// Copyright (c) 2017 Shivaram Lingamneni <slingamn@cs.stanford.edu>
// released under the MIT license

package irc

import (
	"net"
	"sync/atomic"
	"time"
	"unsafe"

	"github.com/oragono/oragono/irc/languages"
	"github.com/oragono/oragono/irc/modes"
)

func (server *Server) Config() (config *Config) {
	return (*Config)(atomic.LoadPointer(&server.config))
}

func (server *Server) SetConfig(config *Config) {
	atomic.StorePointer(&server.config, unsafe.Pointer(config))
}

func (server *Server) ChannelRegistrationEnabled() bool {
	return server.Config().Channels.Registration.Enabled
}

func (server *Server) GetOperator(name string) (oper *Oper) {
	name, err := CasefoldName(name)
	if err != nil {
		return
	}
	return server.Config().operators[name]
}

func (server *Server) Languages() (lm *languages.Manager) {
	return server.Config().languageManager
}

func (server *Server) Defcon() uint32 {
	return atomic.LoadUint32(&server.defcon)
}

func (server *Server) SetDefcon(defcon uint32) {
	atomic.StoreUint32(&server.defcon, defcon)
}

func (client *Client) Sessions() (sessions []*Session) {
	client.stateMutex.RLock()
	sessions = client.sessions
	client.stateMutex.RUnlock()
	return
}

func (client *Client) GetSessionByResumeID(resumeID string) (result *Session) {
	client.stateMutex.RLock()
	defer client.stateMutex.RUnlock()

	for _, session := range client.sessions {
		if session.resumeID == resumeID {
			return session
		}
	}
	return
}

type SessionData struct {
	ctime    time.Time
	atime    time.Time
	ip       net.IP
	hostname string
	certfp   string
	deviceID string
}

func (client *Client) AllSessionData(currentSession *Session) (data []SessionData, currentIndex int) {
	currentIndex = -1
	client.stateMutex.RLock()
	defer client.stateMutex.RUnlock()

	data = make([]SessionData, len(client.sessions))
	for i, session := range client.sessions {
		if session == currentSession {
			currentIndex = i
		}
		data[i] = SessionData{
			atime:    session.lastActive,
			ctime:    session.ctime,
			hostname: session.rawHostname,
			certfp:   session.certfp,
			deviceID: session.deviceID,
		}
		if session.proxiedIP != nil {
			data[i].ip = session.proxiedIP
		} else {
			data[i].ip = session.realIP
		}
	}
	return
}

func (client *Client) AddSession(session *Session) (success bool, numSessions int, lastSeen time.Time, back bool) {
	client.stateMutex.Lock()
	defer client.stateMutex.Unlock()

	// client may be dying and ineligible to receive another session
	if client.destroyed {
		return
	}
	// success, attach the new session to the client
	session.client = client
	newSessions := make([]*Session, len(client.sessions)+1)
	copy(newSessions, client.sessions)
	newSessions[len(newSessions)-1] = session
	if client.accountSettings.AutoreplayMissed || session.deviceID != "" {
		lastSeen = client.lastSeen[session.deviceID]
		client.setLastSeen(time.Now().UTC(), session.deviceID)
	}
	client.sessions = newSessions
	if client.autoAway {
		back = true
		client.autoAway = false
		client.away = false
		client.awayMessage = ""
	}
	return true, len(client.sessions), lastSeen, back
}

func (client *Client) removeSession(session *Session) (success bool, length int) {
	if len(client.sessions) == 0 {
		return
	}
	sessions := make([]*Session, 0, len(client.sessions)-1)
	for _, currentSession := range client.sessions {
		if session == currentSession {
			success = true
		} else {
			sessions = append(sessions, currentSession)
		}
	}
	client.sessions = sessions
	length = len(sessions)
	return
}

func (session *Session) SetResumeID(resumeID string) {
	session.client.stateMutex.Lock()
	session.resumeID = resumeID
	session.client.stateMutex.Unlock()
}

func (client *Client) Nick() string {
	client.stateMutex.RLock()
	defer client.stateMutex.RUnlock()
	return client.nick
}

func (client *Client) NickMaskString() string {
	client.stateMutex.RLock()
	defer client.stateMutex.RUnlock()
	return client.nickMaskString
}

func (client *Client) NickCasefolded() string {
	client.stateMutex.RLock()
	defer client.stateMutex.RUnlock()
	return client.nickCasefolded
}

func (client *Client) NickMaskCasefolded() string {
	client.stateMutex.RLock()
	defer client.stateMutex.RUnlock()
	return client.nickMaskCasefolded
}

