package transport

import (
	"net/http"
	"time"

	"github.com/gin-gonic/gin"

	"github.com/geo-platform/tenant-api/internal/bootstrap"
)

type DesktopEventsHandler struct {
	streams *bootstrap.App
}

func NewDesktopEventsHandler(a *bootstrap.App) *DesktopEventsHandler {
	return &DesktopEventsHandler{streams: a}
}

func (h *DesktopEventsHandler) Stream(c *gin.Context) {
	client := MustDesktopClient(c.Request.Context())
	events, cancel := h.streams.DesktopTaskStreams.Subscribe(client.ID.String())
	defer cancel()

	c.Header("Content-Type", "text/event-stream")
	c.Header("Cache-Control", "no-cache")
	c.Header("Connection", "keep-alive")
	c.Header("X-Accel-Buffering", "no")

	flusher, ok := c.Writer.(http.Flusher)
	if !ok {
		return
	}

	if err := writeSSE(c, "connected", gin.H{
		"client_id":    client.ID.String(),
		"workspace_id": client.WorkspaceID,
		"server_time":  time.Now().UTC(),
	}); err != nil {
		return
	}
	flusher.Flush()

	heartbeat := time.NewTicker(15 * time.Second)
	defer heartbeat.Stop()

	for {
		select {
		case <-c.Request.Context().Done():
			return
		case <-heartbeat.C:
			if err := writeSSE(c, "ping", gin.H{"ts": time.Now().UTC()}); err != nil {
				return
			}
			flusher.Flush()
		case event, ok := <-events:
			if !ok {
				return
			}
			if err := writeSSE(c, event.Type, event); err != nil {
				return
			}
			flusher.Flush()
		}
	}
}