package service

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

func TestValidateOutboundURLRejectsPrivateHosts(t *testing.T) {
	t.Setenv("CANVAS_ALLOW_PRIVATE_UPSTREAMS", "false")
	t.Setenv("CANVAS_ALLOWED_PRIVATE_UPSTREAM_HOSTS", "")
	for _, rawURL := range []string{"http://127.0.0.1:8080", "http://localhost:8080", "http://169.254.169.254/latest/meta-data"} {
		if _, err := ValidateOutboundURL(rawURL); err == nil {
			t.Fatalf("ValidateOutboundURL(%q) should fail", rawURL)
		}
	}
}

func TestValidateOutboundURLAllowsExplicitPrivateUpstreamOverride(t *testing.T) {
	t.Setenv("CANVAS_ALLOW_PRIVATE_UPSTREAMS", "true")
	t.Setenv("CANVAS_ALLOWED_PRIVATE_UPSTREAM_HOSTS", "")
	if _, err := ValidateOutboundURL("http://127.0.0.1:8080"); err != nil {
		t.Fatalf("ValidateOutboundURL() error = %v", err)
	}
}

func TestValidateOutboundURLAllowsOnlyNamedPrivateUpstream(t *testing.T) {
	t.Setenv("CANVAS_ALLOW_PRIVATE_UPSTREAMS", "false")
	t.Setenv("CANVAS_ALLOWED_PRIVATE_UPSTREAM_HOSTS", "127.0.0.1")
	if _, err := ValidateOutboundURL("http://127.0.0.1:8080"); err != nil {
		t.Fatalf("ValidateOutboundURL() error = %v", err)
	}
	if _, err := ValidateOutboundURL("http://127.0.0.2:8080"); err == nil {
		t.Fatal("ValidateOutboundURL() should reject an unlisted private host")
	}
}

func TestAllowedPrivateUpstreamHostUsesExactCaseInsensitiveMatch(t *testing.T) {
	t.Setenv("CANVAS_ALLOWED_PRIVATE_UPSTREAM_HOSTS", " API.EXAMPLE.COM.,trusted.internal ")
	if !allowedPrivateUpstreamHost("api.example.com") {
		t.Fatal("allowedPrivateUpstreamHost() should allow exact normalized hostname")
	}
	if allowedPrivateUpstreamHost("api.example.com.evil.test") {
		t.Fatal("allowedPrivateUpstreamHost() should reject hostname suffix confusion")
	}
}

func TestValidateCustomRelayURLUsesHTTPSAndExactPrivateAllowlist(t *testing.T) {
	t.Setenv("CANVAS_ALLOW_PRIVATE_UPSTREAMS", "true")
	t.Setenv("CANVAS_ALLOWED_PRIVATE_UPSTREAM_HOSTS", "")
	if _, err := ValidateCustomRelayURL("http://127.0.0.1:8080/v1/models"); err == nil {
		t.Fatal("ValidateCustomRelayURL() should reject HTTP")
	}
	if _, err := ValidateCustomRelayURL("https://127.0.0.1:8080/v1/models"); err == nil {
		t.Fatal("ValidateCustomRelayURL() should ignore the global private upstream override")
	}
	t.Setenv("CANVAS_ALLOWED_PRIVATE_UPSTREAM_HOSTS", "127.0.0.1")
	if _, err := ValidateCustomRelayURL("https://127.0.0.1:8080/v1/models"); err != nil {
		t.Fatalf("ValidateCustomRelayURL() error = %v", err)
	}
}

func TestValidateCustomRelayURLRejectsCredentialsAndFragment(t *testing.T) {
	t.Setenv("CANVAS_ALLOWED_PRIVATE_UPSTREAM_HOSTS", "127.0.0.1")
	for _, rawURL := range []string{
		"https://user:pass@127.0.0.1/v1/models",
		"https://127.0.0.1/v1/models#secret",
	} {
		if _, err := ValidateCustomRelayURL(rawURL); err == nil {
			t.Fatalf("ValidateCustomRelayURL(%q) should fail", rawURL)
		}
	}
}

func TestBlockedCustomRelayIPRejectsCarrierGradeNATAndReservedRanges(t *testing.T) {
	for _, value := range []string{"100.100.100.200", "192.0.2.10", "198.18.0.1", "2001:db8::1"} {
		if !blockedCustomRelayIP(net.ParseIP(value)) {
			t.Fatalf("blockedCustomRelayIP(%q) = false", value)
		}
	}
	if blockedCustomRelayIP(net.ParseIP("8.8.8.8")) {
		t.Fatal("blockedCustomRelayIP() rejected a public address")
	}
}

func TestCustomRelayHTTPClientDoesNotFollowRedirects(t *testing.T) {
	redirected := false
	destination := httptest.NewTLSServer(http.HandlerFunc(func(http.ResponseWriter, *http.Request) {
		redirected = true
	}))
	defer destination.Close()
	source := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		w.Header().Set("Location", destination.URL)
		w.WriteHeader(http.StatusFound)
	}))
	defer source.Close()

	client := CustomRelayHTTPClient(time.Second)
	client.Transport = source.Client().Transport
	if _, err := client.Get(source.URL); err == nil {
		t.Fatal("CustomRelayHTTPClient() should reject redirects")
	}
	if redirected {
		t.Fatal("redirect destination should not receive the request")
	}
}