package storm

import (
	"fmt"
	"reflect"

	"github.com/asdine/storm/index"
	"github.com/boltdb/bolt"
	"github.com/fatih/structs"
)

// Range returns one or more records by the specified index within the specified range
func (n *Node) Range(fieldName string, min, max, to interface{}, options ...func(*index.Options)) error {
	ref := reflect.ValueOf(to)

	if ref.Kind() != reflect.Ptr || reflect.Indirect(ref).Kind() != reflect.Slice {
		return ErrSlicePtrNeeded
	}

	typ := reflect.Indirect(ref).Type().Elem()
	newElem := reflect.New(typ)

	d := structs.New(newElem.Interface())
	bucketName := d.Name()
	if bucketName == "" {
		return ErrNoName
	}

	field, ok := d.FieldOk(fieldName)
	if !ok {
		return fmt.Errorf("field %s not found", fieldName)
	}

	tag := field.Tag("storm")
	if tag == "" {
		return fmt.Errorf("index %s not found", fieldName)
	}

	mn, err := toBytes(min, n.s.Codec)
	if err != nil {
		return err
	}

	mx, err := toBytes(max, n.s.Codec)
	if err != nil {
		return err
	}

	opts := index.NewOptions()
	for _, fn := range options {
		fn(opts)
	}

	if n.tx != nil {
		return n.rnge(n.tx, bucketName, fieldName, tag, &ref, mn, mx, opts)
	}

	return n.s.Bolt.View(func(tx *bolt.Tx) error {
		return n.rnge(tx, bucketName, fieldName, tag, &ref, mn, mx, opts)
	})
}

func (n *Node) rnge(tx *bolt.Tx, bucketName, fieldName, tag string, ref *reflect.Value, min, max []byte, opts *index.Options) error {
	bucket := n.GetBucket(tx, bucketName)
	if bucket == nil {
		return fmt.Errorf("bucket %s not found", bucketName)
	}

	idx, err := getIndex(bucket, tag, fieldName)
	if err != nil {
		return err
	}

	list, err := idx.Range(min, max, opts)
	if err != nil {
		return err
	}

	results := reflect.MakeSlice(reflect.Indirect(*ref).Type(), len(list), len(list))

	for i := range list {
		raw := bucket.Get(list[i])
		if raw == nil {
			return ErrNotFound
		}

		err = n.s.Codec.Decode(raw, results.Index(i).Addr().Interface())
		if err != nil {
			return err
		}
	}

	reflect.Indirect(*ref).Set(results)
	return nil
}

// Range returns one or more records by the specified index within the specified range
func (s *DB) Range(fieldName string, min, max, to interface{}, options ...func(*index.Options)) error {
	return s.root.Range(fieldName, min, max, to, options...)
}