package mdb

import (
	"fmt"
	"reflect"
)

func (bt *BTreeIndex[T]) Equals(rhs *BTreeIndex[T]) error {
	if bt.Len() != rhs.Len() {
		return fmt.Errorf("Expected %d items, but found %d.", bt.Len(), rhs.Len())
	}

	it1 := bt.Ascend()
	defer it1.Close()

	it2 := rhs.Ascend()
	defer it2.Close()

	for it1.Next() {
		it2.Next()

		v1 := it1.Value()
		v2 := it2.Value()

		if !reflect.DeepEqual(v1, v2) {
			return fmt.Errorf("Value mismatch: %v != %v", v1, v2)
		}
	}

	return nil
}

func (bt *BTreeIndex[T]) EqualsList(data []*T) error {
	if bt.Len() != len(data) {
		return fmt.Errorf("Expected %d items, but found %d.", bt.Len(), len(data))
	}

	if len(data) == 0 {
		return nil
	}

	// Ascend fully.
	it := bt.Ascend()
	for _, v1 := range data {
		it.Next()
		v2 := it.Value()

		if !reflect.DeepEqual(*v1, v2) {
			return fmt.Errorf("Value mismatch: %v != %v", *v1, v2)
		}
	}
	if it.Next() {
		return fmt.Errorf("Next returned true after full ascend.")
	}
	it.Close()

	// Descend fully.
	it = bt.Descend()
	dataList := data
	for len(dataList) > 0 {
		v1 := dataList[len(dataList)-1]
		dataList = dataList[:len(dataList)-1]
		it.Next()
		v2 := it.Value()

		if !reflect.DeepEqual(*v1, v2) {
			return fmt.Errorf("Value mismatch: %v != %v", *v1, v2)
		}
	}
	if it.Next() {
		return fmt.Errorf("Next returned true after full descend.")
	}
	it.Close()

	// AscendAfter
	dataList = data
	for len(dataList) > 1 {
		dataList = dataList[1:]
		it = bt.AscendAfter(*dataList[0])

		for _, v1 := range dataList {
			it.Next()
			v2 := it.Value()
			if !reflect.DeepEqual(*v1, v2) {
				return fmt.Errorf("Value mismatch: %v != %v", *v1, v2)
			}
		}
		if it.Next() {
			return fmt.Errorf("Next returned true after partial ascend.")
		}
		it.Close()
	}

	// DescendAfter
	dataList = data
	for len(dataList) > 1 {
		dataList = dataList[:len(dataList)-1]
		it = bt.DescendAfter(*dataList[len(dataList)-1])

		for i := len(dataList) - 1; i >= 0; i-- {
			v1 := dataList[i]
			it.Next()
			v2 := it.Value()
			if !reflect.DeepEqual(*v1, v2) {
				return fmt.Errorf("Value mismatch: %v != %v", *v1, v2)
			}
		}
		if it.Next() {
			return fmt.Errorf("Next returned true after partial descend: %#v", it.Value())
		}
		it.Close()
	}

	// Using Get.
	for _, v1 := range data {
		v2, ok := bt.Get(*v1)
		if !ok || !reflect.DeepEqual(*v1, v2) {
			return fmt.Errorf("Value mismatch: %v != %v", *v1, v2)
		}
	}

	// Min.
	v1 := data[0]
	v2, ok := bt.Min()
	if !ok || !reflect.DeepEqual(*v1, v2) {
		return fmt.Errorf("Value mismatch: %v != %v", *v1, v2)
	}

	// Max.
	v1 = data[len(data)-1]
	v2, ok = bt.Max()
	if !ok || !reflect.DeepEqual(*v1, v2) {
		return fmt.Errorf("Value mismatch: %v != %v", *v1, v2)
	}

	return nil
}