package httpserver

// HubOptions 是节点内 Worker/Event WebSocket Hub 的有界运行参数。
// 这些参数只控制本节点内存和领取并发，不改变 MySQL 中的授权、租约或配额事实。
type HubOptions struct {
	// ConnectionLimit 是该 Hub 允许的同时连接数；超过后返回 429。
	ConnectionLimit int
	// DispatchWorkers 是本 Hub 同时执行数据库领取调用的 Go 协程上限。
	DispatchWorkers int
	// DispatchCapacity 是领取调用的有界内存排队槽位；满额时连接等待下一轮扫描。
	DispatchCapacity int
}

const (
	defaultHubConnectionLimit  = 128
	defaultHubDispatchWorkers  = 4
	defaultHubDispatchCapacity = 128
	maxHubConnectionLimit      = 4096
	maxHubDispatchWorkers      = 256
	maxHubDispatchCapacity     = 65536
)

func resolveHubOptions(options []HubOptions) HubOptions {
	out := HubOptions{
		ConnectionLimit:  defaultHubConnectionLimit,
		DispatchWorkers:  defaultHubDispatchWorkers,
		DispatchCapacity: defaultHubDispatchCapacity,
	}
	if len(options) > 1 {
		panic("at most one HubOptions value is allowed")
	}
	if len(options) == 1 {
		in := options[0]
		if in.ConnectionLimit != 0 {
			out.ConnectionLimit = in.ConnectionLimit
		}
		if in.DispatchWorkers != 0 {
			out.DispatchWorkers = in.DispatchWorkers
		}
		if in.DispatchCapacity != 0 {
			out.DispatchCapacity = in.DispatchCapacity
		}
	}
	if out.ConnectionLimit < 1 || out.ConnectionLimit > maxHubConnectionLimit || out.DispatchWorkers < 1 || out.DispatchWorkers > maxHubDispatchWorkers || out.DispatchCapacity < 1 || out.DispatchCapacity > maxHubDispatchCapacity {
		panic("HubOptions values exceed bounded range")
	}
	return out
}