package config_test

import (
	"net/netip"
	"os"
	"path/filepath"
	"slices"
	"strings"
	"testing"
	"time"

	"sneak.berlin/go/smallwebwaf/internal/config"
)

// rproxy's settings, by name, and their values in these tests.
const (
	wafBackend        = "SWRP_WAF_BACKEND"
	rproxyTimeout     = "SWRP_TIMEOUT_MS"
	rproxyDefault     = "SWRP_DEFAULT_DISPOSITION"
	rproxyListen      = "SWRP_LISTEN_ADDR"
	rproxyUpstream    = "SWRP_UPSTREAM_URL"
	rproxyTrusted     = "SWRP_TRUSTED_PROXIES"
	rproxyMaxRequest  = "SWRP_MAX_REQUEST_SIZE"
	rproxyMaxResponse = "SWRP_MAX_RESPONSE_SIZE"
	rproxyRequestTime = "SWRP_MAX_REQUEST_TIME_MS"
	rproxyAnswerTime  = "SWRP_MAX_RESPONSE_TIME_MS"
	backendURL        = "http://servewaf:8080"
	rproxyDefaultAddr = ":8080"
	rproxyDefaultApp  = "http://127.0.0.1:8081"
	notASize          = "a lot"
)

// rproxyConfig reads rproxy's settings from env.
func rproxyConfig(env map[string]string) (*config.RProxy, error) {
	return config.RProxyFromEnvironment(func(name string) (string, bool) {
		value, ok := env[name]

		return value, ok
	})
}

func TestRProxyDefaults(t *testing.T) {
	t.Parallel()

	cfg, err := rproxyConfig(map[string]string{wafBackend: backendURL})
	if err != nil {
		t.Fatalf("settings: %v", err)
	}

	if cfg.ListenAddr != rproxyDefaultAddr ||
		cfg.UpstreamURL.String() != rproxyDefaultApp ||
		cfg.WAFBackend.String() != backendURL {
		t.Errorf("addresses %q, %v, %v", cfg.ListenAddr, cfg.UpstreamURL, cfg.WAFBackend)
	}

	if cfg.Timeout != 2*time.Second || cfg.DefaultDisposition != "allow" {
		t.Errorf("timeout %v, default disposition %q", cfg.Timeout, cfg.DefaultDisposition)
	}

	if cfg.MaxRequestSize != 100<<20 || cfg.MaxResponseSize != 1<<30 {
		t.Errorf("sizes %d and %d", cfg.MaxRequestSize, cfg.MaxResponseSize)
	}

	if cfg.MaxRequestTime != time.Minute || cfg.MaxResponseTime != 30*time.Minute {
		t.Errorf("times %v and %v", cfg.MaxRequestTime, cfg.MaxResponseTime)
	}

	want := []netip.Prefix{
		netip.MustParsePrefix("10.0.0.0/8"),
		netip.MustParsePrefix("172.16.0.0/12"),
		netip.MustParsePrefix("192.168.0.0/16"),
	}
	if !slices.Equal(cfg.TrustedProxies, want) {
		t.Errorf("trusted proxies %v, want %v", cfg.TrustedProxies, want)
	}
}

func TestRProxySettingsAreRead(t *testing.T) {
	t.Parallel()

	cfg, err := rproxyConfig(map[string]string{
		wafBackend:        "https://waf.example:8443",
		rproxyListen:      ":9000",
		rproxyUpstream:    "http://app:3000",
		rproxyTrusted:     "192.0.2.0/24",
		rproxyTimeout:     "150",
		rproxyDefault:     "deny",
		rproxyMaxRequest:  "1K",
		rproxyMaxResponse: off,
		rproxyRequestTime: off,
		rproxyAnswerTime:  "250",
	})
	if err != nil {
		t.Fatalf("settings: %v", err)
	}

	if cfg.ListenAddr != ":9000" || cfg.UpstreamURL.Host != "app:3000" ||
		cfg.WAFBackend.Host != "waf.example:8443" ||
		cfg.TrustedProxies[0] != netip.MustParsePrefix("192.0.2.0/24") {
		t.Errorf("addresses %+v", cfg)
	}

	if cfg.Timeout != 150*time.Millisecond || cfg.DefaultDisposition != "deny" ||
		cfg.MaxRequestSize != 1024 || cfg.MaxResponseSize != 0 ||
		cfg.MaxRequestTime != 0 || cfg.MaxResponseTime != 250*time.Millisecond {
		t.Errorf("limits %+v", cfg)
	}
}

func TestRProxyInvalidSettingsAreRefused(t *testing.T) {
	t.Parallel()

