package channel

import (
	"errors"
	"strings"

	"git.aiterp.net/rpdata/api/internal/store"
	"github.com/globalsign/mgo"
	"github.com/globalsign/mgo/bson"
)

var collection *mgo.Collection

// ErrInvalidName is an error for an invalid channel name
var ErrInvalidName = errors.New("Invalid channel name")

// A Channel represents information abount an IRC RP channel, and whether it should be logged
type Channel struct {
	Name     string `bson:"_id"`
	Logged   bool   `bson:"logged"`
	Hub      bool   `bson:"hub"`
	Event    string `bson:"event,omitempty"`
	Location string `bson:"location,omitempty"`
}

// Edit edits the channel
func (channel *Channel) Edit(logged, hub *bool, event, location *string) error {
	changes := bson.M{}
	changed := *channel

	if logged != nil && channel.Logged != *logged {
		changes["logged"] = *logged
		changed.Logged = *logged
	}
	if hub != nil && channel.Hub != *hub {
		changes["hub"] = *hub
		changed.Hub = *hub
	}
	if event != nil && channel.Event != *event {
		changes["event"] = *event
		changed.Event = *event
	}
	if location != nil && channel.Event != *location {
		changes["location"] = *location
		changed.Location = *location
	}

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

	err := collection.UpdateId(channel.Name, bson.M{"$set": changes})
	if err != nil {
		return err
	}

	*channel = changed

	return nil
}

// Remove removes the channel information from the database.
func (channel *Channel) Remove() error {
	return collection.RemoveId(channel.Name)
}

// Ensure ensures a channel's existence. It does not change `logged` if there is
// an existing channel.
func Ensure(name string, logged bool) (Channel, error) {
	channel, err := FindName(name)
	if err == mgo.ErrNotFound {
		return New(name, logged, false, "", "")
	} else if err != nil {
		return Channel{}, err
	}

	return channel, nil
}

// New creates a new channel
func New(name string, logged, hub bool, event, location string) (Channel, error) {
	if len(name) < 3 && !strings.HasPrefix(name, "#") {
		return Channel{}, ErrInvalidName
	}

	channel := Channel{
		Name:     name,
		Logged:   logged,
		Hub:      hub,
		Event:    event,
		Location: location,
	}

	err := collection.Insert(channel)
	if err != nil {
		return Channel{}, err
	}

	return channel, nil
}

// FindName finds a channel by its id (its name).
func FindName(name string) (Channel, error) {
	channel := Channel{}
	err := collection.FindId(name).One(&channel)

	return channel, err
}

// List finds channels, if logged is true it will be limited to logged
// channels
func List(logged bool) ([]Channel, error) {
	query := bson.M{}
	if logged {
		query["logged"] = true
	}

	channels := make([]Channel, 0, 32)
	err := collection.Find(query).All(&channels)

	return channels, err
}

func init() {
	store.HandleInit(func(db *mgo.Database) {
		collection = db.C("common.channels")

		collection.EnsureIndexKey("logged")
		collection.EnsureIndexKey("hub")
		collection.EnsureIndexKey("event")
		collection.EnsureIndexKey("location")
	})
}