package buffer

import (
	"bufio"
	"crypto/tls"
	"fmt"
	"io"
	"net"
	"net/http"
	"net/http/httptest"
	"strconv"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"github.com/vulcand/oxy/forward"
	"github.com/vulcand/oxy/testutils"
	"github.com/vulcand/oxy/utils"
)

func TestSimple(t *testing.T) {
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		_, _ = w.Write([]byte("hello"))
	})
	defer srv.Close()

	// forwarder will proxy the request to whatever destination
	fwd := forward.New(false)

	// this is our redirect to server
	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		req.URL = testutils.ParseURI(srv.URL)
		fwd.ServeHTTP(w, req)
	})

	// stream handler will forward requests to redirect
	st, err := New(rdr)
	require.NoError(t, err)

	proxy := httptest.NewServer(st)
	defer proxy.Close()

	re, body, err := testutils.Get(proxy.URL)
	require.NoError(t, err)
	assert.Equal(t, http.StatusOK, re.StatusCode)
	assert.Equal(t, "hello", string(body))
}

func TestChunkedEncodingSuccess(t *testing.T) {
	var reqBody string
	var contentLength int64
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		body, err := io.ReadAll(req.Body)
		require.NoError(t, err)
		reqBody = string(body)
		contentLength = req.ContentLength
		_, _ = w.Write([]byte("hello"))
	})
	defer srv.Close()

	// forwarder will proxy the request to whatever destination
	fwd := forward.New(false)

	// this is our redirect to server
	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		req.URL = testutils.ParseURI(srv.URL)
		fwd.ServeHTTP(w, req)
	})

	// stream handler will forward requests to redirect
	st, err := New(rdr)
	require.NoError(t, err)

	proxy := httptest.NewServer(st)
	defer proxy.Close()

	conn, err := net.Dial("tcp", testutils.ParseURI(proxy.URL).Host)
	require.NoError(t, err)

	_, _ = fmt.Fprintf(conn, "POST / HTTP/1.1\r\nHost: 127.0.0.1:8080\r\nTransfer-Encoding: chunked\r\n\r\n4\r\ntest\r\n5\r\ntest1\r\n5\r\ntest2\r\n0\r\n\r\n")
	status, err := bufio.NewReader(conn).ReadString('\n')
	require.NoError(t, err)

	assert.Equal(t, "testtest1test2", reqBody)
	assert.Equal(t, "HTTP/1.1 200 OK\r\n", status)
	assert.EqualValues(t, len(reqBody), contentLength)
}

func TestChunkedEncodingLimitReached(t *testing.T) {
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		_, _ = w.Write([]byte("hello"))
	})
	defer srv.Close()

	// forwarder will proxy the request to whatever destination
	fwd := forward.New(false)

	// this is our redirect to server
	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		req.URL = testutils.ParseURI(srv.URL)
		fwd.ServeHTTP(w, req)
	})

	// stream handler will forward requests to redirect
	st, err := New(rdr, MemRequestBodyBytes(4), MaxRequestBodyBytes(8))
	require.NoError(t, err)

	proxy := httptest.NewServer(st)
	defer proxy.Close()

	conn, err := net.Dial("tcp", testutils.ParseURI(proxy.URL).Host)
	require.NoError(t, err)
	_, _ = fmt.Fprint(conn, "POST / HTTP/1.1\r\nHost: 127.0.0.1:8080\r\nTransfer-Encoding: chunked\r\n\r\n4\r\ntest\r\n5\r\ntest1\r\n5\r\ntest2\r\n0\r\n\r\n")
	status, err := bufio.NewReader(conn).ReadString('\n')
	require.NoError(t, err)

	assert.Equal(t, "HTTP/1.1 413 Request Entity Too Large\r\n", status)
}

func TestChunkedResponse(t *testing.T) {
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		h := w.(http.Hijacker)
		conn, _, _ := h.Hijack()
		_, _ = fmt.Fprintf(conn, "HTTP/1.1 200 OK\r\nTransfer-Encoding: chunked\r\n\r\n4\r\ntest\r\n5\r\ntest1\r\n5\r\ntest2\r\n0\r\n\r\n")
		_ = conn.Close()
	})
	defer srv.Close()

	fwd := forward.New(false)

