package services

import (
	"context"
	"errors"
	"git.aiterp.net/rpdata/api/models"
	"git.aiterp.net/rpdata/api/models/changekeys"
	"git.aiterp.net/rpdata/api/repositories"
	"git.aiterp.net/rpdata/api/services/parsers"
	"golang.org/x/sync/errgroup"
	"log"
	"sort"
	"strings"
	"sync"
	"time"
)

type LogService struct {
	logs             repositories.LogRepository
	posts            repositories.PostRepository
	changeService    *ChangeService
	channelService   *ChannelService
	characterService *CharacterService
	authService      *AuthService

	unknownNicks      map[string]int
	unknownNicksMutex sync.Mutex
}

func (s *LogService) Find(ctx context.Context, id string) (*models.Log, error) {
	return s.logs.Find(ctx, id)
}

func (s *LogService) FindPosts(ctx context.Context, id string) (*models.Post, error) {
	return s.posts.Find(ctx, id)
}

func (s *LogService) List(ctx context.Context, filter *models.LogFilter) ([]*models.Log, error) {
	if filter == nil {
		filter = &models.LogFilter{}
	}

	return s.logs.List(ctx, *filter)
}

func (s *LogService) ListPosts(ctx context.Context, filter *models.PostFilter) ([]*models.Post, error) {
	// Some sanity checks to avoid querying an insame amount of posts.
	if filter == nil {
		filter = &models.PostFilter{Limit: 100}
	} else {
		if (filter.Limit <= 0 || filter.Limit > 512) && (filter.LogID == nil && len(filter.IDs) == 0) {
			return nil, errors.New("a limit of 0 (no limit) or >512 without a logId or a set of IDs is not allowed")
		}

		if len(filter.IDs) > 100 {
			return nil, errors.New("you may not query for more than 100 ids, split your query")
		}
	}

	return s.posts.List(ctx, *filter)
}

func (s *LogService) ListUnknownNicks() []*models.UnknownNick {
	s.unknownNicksMutex.Lock()
	nicks := make([]*models.UnknownNick, 0, len(s.unknownNicks))
	for nick, score := range s.unknownNicks {
		nicks = append(nicks, &models.UnknownNick{
			Nick:  nick,
			Score: score,
		})
	}
	s.unknownNicksMutex.Unlock()

	sort.Slice(nicks, func(i, j int) bool {
		return nicks[i].Score > nicks[j].Score
	})

	return nicks
}

func (s *LogService) Create(ctx context.Context, title, description, channelName, eventName string, open bool) (*models.Log, error) {
	if channelName == "" {
		return nil, errors.New("channel name cannot be empty")
	}

	log := &models.Log{
		Title:       title,
		Description: description,
		ChannelName: channelName,
		EventName:   eventName,
		Date:        time.Now(),
		Open:        open,
	}

	if err := s.authService.CheckPermission(ctx, "add", log); err != nil {
		return nil, err
	}

	_, err := s.channelService.Ensure(ctx, channelName)
	if err != nil {
		return nil, err
	}

	log, err = s.logs.Insert(ctx, *log)
	if err != nil {
		return nil, err
	}

	s.changeService.Submit(ctx, models.ChangeModelLog, "add", true, changekeys.Listed(log), log)

	return log, nil
}

// Import creates new logs from common formats.
func (s *LogService) Import(ctx context.Context, importer models.LogImporter, date time.Time, tz *time.Location, channelName string, data string) ([]*models.Log, error) {
	if err := s.authService.CheckPermission(ctx, "add", &models.Log{}); err != nil {
		return nil, err
	}

	results := make([]*models.Log, 0, 8)

	_, err := s.channelService.Ensure(ctx, channelName)
	if err != nil {
		return nil, err
	}

	eventName := ""
	if channel, err := s.channelService.Find(ctx, channelName); err == nil {
		eventName = channel.EventName
	}

	date = date.In(tz)

	switch importer {
	case models.LogImporterMircLike:
		{
			if date.IsZero() {
				return nil, errors.New("date is not optional for mirc-like logs")
			}

			parsed, err := parsers.MircLog(data, date, true)
			if err != nil {
				return nil, err
			}
			parsed.Log.EventName = eventName
			parsed.Log.ChannelName = channelName

			log, err := s.logs.Insert(ctx, parsed.Log)
			if err != nil {
				return nil, err
			}

			for _, post := range parsed.Posts {
				post.LogID = log.ShortID
			}

			posts, err := s.posts.InsertMany(ctx, parsed.Posts...)
			if err != nil {
				_ = s.logs.Delete(ctx, *log)

