package com.astalange.web.controller;

import com.astalange.core.entity.AppUser;
import com.astalange.core.entity.Role;
import com.astalange.core.repository.AppUserRepository;
import org.springframework.security.access.prepost.PreAuthorize;
import org.springframework.security.core.session.SessionRegistry;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;

import java.time.LocalDateTime;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

@Controller
@RequestMapping("/admin/sessions")
public class SessionController {

    private final SessionRegistry sessionRegistry;
    private final AppUserRepository userRepository;

    public SessionController(SessionRegistry sessionRegistry, AppUserRepository userRepository) {
        this.sessionRegistry = sessionRegistry;
        this.userRepository = userRepository;
    }

    public static class UserSessionDTO {
        private final Long id;
        private final String username;
        private final boolean online;
        private final LocalDateTime lastLoginAt;
        private final LocalDateTime lastLogoutAt;
        private final String roles;

        public UserSessionDTO(Long id, String username, boolean online, LocalDateTime lastLoginAt, LocalDateTime lastLogoutAt, String roles) {
            this.id = id;
            this.username = username;
            this.online = online;
            this.lastLoginAt = lastLoginAt;
            this.lastLogoutAt = lastLogoutAt;
            this.roles = roles;
        }

        public Long getId() { return id; }
        public String getUsername() { return username; }
        public boolean isOnline() { return online; }
        public LocalDateTime getLastLoginAt() { return lastLoginAt; }
        public LocalDateTime getLastLogoutAt() { return lastLogoutAt; }
        public String getRoles() { return roles; }
    }

    @GetMapping
    @PreAuthorize("hasRole('ADMIN')")
    public String viewSessions(Model model) {
        List<Object> principals = sessionRegistry.getAllPrincipals();
        Set<String> activeUsernames = principals.stream()
                .filter(principal -> principal instanceof UserDetails)
                .map(principal -> ((UserDetails) principal).getUsername())
                .collect(Collectors.toSet());

        List<AppUser> allUsers = userRepository.findAll();

        List<UserSessionDTO> userSessions = allUsers.stream().map(user -> {
            boolean isOnline = activeUsernames.contains(user.getUsername());
            String rolesStr = user.getRoles().stream()
                    .map(Role::getName)
                    .map(r -> r.replace("ROLE_", ""))
                    .collect(Collectors.joining(", "));

            return new UserSessionDTO(
                    user.getId(),
                    user.getUsername(),
                    isOnline,
                    user.getLastLoginAt(),
                    user.getLastLogoutAt(),
                    rolesStr
            );
        }).collect(Collectors.toList());

        long activeCount = userSessions.stream().filter(UserSessionDTO::isOnline).count();
        long offlineCount = userSessions.size() - activeCount;

        model.addAttribute("userSessions", userSessions);
        model.addAttribute("activeCount", activeCount);
        model.addAttribute("offlineCount", offlineCount);
        model.addAttribute("totalCount", userSessions.size());
        return "admin/sessions";
    }
}