// Copyright 2022 The Ip2Region Authors. All rights reserved.
// Use of this source code is governed by a Apache2.0-style
// license that can be found in the LICENSE file.

package xdb

import (
	"testing"
)

func TestVersionFromHeader(t *testing.T) {
	// Structure20 -> always IPv4 (legacy format)
	h := &Header{Version: Structure20}
	v, err := VersionFromHeader(h)
	if err != nil {
		t.Fatalf("VersionFromHeader(Structure20) unexpected error: %s", err)
	}
	if v != IPv4 {
		t.Fatalf("VersionFromHeader(Structure20) = %s, want IPv4", v)
	}

	// Structure30 + IPv4VersionNo
	h = &Header{Version: Structure30, IPVersion: IPv4VersionNo}
	v, err = VersionFromHeader(h)
	if err != nil {
		t.Fatalf("VersionFromHeader(Structure30,IPv4) unexpected error: %s", err)
	}
	if v != IPv4 {
		t.Fatalf("VersionFromHeader(Structure30,IPv4) = %s, want IPv4", v)
	}

	// Structure30 + IPv6VersionNo
	h = &Header{Version: Structure30, IPVersion: IPv6VersionNo}
	v, err = VersionFromHeader(h)
	if err != nil {
		t.Fatalf("VersionFromHeader(Structure30,IPv6) unexpected error: %s", err)
	}
	if v != IPv6 {
		t.Fatalf("VersionFromHeader(Structure30,IPv6) = %s, want IPv6", v)
	}

	// invalid structure version
	h = &Header{Version: 999}
	_, err = VersionFromHeader(h)
	if err == nil {
		t.Fatal("VersionFromHeader(invalid version) should return error")
	}

	// Structure30 + invalid IP version
	h = &Header{Version: Structure30, IPVersion: 999}
	_, err = VersionFromHeader(h)
	if err == nil {
		t.Fatal("VersionFromHeader(Structure30,invalid IPVersion) should return error")
	}
}

func TestVersionFromName(t *testing.T) {
	tests := []struct {
		name string
		want *Version
		ok   bool
	}{
		{"v4", IPv4, true},
		{"V4", IPv4, true},
		{"ipv4", IPv4, true},
		{"IPv4", IPv4, true},
		{"v6", IPv6, true},
		{"V6", IPv6, true},
		{"ipv6", IPv6, true},
		{"IPv6", IPv6, true},
		{"ipv4", IPv4, true},
		{"IPV6", IPv6, true},
		{"", nil, false},
		{"invalid", nil, false},
		{"v7", nil, false},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			v, err := VersionFromName(tc.name)
			if tc.ok {
				if err != nil {
					t.Fatalf("VersionFromName(%q) unexpected error: %s", tc.name, err)
				}
				if v != tc.want {
					t.Fatalf("VersionFromName(%q) = %s, want %s", tc.name, v, tc.want)
				}
			} else {
				if err == nil {
					t.Fatalf("VersionFromName(%q) should return error", tc.name)
				}
			}
		})
	}
}

func TestVersionFromIP(t *testing.T) {
	tests := []struct {
		ip   string
		want *Version
		ok   bool
	}{
		{"1.2.3.4", IPv4, true},
		{"0.0.0.0", IPv4, true},
		{"255.255.255.255", IPv4, true},
		{"::1", IPv6, true},
		{"240e:3b7::1", IPv6, true},
		{"", nil, false},
		{"not-an-ip", nil, false},
	}

	for _, tc := range tests {
		t.Run(tc.ip, func(t *testing.T) {
			v, err := VersionFromIP(tc.ip)
			if tc.ok {
				if err != nil {
					t.Fatalf("VersionFromIP(%q) unexpected error: %s", tc.ip, err)
				}
				if v != tc.want {
					t.Fatalf("VersionFromIP(%q) = %s, want %s", tc.ip, v, tc.want)
				}
			} else {
				if err == nil {
					t.Fatalf("VersionFromIP(%q) should return error", tc.ip)
				}
			}
		})
	}
}

func TestIPv6Compare(t *testing.T) {
	// IPv6.IPCompare uses bytes.Compare directly, no byte-order swapping needed
	tests := []struct {
		name string
		ip1  []byte
		ip2  []byte
		want int
	}{
		{"equal", []byte{0x20, 0x01, 0x0d, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, []byte{0x20, 0x01, 0x0d, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, 0},
		{"less_b0", []byte{0x1f, 0x01, 0x0d, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, []byte{0x20, 0x01, 0x0d, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, -1},
		{"greater_b0", []byte{0x21, 0x01, 0x0d, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, []byte{0x20, 0x01, 0x0d, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, 1},
		{"zero_vs_max", []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, []byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}, -1},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			got := IPv6.IPCompare(tc.ip1, tc.ip2)
			if got != tc.want {
				t.Fatalf("IPv6.IPCompare(%v, %v) = %d, want %d", tc.ip1, tc.ip2, got, tc.want)
			}
		})
	}
}