package telegram

import (
	"github.com/pkg/errors"
	"path/filepath"
	"strconv"
	"sync"
	"time"

	"dev.narayana.im/narayana/telegabber/config"
	"dev.narayana.im/narayana/telegabber/persistence"
	"dev.narayana.im/narayana/telegabber/telegram/cache"
	"dev.narayana.im/narayana/telegabber/xmpp/gateway"

	"github.com/zelenin/go-tdlib/client"
	"gosrc.io/xmpp"
)

// DelayedStatus describes an online status expiring on timeout
type DelayedStatus struct {
	TimestampOnline  int64
	TimestampExpired int64
}

// IntPair holds two int64 values
type IntPair struct {
	ChatId    int64
	MessageId int64
}

type barrier struct {
	mu        sync.Mutex
	open      bool
	released  bool
	releaseCh chan struct{}
}

// Wait blocks until the barrier is released.
func (b *barrier) Wait() {
	b.mu.Lock()

	if b.released {
		b.mu.Unlock()
		return
	}

	if !b.open {
		b.open = true
		b.releaseCh = make(chan struct{}) // Reinitialize the channel
	}
	b.mu.Unlock()

	// Wait for the barrier to be released
	<-b.releaseCh
}

// Done releases the barrier.
func (b *barrier) Done() {
	b.mu.Lock()
	defer b.mu.Unlock()

	if b.open {
		close(b.releaseCh) // Close the channel to release waiting goroutines
		b.open = false     // Mark the barrier as closed
	} else {
		b.released = true
	}
}

// IsPending checks if the barrier is currently being waited
func (b *barrier) IsPending() bool {
	b.mu.Lock()
	defer b.mu.Unlock()

	return b.open
}

// NewId stores message ids and timestamps of their additions so old ones can be truncated to save memory
type newId struct {
	Id      int64
	Ts      int64
	lock    sync.Mutex
	ownLock sync.Mutex
	locked  bool
	fired   bool
}

func newNewId() *newId {
	return &newId{Ts: time.Now().Unix()}
}

func (i *newId) Lock() {
	i.ownLock.Lock()
	if i.fired {
		i.ownLock.Unlock()
		return
	}
	i.locked = true
	i.ownLock.Unlock()
	i.lock.Lock()
}

func (i *newId) Unlock() {
	i.ownLock.Lock()
	if i.locked {
		i.lock.Unlock()
		i.locked = false
		i.fired = true
	}
	i.ownLock.Unlock()
}

// Client stores the metadata for lazily invoked TDlib instance
type Client struct {
	client     *client.Client
	authorizer *clientAuthorizer
	parameters *client.SetTdlibParametersRequest
	options    []client.Option
	me         *client.User

	xmpp      *xmpp.Component
	jid       string
	Session   *persistence.Session
	resources map[string]bool
	content   *config.TelegramContentConfig
	cache     *cache.Cache
	online    bool

	loginWizard *loginWizardMetadata
	loginStage  LoginStage

	lastAuthorizationStateType string

	outbox     map[string]string
	editOutbox map[string]string
	pinOutbox  map[IntPair]chan int64

	DelayedStatuses     map[int64]*DelayedStatus
	DelayedStatusesLock sync.Mutex

	lastMsgHashes map[int64]uint64
	lastMsgIds    map[int64]string

	mucCache map[int64]*MUCState

	uploadingFiles map[int32]string

	LastBotCmdString string

	XmppClientFeatures     map[string]*[]string
	XmppClientFeaturesLock sync.Mutex

	avatarHashes     map[int64]*gateway.HashedAvatar
	avatarHashesLock sync.Mutex

	MessageIdChanges     map[int64]map[int64]*newId
	MessageIdChangesLock sync.Mutex

	locks           clientLocks
	SendMessageLock sync.Mutex
}

type clientLocks struct {
	authorizationReady sync.Mutex
	chatMessageLocks   map[int64]*sync.Mutex
	resourcesLock      sync.Mutex
	outboxLock         sync.Mutex
	mucCacheLock       sync.Mutex
	editOutboxLock     sync.Mutex
	pinOutboxLock      sync.Mutex
	lastMsgHashesLock  sync.Mutex
	lastMsgIdsLock     sync.RWMutex
	loginFinish        barrier
	uploadingFilesLock sync.Mutex

	authorizerReadLock  sync.Mutex
	authorizerWriteLock sync.Mutex

	loginWizardReadLock  sync.Mutex
	loginWizardWriteLock sync.Mutex
}

type loginWizardMetadata struct {
	nextStage   chan LoginStage
	chanBusy    bool
	commandSent bool
}

// NewClient instantiates a Telegram App
func NewClient(conf config.TelegramConfig, jid string, component *xmpp.Component, session *persistence.Session) (*Client, error) {
	var options []client.Option

	if conf.Tdlib.Client.CatchTimeout != 0 {
		options = append(options, client.WithCatchTimeout(
			time.Duration(conf.Tdlib.Client.CatchTimeout)*time.Second,
		))
	}

	apiID, err := strconv.ParseInt(conf.Tdlib.Client.APIID, 10, 32)
	if err != nil {
		return &Client{}, errors.Wrap(err, "Wrong api_id")
	}

	datadir := conf.Tdlib.Datadir
	if datadir == "" {
		datadir = "./sessions/" // ye olde defaute
	}

	parameters := client.SetTdlibParametersRequest{
		UseTestDc: false,

		DatabaseDirectory: filepath.Join(datadir, jid),
		FilesDirectory:    filepath.Join(datadir, jid, "/files/"),

		UseFileDatabase:     true,
		UseChatInfoDatabase: conf.Tdlib.Client.UseChatInfoDatabase,
		UseMessageDatabase:  true,
		UseSecretChats:      conf.Tdlib.Client.UseSecretChats,

		ApiId:   int32(apiID),
		ApiHash: conf.Tdlib.Client.APIHash,

		SystemLanguageCode: "en",
		DeviceModel:        conf.Tdlib.Client.DeviceModel,
		SystemVersion:      "1.0.0",
		ApplicationVersion: conf.Tdlib.Client.ApplicationVersion,

		EnableStorageOptimizer: true,
		IgnoreFileNames:        false,
	}

	return &Client{
		parameters:         &parameters,
		xmpp:               component,
		jid:                jid,
		Session:            session,
		resources:          make(map[string]bool),
		content:            &conf.Content,
		cache:              cache.NewCache(),
		outbox:             make(map[string]string),
		editOutbox:         make(map[string]string),
		pinOutbox:          make(map[IntPair]chan int64),
		mucCache:           make(map[int64]*MUCState),
		uploadingFiles:     make(map[int32]string),
		options:            options,
		DelayedStatuses:    make(map[int64]*DelayedStatus),
		lastMsgHashes:      make(map[int64]uint64),
		lastMsgIds:         make(map[int64]string),
		XmppClientFeatures: make(map[string]*[]string),
		avatarHashes:       make(map[int64]*gateway.HashedAvatar),
		MessageIdChanges:   make(map[int64]map[int64]*newId),
		locks: clientLocks{
			chatMessageLocks: make(map[int64]*sync.Mutex),
		},
	}, nil
}

// GetPersistenceSession retrieves the internal session configuration
func (c *Client) GetPersistenceSession() *persistence.Session {
	return c.Session
}