package core

type (
	Middleware func(next HandlerFunc) HandlerFunc

	Route struct {
		Matches interface{} // 用于匹配的关键字段
		Handler HandlerFunc // 处理方法
	}

	Router interface {
		Handler
		Register(matches interface{}, handler Handler) error
		SetNotFoundHandler(handler Handler)
	}

	Constructor func(Handler) Handler
)

type Chain struct {
	constructors []Constructor
}

func newChain(constructors ...Constructor) Chain {
	return Chain{append(([]Constructor)(nil), constructors...)}
}

func (c Chain) Then(h Handler) Handler {
	// TODO nil

	for i := range c.constructors {
		h = c.constructors[len(c.constructors)-1-i](h)
	}
	return h
}

func (c Chain) ThenFunc(fn HandlerFunc) Handler {
	if fn == nil {
		return c.Then(nil)
	}
	return c.Then(fn)
}

func (c Chain) Append(constructors ...Constructor) Chain {
	newCons := make([]Constructor, 0, len(c.constructors)+len(constructors))
	newCons = append(newCons, c.constructors...)
	newCons = append(newCons, constructors...)

	return Chain{newCons}
}

func (c Chain) Extend(chain Chain) Chain {
	return c.Append(chain.constructors...)
}