package log

import (
	"errors"
	"fmt"
	"log"
	"sort"
	"strconv"
	"strings"
	"sync"
	"time"

	"git.aiterp.net/rpdata/api/internal/store"
	"git.aiterp.net/rpdata/api/model/channel"
	"git.aiterp.net/rpdata/api/model/character"
	"git.aiterp.net/rpdata/api/model/counter"

	"github.com/globalsign/mgo/bson"

	"github.com/globalsign/mgo"
)

var postMutex sync.RWMutex

var characterUpdateMutex sync.Mutex

var logsCollection *mgo.Collection

// Log is the header/session for a log file.
type Log struct {
	ID           string    `bson:"_id"`
	ShortID      string    `bson:"shortId"`
	Date         time.Time `bson:"date"`
	Channel      string    `bson:"channel"`
	Title        string    `bson:"title,omitempty"`
	Event        string    `bson:"event,omitempty"`
	Description  string    `bson:"description,omitempty"`
	Open         bool      `bson:"open"`
	CharacterIDs []string  `bson:"characterIds"`
}

// New creates a new Log
func New(date time.Time, channelName, title, event, description string, open bool) (Log, error) {
	nextID, err := counter.Next("auto_increment", "Log")
	if err != nil {
		return Log{}, err
	}

	_, err = channel.Ensure(channelName, open)
	if err != nil {
		return Log{}, err
	}

	log := Log{
		ID:           MakeLogID(date, channelName),
		ShortID:      "L" + strconv.Itoa(nextID),
		Date:         date,
		Channel:      channelName,
		Title:        title,
		Event:        event,
		Description:  description,
		Open:         open,
		CharacterIDs: nil,
	}

	err = logsCollection.Insert(log)
	if err != nil {
		return Log{}, err
	}

	return log, nil
}

// FindID finds a log either by it's ID or short ID.
func FindID(id string) (Log, error) {
	return findLog(bson.M{
		"$or": []bson.M{
			bson.M{"_id": id},
			bson.M{"shortId": id},
		},
	})
}

// List lists all logs
func List(filter *Filter) ([]Log, error) {
	query := bson.M{}

	// Run a text search
	if filter.Search != nil {
		searchResults := make([]string, 0, 32)

		postMutex.RLock()
		err := postCollection.Find(bson.M{"$text": bson.M{"$search": *filter.Search}}).Distinct("logId", &searchResults)
		if err != nil {
			return nil, err
		}
		postMutex.RUnlock()

		// Posts always use shortId to refer to the log
		query["shortId"] = bson.M{"$in": searchResults}
	}

	// Find logs including any of the specified events and channels
	if filter.Channels != nil {
		query["channel"] = bson.M{"$in": *filter.Channels}
	}
	if filter.Events != nil {
		query["event"] = bson.M{"$in": *filter.Events}
	}

	// Find logs including all of the specified character IDs.
	if filter.Characters != nil {
		query["characterIds"] = bson.M{"$all": *filter.Characters}
	}

	// Limit to only open logs
	if filter.Open != nil {
		query["open"] = *filter.Open
	}

	limit := 0
	if filter.Limit != nil {
		limit = int(*filter.Limit)
	}

	return listLog(query, limit)
}

// Edit sets the metadata
func (log *Log) Edit(title *string, event *string, description *string, open *bool) error {
	changes := bson.M{}

	if title != nil && *title != log.Title {
		changes["title"] = *title
	}
	if event != nil && *event != log.Event {
		changes["event"] = *event
	}
	if description != nil && *description != log.Description {
		changes["description"] = *description
	}
	if open != nil && *open != log.Open {
		changes["open"] = *open
	}

	if len(changes) == 0 {
		return nil
	}

	err := logsCollection.UpdateId(log.ID, bson.M{"$set": changes})
	if err != nil {
		return err
	}

	if title != nil {
		log.Title = *title
	}
	if event != nil {
		log.Event = *event
	}
	if description != nil {
		log.Description = *description
	}
	if open != nil {
		log.Open = *open
	}

	return nil
}

// Posts gets all the posts under the log. If no kinds are specified, it
// will get all posts
func (log *Log) Posts(kinds ...string) ([]Post, error) {
	postMutex.RLock()
	defer postMutex.RUnlock()

