package change

import (
	"log"
	"sync"
	"time"

	"git.aiterp.net/rpdata/api/model/counter"

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

var collection *mgo.Collection

// A Change represents a change in any other model
type Change struct {
	ID       int         `bson:"_id" json:"id"`
	Time     time.Time   `bson:"time" json:"time"`
	Model    string      `bson:"model" json:"model"`
	Op       string      `bson:"op" json:"op"`
	Author   string      `bson:"author,omitempty" json:"author,omitempty"`
	ObjectID string      `bson:"objectId,omitempty" json:"objectId,omitempty"`
	Data     interface{} `bson:"data,omitempty" json:"data,omitempty"`
}

// PublicModels lists which models can be listed in bulk by anyone.
var PublicModels = []string{
	"Character",
	"Log",
	"Post",
}

var submitMutex sync.Mutex

// Submit submits a change to the history.
func Submit(model, op, author, objectID string, data interface{}) (Change, error) {
	submitMutex.Lock()
	defer submitMutex.Unlock()

	index, err := counter.Next("auto_increment", "Change")
	if err != nil {
		return Change{}, err
	}

	change := Change{
		ID:       index,
		Time:     time.Now(),
		Model:    model,
		Op:       op,
		Author:   author,
		ObjectID: objectID,
		Data:     data,
	}

	Timeline.push(change)

	err = collection.Insert(&change)
	if err != nil {
		return Change{}, err
	}

	return change, err
}

// FindID gets a change by ID
func FindID(id int) (Change, error) {
	change := Change{}
	err := collection.FindId(id).One(&change)
	if err != nil {
		return Change{}, err
	}

	return change, nil
}

// List gets all changes in ascending order
func List() ([]Change, error) {
	changes := make([]Change, 0, 64)
	err := collection.Find(nil).Sort("_id").All(&changes)
	if err != nil {
		return nil, err
	}

	return changes, nil
}

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

		collection.EnsureIndexKey("model")
		collection.EnsureIndexKey("author")
		collection.EnsureIndexKey("objectId")

		err := collection.EnsureIndex(mgo.Index{
			Name:        "expiry",
			Key:         []string{"time"},
			ExpireAfter: time.Hour * 336,
		})
		if err != nil {
			log.Fatalln(err)
		}
	})
}