package server

import (
	"context"
	"errors"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"

	"proxy-pool/internal/config"
	"proxy-pool/internal/gateway/policy"
	"proxy-pool/internal/platform/httpsecurity"
)

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

	protection, err := BuildProtection(config.Listener{
		Access: config.Access{AllowCIDRs: []string{"198.51.100.0/24"}},
		Auth: config.Auth{
			Mode:     "usernamePassword",
			Username: "client",
			Password: "secret",
		},
		Limits: config.Limits{RequestsPerMinute: 10, RequestsPerMinutePerClient: 2},
	})
	if err != nil {
		t.Fatalf("BuildProtection() error = %v", err)
	}
	request := httptest.NewRequest(http.MethodGet, "http://example.test", nil)
	request.RemoteAddr = "198.51.100.8:1234"
	request.Header.Set("Proxy-Authorization", "Basic Y2xpZW50OnNlY3JldA==")
	for name, guard := range map[string]Guard{
		"auth": protection.Auth, "access": protection.Access, "admission": protection.Admission,
	} {
		if err := guard.Check(context.Background(), request); err != nil {
			t.Fatalf("%s guard error = %v", name, err)
		}
	}
}

func TestBuildProtectionSupportsBearerProxyAuthentication(t *testing.T) {
	t.Parallel()
	protection, err := BuildProtection(config.Listener{Auth: config.Auth{Mode: "bearer", Token: "proxy-token"}})
	if err != nil {
		t.Fatalf("BuildProtection() error = %v", err)
	}
	request := httptest.NewRequest(http.MethodGet, "http://example.test", nil)
	request.RemoteAddr = "198.51.100.8:1234"
	request.Header.Set("Proxy-Authorization", "Bearer proxy-token")
	if err := protection.Auth.Check(context.Background(), request); err != nil {
		t.Fatalf("auth.Check() error = %v", err)
	}

	request.Header.Set("Proxy-Authorization", "Bearer wrong")
	err = protection.Auth.Check(context.Background(), request)
	var securityError *httpsecurity.HTTPError
	if !errors.As(err, &securityError) || securityError.StatusCode != http.StatusProxyAuthRequired {
		t.Fatalf("auth.Check(wrong) error = %T %v", err, err)
	}
	recorder := httptest.NewRecorder()
	writeGatewayError(recorder, err)
	if recorder.Code != http.StatusProxyAuthRequired || recorder.Header().Get("Proxy-Authenticate") == "" {
		t.Fatalf("gateway response = status %d headers %v", recorder.Code, recorder.Header())
	}
}

func TestBuildProtectionAnyPreservesIPWhitelistRejectionIndependentOfOrder(t *testing.T) {
	t.Parallel()
	methods := [][]config.AuthMethod{
		{
			{Mode: "ipWhitelist", CIDRs: []string{"10.0.0.0/8"}},
			{Mode: "apiKey", Header: "X-Proxy-Key", Value: "secret"},
		},
		{
			{Mode: "apiKey", Header: "X-Proxy-Key", Value: "secret"},
			{Mode: "ipWhitelist", CIDRs: []string{"10.0.0.0/8"}},
		},
	}
	for index, configuredMethods := range methods {
		protection, err := BuildProtection(config.Listener{
			Auth: config.Auth{Mode: "any", Methods: configuredMethods},
		})
		if err != nil {
			t.Fatalf("BuildProtection(%d) error = %v", index, err)
		}
		request := httptest.NewRequest(http.MethodGet, "http://example.test", nil)
		request.RemoteAddr = "198.51.100.8:1234"
		err = protection.Auth.Check(context.Background(), request)
		recorder := httptest.NewRecorder()
		writeGatewayError(recorder, err)
		if recorder.Code != http.StatusForbidden {
			t.Fatalf("method order %d status = %d, want 403", index, recorder.Code)
		}
	}
}

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

	targets, err := TargetPolicyFromListener(config.Listener{})
	if err != nil {
		t.Fatalf("TargetPolicyFromListener() error = %v", err)
	}
	if _, err := targets.EvaluateURL(context.Background(), "http://127.0.0.1/"); !errors.Is(err, policy.ErrTargetDenied) {
		t.Fatalf("EvaluateURL(loopback) error = %v, want ErrTargetDenied", err)
	}
	if _, err := targets.EvaluateConnectAuthority(context.Background(), "8.8.8.8:22"); !errors.Is(err, policy.ErrTargetDenied) {
		t.Fatalf("EvaluateConnectAuthority(port 22) error = %v, want ErrTargetDenied", err)
	}
}

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

	targets, err := TargetPolicyFromListener(config.Listener{
		DestinationPolicy: config.DestinationPolicy{AllowedPorts: []uint16{8443}},
	})
	if err != nil {
		t.Fatalf("TargetPolicyFromListener() error = %v", err)
	}
	if _, err := targets.EvaluateConnectAuthority(context.Background(), "8.8.8.8:8443"); err != nil {
		t.Fatalf("EvaluateConnectAuthority(port 8443) error = %v", err)
	}
	if _, err := targets.EvaluateConnectAuthority(context.Background(), "8.8.8.8:443"); !errors.Is(err, policy.ErrTargetDenied) {
		t.Fatalf("EvaluateConnectAuthority(port 443) error = %v, want ErrTargetDenied", err)
	}
}

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

	deny := true
	targets, err := TargetPolicyFromListener(config.Listener{
		DestinationPolicy: config.DestinationPolicy{DenyPrivateNetworks: &deny},
	})
	if err != nil {
		t.Fatalf("TargetPolicyFromListener() error = %v", err)
	}
	for _, target := range []string{"http://127.0.0.1/", "http://169.254.10.20/"} {
		if _, err := targets.EvaluateURL(context.Background(), target); !errors.Is(err, policy.ErrTargetDenied) {
			t.Fatalf("EvaluateURL(%q) error = %v, want ErrTargetDenied", target, err)
		}
	}
}

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

	allow := false
	targets, err := TargetPolicyFromListener(config.Listener{
		DestinationPolicy: config.DestinationPolicy{DenyLoopback: &allow},
	})
	if err != nil {
		t.Fatalf("TargetPolicyFromListener() error = %v", err)
	}
	if _, err := targets.EvaluateURL(context.Background(), "http://127.0.0.1/"); err != nil {
		t.Fatalf("EvaluateURL(loopback) error = %v", err)
	}
	for _, target := range []string{"http://10.0.0.1/", "http://169.254.10.20/"} {
		if _, err := targets.EvaluateURL(context.Background(), target); !errors.Is(err, policy.ErrTargetDenied) {
			t.Fatalf("EvaluateURL(%q) error = %v, want ErrTargetDenied", target, err)
		}
	}
}

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

	result := ConfigFromListener(config.Listener{
		Limits: config.Limits{MaxConcurrentConnections: 123},
		Retry:  config.Retry{MaxAttempts: 2, RetryMethods: []string{"GET", "HEAD"}},
		StickySession: config.StickySession{
			Enabled: true, Header: "X-Proxy-Session", TTL: config.Duration(time.Minute), MaxEntries: 456,
		},
	})
	if result.MaxConcurrentRequests != 123 || result.MaxAttempts != 2 || len(result.RetryMethods) != 2 ||
		result.StickySession.Header != "X-Proxy-Session" || result.StickySession.TTL != time.Minute ||
		result.StickySession.MaxEntries != 456 {
		t.Fatalf("handler config = %+v", result)
	}
}