/**
 * S-03 — send-keys input route.
 *
 * POST /sessions/:id/input
 *
 * Body (IC-1 ClientToServer subset, but as HTTP POST for non-WS clients):
 *   { type: "key"; name: string }
 *   { type: "keys"; data: string }
 *   { type: "paste"; data: string }
 *
 * Response: 204 No Content on success, 400 on bad input, 404 if session missing.
 *
 * Note: the primary path for send-keys is via WS (T-1.5 stream route handles
 * key/keys/paste messages inline). This HTTP endpoint is for clients that
 * don't have an open stream (e.g. one-shot CLI tools).
 *
 * Owner: T-1.5
 */

import type { IncomingMessage, ServerResponse } from "node:http";
import { sendKey, sendKeys, sendPaste } from "../../tmux/input.js";
import { getSession } from "../../tmux/manager.js";
import { readBody, sendJson } from "../util.js";

export async function handleInput(
  req: IncomingMessage,
  res: ServerResponse,
  sessionId: string,
): Promise<void> {
  const session = await getSession(sessionId).catch(() => null);
  if (!session) {
    sendJson(res, 404, {
      error: "session_not_found",
      message: `Session "${sessionId}" not found`,
    });
    return;
  }

  let body: unknown;
  try {
    body = JSON.parse(await readBody(req));
  } catch {
    sendJson(res, 400, { error: "bad_request", message: "Invalid JSON body" });
    return;
  }

  if (!body || typeof body !== "object") {
    sendJson(res, 400, {
      error: "bad_request",
      message: "Body must be a JSON object",
    });
    return;
  }

  const m = body as Record<string, unknown>;

  try {
    switch (m.type) {
      case "key": {
        if (typeof m.name !== "string") {
          sendJson(res, 400, {
            error: "bad_request",
            message: "key.name must be a string",
          });
          return;
        }
        await sendKey(sessionId, m.name);
        break;
      }
      case "keys": {
        if (typeof m.data !== "string") {
          sendJson(res, 400, {
            error: "bad_request",
            message: "keys.data must be a string",
          });
          return;
        }
        await sendKeys(sessionId, m.data);
        break;
      }
      case "paste": {
        if (typeof m.data !== "string") {
          sendJson(res, 400, {
            error: "bad_request",
            message: "paste.data must be a string",
          });
          return;
        }
        await sendPaste(sessionId, m.data);
        break;
      }
      default:
        sendJson(res, 400, {
          error: "bad_request",
          message: `Unknown type: ${String(m.type)}`,
        });
        return;
    }
  } catch (err) {
    sendJson(res, 500, { error: "internal_error", message: String(err) });
    return;
  }

  res.writeHead(204).end();
}