package main

import (
	"archive/zip"
	"fmt"
	"os"
	"path/filepath"
	"testing"
	"time"
)

func writeZipFiles(t *testing.T, files map[string]string) string {
	t.Helper()
	path := filepath.Join(t.TempDir(), "fixture.zip")
	output, err := os.Create(path)
	if err != nil {
		t.Fatal(err)
	}
	archive := zip.NewWriter(output)
	for name, contents := range files {
		entry, err := archive.Create(name)
		if err != nil {
			t.Fatal(err)
		}
		if _, err := fmt.Fprint(entry, contents); err != nil {
			t.Fatal(err)
		}
	}
	if err := archive.Close(); err != nil {
		t.Fatal(err)
	}
	if err := output.Close(); err != nil {
		t.Fatal(err)
	}
	return path
}

func mustAddress(t *testing.T, value string) uint32 {
	t.Helper()
	address, ok := rangeFromPrefix(value + "/32")
	if !ok {
		t.Fatalf("invalid test address %q", value)
	}
	return address.start
}

func rangeContains(ranges []addressRange, address uint32) bool {
	for _, candidate := range ranges {
		if candidate.start <= address && candidate.end >= address {
			return true
		}
	}
	return false
}

func rangesEqual(left, right []addressRange) bool {
	left = mergeRanges(left)
	right = mergeRanges(right)
	if len(left) != len(right) {
		return false
	}
	for index := range left {
		if left[index] != right[index] {
			return false
		}
	}
	return true
}

func TestGeographySetsSeparateVPNExceptionCountries(t *testing.T) {
	path := writeZipFiles(t, map[string]string{
		"ip-to-country.csv": "network,country_code,continent_code\n192.0.2.0/28,JP,AS\n192.0.2.16/28,KR,AS\n198.51.100.0/24,US,NA\n203.0.113.0/24,BR,SA\n",
	})
	sets, err := ipLocateGeography(path)
	if err != nil {
		t.Fatal(err)
	}
	if !rangeContains(sets.admission, mustAddress(t, "198.51.100.1")) || rangeContains(sets.admission, mustAddress(t, "203.0.113.1")) {
		t.Fatalf("unexpected admission ranges: %#v", sets.admission)
	}
	if !rangeContains(sets.vpnException, mustAddress(t, "192.0.2.1")) || !rangeContains(sets.vpnException, mustAddress(t, "192.0.2.17")) || rangeContains(sets.vpnException, mustAddress(t, "198.51.100.1")) {
		t.Fatalf("unexpected VPN exception ranges: %#v", sets.vpnException)
	}
}

func TestMaxMindGeographySetsSeparateVPNExceptionCountries(t *testing.T) {
	path := writeZipFiles(t, map[string]string{
		"GeoLite2-Country-Locations-en.csv": "geoname_id,locale_code,continent_code,country_iso_code\n1,en,AS,JP\n2,en,AS,KR\n3,en,NA,US\n4,en,SA,BR\n",
		"GeoLite2-Country-Blocks-IPv4.csv":  "network,geoname_id,registered_country_geoname_id\n192.0.2.0/28,1,1\n192.0.2.16/28,2,2\n198.51.100.0/24,3,3\n203.0.113.0/24,4,4\n",
	})
	sets, err := maxMindGeography(path)
	if err != nil {
		t.Fatal(err)
	}
	if !rangeContains(sets.admission, mustAddress(t, "198.51.100.1")) || rangeContains(sets.admission, mustAddress(t, "203.0.113.1")) {
		t.Fatalf("unexpected admission ranges: %#v", sets.admission)
	}
	if !rangeContains(sets.vpnException, mustAddress(t, "192.0.2.1")) || !rangeContains(sets.vpnException, mustAddress(t, "192.0.2.17")) || rangeContains(sets.vpnException, mustAddress(t, "198.51.100.1")) {
		t.Fatalf("unexpected VPN exception ranges: %#v", sets.vpnException)
	}
}