func (client *Client) Username() string {
	client.stateMutex.RLock()
	defer client.stateMutex.RUnlock()
	return client.username
}

func (client *Client) Hostname() string {
	client.stateMutex.RLock()
	defer client.stateMutex.RUnlock()
	return client.hostname
}

func (client *Client) Away() (result bool) {
	client.stateMutex.Lock()
	result = client.away
	client.stateMutex.Unlock()
	return
}

func (client *Client) SetAway(away bool, awayMessage string) (changed bool) {
	client.stateMutex.Lock()
	changed = away != client.away
	client.away = away
	client.awayMessage = awayMessage
	client.stateMutex.Unlock()
	return
}

func (client *Client) AlwaysOn() (alwaysOn bool) {
	client.stateMutex.Lock()
	alwaysOn = client.alwaysOn
	client.stateMutex.Unlock()
	return
}

// uniqueIdentifiers returns the strings for which the server enforces per-client
// uniqueness/ownership; no two clients can have colliding casefolded nicks or
// skeletons.
func (client *Client) uniqueIdentifiers() (nickCasefolded string, skeleton string) {
	client.stateMutex.RLock()
	defer client.stateMutex.RUnlock()
	return client.nickCasefolded, client.skeleton
}

func (client *Client) ResumeID() string {
	client.stateMutex.RLock()
	defer client.stateMutex.RUnlock()
	return client.resumeID
}

func (client *Client) SetResumeID(id string) {
	client.stateMutex.Lock()
	defer client.stateMutex.Unlock()
	client.resumeID = id
}

func (client *Client) Oper() *Oper {
	client.stateMutex.RLock()
	defer client.stateMutex.RUnlock()
	return client.oper
}

func (client *Client) Registered() bool {
	client.stateMutex.RLock()
	defer client.stateMutex.RUnlock()
	return client.registered
}

func (client *Client) SetRegistered() {
	// `registered` is only written from the client's own goroutine, but may be
	// read from other goroutines; therefore, the client's own goroutine may read
	// the value without synchronization, but must write it with synchronization,
	// and other goroutines must read it with synchronization
	client.stateMutex.Lock()
	client.registered = true
	client.stateMutex.Unlock()
}

func (client *Client) RawHostname() (result string) {
	client.stateMutex.Lock()
	result = client.rawHostname
	client.stateMutex.Unlock()
	return
}

func (client *Client) AwayMessage() (result string) {
	client.stateMutex.RLock()
	result = client.awayMessage
	client.stateMutex.RUnlock()
	return
}

func (client *Client) SetAwayMessage(message string) {
	client.stateMutex.Lock()
	client.awayMessage = message
	client.stateMutex.Unlock()
}

func (client *Client) Account() string {
	client.stateMutex.RLock()
	defer client.stateMutex.RUnlock()
	return client.account
}

func (client *Client) AccountName() string {
	client.stateMutex.RLock()
	defer client.stateMutex.RUnlock()
	return client.accountName
}

func (client *Client) Login(account ClientAccount) {
	alwaysOn := persistenceEnabled(client.server.Config().Accounts.Multiclient.AlwaysOn, account.Settings.AlwaysOn)
	client.stateMutex.Lock()
	defer client.stateMutex.Unlock()
	client.account = account.NameCasefolded
	client.accountName = account.Name
	client.accountSettings = account.Settings
	// check `registered` to avoid incorrectly marking a temporary (pre-reattach),
	// SASL'ing client as always-on
	if client.registered {
		client.alwaysOn = alwaysOn
	}
	client.accountRegDate = account.RegisteredAt
	return
}

func (client *Client) historyCutoff() (cutoff time.Time) {
	client.stateMutex.Lock()
	if client.account != "" {
		cutoff = client.accountRegDate
	} else {
		cutoff = client.ctime
	}
	client.stateMutex.Unlock()
	return
}

func (client *Client) Logout() {
	client.stateMutex.Lock()
	client.account = ""
	client.accountName = "*"
	client.alwaysOn = false
	client.accountRegDate = time.Time{}
	client.accountSettings = AccountSettings{}
	client.stateMutex.Unlock()
}

func (client *Client) AccountSettings() (result AccountSettings) {
	client.stateMutex.RLock()
	result = client.accountSettings
	client.stateMutex.RUnlock()
	return
}

