import { fail, handleOptions, json } from "../_shared/http.ts";
import { requireUser } from "../_shared/supabase.ts";

Deno.serve(async (req) => {
  const preflight = handleOptions(req);
  if (preflight) return preflight;

  if (req.method !== "POST") return fail("Method not allowed", 405);

  const { client, user, error: userError } = await requireUser(req);
  if (!user) return fail(userError ?? "Unauthorized", 401);

  let body: { channel_id?: string; before?: string; limit?: number };
  try {
    body = await req.json();
  } catch {
    return fail("Invalid JSON body");
  }

  const channelId = body.channel_id;
  if (!channelId) return fail("channel_id is required");

  const limit = Math.max(1, Math.min(Number(body.limit) || 50, 100));
  const before = body.before?.trim();

  let query = client
    .from("messages")
    .select("id, channel_id, author_user_id, content, created_at, edited_at")
    .eq("channel_id", channelId)
    .is("deleted_at", null)
    .order("created_at", { ascending: false })
    .limit(limit);

  if (before) {
    query = query.lt("created_at", before);
  }

  const { data: rows, error } = await query;
  if (error) {
    if (error.code === "42501") return fail("forbidden", 403);
    return fail(error.message, 400);
  }

  return json({
    messages: (rows ?? []).reverse(),
    next_before: rows && rows.length > 0 ? rows[rows.length - 1].created_at : null,
  });
});