package auth

import (
	"log"
	"sync"
	"time"

	"git.aiterp.net/gisle/wrouter/generate"
)

const SessionMaxTime = time.Hour * 72

var sessionMutex sync.RWMutex
var sessions = make(map[string]*Session, 512)
var lastCheck = time.Now()

// SessionCookieName for the session cookie
var SessionCookieName = "sessid"

// Session is a simple in-memory structure describing a suer session
type Session struct {
	ID     string    `json:"id"`
	UserID string    `json:"user"`
	Time   time.Time `json:"time"`
	data   map[string]string
}

// SetData sets session data
func (sess *Session) SetData(key, value string) {
	sess.data[key] = value
}

// GetData gets session data for the following key
func (sess *Session) GetData(key string) string {
	return sess.data[key]
}

// HasData checks if the session data contains the key
func (sess *Session) HasData(key string) bool {
	_, ok := sess.data[key]
	return ok
}

// OpenSession creates a new session from the supplied user's ID
func OpenSession(user *User) *Session {
	session := &Session{generate.SessionID(), user.FullID(), time.Now(), make(map[string]string)}

	sessionMutex.Lock()
	sessions[session.ID] = session
	sessionMutex.Unlock()

	// No need to do these checks when there's no activity.
	if time.Since(lastCheck) > time.Hour {
		lastCheck = time.Now()
		go cleanup()
	}

	user.Session = session

	return session
}

// FindSession returns a session if the id maps to a still valid session
func FindSession(id string) *Session {
	sessionMutex.RLock()
	session := sessions[id]
	sessionMutex.RUnlock()

	// Check expiry and update
	if session != nil {
		if time.Since(session.Time) > SessionMaxTime {
			return nil
		}

		if time.Since(session.Time) > time.Hour {
			session.Time = time.Now()
		}
	}

	return session
}

// CloseSession deletes a session by the id
func CloseSession(id string) {
	sessionMutex.Lock()
	delete(sessions, id)
	sessionMutex.Unlock()
}

// ClearSessions removes all sessions with the given user ID
func ClearSessions(user *User) {
	sessionMutex.Lock()
	for _, sess := range sessions {
		if sess.UserID == user.FullID() {
			delete(sessions, sess.ID)
		}
	}
	sessionMutex.Unlock()
}

func cleanup() {
	count := 0

	sessionMutex.Lock()
	for key, session := range sessions {
		if time.Since(session.Time) > SessionMaxTime {
			delete(sessions, key)
			count++
		}
	}
	sessionMutex.Unlock()

	if count > 0 {
		log.Println("Removed", count, "sessions.")
	}
}