	for _, tc := range []struct {
		name, value string
	}{
		{wafBackend, ""},
		{wafBackend, "servewaf:8080"},
		{wafBackend, "http://servewaf:8080/path"},
		{rproxyTimeout, "0"},
		{rproxyTimeout, "-1"},
		{rproxyTimeout, off},
		{rproxyTimeout, "2s"},
		{rproxyTimeout, "1.25"},
		{rproxyTimeout, "99999999999999999"},
		{rproxyDefault, "maybe"},
		{rproxyListen, "8080"},
		{rproxyUpstream, "app"},
		{rproxyUpstream, "127.0.0.1:8081"},
		{rproxyUpstream, "ftp://127.0.0.1:8081"},
		{rproxyUpstream, "http://"},
		{rproxyUpstream, "http://:8081"},
		{rproxyUpstream, "http://127.0.0.1:0"},
		{rproxyUpstream, "http://127.0.0.1:99999"},
		{rproxyUpstream, "http://127.0.0.1:8081/app"},
		{rproxyUpstream, "http://127.0.0.1:8081/?a=1"},
		{rproxyUpstream, "http://user:secret@127.0.0.1:8081"},
		{rproxyTrusted, "not a netblock"},
		{rproxyTrusted, "10.0.0.0/33"},
		{rproxyTrusted, "10.0.0.0/8,,192.168.0.0/16"},
		{rproxyTrusted, "fe80::1%eth0"},
		{rproxyMaxRequest, notASize},
		{rproxyMaxResponse, notASize},
		{rproxyRequestTime, "0"},
		{rproxyRequestTime, "1m"},
		{rproxyAnswerTime, "0"},
	} {
		t.Run(tc.name+"="+tc.value, func(t *testing.T) {
			t.Parallel()

			_, err := rproxyConfig(map[string]string{wafBackend: backendURL, tc.name: tc.value})
			if err == nil || !strings.HasPrefix(err.Error(), tc.name+": ") {
				t.Errorf("error %v, want one naming %s", err, tc.name)
			}
		})
	}
}

func TestRProxyTrustedProxiesSetButEmptyTrustNothing(t *testing.T) {
	t.Parallel()

	cfg, err := rproxyConfig(map[string]string{wafBackend: backendURL, rproxyTrusted: ""})
	if err != nil {
		t.Fatalf("settings: %v", err)
	}

	if len(cfg.TrustedProxies) != 0 {
		t.Errorf("trusted proxies %v, want none", cfg.TrustedProxies)
	}
}

func TestRProxyNeedsItsBackend(t *testing.T) {
	t.Parallel()

	_, err := rproxyConfig(nil)
	if err == nil || !strings.HasPrefix(err.Error(), wafBackend+": is required") {
		t.Errorf("error %v, want one saying %s is required", err, wafBackend)
	}
}

func TestRProxyReadsNoFile(t *testing.T) {
	t.Parallel()

	path := filepath.Join(t.TempDir(), "backend")

	err := os.WriteFile(path, []byte("http://from-a-file:8080\n"), 0o600)
	if err != nil {
		t.Fatalf("write: %v", err)
	}

	_, err = rproxyConfig(map[string]string{wafBackend + "_FILE": path})
	if err == nil || !strings.HasPrefix(err.Error(), wafBackend+": is required") {
		t.Errorf("error %v, want %s still required", err, wafBackend)
	}

	cfg, err := rproxyConfig(map[string]string{
		wafBackend:              backendURL,
		rproxyTimeout + "_FILE": "/nonexistent/timeout",
	})
	if err != nil {
		t.Fatalf("settings: %v, with the file left unread", err)
	}

	if cfg.Timeout != 2*time.Second {
		t.Errorf("timeout %v, want the default", cfg.Timeout)
	}
}

func TestRProxySettingsAreLoggedByName(t *testing.T) {
	t.Parallel()

	cfg, err := rproxyConfig(map[string]string{wafBackend: backendURL})
	if err != nil {
		t.Fatalf("settings: %v", err)
	}

	group := cfg.LogValue().Group()

	names := make([]string, 0, len(group))
	for _, attr := range group {
		names = append(names, attr.Key)
	}

	for _, name := range []string{
		rproxyListen, rproxyUpstream, rproxyTrusted, wafBackend, rproxyTimeout, rproxyDefault,
		rproxyMaxRequest, rproxyMaxResponse, rproxyRequestTime, rproxyAnswerTime,
	} {
		if !slices.Contains(names, name) {
			t.Errorf("%s is not logged, only %v", name, names)
		}
	}
}