package proxy

import (
	"crypto/tls"
	"io"
	"net"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"

	"github.com/gofiber/fiber/v3"
	"github.com/gofiber/fiber/v3/internal/tlstest"
	"github.com/gofiber/fiber/v3/utils"
	"github.com/stretchr/testify/require"
)

func createProxyTestServer(handler fiber.Handler, t *testing.T) (*fiber.App, string) {
	t.Helper()

	target := fiber.New()
	target.Get("/", handler)

	ln, err := net.Listen(fiber.NetworkTCP4, "127.0.0.1:0")
	require.NoError(t, err)

	addr := ln.Addr().String()

	go func() {
		require.Nil(t, target.Listener(ln, fiber.ListenConfig{
			DisableStartupMessage: true,
		}))
	}()

	time.Sleep(2 * time.Second)

	return target, addr
}

// go test -run Test_Proxy_Empty_Host
func Test_Proxy_Empty_Upstream_Servers(t *testing.T) {
	t.Parallel()

	defer func() {
		if r := recover(); r != nil {
			require.Equal(t, "Servers cannot be empty", r)
		}
	}()
	app := fiber.New()
	app.Use(Balancer(Config{Servers: []string{}}))
}

// go test -run Test_Proxy_Next
func Test_Proxy_Next(t *testing.T) {
	t.Parallel()

	app := fiber.New()
	app.Use(Balancer(Config{
		Servers: []string{"127.0.0.1"},
		Next: func(_ fiber.Ctx) bool {
			return true
		},
	}))

	resp, err := app.Test(httptest.NewRequest("GET", "/", nil))
	require.NoError(t, err)
	require.Equal(t, fiber.StatusNotFound, resp.StatusCode)
}

// go test -run Test_Proxy
func Test_Proxy(t *testing.T) {
	t.Parallel()

	target, addr := createProxyTestServer(
		func(c fiber.Ctx) error { return c.SendStatus(fiber.StatusTeapot) }, t,
	)

	resp, err := target.Test(httptest.NewRequest("GET", "/", nil), 2000)
	require.NoError(t, err)
	require.Equal(t, fiber.StatusTeapot, resp.StatusCode)

	app := fiber.New()

	app.Use(Balancer(Config{Servers: []string{addr}}))

	req := httptest.NewRequest("GET", "/", nil)
	req.Host = addr
	resp, err = app.Test(req)
	require.NoError(t, err)
	require.Equal(t, fiber.StatusTeapot, resp.StatusCode)
}

// go test -run Test_Proxy_Balancer_WithTlsConfig
func Test_Proxy_Balancer_WithTlsConfig(t *testing.T) {
	t.Parallel()

	serverTLSConf, _, err := tlstest.GetTLSConfigs()
	require.NoError(t, err)

	ln, err := net.Listen(fiber.NetworkTCP4, "127.0.0.1:0")
	require.NoError(t, err)

	ln = tls.NewListener(ln, serverTLSConf)

	app := fiber.New()

	app.Get("/tlsbalaner", func(c fiber.Ctx) error {
		return c.SendString("tls balancer")
	})

	addr := ln.Addr().String()
	clientTLSConf := &tls.Config{InsecureSkipVerify: true}

	// disable certificate verification in Balancer
	app.Use(Balancer(Config{
		Servers:   []string{addr},
		TlsConfig: clientTLSConf,
	}))

	go func() {
		require.Nil(t, app.Listener(ln, fiber.ListenConfig{
			DisableStartupMessage: true,
		}))
	}()

	code, body, errs := fiber.Get("https://" + addr + "/tlsbalaner").TLSConfig(clientTLSConf).String()

	require.Equal(t, 0, len(errs))
	require.Equal(t, fiber.StatusOK, code)
	require.Equal(t, "tls balancer", body)
}

// go test -run Test_Proxy_Forward_WithTlsConfig_To_Http
func Test_Proxy_Forward_WithTlsConfig_To_Http(t *testing.T) {
	//t.Parallel()