	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		req.URL = testutils.ParseURI(srv.URL)
		fwd.ServeHTTP(w, req)
	})
	st, err := New(rdr)
	require.NoError(t, err)
	proxy := httptest.NewServer(st)

	defer proxy.Close()

	re, body, err := testutils.Get(proxy.URL)
	require.NoError(t, err)
	assert.Equal(t, "testtest1test2", string(body))
	assert.Equal(t, http.StatusOK, re.StatusCode)
	assert.Equal(t, strconv.Itoa(len("testtest1test2")), re.Header.Get("Content-Length"))
}

func TestRequestLimitReached(t *testing.T) {
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		_, _ = w.Write([]byte("hello"))
	})
	defer srv.Close()

	// forwarder will proxy the request to whatever destination
	fwd := forward.New(false)

	// this is our redirect to server
	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		req.URL = testutils.ParseURI(srv.URL)
		fwd.ServeHTTP(w, req)
	})

	// stream handler will forward requests to redirect
	st, err := New(rdr, MaxRequestBodyBytes(4))
	require.NoError(t, err)

	proxy := httptest.NewServer(st)
	defer proxy.Close()

	re, _, err := testutils.Get(proxy.URL, testutils.Body("this request is too long"))
	require.NoError(t, err)
	assert.Equal(t, http.StatusRequestEntityTooLarge, re.StatusCode)
}

func TestResponseLimitReached(t *testing.T) {
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		_, _ = w.Write([]byte("hello, this response is too large"))
	})
	defer srv.Close()

	// forwarder will proxy the request to whatever destination
	fwd := forward.New(false)

	// this is our redirect to server
	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		req.URL = testutils.ParseURI(srv.URL)
		fwd.ServeHTTP(w, req)
	})

	// stream handler will forward requests to redirect
	st, err := New(rdr, MaxResponseBodyBytes(4))
	require.NoError(t, err)

	proxy := httptest.NewServer(st)
	defer proxy.Close()

	re, _, err := testutils.Get(proxy.URL)
	require.NoError(t, err)
	assert.Equal(t, http.StatusInternalServerError, re.StatusCode)
}

func TestFileStreamingResponse(t *testing.T) {
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		_, _ = w.Write([]byte("hello, this response is too large to fit in memory"))
	})
	defer srv.Close()

	// forwarder will proxy the request to whatever destination
	fwd := forward.New(false)

	// this is our redirect to server
	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		req.URL = testutils.ParseURI(srv.URL)
		fwd.ServeHTTP(w, req)
	})

	// stream handler will forward requests to redirect
	st, err := New(rdr, MemResponseBodyBytes(4))
	require.NoError(t, err)

	proxy := httptest.NewServer(st)
	defer proxy.Close()

	re, body, err := testutils.Get(proxy.URL)
	require.NoError(t, err)
	assert.Equal(t, http.StatusOK, re.StatusCode)
	assert.Equal(t, "hello, this response is too large to fit in memory", string(body))
}

func TestCustomErrorHandler(t *testing.T) {
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		_, _ = w.Write([]byte("hello, this response is too large"))
	})
	defer srv.Close()

	// forwarder will proxy the request to whatever destination
	fwd := forward.New(false)

	// this is our redirect to server
	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		req.URL = testutils.ParseURI(srv.URL)
		fwd.ServeHTTP(w, req)
	})

