package main

import (
	"fmt"
	"net/http"
	"time"
)

// handleSyncPull returns all records modified since the `since` query parameter.
// If `since` is empty, returns all records (initial sync).
func (app *App) handleSyncPull(w http.ResponseWriter, r *http.Request) {
	since := r.URL.Query().Get("since")

	event, _ := app.getEvent()
	attendees, _ := app.attendeesSince(since)
	departments, _ := app.listDepartments(since)
	volunteers, _ := app.listVolunteers("", nil, since)
	shifts, _ := app.listShifts(nil, "", since)
	volunteerShifts, _ := app.listVolunteerShifts(since)

	if attendees == nil {
		attendees = []Attendee{}
	}
	if departments == nil {
		departments = []Department{}
	}
	if volunteers == nil {
		volunteers = []Volunteer{}
	}
	if shifts == nil {
		shifts = []Shift{}
	}
	if volunteerShifts == nil {
		volunteerShifts = []VolunteerShift{}
	}

	writeJSON(w, map[string]any{
		"server_time":      time.Now().UTC().Format("2006-01-02T15:04:05Z"),
		"event":            event,
		"attendees":        attendees,
		"departments":      departments,
		"volunteers":       volunteers,
		"shifts":           shifts,
		"volunteer_shifts": volunteerShifts,
	})
}

// handleSyncStream is an SSE endpoint that broadcasts real-time events
// (check-ins, etc.) to connected clients.
func (app *App) handleSyncStream(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "text/event-stream")
	w.Header().Set("Cache-Control", "no-cache")
	w.Header().Set("Connection", "keep-alive")
	w.Header().Set("X-Accel-Buffering", "no")

	flusher, ok := w.(http.Flusher)
	if !ok {
		http.Error(w, "streaming not supported", http.StatusInternalServerError)
		return
	}

	ch := app.broker.subscribe()
	defer app.broker.unsubscribe(ch)

	fmt.Fprintf(w, "data: {\"event\":\"connected\"}\n\n")
	flusher.Flush()

	ticker := time.NewTicker(30 * time.Second)
	defer ticker.Stop()

	for {
		select {
		case <-r.Context().Done():
			return
		case payload, ok := <-ch:
			if !ok {
				return
			}
			fmt.Fprintf(w, "data: %s\n\n", payload)
			flusher.Flush()
		case <-ticker.C:
			fmt.Fprintf(w, ": ping\n\n")
			flusher.Flush()
		}
	}
}