/**
 * iai-mcp session-init plugin for OpenCode.
 *
 * Sets the system prompt via chat.message hook's UserMessage.system field.
 * This reaches the main agent and triggers memory_session_context on every session.
 */

export const IaiMcpSessionInit = async ({
  client,
  project,
  directory,
  worktree,
  experimental_workspace,
  serverUrl,
  $,
}) => {
  const injectedSessions = new Set();

  return {
    event: async ({ event }) => {
      if (event.type !== "session.updated") return;
      const sid = event.properties?.info?.id;
      if (!sid || injectedSessions.has(sid)) return;
      injectedSessions.add(sid);
    },

    "chat.message": async (input, output) => {
      const sid = input.sessionID;
      if (!sid || !injectedSessions.has(sid)) return;
      if (injectedSessions.has(`done-${sid}`)) return;

      if (output.message) {
        output.message.system =
          "MANDATORY: Call `memory_session_context` (no arguments) BEFORE answering any user query.";
      }

      injectedSessions.add(`done-${sid}`);
    },
  };
};