// Package session provides session management functionality.
// It includes session storage, flash messages, and data persistence.
package session

import (
	"crypto/rand"
	"encoding/hex"
	"time"
)

const (
	DefaultExpiration = 24 * time.Hour
	IDLength          = 32
)

type Session struct {
	ID        string         `json:"-"`
	UserID    int            `json:"user_id"`
	Username  string         `json:"username"`
	Email     string         `json:"email"`
	CreatedAt time.Time      `json:"created_at"`
	ExpiresAt time.Time      `json:"expires_at"`
	LastSeen  time.Time      `json:"last_seen"`
	Data      map[string]any `json:"data,omitempty"`
}

func New(userID int, username, email string) *Session {
	return &Session{
		ID:        generateID(),
		UserID:    userID,
		Username:  username,
		Email:     email,
		CreatedAt: time.Now(),
		ExpiresAt: time.Now().Add(DefaultExpiration),
		LastSeen:  time.Now(),
		Data:      make(map[string]any),
	}
}

func (s *Session) IsExpired() bool {
	return time.Now().After(s.ExpiresAt)
}

func (s *Session) Touch() {
	s.LastSeen = time.Now()
	s.ExpiresAt = time.Now().Add(DefaultExpiration)
}

func (s *Session) Set(key string, value any) {
	if s.Data == nil {
		s.Data = make(map[string]any)
	}
	s.Data[key] = value
}

func (s *Session) Get(key string) (any, bool) {
	if s.Data == nil {
		return nil, false
	}
	value, exists := s.Data[key]
	return value, exists
}

func (s *Session) Delete(key string) {
	if s.Data != nil {
		delete(s.Data, key)
	}
}

func generateID() string {
	bytes := make([]byte, IDLength)
	rand.Read(bytes)
	return hex.EncodeToString(bytes)
}