package api

import (
	"context"
	"net"
	"net/http"
	"net/http/httptest"
	"strings"
	"sync"
	"testing"

	"github.com/gorilla/websocket"
	"github.com/rcourtman/pulse-go-rewrite/internal/config"
	pulsews "github.com/rcourtman/pulse-go-rewrite/internal/websocket"
)

func resetTrustedProxyCIDRsForTests() {
	trustedProxyCIDRs = nil
	trustedProxyOnce = sync.Once{}
}

func newWebSocketRouterWithServer(t *testing.T, allowedOrigins []string, tokenRecord config.APITokenRecord, serverFactory func(*testing.T, http.Handler) *httptest.Server) (*httptest.Server, func()) {
	t.Helper()

	cfg := newTestConfigWithTokens(t, tokenRecord)

	hub := pulsews.NewHub(nil)
	hub.SetAllowedOrigins(allowedOrigins)
	go hub.Run()

	router := NewRouter(cfg, nil, nil, hub, nil, "1.0.0")
	server := serverFactory(t, router.Handler())

	cleanup := func() {
		server.Close()
		hub.Stop()
	}

	return server, cleanup
}

func newWebSocketRouter(t *testing.T, allowedOrigins []string, tokenRecord config.APITokenRecord) (*httptest.Server, func()) {
	t.Helper()
	return newWebSocketRouterWithServer(t, allowedOrigins, tokenRecord, newIPv4HTTPServer)
}

func newWebSocketRouterIPv6(t *testing.T, allowedOrigins []string, tokenRecord config.APITokenRecord) (*httptest.Server, func()) {
	t.Helper()
	return newWebSocketRouterWithServer(t, allowedOrigins, tokenRecord, newIPv6HTTPServer)
}

func TestWebSocketOriginRejectedWhenNotAllowed(t *testing.T) {
	rawToken := "ws-origin-reject-123.12345678"
	record := newTokenRecord(t, rawToken, []string{config.ScopeMonitoringRead}, nil)

	server, cleanup := newWebSocketRouter(t, []string{"https://allowed.example.com"}, record)
	defer cleanup()

	wsURL := "ws" + strings.TrimPrefix(server.URL, "http") + "/ws?org_id=default"
	headers := http.Header{}
	headers.Set("X-API-Token", rawToken)
	headers.Set("Origin", "https://evil.example.com")

	conn, resp, err := websocket.DefaultDialer.Dial(wsURL, headers)
	if err == nil {
		conn.Close()
		t.Fatalf("expected websocket origin rejection")
	}
	if resp == nil {
		t.Fatalf("expected HTTP response for rejected origin")
	}
	if resp.StatusCode != http.StatusForbidden {
		t.Fatalf("expected status %d, got %d", http.StatusForbidden, resp.StatusCode)
	}
}

func TestWebSocketOriginRejectedWhenMissing(t *testing.T) {
	rawToken := "ws-origin-missing-123.12345678"
	record := newTokenRecord(t, rawToken, []string{config.ScopeMonitoringRead}, nil)

	server, cleanup := newWebSocketRouter(t, []string{"*"}, record)
	defer cleanup()

	wsURL := "ws" + strings.TrimPrefix(server.URL, "http") + "/ws?org_id=default"
	headers := http.Header{}
	headers.Set("X-API-Token", rawToken)

	conn, resp, err := websocket.DefaultDialer.Dial(wsURL, headers)
	if err == nil {
		conn.Close()
		t.Fatalf("expected websocket origin rejection when Origin header is missing")
	}
	if resp == nil {
		t.Fatalf("expected HTTP response for rejected websocket origin")
	}
	if resp.StatusCode != http.StatusForbidden {
		t.Fatalf("expected status %d, got %d", http.StatusForbidden, resp.StatusCode)
	}
}

func TestWebSocketOriginAllowedWhenConfigured(t *testing.T) {
	rawToken := "ws-origin-allow-123.12345678"
	record := newTokenRecord(t, rawToken, []string{config.ScopeMonitoringRead}, nil)

	server, cleanup := newWebSocketRouter(t, []string{"https://allowed.example.com"}, record)
	defer cleanup()

	wsURL := "ws" + strings.TrimPrefix(server.URL, "http") + "/ws?org_id=default"
	headers := http.Header{}
	headers.Set("X-API-Token", rawToken)
	headers.Set("Origin", "https://allowed.example.com")

	conn, resp, err := websocket.DefaultDialer.Dial(wsURL, headers)
	if err != nil {
		t.Fatalf("expected websocket connection, got %v", err)
	}
	if resp == nil || resp.StatusCode != http.StatusSwitchingProtocols {
		t.Fatalf("expected 101 switching protocols, got %v", resp)
	}
	conn.Close()
}

func TestWebSocketOriginRejectedWhenNoAllowedOriginsAndPublicOrigin(t *testing.T) {
	rawToken := "ws-origin-default-reject-123.12345678"
	record := newTokenRecord(t, rawToken, []string{config.ScopeMonitoringRead}, nil)

	server, cleanup := newWebSocketRouter(t, []string{}, record)
	defer cleanup()

	wsURL := "ws" + strings.TrimPrefix(server.URL, "http") + "/ws?org_id=default"
	headers := http.Header{}
	headers.Set("X-API-Token", rawToken)
	headers.Set("Origin", "https://evil.example.com")

