// Copyright © 2016 Abcum Ltd
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package indx

import (
	"reflect"

	"github.com/abcum/surreal/sql"
	"github.com/abcum/surreal/util/data"
)

func Diff(old, now [][]interface{}) {

	var d bool

	for i := len(old) - 1; i >= 0; i-- {
		o := old[i]
		for j := len(now) - 1; j >= 0; j-- {
			n := now[j]
			if reflect.DeepEqual(o, n) {
				d = true
				copy(now[j:], now[j+1:])
				now[len(now)-1] = nil
				now = now[:len(now)-1]
			}
		}
		if d {
			d = false
			copy(old[i:], old[i+1:])
			old[len(old)-1] = nil
			old = old[:len(old)-1]
		}
	}

}

func Build(cols sql.Idents, item *data.Doc) (out [][]interface{}) {

	if len(cols) == 0 {
		return [][]interface{}{nil}
	}

	col, cols := cols[0], cols[1:]

	sub := Build(cols, item)

	if arr, ok := item.Get(col.ID).Data().([]interface{}); ok {
		for _, s := range sub {
			for _, a := range arr {
				idx := []interface{}{}
				idx = append(idx, a)
				idx = append(idx, s...)
				out = append(out, idx)
			}
		}
	} else {
		for _, s := range sub {
			idx := []interface{}{}
			idx = append(idx, item.Get(col.ID).Data())
			idx = append(idx, s...)
			out = append(out, idx)
		}
	}

	return

}