	// stream handler will forward requests to redirect
	errHandler := utils.ErrorHandlerFunc(func(w http.ResponseWriter, req *http.Request, err error) {
		w.WriteHeader(http.StatusTeapot)
		_, _ = w.Write([]byte(http.StatusText(http.StatusTeapot)))
	})
	st, err := New(rdr, MaxResponseBodyBytes(4), ErrorHandler(errHandler))
	require.NoError(t, err)

	proxy := httptest.NewServer(st)
	defer proxy.Close()

	re, _, err := testutils.Get(proxy.URL)
	require.NoError(t, err)
	assert.Equal(t, http.StatusTeapot, re.StatusCode)
}

func TestNotModified(t *testing.T) {
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		w.WriteHeader(http.StatusNotModified)
	})
	defer srv.Close()

	// forwarder will proxy the request to whatever destination
	fwd := forward.New(false)

	// this is our redirect to server
	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		req.URL = testutils.ParseURI(srv.URL)
		fwd.ServeHTTP(w, req)
	})

	// stream handler will forward requests to redirect
	st, err := New(rdr)
	require.NoError(t, err)

	proxy := httptest.NewServer(st)
	defer proxy.Close()

	re, _, err := testutils.Get(proxy.URL)
	require.NoError(t, err)
	assert.Equal(t, http.StatusNotModified, re.StatusCode)
}

func TestNoBody(t *testing.T) {
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		w.WriteHeader(http.StatusOK)
	})
	defer srv.Close()

	// forwarder will proxy the request to whatever destination
	fwd := forward.New(false)

	// this is our redirect to server
	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		req.URL = testutils.ParseURI(srv.URL)
		fwd.ServeHTTP(w, req)
	})

	// stream handler will forward requests to redirect
	st, err := New(rdr)
	require.NoError(t, err)

	proxy := httptest.NewServer(st)
	defer proxy.Close()

	re, _, err := testutils.Get(proxy.URL)
	require.NoError(t, err)
	assert.Equal(t, http.StatusOK, re.StatusCode)
}

// Make sure that stream handler preserves TLS settings.
func TestPreservesTLS(t *testing.T) {
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		w.WriteHeader(http.StatusOK)
		_, _ = w.Write([]byte("ok"))
	})
	defer srv.Close()

	// forwarder will proxy the request to whatever destination
	fwd := forward.New(false)

	var cs *tls.ConnectionState
	// this is our redirect to server
	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		cs = req.TLS
		req.URL = testutils.ParseURI(srv.URL)
		fwd.ServeHTTP(w, req)
	})

	// stream handler will forward requests to redirect
	st, err := New(rdr)
	require.NoError(t, err)

	proxy := httptest.NewUnstartedServer(st)
	proxy.StartTLS()
	defer proxy.Close()

	re, _, err := testutils.Get(proxy.URL)
	require.NoError(t, err)
	assert.Equal(t, http.StatusOK, re.StatusCode)
	assert.NotNil(t, cs)
}

func TestNotNilBody(t *testing.T) {
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		_, _ = w.Write([]byte("hello"))
	})
	defer srv.Close()

	// forwarder will proxy the request to whatever destination
	fwd := forward.New(false)

	// this is our redirect to server
	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		req.URL = testutils.ParseURI(srv.URL)
		// During a request check if the request body is no nil before sending to the next middleware
		// Because we can send a POST request without body
		assert.NotNil(t, req.Body)
		fwd.ServeHTTP(w, req)
	})

	// stream handler will forward requests to redirect
	st, err := New(rdr, MaxRequestBodyBytes(10))
	require.NoError(t, err)

	proxy := httptest.NewServer(st)
	defer proxy.Close()

	re, body, err := testutils.Get(proxy.URL)
	require.NoError(t, err)
	assert.Equal(t, http.StatusOK, re.StatusCode)
	assert.Equal(t, "hello", string(body))

	re, body, err = testutils.Post(proxy.URL)
	require.NoError(t, err)
	assert.Equal(t, http.StatusOK, re.StatusCode)
	assert.Equal(t, "hello", string(body))
}