package router

import (
	"git.noahlan.cn/noahlan/nnet/connection"
	"git.noahlan.cn/noahlan/nnet/packet"
	"git.noahlan.cn/noahlan/ntool/nlog"
)

type (
	Handler interface {
		Handle(c *connection.Connection, pkg packet.IPacket)
	}
	// HandlerFunc 消息处理方法
	HandlerFunc func(conn *connection.Connection, pkg packet.IPacket)

	Middleware func(next HandlerFunc) HandlerFunc

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

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

	Constructor func(Handler) Handler
)

func notFound(conn *connection.Connection, _ packet.IPacket) {
	nlog.Error("handler not found")
	_ = conn.SendBytes([]byte("404"))
}

func NotFoundHandler(next Handler) Handler {
	return HandlerFunc(func(c *connection.Connection, packet packet.IPacket) {
		h := next
		if next == nil {
			h = HandlerFunc(notFound)
		}
		// TODO write to client
		h.Handle(c, packet)
	})
}

func (f HandlerFunc) Handle(c *connection.Connection, pkg packet.IPacket) {
	f(c, pkg)
}

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...)
}

type plainRouter struct {
	handler  Handler
	notFound Handler
}

func NewDefaultRouter() Router {
	return &plainRouter{}
}

func (p *plainRouter) Handle(c *connection.Connection, pkg packet.IPacket) {
	if p.handler == nil {
		return
	}
	p.handler.Handle(c, pkg)
}

func (p *plainRouter) Register(_ any, handler Handler) error {
	p.handler = handler
	return nil
}

func (p *plainRouter) SetNotFoundHandler(handler Handler) {
	p.notFound = handler
}