func TestIPLocateASNRangesSelectConfiguredOperators(t *testing.T) {
	path := writeZipFiles(t, map[string]string{
		"ip-to-asn.csv": "network,asn,country_code,name,org,domain\n192.0.2.0/28,147049,AU,selected,selected,example.test\n192.0.2.16/28,64500,JP,other,other,example.test\n198.51.100.0/24,AS147049,AU,selected,selected,example.test\n",
	})
	ranges, err := ipLocateASNRanges(path, map[uint32]struct{}{147049: {}})
	if err != nil {
		t.Fatal(err)
	}
	if !rangeContains(ranges, mustAddress(t, "192.0.2.1")) || !rangeContains(ranges, mustAddress(t, "198.51.100.1")) || rangeContains(ranges, mustAddress(t, "192.0.2.17")) {
		t.Fatalf("unexpected ASN ranges: %#v", ranges)
	}
}

func TestVPNExceptionCompositionPreservesConsensusAndDenies(t *testing.T) {
	consensus := []addressRange{{start: 10, end: 20}}
	vpnASN := []addressRange{{start: 15, end: 30}}
	vpnGeography := []addressRange{{start: 18, end: 28}}
	denied := []addressRange{{start: 24, end: 25}}
	candidate := subtractRanges(intersectRanges(vpnASN, vpnGeography), consensus)
	exceptions := subtractRanges(candidate, denied)
	want := []addressRange{{start: 21, end: 23}, {start: 26, end: 28}}
	if !rangesEqual(exceptions, want) {
		t.Fatalf("exceptions=%#v want=%#v", exceptions, want)
	}
}

func TestParseASN(t *testing.T) {
	for _, value := range []string{"147049", "AS147049", "as147049"} {
		asn, err := parseASN(value)
		if err != nil || asn != 147049 {
			t.Fatalf("parseASN(%q)=%d,%v", value, asn, err)
		}
	}
	for _, value := range []string{"", "AS", "0", "-1", "4294967296"} {
		if _, err := parseASN(value); err == nil {
			t.Fatalf("parseASN(%q) succeeded", value)
		}
	}
}

func TestLoadIP2ProxyClassificationsOmitsStaleCache(t *testing.T) {
	now := time.Unix(2000000000, 0)
	path := filepath.Join(t.TempDir(), "ip2proxy.zip")
	if err := os.WriteFile(path, []byte("invalid archive"), 0o600); err != nil {
		t.Fatal(err)
	}
	modified := now.Add(-36 * 24 * time.Hour)
	if err := os.Chtimes(path, modified, modified); err != nil {
		t.Fatal(err)
	}
	result, state, age, err := loadIP2ProxyClassifications(path, now, 35*24*time.Hour)
	if err != nil {
		t.Fatal(err)
	}
	if state != "stale" || age != 36*24*time.Hour || len(result.all) != 0 {
		t.Fatalf("state=%s age=%s ranges=%d", state, age, len(result.all))
	}
}

func TestLoadIP2ProxyClassificationsRequiresValidFreshCache(t *testing.T) {
	now := time.Unix(2000000000, 0)
	path := filepath.Join(t.TempDir(), "ip2proxy.zip")
	if err := os.WriteFile(path, []byte("invalid archive"), 0o600); err != nil {
		t.Fatal(err)
	}
	if err := os.Chtimes(path, now, now); err != nil {
		t.Fatal(err)
	}
	if _, _, _, err := loadIP2ProxyClassifications(path, now, 35*24*time.Hour); err == nil {
		t.Fatal("expected fresh invalid cache to fail")
	}
}

func TestLoadIP2ProxyClassificationsAllowsAbsentCache(t *testing.T) {
	result, state, age, err := loadIP2ProxyClassifications(filepath.Join(t.TempDir(), "missing.zip"), time.Now(), 35*24*time.Hour)
	if err != nil {
		t.Fatal(err)
	}
	if state != "absent" || age != 0 || len(result.all) != 0 {
		t.Fatalf("state=%s age=%s ranges=%d", state, age, len(result.all))
	}
}