	_, targetAddr := createProxyTestServer(func(c fiber.Ctx) error {
		return c.SendString("hello from target")
	}, t)

	proxyServerTLSConf, _, err := tlstest.GetTLSConfigs()
	require.NoError(t, err)

	proxyServerLn, err := net.Listen(fiber.NetworkTCP4, "127.0.0.1:0")
	require.NoError(t, err)

	proxyServerLn = tls.NewListener(proxyServerLn, proxyServerTLSConf)

	app := fiber.New()

	proxyAddr := proxyServerLn.Addr().String()

	app.Use(Forward("http://" + targetAddr))

	go func() {
		require.Nil(t, app.Listener(proxyServerLn, fiber.ListenConfig{
			DisableStartupMessage: true,
		}))
	}()

	code, body, errs := fiber.Get("https://" + proxyAddr).
		InsecureSkipVerify().
		Timeout(5 * time.Second).
		String()

	require.Equal(t, 0, len(errs))
	require.Equal(t, fiber.StatusOK, code)
	require.Equal(t, "hello from target", body)
}

// go test -run Test_Proxy_Forward
func Test_Proxy_Forward(t *testing.T) {
	t.Parallel()

	app := fiber.New()

	_, addr := createProxyTestServer(
		func(c fiber.Ctx) error { return c.SendString("forwarded") }, t,
	)

	app.Use(Forward("http://" + addr))

	resp, err := app.Test(httptest.NewRequest("GET", "/", nil))
	require.NoError(t, err)
	require.Equal(t, fiber.StatusOK, resp.StatusCode)

	b, err := io.ReadAll(resp.Body)
	require.NoError(t, err)
	require.Equal(t, "forwarded", string(b))
}

// go test -run Test_Proxy_Forward_WithTlsConfig
func Test_Proxy_Forward_WithTlsConfig(t *testing.T) {
	t.Parallel()

	serverTLSConf, _, err := tlstest.GetTLSConfigs()
	require.NoError(t, err)

	ln, err := net.Listen(fiber.NetworkTCP4, "127.0.0.1:0")
	require.NoError(t, err)

	ln = tls.NewListener(ln, serverTLSConf)

	app := fiber.New()

	app.Get("/tlsfwd", func(c fiber.Ctx) error {
		return c.SendString("tls forward")
	})

	addr := ln.Addr().String()
	clientTLSConf := &tls.Config{InsecureSkipVerify: true}

	// disable certificate verification
	WithTlsConfig(clientTLSConf)
	app.Use(Forward("https://" + addr + "/tlsfwd"))

	go func() {
		require.Nil(t, app.Listener(ln, fiber.ListenConfig{
			DisableStartupMessage: true,
		}))
	}()

	code, body, errs := fiber.Get("https://" + addr).TLSConfig(clientTLSConf).String()

	require.Equal(t, 0, len(errs))
	require.Equal(t, fiber.StatusOK, code)
	require.Equal(t, "tls forward", body)
}

// go test -run Test_Proxy_Modify_Response
func Test_Proxy_Modify_Response(t *testing.T) {
	t.Parallel()

	_, addr := createProxyTestServer(func(c fiber.Ctx) error {
		return c.Status(500).SendString("not modified")
	}, t)

	app := fiber.New()
	app.Use(Balancer(Config{
		Servers: []string{addr},
		ModifyResponse: func(c fiber.Ctx) error {
			c.Response().SetStatusCode(fiber.StatusOK)
			return c.SendString("modified response")
		},
	}))

	resp, err := app.Test(httptest.NewRequest("GET", "/", nil))
	require.NoError(t, err)
	require.Equal(t, fiber.StatusOK, resp.StatusCode)

	b, err := io.ReadAll(resp.Body)
	require.NoError(t, err)
	require.Equal(t, "modified response", string(b))
}

// go test -run Test_Proxy_Modify_Request
func Test_Proxy_Modify_Request(t *testing.T) {
	t.Parallel()

	_, addr := createProxyTestServer(func(c fiber.Ctx) error {
		b := c.Request().Body()
		return c.SendString(string(b))
	}, t)

	app := fiber.New()
	app.Use(Balancer(Config{
		Servers: []string{addr},
		ModifyRequest: func(c fiber.Ctx) error {
			c.Request().SetBody([]byte("modified request"))
			return nil
		},
	}))

	resp, err := app.Test(httptest.NewRequest("GET", "/", nil))
	require.NoError(t, err)
	require.Equal(t, fiber.StatusOK, resp.StatusCode)

	b, err := io.ReadAll(resp.Body)
	require.NoError(t, err)
	require.Equal(t, "modified request", string(b))
}