				return nil, err
			}

			s.changeService.Submit(ctx, models.ChangeModelLog, "add", true, changekeys.Listed(log), log)
			s.changeService.Submit(ctx, models.ChangeModelPost, "add", true, changekeys.Listed(log, posts), log, posts)

			results = append(results, log)
		}
	case models.LogImporterForumLog:
		{
			parseResults, err := parsers.ForumLog(data, tz)
			if err != nil {
				return nil, err
			}

			for _, parsed := range parseResults {
				log, err := s.logs.Insert(ctx, parsed.Log)
				if err != nil {
					return nil, err
				}
				parsed.Log.EventName = eventName
				parsed.Log.ChannelName = channelName

				for _, post := range parsed.Posts {
					post.LogID = log.ShortID
				}

				posts, err := s.posts.InsertMany(ctx, parsed.Posts...)
				if err != nil {
					_ = s.logs.Delete(ctx, *log)

					return nil, err
				}

				s.changeService.Submit(ctx, models.ChangeModelLog, "add", true, changekeys.Listed(log), log)
				s.changeService.Submit(ctx, models.ChangeModelPost, "add", true, changekeys.Listed(log, posts), log, posts)
			}
		}
	default:
		{
			return nil, errors.New("Invalid importer: " + importer.String())
		}
	}

	return results, nil
}

func (s *LogService) Update(ctx context.Context, id string, update models.LogUpdate) (*models.Log, error) {
	log, err := s.logs.Find(ctx, id)
	if err != nil {
		return nil, err
	}

	if err := s.authService.CheckPermission(ctx, "edit", log); err != nil {
		return nil, err
	}

	log, err = s.logs.Update(ctx, *log, update)
	if err != nil {
		return nil, err
	}

	s.changeService.Submit(ctx, models.ChangeModelLog, "edit", true, changekeys.Listed(log), log)

	return log, nil
}

func (s *LogService) SplitLog(ctx context.Context, logId string, startPostId string) (*models.Log, error) {
	// Find log
	l, err := s.logs.Find(ctx, logId)
	if err != nil {
		return nil, err
	}
	if err := s.authService.CheckPermission(ctx, "add", l); err != nil {
		return nil, err
	}

	// Find posts
	posts, err := s.ListPosts(ctx, &models.PostFilter{LogID: &l.ShortID})
	if err != nil {
		return nil, err
	}
	if len(posts) == 0 {
		return nil, errors.New("cannot split empty log")
	}

	// Cut the posts slice.
	firstPost := posts[0]
	cutPosts := posts[len(posts):]
	for i, post := range posts {
		if post.ID == startPostId {
			cutPosts = posts[i:]
			firstPost = post
			break
		}
	}
	if len(cutPosts) == 0 {
		return nil, errors.New("post not found")
	}
	if len(cutPosts) == len(posts) || firstPost.Time.Equal(l.Date) {
		return nil, errors.New("cannot move posts")
	}

	// Create a new log
	newLog := &models.Log{
		Date:        firstPost.Time,
		ChannelName: l.ChannelName,
		EventName:   l.EventName,
	}
	newLog, err = s.logs.Insert(ctx, *newLog)
	if err != nil {
		return nil, err
	}

	// Put the cut posts in the new log
	newPosts := make([]*models.Post, 0, len(cutPosts))
	for _, post := range cutPosts {
		postCopy := *post
		postCopy.ID = ""
		postCopy.LogID = newLog.ShortID

		newPost, err := s.posts.Insert(ctx, postCopy)
		if err != nil {
			_ = s.logs.Delete(ctx, *newLog)
			return nil, err
		}

		newPosts = append(newPosts, newPost)
	}

	// Remove the posts from the old log (this can't error because that'll make a mess)
	for _, post := range cutPosts {
		err := s.posts.Delete(ctx, *post)
		if err != nil {
			log.Printf("Failed to delete post %s: %s", post.ID, err)
		}
	}

	// Submit the changes
	s.changeService.Submit(ctx, models.ChangeModelPost, "remove", true, changekeys.Many(l, cutPosts), cutPosts)
	s.changeService.Submit(ctx, models.ChangeModelLog, "add", true, changekeys.Listed(newLog), newLog)
	s.changeService.Submit(ctx, models.ChangeModelPost, "add", true, changekeys.Many(newLog, newPosts), newPosts)

