import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";

export default function (pi: ExtensionAPI) {
  // --- Configuration ---
  const MODEL_PREFIX_REGEX = /^qwen3/i;
  const PREPEND_TEXT = `You are Qwen, created by Alibaba Cloud. You are a helpful assistant.`;

  // --- Extension logic ---

  pi.on("session_start", async (_event, ctx) => {
    const modelId = ctx.model?.id;
    if (modelId && MODEL_PREFIX_REGEX.test(modelId)) {
      ctx.ui.notify(`Qwen3 prompt: active (model: ${modelId})`, "info");
    }
  });

  pi.on("model_select", async (event, ctx) => {
    const modelId = event.model.id;
    if (MODEL_PREFIX_REGEX.test(modelId)) {
      ctx.ui.notify(`Qwen3 prompt: enabled for ${modelId}`, "info");
    }
  });

  pi.on("before_agent_start", async (event, ctx) => {
    const modelId = ctx.model?.id;
    if (!modelId) return;
    if (!MODEL_PREFIX_REGEX.test(modelId)) return;

    return {
      systemPrompt: PREPEND_TEXT + "\n\n" + event.systemPrompt,
    };
  });
}