package connector

import (
	"bytes"
	"fmt"
	"github.com/google/uuid"
	"log"
	"openreplay/backend/internal/http/geoip"
	"openreplay/backend/pkg/sessions"
	"strconv"
	"time"

	config "openreplay/backend/internal/config/connector"
	"openreplay/backend/pkg/messages"
	"openreplay/backend/pkg/objectstorage"
)

// Saver collect sessions and events and saves them to Redshift
type Saver struct {
	cfg              *config.Config
	objStorage       objectstorage.ObjectStorage
	db               *Redshift
	sessModule       sessions.Sessions
	sessions         map[uint64]map[string]string
	updatedSessions  map[uint64]bool
	lastUpdate       map[uint64]time.Time
	finishedSessions []uint64
	events           []map[string]string
}

func New(cfg *config.Config, objStorage objectstorage.ObjectStorage, db *Redshift, sessions sessions.Sessions) *Saver {
	if cfg == nil {
		log.Fatal("connector config is empty")
	}
	// Validate column names in sessions table
	if err := validateColumnNames(sessionColumns); err != nil {
		log.Printf("can't validate column names: %s", err)
	}
	// Validate column names in events table
	if err := validateColumnNames(eventColumns); err != nil {
		log.Printf("can't validate column names: %s", err)
	}
	return &Saver{
		cfg:             cfg,
		objStorage:      objStorage,
		db:              db,
		sessModule:      sessions,
		updatedSessions: make(map[uint64]bool, 0),
		lastUpdate:      make(map[uint64]time.Time, 0),
	}
}

var sessionColumns = []string{
	"sessionid",
	"user_agent",
	"user_browser",
	"user_browser_version",
	"user_country",
	"user_device",
	"user_device_heap_size",
	"user_device_memory_size",
	"user_device_type",
	"user_os",
	"user_os_version",
	"user_uuid",
	"connection_effective_bandwidth",
	"connection_type",
	"metadata_key",
	"metadata_value",
	"referrer",
	"user_anonymous_id",
	"user_id",
	"session_start_timestamp",
	"session_end_timestamp",
	"session_duration",
	"first_contentful_paint",
	"speed_index",
	"visually_complete",
	"timing_time_to_interactive",
	"avg_cpu",
	"avg_fps",
	"max_cpu",
	"max_fps",
	"max_total_js_heap_size",
	"max_used_js_heap_size",
	"js_exceptions_count",
	"inputs_count",
	"clicks_count",
	"issues_count",
	"urls_count",
}

var sessionInts = []string{
	"user_device_heap_size",
	"user_device_memory_size",
	"connection_effective_bandwidth",
	"first_contentful_paint",
	"speed_index",
	"visually_complete",
	"timing_time_to_interactive",
	"avg_cpu",
	"avg_fps",
	"max_cpu",
	"max_fps",
	"max_total_js_heap_size",
	"max_used_js_heap_size",
	"js_exceptions_count",
	"inputs_count",
	"clicks_count",
	"issues_count",
	"urls_count",
}

var eventColumns = []string{
	"sessionid",
	"consolelog_level",
	"consolelog_value",
	"customevent_name",
	"customevent_payload",
	"jsexception_message",
	"jsexception_name",
	"jsexception_payload",
	"jsexception_metadata",
	"networkrequest_type",
	"networkrequest_method",
	"networkrequest_url",
	"networkrequest_request",
	"networkrequest_response",
	"networkrequest_status",
	"networkrequest_timestamp",
	"networkrequest_duration",
	"issueevent_message_id",
	"issueevent_timestamp",
	"issueevent_type",
	"issueevent_context_string",
	"issueevent_context",
	"issueevent_payload",
	"issueevent_url",
	"customissue_name",
	"customissue_payload",
	"received_at",
	"batch_order_number",
}

func QUOTES(s string) string {
	return strconv.Quote(s)
}

func handleEvent(msg messages.Message) map[string]string {
	event := make(map[string]string)

