import { useState, useEffect, useCallback } from "react";
import type { SessionEntry, SessionDetailResponse } from "../lib/types";

interface SessionState {
  sessions: SessionEntry[];
  sessionsLoading: boolean;
  sessionsError: string | null;
  currentSession: SessionDetailResponse | null;
  sessionLoading: boolean;
  sessionError: string | null;
  loadSessions: () => Promise<void>;
  loadSession: (id: string) => Promise<void>;
}

export function useSession(): SessionState {
  const [sessions, setSessions] = useState<SessionEntry[]>([]);
  const [sessionsLoading, setSessionsLoading] = useState(true);
  const [sessionsError, setSessionsError] = useState<string | null>(null);
  const [currentSession, setCurrentSession] =
    useState<SessionDetailResponse | null>(null);
  const [sessionLoading, setSessionLoading] = useState(false);
  const [sessionError, setSessionError] = useState<string | null>(null);

  const loadSessions = useCallback(async () => {
    setSessionsLoading(true);
    setSessionsError(null);
    try {
      const res = await fetch("/api/sessions");
      if (!res.ok) throw new Error(`HTTP ${res.status}`);
      const data = await res.json();
      setSessions(data.sessions);
    } catch (err) {
      setSessionsError(
        err instanceof Error ? err.message : "Failed to load sessions"
      );
    } finally {
      setSessionsLoading(false);
    }
  }, []);

  const loadSession = useCallback(async (id: string) => {
    setSessionLoading(true);
    setSessionError(null);
    try {
      const res = await fetch(`/api/sessions/${encodeURIComponent(id)}`);
      if (!res.ok) throw new Error(`HTTP ${res.status}`);
      const data = await res.json();
      setCurrentSession(data);
    } catch (err) {
      setSessionError(
        err instanceof Error ? err.message : "Failed to load session"
      );
    } finally {
      setSessionLoading(false);
    }
  }, []);

  useEffect(() => {
    loadSessions();
  }, [loadSessions]);

  return {
    sessions,
    sessionsLoading,
    sessionsError,
    currentSession,
    sessionLoading,
    sessionError,
    loadSessions,
    loadSession,
  };
}