	query := bson.M{
		"$or": []bson.M{
			bson.M{"logId": log.ID},
			bson.M{"logId": log.ShortID},
		},
	}

	if len(kinds) > 0 {
		for i := range kinds {
			kinds[i] = strings.ToLower(kinds[i])
		}

		query["kind"] = bson.M{"$in": kinds}
	}

	posts, err := listPosts(query)
	if err != nil {
		return nil, err
	}

	sort.SliceStable(posts, func(i, j int) bool {
		return posts[i].Position < posts[j].Position
	})

	return posts, nil
}

// NewPost creates a new post.
func (log *Log) NewPost(time time.Time, kind, nick, text string) (Post, error) {
	if kind == "" || nick == "" || text == "" {
		return Post{}, errors.New("Missing/empty parameters")
	}

	postMutex.RLock()
	defer postMutex.RUnlock()

	position, err := counter.Next("next_post_id", log.ShortID)
	if err != nil {
		return Post{}, err
	}

	post := Post{
		ID:       MakePostID(time),
		Position: position,
		LogID:    log.ShortID,
		Time:     time,
		Kind:     kind,
		Nick:     nick,
		Text:     text,
	}

	err = postCollection.Insert(post)
	if err != nil {
		return Post{}, err
	}

	return post, nil
}

// UpdateCharacters updates the character list
func (log *Log) UpdateCharacters() error {
	characterUpdateMutex.Lock()
	defer characterUpdateMutex.Unlock()

	posts, err := log.Posts()
	if err != nil {
		return err
	}

	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]") {
				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
		}
		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)
		}
	}

	characters, err := character.ListNicks(nicks...)
	if err != nil {
		return err
	}

	characterIDs := make([]string, len(characters))
	for i, char := range characters {
		characterIDs[i] = char.ID
	}

	err = logsCollection.UpdateId(log.ID, bson.M{"$set": bson.M{"characterIds": characterIDs}})
	if err != nil {
		return err
	}

	for _, nick := range nicks {
		found := false

		for _, character := range characters {
			if character.HasNick(nick) {
				found = true
				break
			}
		}

		if !found {
			addUnknownNick(nick)
		}
	}

	log.CharacterIDs = characterIDs

	return nil
}

// Remove removes the log and all associated posts from the database
func (log *Log) Remove() error {
	err := logsCollection.Remove(bson.M{"_id": log.ID})
	if err != nil {
		return err
	}

	_, err = postCollection.RemoveAll(bson.M{"$or": []bson.M{
		bson.M{"logId": log.ID},
		bson.M{"logId": log.ShortID},
	}})
	if err != nil {
		return err
	}

	return nil
}

func findLog(query interface{}) (Log, error) {
	log := Log{}
	err := logsCollection.Find(query).One(&log)
	if err != nil {
		return Log{}, err
	}

	return log, nil
}

func listLog(query interface{}, limit int) ([]Log, error) {
	logs := make([]Log, 0, 64)
	err := logsCollection.Find(query).Limit(limit).Sort("-date").All(&logs)
	if err != nil {
		return nil, err
	}

	return logs, nil
}

func iterLogs(query interface{}, limit int) *mgo.Iter {
	return logsCollection.Find(query).Sort("-date").Limit(limit).Batch(8).Iter()
}

// MakeLogID generates log IDs that are of the format from logbot2, though it will break compatibility.
func MakeLogID(date time.Time, channel string) string {
	return fmt.Sprintf("%s%03d_%s", date.UTC().Format("2006-01-02_150405"), (date.Nanosecond() / int(time.Millisecond/time.Nanosecond)), channel[1:])
}

func init() {
	store.HandleInit(func(db *mgo.Database) {
		logsCollection = db.C("logbot3.logs")

		logsCollection.EnsureIndexKey("date")
		logsCollection.EnsureIndexKey("channel")
		logsCollection.EnsureIndexKey("characterIds")
		logsCollection.EnsureIndexKey("event")
		logsCollection.EnsureIndex(mgo.Index{
			Key: []string{"channel", "open"},
		})
		err := logsCollection.EnsureIndex(mgo.Index{
			Key:      []string{"shortId"},
			Unique:   true,
			DropDups: true,
		})
		if err != nil {
			log.Fatalln("init logbot3.logs:", err)
		}
	})
}