	switch m := msg.(type) {
	case *messages.ConsoleLog:
		event["consolelog_level"] = QUOTES(m.Level)
		event["consolelog_value"] = QUOTES(m.Value)
	case *messages.CustomEvent:
		event["customevent_name"] = QUOTES(m.Name)
		event["customevent_payload"] = QUOTES(m.Payload)
	case *messages.JSException:
		event["jsexception_name"] = QUOTES(m.Name)
		event["jsexception_message"] = QUOTES(m.Message)
		event["jsexception_payload"] = QUOTES(m.Payload)
		event["jsexception_metadata"] = QUOTES(m.Metadata)
	case *messages.NetworkRequest:
		event["networkrequest_type"] = QUOTES(m.Type)
		event["networkrequest_method"] = QUOTES(m.Method)
		event["networkrequest_url"] = QUOTES(m.URL)
		event["networkrequest_request"] = QUOTES(m.Request)
		event["networkrequest_response"] = QUOTES(m.Response)
		event["networkrequest_status"] = fmt.Sprintf("%d", m.Status)
		event["networkrequest_timestamp"] = fmt.Sprintf("%d", m.Timestamp)
		event["networkrequest_duration"] = fmt.Sprintf("%d", m.Duration)
	case *messages.IssueEvent:
		event["issueevent_message_id"] = fmt.Sprintf("%d", m.MessageID)
		event["issueevent_timestamp"] = fmt.Sprintf("%d", m.Timestamp)
		event["issueevent_type"] = QUOTES(m.Type)
		event["issueevent_context_string"] = QUOTES(m.ContextString)
		event["issueevent_context"] = QUOTES(m.Context)
		event["issueevent_payload"] = QUOTES(m.Payload)
		event["issueevent_url"] = QUOTES(m.URL)
	case *messages.CustomIssue:
		event["customissue_name"] = QUOTES(m.Name)
		event["customissue_payload"] = QUOTES(m.Payload)
	}

	if len(event) == 0 {
		return nil
	}
	event["sessionid"] = fmt.Sprintf("%d", msg.SessionID())
	event["received_at"] = fmt.Sprintf("%d", uint64(time.Now().UnixMilli()))
	event["batch_order_number"] = fmt.Sprintf("%d", 0)
	return event
}

func (s *Saver) handleSession(msg messages.Message) {
	// Filter out messages that are not related to session table
	switch msg.(type) {
	case *messages.SessionStart, *messages.SessionEnd, *messages.ConnectionInformation, *messages.Metadata,
		*messages.PageEvent, *messages.PerformanceTrackAggr, *messages.UserID, *messages.UserAnonymousID,
		*messages.JSException, *messages.JSExceptionDeprecated, *messages.InputEvent, *messages.MouseClick,
		*messages.IssueEvent, *messages.IssueEventDeprecated:
	default:
		return
	}
	if s.sessions == nil {
		s.sessions = make(map[uint64]map[string]string)
	}
	sess, ok := s.sessions[msg.SessionID()]
	if !ok {
		// Try to load session from cache
		cached, err := s.sessModule.GetCached(msg.SessionID())
		if err != nil && err != sessions.ErrSessionNotFound {
			log.Printf("Failed to get cached session: %v", err)
		}
		if cached != nil {
			sess = cached
		} else {
			sess = make(map[string]string)
			sess[`sessionid`] = fmt.Sprintf("%d", msg.SessionID())
		}
	}
	if s.sessions[msg.SessionID()] == nil {
		s.sessions[msg.SessionID()] = make(map[string]string)
		s.sessions[msg.SessionID()][`sessionid`] = fmt.Sprintf("%d", msg.SessionID())
		sess = s.sessions[msg.SessionID()]
	}

