package controller

import (
	"bufio"
	"context"
	"errors"
	"net/http"
	"net/http/httptest"
	"sync/atomic"
	"testing"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/stretchr/testify/require"
)

func TestGroupStatusStreamPushAndReconnect(t *testing.T) {
	var reads atomic.Int32
	router := gin.New()
	router.GET("/events", func(c *gin.Context) {
		streamGroupStatus(c, func(context.Context) (any, error) {
			return gin.H{"success": true, "revision": reads.Add(1)}, nil
		})
	})
	server := httptest.NewServer(router)
	defer server.Close()
	client := &http.Client{Timeout: 3 * time.Second}
	response, err := client.Get(server.URL + "/events")
	require.NoError(t, err)
	defer response.Body.Close()
	require.Equal(t, "text/event-stream", response.Header.Get("Content-Type"))
	require.Equal(t, "no", response.Header.Get("X-Accel-Buffering"))
	reader := bufio.NewReader(response.Body)
	frame := func() string {
		var value string
		for {
			line, err := reader.ReadString('\n')
			require.NoError(t, err)
			value += line
			if line == "\n" {
				return value
			}
		}
	}
	require.Contains(t, frame(), `"revision":1`)
	require.EqualValues(t, 1, reads.Load())
	publishGroupStatusChange()
	require.Contains(t, frame(), `"revision":2`)
	response.Body.Close()
	response, err = client.Get(server.URL + "/events")
	require.NoError(t, err)
	defer response.Body.Close()
	reader = bufio.NewReader(response.Body)
	require.Contains(t, frame(), `"revision":3`)
}

func TestGroupStatusStreamReadFailure(t *testing.T) {
	c, _ := gin.CreateTestContext(httptest.NewRecorder())
	c.Request = httptest.NewRequest("GET", "/events", nil)
	streamGroupStatus(c, func(context.Context) (any, error) { return nil, errors.New("unavailable") })
	require.Equal(t, http.StatusServiceUnavailable, c.Writer.Status())
}

func TestGroupStatusEventsCoalesceAndRelease(t *testing.T) {
	ch, unsubscribe, err := subscribeGroupStatus()
	require.NoError(t, err)
	publishGroupStatusChange()
	publishGroupStatusChange()
	require.Len(t, ch, 1)
	unsubscribe()
	<-ch
	publishGroupStatusChange()
	require.Empty(t, ch)
}