	// Refresh character lists.
	_, _ = s.refreshLogCharacters(ctx, *l, nil, false)
	newLog2, err := s.refreshLogCharacters(ctx, *newLog, nil, false)
	if err == nil {
		newLog = newLog2
	}

	return newLog, nil
}

func (s *LogService) MergeLogs(ctx context.Context, targetID string, sourceID string, removeAfter bool) (*models.Log, error) {
	// Check permissions
	if err := s.authService.CheckPermission(ctx, "edit", &models.Log{}); err != nil {
		return nil, err
	}
	if removeAfter {
		if err := s.authService.CheckPermission(ctx, "remove", &models.Log{}); err != nil {
			return nil, err
		}
	}

	// Merge log posts into log.
	source, err := s.logs.Find(ctx, sourceID)
	if err != nil {
		return nil, errors.New("could not find source log: " + err.Error())
	}
	target, err := s.logs.Find(ctx, targetID)
	if err != nil {
		return nil, errors.New("could not find target log: " + err.Error())
	}

	// Get the source posts.
	posts, err := s.posts.List(ctx, models.PostFilter{LogID: &source.ShortID})
	if err != nil {
		return nil, errors.New("could not fetch source posts: " + err.Error())
	}

	// Associate the posts with the target logs
	for _, post := range posts {
		post.ID = ""
		post.LogID = target.ShortID
	}

	// Insert them
	posts, err = s.posts.InsertMany(ctx, posts...)
	if err != nil {
		return nil, errors.New("could not insert posts into target: " + err.Error())
	}

	// Remove other log
	if removeAfter {
		err = s.logs.Delete(ctx, *source)
		if err != nil {
			return nil, errors.New("posts have been inserted, but could not remove source: " + err.Error())
		}

		s.changeService.Submit(ctx, models.ChangeModelLog, "remove", true, changekeys.Listed(source), source)
	}

	// Refresh characters
	target2, err := s.refreshLogCharacters(ctx, *target, nil, false)
	if err != nil {
		log.Printf("Failed to update characters in log %s: %s", target.ID, err)
	} else {
		target = target2
	}

	// Submit changes after the target
	s.changeService.Submit(ctx, models.ChangeModelPost, "add", true, changekeys.Many(target, posts), target, posts)

	return target, nil
}

func (s *LogService) AddPost(ctx context.Context, logId string, time time.Time, kind, nick, text string) (*models.Post, error) {
	if kind == "" || nick == "" || time.IsZero() {
		return nil, errors.New("kind, nick and time must be non-empty")
	}

	l, err := s.logs.Find(ctx, logId)
	if err != nil {
		return nil, err
	}

	post := &models.Post{
		LogID: l.ShortID,
		Kind:  kind,
		Nick:  nick,
		Text:  text,
		Time:  time,
	}

	if err := s.authService.CheckPermission(ctx, "add", post); err != nil {
		return nil, err
	}

	post, err = s.posts.Insert(ctx, *post)
	if err != nil {
		return nil, err
	}

	l2, err := s.refreshLogCharacters(ctx, *l, nil, false)
	if err != nil {
		log.Printf("Failed to update characters in log %s: %s", l.ID, err)
	} else {
		l = l2
	}

	s.changeService.Submit(ctx, models.ChangeModelPost, "add", true, changekeys.Many(l, post), post)

	return post, nil
}

func (s *LogService) EditPost(ctx context.Context, id string, update models.PostUpdate) (*models.Post, error) {
	if (update.Kind != nil && *update.Kind == "") || (update.Nick != nil && *update.Nick == "") || (update.Text != nil && *update.Text == "") {
		return nil, errors.New("kind, nick and time must be non-empty")
	}

	post, err := s.posts.Find(ctx, id)
	if err != nil {
		return nil, err
	}

	if err := s.authService.CheckPermission(ctx, "edit", post); err != nil {
		return nil, err
	}

	post, err = s.posts.Update(ctx, *post, update)
	if err != nil {
		return nil, err
	}

	go func() {
		l, err := s.logs.Find(context.Background(), post.LogID)
		if err != nil {
			return
		}

