import {
  normalizeAgentId,
  normalizeMainKey,
  resolveAgentIdFromSessionKey,
} from "../../routing/session-key.js";
import type { SessionScope } from "./types.js";

const FALLBACK_DEFAULT_AGENT_ID = "main";

function buildMainSessionKey(agentId: string, mainKey?: string): string {
  return `agent:${normalizeAgentId(agentId)}:${normalizeMainKey(mainKey)}`;
}

export function resolveMainSessionKey(cfg?: {
  session?: { scope?: SessionScope; mainKey?: string };
  agents?: { list?: Array<{ id?: string; default?: boolean }> };
}): string {
  if (cfg?.session?.scope === "global") {
    return "global";
  }
  const agents = cfg?.agents?.list ?? [];
  const defaultAgentId =
    agents.find((agent) => agent?.default)?.id ?? agents[0]?.id ?? FALLBACK_DEFAULT_AGENT_ID;
  return buildMainSessionKey(defaultAgentId, cfg?.session?.mainKey);
}

export { resolveAgentIdFromSessionKey };

export function resolveAgentMainSessionKey(params: {
  cfg?: { session?: { mainKey?: string } };
  agentId: string;
}): string {
  return buildMainSessionKey(params.agentId, params.cfg?.session?.mainKey);
}

export function resolveExplicitAgentSessionKey(params: {
  cfg?: { session?: { scope?: SessionScope; mainKey?: string } };
  agentId?: string | null;
}): string | undefined {
  const agentId = params.agentId?.trim();
  if (!agentId) {
    return undefined;
  }
  return resolveAgentMainSessionKey({ cfg: params.cfg, agentId });
}

export function canonicalizeMainSessionAlias(params: {
  cfg?: { session?: { scope?: SessionScope; mainKey?: string } };
  agentId: string;
  sessionKey: string;
}): string {
  const raw = params.sessionKey.trim();
  if (!raw) {
    return raw;
  }

  const agentId = normalizeAgentId(params.agentId);
  const mainKey = normalizeMainKey(params.cfg?.session?.mainKey);
  const agentMainSessionKey = buildMainSessionKey(agentId, mainKey);
  const agentMainAliasKey = buildMainSessionKey(agentId, "main");

  const isMainAlias =
    raw === "main" || raw === mainKey || raw === agentMainSessionKey || raw === agentMainAliasKey;

  if (params.cfg?.session?.scope === "global" && isMainAlias) {
    return "global";
  }
  if (isMainAlias) {
    return agentMainSessionKey;
  }
  return raw;
}