func (client *Client) SetAccountSettings(settings AccountSettings) {
	// we mark dirty if the client is transitioning to always-on
	var becameAlwaysOn, autoreplayMissedDisabled bool
	alwaysOn := persistenceEnabled(client.server.Config().Accounts.Multiclient.AlwaysOn, settings.AlwaysOn)
	client.stateMutex.Lock()
	if client.registered {
		autoreplayMissedDisabled = (client.accountSettings.AutoreplayMissed && !settings.AutoreplayMissed)
		becameAlwaysOn = (!client.alwaysOn && alwaysOn)
		client.alwaysOn = alwaysOn
		if autoreplayMissedDisabled {
			// clear the lastSeen entry for the default session, but not for device IDs
			delete(client.lastSeen, "")
		}
	}
	client.accountSettings = settings
	client.stateMutex.Unlock()
	if becameAlwaysOn {
		client.markDirty(IncludeAllAttrs)
	} else if autoreplayMissedDisabled {
		client.markDirty(IncludeLastSeen)
	}
}

func (client *Client) Languages() (languages []string) {
	client.stateMutex.RLock()
	languages = client.languages
	client.stateMutex.RUnlock()
	return languages
}

func (client *Client) SetLanguages(languages []string) {
	client.stateMutex.Lock()
	client.languages = languages
	client.stateMutex.Unlock()
}

func (client *Client) HasMode(mode modes.Mode) bool {
	// client.flags has its own synch
	return client.modes.HasMode(mode)
}

func (client *Client) SetMode(mode modes.Mode, on bool) bool {
	return client.modes.SetMode(mode, on)
}

func (client *Client) SetRealname(realname string) {
	client.stateMutex.Lock()
	client.realname = realname
	client.stateMutex.Unlock()
}

func (client *Client) Channels() (result []*Channel) {
	client.stateMutex.RLock()
	defer client.stateMutex.RUnlock()
	length := len(client.channels)
	result = make([]*Channel, length)
	i := 0
	for channel := range client.channels {
		result[i] = channel
		i++
	}
	return
}

func (client *Client) NumChannels() int {
	client.stateMutex.RLock()
	defer client.stateMutex.RUnlock()
	return len(client.channels)
}

func (client *Client) WhoWas() (result WhoWas) {
	return client.Details().WhoWas
}

func (client *Client) Details() (result ClientDetails) {
	client.stateMutex.RLock()
	defer client.stateMutex.RUnlock()
	return client.detailsNoMutex()
}

func (client *Client) detailsNoMutex() (result ClientDetails) {
	result.nick = client.nick
	result.nickCasefolded = client.nickCasefolded
	result.username = client.username
	result.hostname = client.hostname
	result.realname = client.realname
	result.nickMask = client.nickMaskString
	result.nickMaskCasefolded = client.nickMaskCasefolded
	result.account = client.account
	result.accountName = client.accountName
	return
}

func (client *Client) UpdateActive(session *Session) {
	now := time.Now().UTC()
	client.stateMutex.Lock()
	defer client.stateMutex.Unlock()
	client.lastActive = now
	session.lastActive = now
}

func (channel *Channel) Name() string {
	channel.stateMutex.RLock()
	defer channel.stateMutex.RUnlock()
	return channel.name
}

func (channel *Channel) NameCasefolded() string {
	channel.stateMutex.RLock()
	defer channel.stateMutex.RUnlock()
	return channel.nameCasefolded
}

func (channel *Channel) Rename(name, nameCasefolded string) {
	channel.stateMutex.Lock()
	channel.name = name
	channel.nameCasefolded = nameCasefolded
	if channel.registeredFounder != "" {
		channel.registeredTime = time.Now().UTC()
	}
	channel.stateMutex.Unlock()
}

func (channel *Channel) Members() (result []*Client) {
	channel.stateMutex.RLock()
	defer channel.stateMutex.RUnlock()
	return channel.membersCache
}

func (channel *Channel) setUserLimit(limit int) {
	channel.stateMutex.Lock()
	channel.userLimit = limit
	channel.stateMutex.Unlock()
}

func (channel *Channel) setKey(key string) {
	channel.stateMutex.Lock()
	defer channel.stateMutex.Unlock()
	channel.key = key
}

func (channel *Channel) Founder() string {
	channel.stateMutex.RLock()
	defer channel.stateMutex.RUnlock()
	return channel.registeredFounder
}

func (channel *Channel) HighestUserMode(client *Client) (result modes.Mode) {
	channel.stateMutex.RLock()
	clientModes := channel.members[client]
	channel.stateMutex.RUnlock()
	return clientModes.HighestChannelUserMode()
}

func (channel *Channel) Settings() (result ChannelSettings) {
	channel.stateMutex.RLock()
	result = channel.settings
	channel.stateMutex.RUnlock()
	return result
}

func (channel *Channel) SetSettings(settings ChannelSettings) {
	channel.stateMutex.Lock()
	channel.settings = settings
	channel.stateMutex.Unlock()
	channel.MarkDirty(IncludeSettings)
}