		_, err = s.refreshLogCharacters(ctx, *l, nil, false)
		if err != nil {
			log.Printf("Failed to update characters in log %s: %s", l.ID, err)
		}

		s.changeService.Submit(ctx, models.ChangeModelPost, "edit", true, changekeys.Many(l, post), post)
	}()

	return post, nil
}

func (s *LogService) MovePost(ctx context.Context, id string, position int) ([]*models.Post, error) {
	if position < 1 {
		return nil, repositories.ErrInvalidPosition
	}

	post, err := s.posts.Find(ctx, id)
	if err != nil {
		return nil, err
	}

	if err := s.authService.CheckPermission(ctx, "move", post); err != nil {
		return nil, err
	}

	posts, err := s.posts.Move(ctx, *post, position)
	if err != nil {
		return nil, err
	}

	go func() {
		if len(posts) == 0 {
			return
		}

		log, err := s.logs.Find(context.Background(), posts[0].LogID)
		if err != nil {
			return
		}

		s.changeService.Submit(ctx, models.ChangeModelPost, "move", true, changekeys.Many(log, posts), posts)
	}()

	return posts, nil
}

func (s *LogService) DeletePost(ctx context.Context, id string) (*models.Post, error) {
	post, err := s.posts.Find(ctx, id)
	if err != nil {
		return nil, err
	}

	if err := s.authService.CheckPermission(ctx, "remove", post); err != nil {
		return nil, err
	}

	err = s.posts.Delete(ctx, *post)
	if err != nil {
		return nil, err
	}

	go func() {
		l, err := s.logs.Find(context.Background(), post.LogID)
		if err != nil {
			return
		}

		_, err = s.refreshLogCharacters(ctx, *l, nil, false)
		if err != nil {
			log.Printf("Failed to update characters in log %s: %s", l.ID, err)
		}

		s.changeService.Submit(ctx, models.ChangeModelPost, "remove", true, changekeys.Many(l, post), post)
	}()

	return post, nil
}

func (s *LogService) Delete(ctx context.Context, id string) (*models.Log, error) {
	log, err := s.logs.Find(ctx, id)
	if err != nil {
		return nil, err
	}

	if err := s.authService.CheckPermission(ctx, "remove", log); err != nil {
		return nil, err
	}

	err = s.logs.Delete(ctx, *log)
	if err != nil {
		return nil, err
	}

	s.changeService.Submit(ctx, models.ChangeModelLog, "remove", true, changekeys.Listed(log), log)

	return log, nil
}

func (s *LogService) FixImportDateBug(ctx context.Context) error {
	start := time.Now()

	logs, err := s.logs.List(ctx, models.LogFilter{})
	if err != nil {
		return err
	}

	eg := errgroup.Group{}
	for i := range logs {
		l := logs[i]

		eg.Go(func() error {
			return s.fixImportDateBug(ctx, *l)
		})
	}
	err = eg.Wait()
	if err != nil {
		return err
	}

	log.Printf("Date import bug check finished: logs: %d, duration: %s", len(logs), time.Since(start))

	return nil
}

func (s *LogService) fixImportDateBug(ctx context.Context, l models.Log) error {
	// Find the log's posts.
	posts, err := s.ListPosts(ctx, &models.PostFilter{LogID: &l.ShortID})
	if err != nil {
		return err
	}
	if len(posts) < 8 {
		return nil
	}

	// Find first action post
	first := posts[0]
	fi := 0
	for first.Kind != "action" && first.Kind != "text" {
		fi++
		if fi >= len(posts) {
			return nil
		}

		first = posts[fi]
	}
	last := posts[len(posts)-1]
	if first == last {
		return nil
	}

	// Stop here if this log probably isn't affected
	if last.Time.Sub(first.Time) < time.Hour*72 {
		return nil
	}

	// Find the first post past midnight.
	midnight := first
	mi := fi
	for i, post := range posts[fi+1:] {
		if post.Time.Hour() < first.Time.Hour() {
			midnight = post
			mi = fi + 1 + i
			break
		}
	}
	if midnight == last {
		return nil
	}

	if len(posts[mi+1:]) == 1 {
		return nil
	}

	hits := 0
	prev := midnight
	for _, offender := range posts[mi+1:] {
		if offender.Time.Day() != prev.Time.Day() {
			hits += 1
		}

		prev = offender
	}
	if hits < ((len(posts[mi+1:]) * 3) / 4) {
		return nil
	}

	for _, offender := range posts[mi+1:] {
		ot := offender.Time.UTC()
		mt := midnight.Time.UTC()

		y, m, d := mt.Date()
		hr, mi, se, ns := ot.Hour(), ot.Minute(), ot.Second(), ot.Nanosecond()

		newTime := time.Date(y, m, d, hr, mi, se, ns, time.UTC)

		_, err := s.posts.Update(ctx, *offender, models.PostUpdate{Time: &newTime})
		if err != nil {
			return err
		}
	}

	log.Printf("Fixed import date bug in %d posts in log %s", len(posts[mi+1:]), l.ID)

	return nil
}

func (s *LogService) RefreshAllLogCharacters(ctx context.Context) error {
	start := time.Now()

