import { MatrixClient, SimpleFsStorageProvider, AutojoinRoomsMixin } from "matrix-bot-sdk";
import { runChatTask } from "./runner.js";
import { askOpenRouter, DEFAULT_MODEL } from "./openrouter.js";

const HOMESERVER_URL = process.env.MATRIX_HOMESERVER_URL;
const ACCESS_TOKEN = process.env.MATRIX_BOT_TOKEN;
const CONTROL_ROOM_ID = process.env.MATRIX_CONTROL_ROOM_ID;
const GITEA_URL = process.env.GITEA_URL;

const MAX_REPLY_LENGTH = 4000;

// "!claude owner/repo do the thing" — everything after the repo slug is the instruction.
function parseClaudeCommand(text) {
  const match = text.match(/^!claude\s+([^\s/]+\/[^\s/]+)\s+(.+)$/s);
  if (!match) return null;
  const [, repoFullName, instruction] = match;
  return { repoFullName, instruction: instruction.trim() };
}

// "!ai <prompt>" uses the default model. "!ai provider/model <prompt>" (first token
// contains a "/") picks a specific OpenRouter model, e.g. "!ai google/gemini-2.0-flash-001
// summarize this repo's README".
function parseAiCommand(text) {
  const match = text.match(/^!ai\s+(.+)$/s);
  if (!match) return null;
  const rest = match[1].trim();
  const firstSpace = rest.search(/\s/);
  const firstToken = firstSpace === -1 ? rest : rest.slice(0, firstSpace);
  if (firstToken.includes("/") && firstSpace !== -1) {
    return { model: firstToken, prompt: rest.slice(firstSpace + 1).trim() };
  }
  return { model: DEFAULT_MODEL, prompt: rest };
}

function truncate(text) {
  if (text.length <= MAX_REPLY_LENGTH) return text;
  return `${text.slice(0, MAX_REPLY_LENGTH)}\n\n[truncated]`;
}

export async function startMatrixBot() {
  if (!HOMESERVER_URL || !ACCESS_TOKEN || !CONTROL_ROOM_ID) {
    console.warn("Matrix env vars not set — skipping bot startup");
    return;
  }

  const storage = new SimpleFsStorageProvider("/workspace/matrix-bot-storage.json");
  const client = new MatrixClient(HOMESERVER_URL, ACCESS_TOKEN, storage);
  AutojoinRoomsMixin.setupOnClient(client);

  client.on("room.message", async (roomId, event) => {
    // Invite-only control room enforces who can reach the bot at all; this just scopes
    // command handling to that one room. No need to fetch/compare the bot's own user ID
    // to filter out its own messages — its replies never match either command pattern
    // below, so they're ignored the same as any other non-command message.
    if (roomId !== CONTROL_ROOM_ID) return;
    const body = event.content?.body;
    if (!body) return;

    const aiCmd = parseAiCommand(body);
    if (aiCmd) {
      try {
        const reply = await askOpenRouter(aiCmd.model, aiCmd.prompt);
        await client.sendText(roomId, `[${aiCmd.model}] ${truncate(reply)}`);
      } catch (err) {
        console.error("openrouter query failed", err);
        await client.sendText(roomId, `Failed: ${err.message}`);
      }
      return;
    }

    const cmd = parseClaudeCommand(body);
    if (!cmd) return;

    const [owner, repo] = cmd.repoFullName.split("/");
    await client.sendText(roomId, `Working on it: ${cmd.repoFullName} — ${cmd.instruction}`);

    try {
      const cloneUrl = `${GITEA_URL}/${owner}/${repo}.git`;
      const pr = await runChatTask({ owner, repo, cloneUrl, instruction: cmd.instruction });
      await client.sendText(roomId, `Opened PR: ${pr.html_url}`);
    } catch (err) {
      console.error("chat task failed", err);
      await client.sendText(roomId, `Failed: ${err.message}`);
    }
  });

  await client.start();
  console.log("Matrix bot started, room:", CONTROL_ROOM_ID);
}