"use server";

import { prisma } from "@/lib/db";
import { requireUserId } from "@/lib/auth-helpers";
import { categoryAccessFilter } from "@/lib/access";
import { formatGroupForPrompt } from "@/lib/ai/context";
import { callChatCompletion } from "@/lib/ai/chat-completion";

export interface StatusChatMessage {
  role: "user" | "assistant";
  content: string;
}

export type StatusChatResult = { content: string } | { error: string };

/**
 * Powers the group card's "Status Update" feature: with no prior
 * messages, produces an initial markdown status summary of the group
 * (notes + todos); with prior messages, answers a follow-up question
 * about it. One action rather than two "generate" / "ask" actions --
 * both are the same shape of call (group context + message history in,
 * plain text out), and splitting them would just duplicate the
 * group-loading and system-prompt code for no behavioral benefit. Unlike
 * lib/actions/group-ai.ts/todo-ai.ts, nothing here is ever saved, so
 * there's no ask/finalize JSON contract to parse -- just plain text.
 */
export async function converseAboutGroupStatus(
  groupId: string,
  messages: StatusChatMessage[]
): Promise<StatusChatResult> {
  const userId = await requireUserId();

  const group = await prisma.group.findFirst({
    where: { id: groupId, category: categoryAccessFilter(userId) },
    select: {
      title: true,
      noteContent: true,
      todos: { orderBy: { order: "asc" } },
    },
  });
  if (!group) return { error: "Group not found." };

  const context = formatGroupForPrompt({
    title: group.title,
    noteContent: group.noteContent,
    todos: group.todos.map((todo) => ({
      title: todo.title,
      details: todo.details,
      completed: todo.completed,
      completedAt: todo.completedAt?.toISOString() ?? null,
    })),
  });
  const systemPrompt = `You are summarizing one group ("${group.title}") from a to-do board for its owner. Here is everything known about it:

${context}

If there are no prior messages below, your reply must be a concise markdown status update: a couple of short paragraphs and/or a short list covering what this group is about, what's been done, and what's still outstanding. Do not repeat the group's title as a heading, and don't add commentary like "Here's the status update" -- output only the summary itself.

If there are prior messages below, they're a follow-up question about this group -- answer it using only the context above, in plain markdown, and say plainly if the answer isn't in the data.`;

  // An empty conversation means "generate the initial summary" -- a
  // synthetic, UI-invisible user turn keeps that a normal chat completion
  // call instead of a special-cased empty-messages request.
  const effectiveMessages: StatusChatMessage[] =
    messages.length > 0 ? messages : [{ role: "user", content: "Generate the status update now." }];

  return callChatCompletion([{ role: "system", content: systemPrompt }, ...effectiveMessages], {
    temperature: 0.3,
  });
}