package hws_test

import (
	"bytes"
	"compress/gzip"
	"io"
	"net/http"
	"net/http/httptest"
	"testing"

	"git.haelnorr.com/h/golib/hlog"
	"git.haelnorr.com/h/golib/hws"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func Test_GZIP_Compression(t *testing.T) {
	var buf bytes.Buffer

	t.Run("GZIP enabled compresses response", func(t *testing.T) {
		server, err := hws.NewServer(&hws.Config{
			Host: "127.0.0.1",
			Port: randomPort(),
			GZIP: true,
		})
		require.NoError(t, err)

		logger, err := hlog.NewLogger(hlog.LogLevel("Debug"), &buf, nil, "")
		require.NoError(t, err)

		err = server.AddLogger(logger)
		require.NoError(t, err)

		handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.WriteHeader(http.StatusOK)
			w.Write([]byte("This is a test response that should be compressed"))
		})

		err = server.AddRoutes(hws.Route{
			Path:    "/test",
			Method:  hws.MethodGET,
			Handler: handler,
		})
		require.NoError(t, err)

		err = server.Start(t.Context())
		require.NoError(t, err)
		defer server.Shutdown(t.Context())

		<-server.Ready()

		// Make request with Accept-Encoding: gzip
		client := &http.Client{}
		req, err := http.NewRequest("GET", "http://"+server.Addr()+"/test", nil)
		require.NoError(t, err)
		req.Header.Set("Accept-Encoding", "gzip")

		resp, err := client.Do(req)
		require.NoError(t, err)
		defer resp.Body.Close()

		// Verify the response is gzip compressed
		assert.Equal(t, "gzip", resp.Header.Get("Content-Encoding"))

		// Decompress and verify content
		gzReader, err := gzip.NewReader(resp.Body)
		require.NoError(t, err)
		defer gzReader.Close()

		decompressed, err := io.ReadAll(gzReader)
		require.NoError(t, err)
		assert.Equal(t, "This is a test response that should be compressed", string(decompressed))
	})

	t.Run("GZIP disabled does not compress", func(t *testing.T) {
		server, err := hws.NewServer(&hws.Config{
			Host: "127.0.0.1",
			Port: randomPort(),
			GZIP: false,
		})
		require.NoError(t, err)

		logger, err := hlog.NewLogger(hlog.LogLevel("Debug"), &buf, nil, "")
		require.NoError(t, err)

		err = server.AddLogger(logger)
		require.NoError(t, err)

		handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.WriteHeader(http.StatusOK)
			w.Write([]byte("This response should not be compressed"))
		})

		err = server.AddRoutes(hws.Route{
			Path:    "/test",
			Method:  hws.MethodGET,
			Handler: handler,
		})
		require.NoError(t, err)

		err = server.Start(t.Context())
		require.NoError(t, err)
		defer server.Shutdown(t.Context())

		<-server.Ready()

		// Make request with Accept-Encoding: gzip
		client := &http.Client{}
		req, err := http.NewRequest("GET", "http://"+server.Addr()+"/test", nil)
		require.NoError(t, err)
		req.Header.Set("Accept-Encoding", "gzip")

		resp, err := client.Do(req)
		require.NoError(t, err)
		defer resp.Body.Close()

		// Verify the response is NOT gzip compressed
		assert.Empty(t, resp.Header.Get("Content-Encoding"))

		// Read plain content
		body, err := io.ReadAll(resp.Body)
		require.NoError(t, err)
		assert.Equal(t, "This response should not be compressed", string(body))
	})

	t.Run("GZIP not used when client doesn't accept it", func(t *testing.T) {
		server, err := hws.NewServer(&hws.Config{
			Host: "127.0.0.1",
			Port: randomPort(),
			GZIP: true,
		})
		require.NoError(t, err)

		logger, err := hlog.NewLogger(hlog.LogLevel("Debug"), &buf, nil, "")
		require.NoError(t, err)

		err = server.AddLogger(logger)
		require.NoError(t, err)

		handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.WriteHeader(http.StatusOK)
			w.Write([]byte("plain text"))
		})

		err = server.AddRoutes(hws.Route{
			Path:    "/test",
			Method:  hws.MethodGET,
			Handler: handler,
		})
		require.NoError(t, err)

		err = server.Start(t.Context())
		require.NoError(t, err)
		defer server.Shutdown(t.Context())

		<-server.Ready()

		// Request without Accept-Encoding header should not be compressed
		client := &http.Client{}
		req, err := http.NewRequest("GET", "http://"+server.Addr()+"/test", nil)
		require.NoError(t, err)
		// Explicitly NOT setting Accept-Encoding header

		resp, err := client.Do(req)
		require.NoError(t, err)
		defer resp.Body.Close()

		// Verify the response is NOT gzip compressed even though server has GZIP enabled
		assert.Empty(t, resp.Header.Get("Content-Encoding"))

		// Read plain content
		body, err := io.ReadAll(resp.Body)
		require.NoError(t, err)
		assert.Equal(t, "plain text", string(body))
	})
}

func Test_GzipResponseWriter(t *testing.T) {
	t.Run("Can write through gzip writer", func(t *testing.T) {
		var buf bytes.Buffer
		gzWriter := gzip.NewWriter(&buf)
		
		testData := []byte("Test data to compress")
		n, err := gzWriter.Write(testData)
		require.NoError(t, err)
		assert.Equal(t, len(testData), n)
		
		err = gzWriter.Close()
		require.NoError(t, err)
		
		// Decompress and verify
		gzReader, err := gzip.NewReader(&buf)
		require.NoError(t, err)
		defer gzReader.Close()
		
		decompressed, err := io.ReadAll(gzReader)
		require.NoError(t, err)
		assert.Equal(t, testData, decompressed)
	})

	t.Run("Headers are set correctly", func(t *testing.T) {
		handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.Write([]byte("test"))
		})

		// Create a simple middleware to test gzip behavior
		testMiddleware := func(next http.Handler) http.Handler {
			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				r.Header.Set("Accept-Encoding", "gzip")
				next.ServeHTTP(w, r)
			})
		}

		wrapped := testMiddleware(handler)
		req := httptest.NewRequest("GET", "/test", nil)
		req.Header.Set("Accept-Encoding", "gzip")
		rr := httptest.NewRecorder()
		
		wrapped.ServeHTTP(rr, req)
		
		// Note: This is a simplified test
	})
}