// go test -run Test_Proxy_Timeout_Slow_Server
func Test_Proxy_Timeout_Slow_Server(t *testing.T) {
	t.Parallel()

	_, addr := createProxyTestServer(func(c fiber.Ctx) error {
		time.Sleep(2 * time.Second)
		return c.SendString("fiber is awesome")
	}, t)

	app := fiber.New()
	app.Use(Balancer(Config{
		Servers: []string{addr},
		Timeout: 3 * time.Second,
	}))

	resp, err := app.Test(httptest.NewRequest("GET", "/", nil), 5000)
	require.NoError(t, err)
	require.Equal(t, fiber.StatusOK, resp.StatusCode)

	b, err := io.ReadAll(resp.Body)
	require.NoError(t, err)
	require.Equal(t, "fiber is awesome", string(b))
}

// go test -run Test_Proxy_With_Timeout
func Test_Proxy_With_Timeout(t *testing.T) {
	t.Parallel()

	_, addr := createProxyTestServer(func(c fiber.Ctx) error {
		time.Sleep(1 * time.Second)
		return c.SendString("fiber is awesome")
	}, t)

	app := fiber.New()
	app.Use(Balancer(Config{
		Servers: []string{addr},
		Timeout: 100 * time.Millisecond,
	}))

	resp, err := app.Test(httptest.NewRequest("GET", "/", nil), 2000)
	require.NoError(t, err)
	require.Equal(t, fiber.StatusInternalServerError, resp.StatusCode)

	b, err := io.ReadAll(resp.Body)
	require.NoError(t, err)
	require.Equal(t, "timeout", string(b))
}

// go test -run Test_Proxy_Buffer_Size_Response
func Test_Proxy_Buffer_Size_Response(t *testing.T) {
	t.Parallel()

	_, addr := createProxyTestServer(func(c fiber.Ctx) error {
		long := strings.Join(make([]string, 5000), "-")
		c.Set("Very-Long-Header", long)
		return c.SendString("ok")
	}, t)

	app := fiber.New()
	app.Use(Balancer(Config{Servers: []string{addr}}))

	resp, err := app.Test(httptest.NewRequest("GET", "/", nil))
	require.NoError(t, err)
	require.Equal(t, fiber.StatusInternalServerError, resp.StatusCode)

	app = fiber.New()
	app.Use(Balancer(Config{
		Servers:        []string{addr},
		ReadBufferSize: 1024 * 8,
	}))

	resp, err = app.Test(httptest.NewRequest("GET", "/", nil))
	require.NoError(t, err)
	require.Equal(t, fiber.StatusOK, resp.StatusCode)
}

// go test -race -run Test_Proxy_Do_RestoreOriginalURL
func Test_Proxy_Do_RestoreOriginalURL(t *testing.T) {
	t.Parallel()
	app := fiber.New()
	app.Get("/proxy", func(c fiber.Ctx) error {
		return c.SendString("ok")
	})
	app.Get("/test", func(c fiber.Ctx) error {
		originalURL := utils.CopyString(c.OriginalURL())
		if err := Do(c, "/proxy"); err != nil {
			return err
		}
		require.Equal(t, originalURL, c.OriginalURL())
		return c.SendString("ok")
	})
	_, err1 := app.Test(httptest.NewRequest("GET", "/test", nil))
	// This test requires multiple requests due to zero allocation used in fiber
	_, err2 := app.Test(httptest.NewRequest("GET", "/test", nil))

	require.Nil(t, err1)
	require.Nil(t, err2)
}

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

	_, addr := createProxyTestServer(func(c fiber.Ctx) error {
		return c.SendString("hello world")
	}, t)

	app := fiber.New()
	app.Get("/*", func(c fiber.Ctx) error {
		path := c.OriginalURL()
		url := strings.TrimPrefix(path, "/")

		require.Equal(t, "http://"+addr, url)
		if err := Do(c, url); err != nil {
			return err
		}
		c.Response().Header.Del(fiber.HeaderServer)
		return nil
	})

	resp, err := app.Test(httptest.NewRequest(http.MethodGet, "/http://"+addr, nil))
	require.NoError(t, err)
	s, err := io.ReadAll(resp.Body)
	require.NoError(t, err)
	require.Equal(t, "hello world", string(s))
}