package httpapi

import (
	"fmt"
	"net/http/httptest"
	"net/netip"
	"testing"
	"time"
)

func TestClientIPTrustedProxyChain(t *testing.T) {
	prefixes := []netip.Prefix{netip.MustParsePrefix("10.0.0.0/8")}
	tests := []struct {
		name   string
		remote string
		xff    string
		want   string
	}{
		{"untrusted peer ignores spoof", "198.51.100.10:1234", "203.0.113.9", "198.51.100.10"},
		{"rightmost untrusted hop", "10.0.0.2:1234", "203.0.113.9, 198.51.100.8", "198.51.100.8"},
		{"trusted chain", "10.0.0.2:1234", "203.0.113.9, 10.0.0.3", "203.0.113.9"},
		{"mapped peer", "[::ffff:10.0.0.2]:1234", "203.0.113.9", "203.0.113.9"},
		{"mapped forwarded client", "10.0.0.2:1234", "::ffff:203.0.113.9", "203.0.113.9"},
		{"malformed nearest hop", "10.0.0.2:1234", "203.0.113.9, bogus", "10.0.0.2"},
		{"malformed farther hop ignored", "10.0.0.2:1234", "bogus, 198.51.100.8", "198.51.100.8"},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			r := httptest.NewRequest("GET", "http://example.test/", nil)
			r.RemoteAddr = tt.remote
			r.Header.Set("X-Forwarded-For", tt.xff)
			if got := clientIPWithTrustedProxies(r, prefixes); got != tt.want {
				t.Fatalf("client IP = %q, want %q", got, tt.want)
			}
		})
	}
}

func TestClientIPConfigurationFailsClosed(t *testing.T) {
	r := httptest.NewRequest("GET", "http://example.test/", nil)
	r.RemoteAddr = "10.0.0.2:1234"
	r.Header.Set("X-Forwarded-For", "203.0.113.9")
	r.Header.Set("X-Real-IP", "203.0.113.8")
	if got := clientIPWithTrustedProxies(r, nil); got != "10.0.0.2" {
		t.Fatalf("direct client IP = %q", got)
	}
	t.Setenv("EVOBGP_TRUSTED_PROXY_CIDRS", "10.0.0.0/8, invalid")
	if got := clientIP(r); got != "10.0.0.2" {
		t.Fatalf("invalid CIDR client IP = %q", got)
	}
	t.Setenv("EVOBGP_TRUSTED_PROXY_CIDRS", "::ffff:10.0.0.2/128")
	if got := clientIP(r); got != "203.0.113.9" {
		t.Fatalf("mapped CIDR client IP = %q", got)
	}
}

func TestPublicControlPlaneURLTrust(t *testing.T) {
	t.Setenv("EVOBGP_TRUSTED_PROXY_CIDRS", "10.0.0.0/8")
	r := httptest.NewRequest("POST", "http://internal.local:8080/v1/speakers", nil)
	r.Header.Set("Origin", "https://evil.example")
	r.Header.Set("X-Forwarded-Proto", "https")
	r.Header.Set("X-Forwarded-Host", "bgp.example.test")
	r.RemoteAddr = "198.51.100.8:1234"
	if got := publicControlPlaneURL(r, ""); got != "http://internal.local:8080" {
		t.Fatalf("direct URL = %q", got)
	}
	r.RemoteAddr = "10.0.0.2:1234"
	if got := publicControlPlaneURL(r, ""); got != "https://bgp.example.test" {
		t.Fatalf("proxied URL = %q", got)
	}
	if got := publicControlPlaneURL(r, "https://explicit.example/"); got != "https://explicit.example" {
		t.Fatalf("override URL = %q", got)
	}
	for _, bad := range []struct{ proto, host string }{
		{"javascript", "bgp.example.test"},
		{"https,http", "bgp.example.test"},
		{"https", "evil.example/path"},
		{"https", "evil.example@bgp.example.test"},
		{"https", "evil.example,bgp.example.test"},
		{"https", "bgp.example.test:99999"},
		{"https", "bgp.example.test:"},
	} {
		r.Header.Set("X-Forwarded-Proto", bad.proto)
		r.Header.Set("X-Forwarded-Host", bad.host)
		if got := publicControlPlaneURL(r, ""); got != "http://internal.local:8080" {
			t.Errorf("bad forwarded headers (%q, %q): %q", bad.proto, bad.host, got)
		}
	}
	r.Header.Set("X-Forwarded-Proto", "https")
	r.Header.Set("X-Forwarded-Host", "bgp.example.test")
	r.Header.Add("X-Forwarded-Host", "evil.example")
	if got := publicControlPlaneURL(r, ""); got != "http://internal.local:8080" {
		t.Fatalf("duplicate forwarded host = %q", got)
	}
}

func TestAuthRateLimiterManyIdentities(t *testing.T) {
	l := &authRateLimiter{hits: make(map[string]authRateHit), limit: 1, window: time.Minute, maxClients: 32}
	now := time.Unix(1000, 0)
	for i := 0; i < 1000; i++ {
		allowed := l.allowAt(fmt.Sprintf("ip-%d", i), now)
		if allowed != (i < l.maxClients) {
			t.Fatalf("identity %d allowed = %t", i, allowed)
		}
	}
	if len(l.hits) != l.maxClients || l.allowAt("ip-0", now) {
		t.Fatalf("active counters changed under cardinality pressure: %d", len(l.hits))
	}
}

func TestAuthRateLimiterCapacityAndExpiry(t *testing.T) {
	l := &authRateLimiter{hits: make(map[string]authRateHit), limit: 2, window: time.Minute, maxClients: 2}
	now := time.Unix(1000, 0)
	if !l.allowAt("a", now) || !l.allowAt("b", now) || !l.allowAt("a", now) {
		t.Fatal("initial requests rejected")
	}
	if l.allowAt("a", now) || l.allowAt("c", now) {
		t.Fatal("active limit or capacity bypassed")
	}
	if len(l.hits) != 2 {
		t.Fatalf("map size = %d", len(l.hits))
	}
	if !l.allowAt("c", now.Add(time.Minute)) {
		t.Fatal("expired entries did not release capacity")
	}
	if len(l.hits) != 1 {
		t.Fatalf("expired entries remained: %d", len(l.hits))
	}
}