package handlers

import (
	"sync"
	"time"
)

// uploadGroupWindow is how long after a batched upload a follow-up upload with
// the same X-Warpbox-Batch value (and same account/IP) is folded into the same
// box. ShareX sends a multi-file selection as separate back-to-back requests;
// the batch header lets it land them in one box.
const uploadGroupWindow = 20 * time.Second

// uploadBatchHeader is the opt-in request header. Without it, uploads behave
// exactly as before (one box per request). With it, requests sharing the same
// value (per account/IP) within uploadGroupWindow are grouped into one box.
const uploadBatchHeader = "X-Warpbox-Batch"

// uploadGrouper tracks the most recent box per batch key so opt-in batched
// uploads land in a single box. Each key has its own lock, which also serialises
// that key's concurrent uploads so they append to the same box instead of racing
// to create several.
type uploadGrouper struct {
	mu      sync.Mutex
	entries map[string]*uploadGroupEntry
}

type uploadGroupEntry struct {
	mu        sync.Mutex
	boxID     string
	manageURL string
	deleteURL string
	at        time.Time
}

func newUploadGrouper() *uploadGrouper {
	return &uploadGrouper{entries: make(map[string]*uploadGroupEntry)}
}

func (g *uploadGrouper) entryFor(key string) *uploadGroupEntry {
	g.mu.Lock()
	defer g.mu.Unlock()
	entry, ok := g.entries[key]
	if !ok {
		entry = &uploadGroupEntry{}
		g.entries[key] = entry
	}
	return entry
}