package handlers

import (
	"encoding/json"
	"net/http"

	"aroll/transcode"
	"aroll/ws"
)

type zoomRequest struct {
	Zoom     float64 `json:"zoom"`     // 1–100, percentage of total duration to show
	Center   float64 `json:"center"`   // scroll center in seconds
	Duration float64 `json:"duration"` // total video duration in seconds
}

func ZoomHandler(hub *ws.Hub) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodPost {
			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
			return
		}

		var req zoomRequest
		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
			http.Error(w, "bad JSON: "+err.Error(), http.StatusBadRequest)
			return
		}

		result := transcode.TimelineZoom(req.Center, req.Zoom, req.Duration)

		data, _ := json.Marshal(result)
		hub.Broadcast(data)

		w.WriteHeader(http.StatusAccepted)
	}
}