	conn, resp, err := websocket.DefaultDialer.Dial(wsURL, headers)
	if err == nil {
		conn.Close()
		t.Fatalf("expected websocket origin rejection with empty allowed origins")
	}
	if resp == nil {
		t.Fatalf("expected HTTP response for rejected origin")
	}
	if resp.StatusCode != http.StatusForbidden {
		t.Fatalf("expected status %d, got %d", http.StatusForbidden, resp.StatusCode)
	}
}

func TestWebSocketOriginAllowsPrivateWhenNoAllowedOrigins(t *testing.T) {
	rawToken := "ws-origin-default-allow-123.12345678"
	record := newTokenRecord(t, rawToken, []string{config.ScopeMonitoringRead}, nil)

	server, cleanup := newWebSocketRouter(t, []string{}, record)
	defer cleanup()

	wsURL := "ws" + strings.TrimPrefix(server.URL, "http") + "/ws?org_id=default"
	headers := http.Header{}
	headers.Set("X-API-Token", rawToken)
	headers.Set("Origin", "http://localhost:3000")

	conn, resp, err := websocket.DefaultDialer.Dial(wsURL, headers)
	if err != nil {
		t.Fatalf("expected websocket connection, got %v", err)
	}
	if resp == nil || resp.StatusCode != http.StatusSwitchingProtocols {
		t.Fatalf("expected 101 switching protocols, got %v", resp)
	}
	conn.Close()
}

func TestWebSocketOriginAllowsSameHostTLSTerminationWithoutTrustedProxy(t *testing.T) {
	rawToken := "ws-origin-same-host-123.12345678"
	record := newTokenRecord(t, rawToken, []string{config.ScopeMonitoringRead}, nil)

	server, cleanup := newWebSocketRouter(t, []string{}, record)
	defer cleanup()

	dialer := websocket.Dialer{
		NetDialContext: func(ctx context.Context, network, _ string) (net.Conn, error) {
			var dialer net.Dialer
			return dialer.DialContext(ctx, network, server.Listener.Addr().String())
		},
	}

	headers := http.Header{}
	headers.Set("X-API-Token", rawToken)
	headers.Set("Origin", "https://tenant.example.com")

	conn, resp, err := dialer.Dial("ws://tenant.example.com/ws?org_id=default", headers)
	if err != nil {
		t.Fatalf("expected websocket connection when proxy preserves host but terminates tls upstream, got %v", err)
	}
	if resp == nil || resp.StatusCode != http.StatusSwitchingProtocols {
		conn.Close()
		t.Fatalf("expected 101 switching protocols, got %v", resp)
	}
	conn.Close()
}

func TestWebSocketOriginAllowsTrustedForwardedHostedOrigin(t *testing.T) {
	t.Setenv("PULSE_TRUSTED_PROXY_CIDRS", "127.0.0.1/32")
	resetTrustedProxyCIDRsForTests()

	rawToken := "ws-origin-forwarded-allow-123.12345678"
	record := newTokenRecord(t, rawToken, []string{config.ScopeMonitoringRead}, nil)

	server, cleanup := newWebSocketRouter(t, []string{}, record)
	defer cleanup()

	wsURL := "ws" + strings.TrimPrefix(server.URL, "http") + "/ws?org_id=default"
	headers := http.Header{}
	headers.Set("X-API-Token", rawToken)
	headers.Set("Origin", "https://tenant.example.com")
	headers.Set("X-Forwarded-Proto", "https")
	headers.Set("X-Forwarded-Host", "tenant.example.com")

	conn, resp, err := websocket.DefaultDialer.Dial(wsURL, headers)
	if err != nil {
		t.Fatalf("expected websocket connection behind trusted proxy, got %v", err)
	}
	if resp == nil || resp.StatusCode != http.StatusSwitchingProtocols {
		conn.Close()
		t.Fatalf("expected 101 switching protocols, got %v", resp)
	}
	conn.Close()
}

func TestWebSocketOriginAllowsTrustedForwardedHostedOriginIPv6Loopback(t *testing.T) {
	t.Setenv("PULSE_TRUSTED_PROXY_CIDRS", "::1/128")
	resetTrustedProxyCIDRsForTests()

	rawToken := "ws-origin-forwarded-ipv6-allow-123.12345678"
	record := newTokenRecord(t, rawToken, []string{config.ScopeMonitoringRead}, nil)

	server, cleanup := newWebSocketRouterIPv6(t, []string{}, record)
	defer cleanup()

	wsURL := "ws" + strings.TrimPrefix(server.URL, "http") + "/ws?org_id=default"
	headers := http.Header{}
	headers.Set("X-API-Token", rawToken)
	headers.Set("Origin", "https://tenant.example.com")
	headers.Set("X-Forwarded-Proto", "https")
	headers.Set("X-Forwarded-Host", "tenant.example.com")

	conn, resp, err := websocket.DefaultDialer.Dial(wsURL, headers)
	if err != nil {
		t.Fatalf("expected websocket connection behind trusted IPv6 loopback proxy, got %v", err)
	}
	if resp == nil || resp.StatusCode != http.StatusSwitchingProtocols {
		conn.Close()
		t.Fatalf("expected 101 switching protocols, got %v", resp)
	}
	conn.Close()
}