package main

import "C"
import (
	"errors"
	"os"

	"github.com/boltdb/bolt"
)

//export GetMagic
func GetMagic() int64 {
	return 0x10203040
}

//export Bolt_Options_New
func Bolt_Options_New() ObjectReference {
	b := *bolt.DefaultOptions

	return gms.Put(&b)
}

//export Bolt_Options_New_Readonly
func Bolt_Options_New_Readonly() ObjectReference {
	b := *bolt.DefaultOptions
	b.ReadOnly = true

	return gms.Put(&b)
}

//export Recall
func Recall(f func(a int64) int64) int64 {
	return f(3)
}

//export Bolt_Open
func Bolt_Open(path string, mode uint32, opts ObjectReference) (ObjectReference, string) {
	optsIFC, ok := gms.Get(opts)
	if !ok {
		return 0, ""
	}

	ptrBoltOps, ok := optsIFC.(*bolt.Options)
	if !ok {
		return 0, ""
	}

	ptrDB, err := bolt.Open(path, os.FileMode(mode), ptrBoltOps)
	if err != nil {
		return 0, err.Error()
	}

	dbRef := gms.Put(ptrDB)
	return dbRef, ""
}

func withBoltDBReference(b ObjectReference, fn func(db *bolt.DB) error) error {
	dbIFC, ok := gms.Get(b)
	if !ok {
		return NullObjectReference
	}

	ptrDB, ok := dbIFC.(*bolt.DB)
	if !ok {
		return NullObjectReference
	}

	return fn(ptrDB)
}

//export Bolt_ListBuckets
func Bolt_ListBuckets(b ObjectReference, browse []string, withEach func(string)) string {
	if len(browse) == 0 {
		return Bolt_ListBucketsAtRoot(b, withEach)
	}

	err := withBoltDBReference(b, func(db *bolt.DB) error {
		return db.View(func(tx *bolt.Tx) error {

			bucket := tx.Bucket([]byte(browse[0]))
			if bucket == nil {
				return errors.New("Unknown bucket")
			}

			for i := 1; i < len(browse); i += 1 {
				bucket = bucket.Bucket([]byte(browse[i]))
				if bucket == nil {
					return errors.New("Unknown bucket")
				}
			}

			return bucket.ForEach(func(k, v []byte) error {

				withEach(string(k))
				return nil
			})

		})
	})

	if err != nil {
		return err.Error()
	}

	return ""
}

//export Bolt_ListBucketsAtRoot
func Bolt_ListBucketsAtRoot(b ObjectReference, withEach func(string)) string {
	err := withBoltDBReference(b, func(db *bolt.DB) error {
		return db.View(func(tx *bolt.Tx) error {

			return tx.ForEach(func(n []byte, bucket *bolt.Bucket) error {

				withEach(string(n))
				return nil
			})

		})
	})

	if err != nil {
		return err.Error()
	}
	return ""
}

//export Bolt_Close
func Bolt_Close(b ObjectReference) string {
	err := withBoltDBReference(b, func(db *bolt.DB) error {
		return db.Close()
	})

	if err != nil {
		return err.Error()
	}

	gms.Delete(b)
	return ""
}

func main() {
	// virtual
}