import { query, mutation } from "./_generated/server";
import { v } from "convex/values";

export const listByUser = query({
  args: { userId: v.id("users") },
  handler: async (ctx, args) => {
    const allChats = await ctx.db.query("chats").order("desc").collect();
    return allChats.filter((chat) => chat.participantIds.includes(args.userId));
  },
});

export const getOrCreate = mutation({
  args: {
    token: v.string(),
    partnerId: v.id("users"),
  },
  handler: async (ctx, args) => {
    const session = await ctx.db
      .query("sessions")
      .withIndex("by_token", (q) => q.eq("token", args.token))
      .first();
    if (!session) throw new Error("Неавторизиран");

    const allChats = await ctx.db.query("chats").collect();
    const existing = allChats.find(
      (c) =>
        c.participantIds.includes(session.userId) &&
        c.participantIds.includes(args.partnerId) &&
        c.participantIds.length === 2
    );

    if (existing) return existing._id;

    const chatId = await ctx.db.insert("chats", {
      participantIds: [session.userId, args.partnerId],
      lastMessageAt: Date.now(),
      createdBy: session.userId,
    });

    return chatId;
  },
});