// The agent loop. This is the whole idea behind an AI agent: call the model,
// run whatever tools it asks for, send the results back, repeat until it
// stops asking. The `on` hook lets the page animate each step; take it out
// and this is a complete, working loop.

import { SYSTEM_PROMPT, TOOLS, TASK, runTool } from "./world.js";

export async function agentLoop({ callModel, lake, maxTurns = 30, on = async () => {} }) {
  const messages = [{ role: "user", content: TASK }];
  await on("start", { messages });

  for (let turn = 1; turn <= maxTurns; turn++) {
    await on("request", { turn, messages });
    const response = await callModel({ system: SYSTEM_PROMPT, tools: TOOLS, messages });
    messages.push({ role: "assistant", content: response.content });
    await on("response", { turn, response, messages });

    // A long server-side turn can pause; sending the history back resumes it.
    if (response.stop_reason === "pause_turn") continue;
    // end_turn, max_tokens or refusal: the model is not asking for tools.
    if (response.stop_reason !== "tool_use") {
      await on("done", { stop: response.stop_reason, messages });
      return { stop: response.stop_reason, messages };
    }

    // Run every tool it asked for. All results go back in ONE user message.
    const results = [];
    for (const block of response.content) {
      if (block.type !== "tool_use") continue;
      const out = runTool(lake, block.name, block.input);
      results.push({
        type: "tool_result",
        tool_use_id: block.id,
        content: out.text,
        ...(out.isError ? { is_error: true } : {}),
      });
      await on("tool", { turn, block, out });
    }
    messages.push({ role: "user", content: results });
    await on("results", { turn, results, messages });
  }

  await on("done", { stop: "max_turns", messages });
  return { stop: "max_turns", messages };
}