	// Parse message and add to session
	updated := true
	switch m := msg.(type) {
	case *messages.SessionStart:
		sess["session_start_timestamp"] = fmt.Sprintf("%d", m.Timestamp)
		sess["user_uuid"] = QUOTES(m.UserUUID)
		sess["user_agent"] = QUOTES(m.UserAgent)
		sess["user_os"] = QUOTES(m.UserOS)
		sess["user_os_version"] = QUOTES(m.UserOSVersion)
		sess["user_browser"] = QUOTES(m.UserBrowser)
		sess["user_browser_version"] = QUOTES(m.UserBrowserVersion)
		sess["user_device"] = QUOTES(m.UserDevice)
		sess["user_device_type"] = QUOTES(m.UserDeviceType)
		sess["user_device_memory_size"] = fmt.Sprintf("%d", m.UserDeviceMemorySize)
		sess["user_device_heap_size"] = fmt.Sprintf("%d", m.UserDeviceHeapSize)
		geoInfo := geoip.UnpackGeoRecord(m.UserCountry)
		sess["user_country"] = QUOTES(geoInfo.Country)
	case *messages.SessionEnd:
		sess["session_end_timestamp"] = fmt.Sprintf("%d", m.Timestamp)
		info, err := s.sessModule.Get(msg.SessionID())
		if err != nil {
			log.Printf("Error getting session info: %v", err)
			break
		}
		// Check all required fields are present
		sess["session_duration"] = fmt.Sprintf("%d", *info.Duration)
		if sess["user_agent"] == "" && info.UserAgent != "" {
			sess["user_agent"] = QUOTES(info.UserAgent)
		}
		if sess["user_browser"] == "" && info.UserBrowser != "" {
			sess["user_browser"] = QUOTES(info.UserBrowser)
		}
		if sess["user_browser_version"] == "" && info.UserBrowserVersion != "" {
			sess["user_browser_version"] = QUOTES(info.UserBrowserVersion)
		}
		if sess["user_os"] == "" && info.UserOS != "" {
			sess["user_os"] = QUOTES(info.UserOS)
		}
		if sess["user_os_version"] == "" && info.UserOSVersion != "" {
			sess["user_os_version"] = QUOTES(info.UserOSVersion)
		}
		if sess["user_device"] == "" && info.UserDevice != "" {
			sess["user_device"] = QUOTES(info.UserDevice)
		}
		if sess["user_device_type"] == "" && info.UserDeviceType != "" {
			sess["user_device_type"] = QUOTES(info.UserDeviceType)
		}
		if sess["user_device_memory_size"] == "" && info.UserDeviceMemorySize != 0 {
			sess["user_device_memory_size"] = fmt.Sprintf("%d", info.UserDeviceMemorySize)
		}
		if sess["user_device_heap_size"] == "" && info.UserDeviceHeapSize != 0 {
			sess["user_device_heap_size"] = fmt.Sprintf("%d", info.UserDeviceHeapSize)
		}
		if sess["user_country"] == "" && info.UserCountry != "" {
			sess["user_country"] = QUOTES(info.UserCountry)
		}
		if sess["user_uuid"] == "" && info.UserUUID != "" {
			sess["user_uuid"] = QUOTES(info.UserUUID)
		}
		if sess["session_start_timestamp"] == "" && info.Timestamp != 0 {
			sess["session_start_timestamp"] = fmt.Sprintf("%d", info.Timestamp)
		}
		if sess["user_anonymous_id"] == "" && info.UserAnonymousID != nil {
			sess["user_anonymous_id"] = QUOTES(*info.UserAnonymousID)
		}
		if sess["user_id"] == "" && info.UserID != nil {
			sess["user_id"] = QUOTES(*info.UserID)
		}
		if sess["urls_count"] == "" && info.PagesCount != 0 {
			sess["urls_count"] = fmt.Sprintf("%d", info.PagesCount)
		}
		// Check int fields
		for _, field := range sessionInts {
			if sess[field] == "" {
				sess[field] = fmt.Sprintf("%d", 0)
			}
		}
	case *messages.ConnectionInformation:
		sess["connection_effective_bandwidth"] = fmt.Sprintf("%d", m.Downlink)
		sess["connection_type"] = QUOTES(m.Type)
	case *messages.Metadata:
		sess["metadata_key"] = QUOTES(m.Key)
		sess["metadata_value"] = QUOTES(m.Value)
	case *messages.PageEvent:
		sess["referrer"] = QUOTES(m.Referrer)
		sess["first_contentful_paint"] = fmt.Sprintf("%d", m.FirstContentfulPaint)
		sess["speed_index"] = fmt.Sprintf("%d", m.SpeedIndex)
		sess["timing_time_to_interactive"] = fmt.Sprintf("%d", m.TimeToInteractive)
		sess["visually_complete"] = fmt.Sprintf("%d", m.VisuallyComplete)
		currUrlsCount, err := strconv.Atoi(sess["urls_count"])
		if err != nil {
			currUrlsCount = 0
		}
		sess["urls_count"] = fmt.Sprintf("%d", currUrlsCount+1)
	case *messages.PerformanceTrackAggr:
		sess["avg_cpu"] = fmt.Sprintf("%d", m.AvgCPU)
		sess["avg_fps"] = fmt.Sprintf("%d", m.AvgFPS)
		sess["max_cpu"] = fmt.Sprintf("%d", m.MaxCPU)
		sess["max_fps"] = fmt.Sprintf("%d", m.MaxFPS)
		sess["max_total_js_heap_size"] = fmt.Sprintf("%d", m.MaxTotalJSHeapSize)
		sess["max_used_js_heap_size"] = fmt.Sprintf("%d", m.MaxUsedJSHeapSize)
	case *messages.UserID:
		if m.ID != "" {
			sess["user_id"] = QUOTES(m.ID)
		}
	case *messages.UserAnonymousID:
		sess["user_anonymous_id"] = QUOTES(m.ID)
	case *messages.JSException, *messages.JSExceptionDeprecated:
		currExceptionsCount, err := strconv.Atoi(sess["js_exceptions_count"])
		if err != nil {
			currExceptionsCount = 0
		}
		sess["js_exceptions_count"] = fmt.Sprintf("%d", currExceptionsCount+1)
	case *messages.InputEvent:
		currInputsCount, err := strconv.Atoi(sess["inputs_count"])
		if err != nil {
			currInputsCount = 0
		}
		sess["inputs_count"] = fmt.Sprintf("%d", currInputsCount+1)
	case *messages.MouseClick:
		currMouseClicksCount, err := strconv.Atoi(sess["clicks_count"])
		if err != nil {
			currMouseClicksCount = 0
		}
		sess["clicks_count"] = fmt.Sprintf("%d", currMouseClicksCount+1)
	case *messages.IssueEvent, *messages.IssueEventDeprecated:
		currIssuesCount, err := strconv.Atoi(sess["issues_count"])
		if err != nil {
			currIssuesCount = 0
		}
		sess["issues_count"] = fmt.Sprintf("%d", currIssuesCount+1)
	default:
		updated = false
	}
	if updated {
		if s.updatedSessions == nil {
			s.updatedSessions = make(map[uint64]bool)
		}
		s.updatedSessions[msg.SessionID()] = true
	}
	s.sessions[msg.SessionID()] = sess
	s.lastUpdate[msg.SessionID()] = time.Now()
}

