AssistantDebugPayload,
    conversation: commitResult.conversation
  };
  return {
    assistantItem,
    commitResult,
    response
  };
}