// Copyright 2014 The go-ethereum Authors
// (original work)
// Copyright 2024 The Erigon Authors
// (modifications)
// This file is part of Erigon.
//
// Erigon is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Erigon is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with Erigon. If not, see <http://www.gnu.org/licenses/>.

package trie

import (
	"bytes"
	"testing"

	"github.com/stretchr/testify/assert"

	"github.com/erigontech/erigon/common"
)

func TestHexCompact(t *testing.T) {
	tests := []struct{ hex, compact []byte }{
		// empty keys, with and without terminator.
		{hex: []byte{}, compact: []byte{0x00}},
		{hex: []byte{16}, compact: []byte{0x20}},
		// odd length, no terminator
		{hex: []byte{1, 2, 3, 4, 5}, compact: []byte{0x11, 0x23, 0x45}},
		// even length, no terminator
		{hex: []byte{0, 1, 2, 3, 4, 5}, compact: []byte{0x00, 0x01, 0x23, 0x45}},
		// odd length, terminator
		{hex: []byte{15, 1, 12, 11, 8, 16 /*term*/}, compact: []byte{0x3f, 0x1c, 0xb8}},
		// even length, terminator
		{hex: []byte{0, 15, 1, 12, 11, 8, 16 /*term*/}, compact: []byte{0x20, 0x0f, 0x1c, 0xb8}},
	}
	for _, test := range tests {
		if c := hexToCompact(test.hex); !bytes.Equal(c, test.compact) {
			t.Errorf("hexToCompact(%x) -> %x, want %x", test.hex, c, test.compact)
		}
		if h := compactToHex(test.compact); !bytes.Equal(h, test.hex) {
			t.Errorf("compactToHex(%x) -> %x, want %x", test.compact, h, test.hex)
		}
	}
}

func TestHexKeybytes(t *testing.T) {
	tests := []struct{ key, hexIn, hexOut []byte }{
		{key: []byte{}, hexIn: []byte{16}, hexOut: []byte{16}},
		{key: []byte{}, hexIn: []byte{}, hexOut: []byte{16}},
		{
			key:    []byte{0x12, 0x34, 0x56},
			hexIn:  []byte{1, 2, 3, 4, 5, 6, 16},
			hexOut: []byte{1, 2, 3, 4, 5, 6, 16},
		},
		{
			key:    []byte{0x12, 0x34, 0x5},
			hexIn:  []byte{1, 2, 3, 4, 0, 5, 16},
			hexOut: []byte{1, 2, 3, 4, 0, 5, 16},
		},
		{
			key:    []byte{0x12, 0x34, 0x56},
			hexIn:  []byte{1, 2, 3, 4, 5, 6},
			hexOut: []byte{1, 2, 3, 4, 5, 6, 16},
		},
	}
	for _, test := range tests {
		if h := keybytesToHex(test.key); !bytes.Equal(h, test.hexOut) {
			t.Errorf("keybytesToHex(%x) -> %x, want %x", test.key, h, test.hexOut)
		}
		if k := hexToKeybytes(test.hexIn); !bytes.Equal(k, test.key) {
			t.Errorf("hexToKeybytes(%x) -> %x, want %x", test.hexIn, k, test.key)
		}
	}
}

func TestKeybytesToCompact(t *testing.T) {
	keybytes := Keybytes{common.FromHex("5a70"), true, true}
	compact := keybytes.ToCompact()
	assert.Equal(t, common.FromHex("35a7"), compact)

	keybytes = Keybytes{common.FromHex("5a70"), true, false}
	compact = keybytes.ToCompact()
	assert.Equal(t, common.FromHex("15a7"), compact)

	keybytes = Keybytes{common.FromHex("5a7c"), false, true}
	compact = keybytes.ToCompact()
	assert.Equal(t, common.FromHex("205a7c"), compact)

	keybytes = Keybytes{common.FromHex("5a7c"), false, false}
	compact = keybytes.ToCompact()
	assert.Equal(t, common.FromHex("005a7c"), compact)
}

func TestCompactToKeybytes(t *testing.T) {
	compact := common.FromHex("35a7")
	keybytes := CompactToKeybytes(compact)
	assert.Equal(t, Keybytes{common.FromHex("5a70"), true, true}, keybytes)

	compact = common.FromHex("15a7")
	keybytes = CompactToKeybytes(compact)
	assert.Equal(t, Keybytes{common.FromHex("5a70"), true, false}, keybytes)

	compact = common.FromHex("205a7c")
	keybytes = CompactToKeybytes(compact)
	assert.Equal(t, Keybytes{common.FromHex("5a7c"), false, true}, keybytes)

	compact = common.FromHex("005a7c")
	keybytes = CompactToKeybytes(compact)
	assert.Equal(t, Keybytes{common.FromHex("5a7c"), false, false}, keybytes)
}

func BenchmarkHexToCompact(b *testing.B) {
	testBytes := []byte{0, 15, 1, 12, 11, 8, 16 /*term*/}
	for b.Loop() {
		hexToCompact(testBytes)
	}
}

func BenchmarkCompactToHex(b *testing.B) {
	testBytes := []byte{0, 15, 1, 12, 11, 8, 16 /*term*/}
	for b.Loop() {
		compactToHex(testBytes)
	}
}

func BenchmarkKeybytesToHex(b *testing.B) {
	testBytes := []byte{7, 6, 6, 5, 7, 2, 6, 2, 16}
	for b.Loop() {
		keybytesToHex(testBytes)
	}
}

func BenchmarkHexToKeybytes(b *testing.B) {
	testBytes := []byte{7, 6, 6, 5, 7, 2, 6, 2, 16}
	for b.Loop() {
		hexToKeybytes(testBytes)
	}
}
