import type { AgentTickActivitySession } from "./types";

function envSessionId(): string | undefined {
   return process.env.AGENT_TICK_SESSION_ID?.trim() || undefined;
}

function envSessionTitle(): string | undefined {
   return process.env.AGENT_TICK_SESSION_TITLE?.trim() || undefined;
}

function normalizePiSessionId(sessionId: string | undefined): string | undefined {
   const trimmed = sessionId?.trim();
   if (!trimmed) return undefined;
   const sanitized = trimmed.replace(/[^A-Za-z0-9_.:-]+/g, "_").replace(/^_+|_+$/g, "").slice(0, 160);
   return sanitized ? `pi_${sanitized}` : undefined;
}

export function piSessionIdFromContext(ctx: unknown): string | undefined {
   const sessionManager = typeof ctx === "object" && ctx !== null && "sessionManager" in ctx
      ? (ctx as { sessionManager?: unknown }).sessionManager
      : undefined;
   if (!sessionManager || typeof sessionManager !== "object" || !("getSessionId" in sessionManager)) return undefined;
   const getSessionId = (sessionManager as { getSessionId?: unknown }).getSessionId;
   return typeof getSessionId === "function" ? String(getSessionId.call(sessionManager)) : undefined;
}

export class AgentTickSessionContext {
   private currentId = envSessionId();
   private currentTitle = envSessionTitle();

   usePiSessionId(piSessionId?: string): void {
      const normalizedPiSessionId = normalizePiSessionId(piSessionId);
      if (!envSessionId() && normalizedPiSessionId) this.currentId = normalizedPiSessionId;
   }

   startRun(title?: string, piSessionId?: string): AgentTickActivitySession {
      this.usePiSessionId(piSessionId);
      this.currentTitle = (envSessionTitle() ?? title?.trim()) || undefined;
      return this.current();
   }

   current(): AgentTickActivitySession {
      const title = envSessionTitle() ?? this.currentTitle;
      return {
         ...(envSessionId() ?? this.currentId ? { sessionId: envSessionId() ?? this.currentId } : {}),
         ...(title ? { session: { title } } : {}),
      };
   }
}

export function createAgentTickSessionContext(): AgentTickSessionContext {
   return new AgentTickSessionContext();
}