func (s *Saver) Handle(msg messages.Message) {
	newEvent := handleEvent(msg)
	if newEvent != nil {
		if s.events == nil {
			s.events = make([]map[string]string, 0, 2)
		}
		s.events = append(s.events, newEvent)
	}
	s.handleSession(msg)
	if msg.TypeID() == messages.MsgSessionEnd {
		if s.finishedSessions == nil {
			s.finishedSessions = make([]uint64, 0)
		}
		s.finishedSessions = append(s.finishedSessions, msg.SessionID())
	}
	return
}

func eventsToBuffer(batch []map[string]string) *bytes.Buffer {
	buf := bytes.NewBuffer(nil)

	// Write header
	for _, column := range eventColumns {
		buf.WriteString(column + "|")
	}
	buf.Truncate(buf.Len() - 1)

	// Write data
	for _, event := range batch {
		buf.WriteString("\n")
		for _, column := range eventColumns {
			buf.WriteString(event[column] + "|")
		}
		buf.Truncate(buf.Len() - 1)
	}
	return buf
}

func (s *Saver) commitEvents() {
	if len(s.events) == 0 {
		log.Printf("empty events batch")
		return
	}
	l := len(s.events)

	// Send data to S3
	fileName := fmt.Sprintf("connector_data/%s-%s.csv", s.cfg.EventsTableName, uuid.New().String())
	// Create csv file
	buf := eventsToBuffer(s.events)
	// Clear events batch
	s.events = nil

	reader := bytes.NewReader(buf.Bytes())
	if err := s.objStorage.Upload(reader, fileName, "text/csv", objectstorage.NoCompression); err != nil {
		log.Printf("can't upload file to s3: %s", err)
		return
	}
	// Copy data from s3 bucket to redshift
	if err := s.db.Copy(s.cfg.EventsTableName, fileName, "|", true, false); err != nil {
		log.Printf("can't copy data from s3 to redshift: %s", err)
		return
	}
	log.Printf("events batch of %d events is successfully saved", l)
}

func sessionsToBuffer(batch []map[string]string) *bytes.Buffer {
	buf := bytes.NewBuffer(nil)

	// Write header
	for _, column := range sessionColumns {
		buf.WriteString(column + "|")
	}
	buf.Truncate(buf.Len() - 1)

	// Write data
	for _, sess := range batch {
		buf.WriteString("\n")
		for _, column := range sessionColumns {
			buf.WriteString(sess[column] + "|")
		}
		buf.Truncate(buf.Len() - 1)
	}
	return buf
}

func (s *Saver) commitSessions() {
	if len(s.finishedSessions) == 0 {
		log.Printf("empty sessions batch")
		return
	}
	l := len(s.finishedSessions)
	sessions := make([]map[string]string, 0, len(s.finishedSessions))
	toKeep := make([]uint64, 0, len(s.finishedSessions))
	toSend := make([]uint64, 0, len(s.finishedSessions))
	for _, sessionID := range s.finishedSessions {
		// ts, now, ts+1min
		if s.lastUpdate[sessionID].Add(time.Minute * 1).After(time.Now()) {
			toKeep = append(toKeep, sessionID)
		} else {
			sessions = append(sessions, s.sessions[sessionID])
			toSend = append(toSend, sessionID)
		}
	}
	log.Printf("finished: %d, to keep: %d, to send: %d", l, len(toKeep), len(toSend))

