package mgocrud

import (
	"errors"
	"runtime"

	mgo "gopkg.in/mgo.v2"
)

type MgoConnection struct {
	connection *mgo.Session
	closed     bool
}

func NewMgoConnection(dial string) (Connection, error) {
	connection, err := mgo.Dial(dial)
	if err != nil {
		return nil, err
	}
	connection.SetMode(mgo.Monotonic, true)
	c := &MgoConnection{connection: connection}
	runtime.SetFinalizer(c, func(c *MgoConnection) {
		if !c.closed {
			c.Close()
		}
	})
	return c, nil
}

func (c *MgoConnection) Close() {
	if !c.closed {
		c.connection.Close()
		c.closed = true
	}
	runtime.SetFinalizer(c, nil)
}

type MgoSession struct {
	session *mgo.Session
	closed  bool
}

func (s *MgoSession) Close() {
	if !s.closed {
		s.session.Close()
		s.closed = true
	}
	runtime.SetFinalizer(s, nil)
}

func (c *MgoConnection) NewSession() Session {
	s := &MgoSession{session: c.connection.Copy()}
	runtime.SetFinalizer(s, func(s *MgoSession) {
		if !s.closed {
			s.Close()
		}
	})
	return s
}

type MgoDatabase struct {
	database *mgo.Database
	session  Session
}

func (s *MgoSession) DB(name string) Database {
	return &MgoDatabase{database: s.session.DB(name), session: s}
}

type MgoCollection struct {
	collection *mgo.Collection
}

func (db *MgoDatabase) Session() Session {
	return db.session
}

func (db *MgoDatabase) C(name string) Collection {
	return &MgoCollection{collection: db.database.C(name)}
}

func (db *MgoDatabase) Name() string {
	return db.database.Name
}

func (c *MgoCollection) Insert(docs ...interface{}) error {
	return c.collection.Insert(docs...)
}

func (c *MgoCollection) UpdateId(id interface{}, update interface{}) error {
	return c.collection.UpdateId(id, update)
}

func (c *MgoCollection) RemoveId(id interface{}) error {
	return c.collection.RemoveId(id)
}

type MgoChangeInfo struct {
	changeInfo *mgo.ChangeInfo
}

func (ci *MgoChangeInfo) Matched() int {
	return ci.changeInfo.Matched
}

func (ci *MgoChangeInfo) Removed() int {
	return ci.changeInfo.Removed
}

func (ci *MgoChangeInfo) Updated() int {
	return ci.changeInfo.Updated
}

func (c *MgoCollection) Upsert(selector interface{}, update interface{}) (ChangeInfo, error) {
	ci, err := c.collection.Upsert(selector, update)
	if err != nil {
		return nil, err
	}
	return &MgoChangeInfo{changeInfo: ci}, nil
}

func (c *MgoCollection) RemoveAll(filter interface{}) (ChangeInfo, error) {
	ci, err := c.collection.RemoveAll(filter)
	if err != nil {
		return nil, err
	}
	return &MgoChangeInfo{changeInfo: ci}, nil
}

type MgoQuery struct {
	query *mgo.Query
}

func (c *MgoCollection) FindId(id interface{}) Query {
	return &MgoQuery{query: c.collection.FindId(id)}
}

func (c *MgoCollection) Find(query interface{}) Query {
	return &MgoQuery{query: c.collection.Find(query)}
}

func (q *MgoQuery) Select(selector interface{}) Query {
	q.query = q.query.Select(selector)
	return q
}

func (q *MgoQuery) One(result interface{}) error {
	err := q.query.One(result)
	if err == mgo.ErrNotFound {
		err = ErrNotFound
	}
	return err
}

func (q *MgoQuery) Sort(fields ...string) Query {
	q.query = q.query.Sort(fields...)
	return q
}

func (q *MgoQuery) Skip(n int) Query {
	q.query = q.query.Skip(n)
	return q
}

func (q *MgoQuery) Limit(n int) Query {
	q.query = q.query.Limit(n)
	return q
}

func (q *MgoQuery) All(result interface{}) error {
	err := q.query.All(result)
	if err == mgo.ErrNotFound {
		err = ErrNotFound
	}
	return err
}

func (q *MgoQuery) Count() (int, error) {
	c, err := q.query.Count()
	if err == mgo.ErrNotFound {
		err = ErrNotFound
	}
	return c, err
}

type MgoIndex struct {
	index *mgo.Index
}

func NewMgoIndex(index mgo.Index) Index {
	return &MgoIndex{index: &index}
}

func (c *MgoCollection) EnsureIndex(index Index) error {
	if i, ok := index.(*MgoIndex); ok {
		if i != nil && i.index != nil {
			return c.collection.EnsureIndex(*i.index)
		}
	}
	return errors.New("index parameter not initialized with mgo.Index")
}

type MgoPipe struct {
	pipe *mgo.Pipe
}

func (p *MgoPipe) All(result interface{}) error {
	err := p.pipe.All(result)
	if err == mgo.ErrNotFound {
		err = ErrNotFound
	}
	return err
}

func (c *MgoCollection) Pipe(pipeline interface{}) Pipe {
	return &MgoPipe{pipe: c.collection.Pipe(pipeline).AllowDiskUse()}
}