	// Get all logs
	logs, err := s.logs.List(ctx, models.LogFilter{})
	if err != nil {
		return err
	}

	// Check all characters now instead of later.
	characters, err := s.characterService.List(ctx, models.CharacterFilter{})
	if err != nil {
		return err
	}
	characterMap := s.makeCharacterMap(characters)

	s.unknownNicksMutex.Lock()
	for key := range s.unknownNicks {
		delete(s.unknownNicks, key)
	}
	s.unknownNicksMutex.Unlock()

	eg := errgroup.Group{}
	for i := range logs {
		l := logs[i]

		eg.Go(func() error {
			_, err := s.refreshLogCharacters(ctx, *l, characterMap, true)
			return err
		})
	}
	err = eg.Wait()
	if err != nil {
		return err
	}

	s.unknownNicksMutex.Lock()
	unknownCount := len(s.unknownNicks)
	s.unknownNicksMutex.Unlock()

	log.Printf("Full log character refresh complete; nicks: %d, unknowns: %d, logs: %d, duration: %s", len(characterMap), unknownCount, len(logs), time.Since(start))

	return nil
}

func (s *LogService) RefreshLogCharacters(ctx context.Context, log models.Log) (*models.Log, error) {
	return s.refreshLogCharacters(ctx, log, nil, false)
}

func (s *LogService) refreshLogCharacters(ctx context.Context, log models.Log, characterMap map[string]*models.Character, useUnknownNicks bool) (*models.Log, error) {
	posts, err := s.ListPosts(ctx, &models.PostFilter{LogID: &log.ShortID})
	if err != nil {
		return &log, nil
	}

	counts := make(map[string]int)
	added := make(map[string]bool)
	removed := make(map[string]bool)
	for _, post := range posts {
		if post.Kind == "text" || post.Kind == "action" {
			if strings.HasPrefix(post.Text, "(") || strings.Contains(post.Nick, "(") || strings.Contains(post.Nick, "[E]") || strings.HasSuffix(post.Nick, "|") {
				continue
			}

			// Clean up the nick (remove possessive suffix, comma, formatting stuff)
			if strings.HasSuffix(post.Nick, "'s") || strings.HasSuffix(post.Nick, "`s") {
				post.Nick = post.Nick[:len(post.Nick)-2]
			} else if strings.HasSuffix(post.Nick, "'") || strings.HasSuffix(post.Nick, "`") || strings.HasSuffix(post.Nick, ",") || strings.HasSuffix(post.Nick, "\x0f") {
				post.Nick = post.Nick[:len(post.Nick)-1]
			}

			added[post.Nick] = true
			counts[post.Nick]++
		}
		if post.Kind == "chars" {
			tokens := strings.Fields(post.Text)
			for _, token := range tokens {
				if strings.HasPrefix(token, "-") {
					removed[token[1:]] = true
				} else {
					added[strings.Replace(token, "+", "", 1)] = true
				}
			}
		}
	}

	nicks := make([]string, 0, len(added))
	for nick := range added {
		if added[nick] && !removed[nick] {
			nicks = append(nicks, nick)
		}
	}

	if characterMap == nil {
		characters, err := s.characterService.List(ctx, models.CharacterFilter{Nicks: nicks})
		if err != nil {
			return nil, err
		}

		characterMap = s.makeCharacterMap(characters)
	}

	log.CharacterIDs = log.CharacterIDs[:0]
	for key := range added {
		delete(added, key)
	}
	unknowned := make(map[string]bool)
	for _, nick := range nicks {
		character := characterMap[nick]
		if character == nil {
			if useUnknownNicks && !unknowned[nick] {
				unknowned[nick] = true
				s.unknownNicksMutex.Lock()
				s.unknownNicks[nick]++
				s.unknownNicksMutex.Unlock()
			}

			continue
		} else if added[character.ID] {
			continue
		}
		added[character.ID] = true

		log.CharacterIDs = append(log.CharacterIDs, character.ID)
	}

	return s.logs.Update(ctx, log, models.LogUpdate{CharacterIDs: log.CharacterIDs})
}

func (s *LogService) makeCharacterMap(characters []*models.Character) map[string]*models.Character {
	characterMap := make(map[string]*models.Character, len(characters)*3)
	for _, character := range characters {
		for _, nick := range character.Nicks {
			characterMap[nick] = character
		}
	}

	return characterMap
}