	// Send data to S3
	fileName := fmt.Sprintf("connector_data/%s-%s.csv", s.cfg.SessionsTableName, uuid.New().String())
	// Create csv file
	buf := sessionsToBuffer(sessions)

	reader := bytes.NewReader(buf.Bytes())
	if err := s.objStorage.Upload(reader, fileName, "text/csv", objectstorage.NoCompression); err != nil {
		log.Printf("can't upload file to s3: %s", err)
		return
	}
	// Copy data from s3 bucket to redshift
	if err := s.db.Copy(s.cfg.SessionsTableName, fileName, "|", true, false); err != nil {
		log.Printf("can't copy data from s3 to redshift: %s", err)
		return
	}
	// Clear current list of finished sessions
	for _, sessionID := range toSend {
		delete(s.sessions, sessionID)   // delete session info
		delete(s.lastUpdate, sessionID) // delete last session update timestamp
	}
	s.finishedSessions = toKeep
	log.Printf("sessions batch of %d sessions is successfully saved", l)
}

// Commit saves batch to Redshift
func (s *Saver) Commit() {
	// Cache updated sessions
	start := time.Now()
	for sessionID, _ := range s.updatedSessions {
		if err := s.sessModule.AddCached(sessionID, s.sessions[sessionID]); err != nil {
			log.Printf("Error adding session to cache: %v", err)
		}
	}
	log.Printf("Cached %d sessions in %s", len(s.updatedSessions), time.Since(start))
	s.updatedSessions = nil
	// Commit events and sessions (send to Redshift)
	s.commitEvents()
	s.checkZombieSessions()
	s.commitSessions()
}

func (s *Saver) checkZombieSessions() {
	// Check if there are old sessions that should be sent to Redshift
	finished := make(map[uint64]bool, len(s.finishedSessions))
	for _, sessionID := range s.finishedSessions {
		finished[sessionID] = true
	}
	now := time.Now()
	zombieSessionsCount := 0
	for sessionID, _ := range s.sessions {
		if finished[sessionID] {
			continue
		}
		if s.lastUpdate[sessionID].Add(time.Minute * 5).Before(now) {
			s.finishedSessions = append(s.finishedSessions, sessionID)
			zombieSessionsCount++
		}
	}
	if zombieSessionsCount > 0 {
		log.Printf("Found %d zombie sessions", zombieSessionsCount)
	}
}

func (s *Saver) Close() error {
	// Close connection to Redshift
	return nil
}

var reservedWords = []string{"ALL", "ANALYSE", "ANALYZE", "AND", "ANY", "ARRAY", "AS", "ASC", "ASYMMETRIC", "BOTH", "CASE", "CAST", "CHECK", "COLLATE", "COLUMN", "CONSTRAINT", "CREATE", "CROSS", "CURRENT_CATALOG", "CURRENT_DATE", "CURRENT_ROLE", "CURRENT_SCHEMA", "CURRENT_TIME", "CURRENT_TIMESTAMP", "CURRENT_USER", "DEFAULT", "DEFERRABLE", "DESC", "DISTINCT", "DO", "ELSE", "END", "EXCEPT", "FALSE", "FOR", "FOREIGN", "FREEZE", "FROM", "FULL", "GRANT", "GROUP", "HAVING", "ILIKE", "IN", "INITIALLY", "INNER", "INTERSECT", "INTO", "IS", "ISNULL", "JOIN", "LEADING", "LEFT", "LIKE", "LIMIT", "LOCALTIME", "LOCALTIMESTAMP", "NATURAL", "NEW", "NOT", "NOTNULL", "NULL", "OFF", "OFFSET", "OLD", "ON", "ONLY", "OR", "ORDER", "OUTER", "OVERLAPS", "PLACING", "PRIMARY", "REFERENCES", "RETURNING", "RIGHT", "SELECT", "SESSION_USER", "SIMILAR", "SOME", "SYMMETRIC", "TABLE", "THEN", "TO", "TRAILING", "TRUE", "UNION", "UNIQUE", "USER", "USING", "VERBOSE", "WHEN", "WHERE", "WINDOW", "WITH"}

func validateColumnNames(columns []string) error {
	for _, column := range columns {
		for _, reservedWord := range reservedWords {
			if column == reservedWord {
				return fmt.Errorf("column name %s is a reserved word", column)
			}
		}
	}
	return nil
}