package tcp

import (
	"encoding/json"
	"io"
	"net"
	"strings"

	"go.uber.org/zap"
)

type Handler func(w ResponseWriter, req *Request) error
type Middleware func(next Handler) Handler

type Router struct {
	middlewares []Middleware
	routes      map[Method]map[string]Handler

	listenAddr string
	doneCh     chan error
}

func NewRouter() *Router {
	return &Router{
		routes: make(map[Method]map[string]Handler),
		doneCh: make(chan error),
	}
}

type Group struct {
	pRouter *Router
	pGroup  *Group

	path        string
	middlewares []Middleware
}

func (self *Router) Group(path string) *Group {
	return &Group{
		pRouter: self,
		pGroup:  nil,

		path: path,
	}
}

func (self *Group) Group(path string) *Group {
	return &Group{
		pRouter: nil,
		pGroup:  self,

		path: path,
	}
}

func (self *Router) Use(middleware Middleware) *Router {
	self.middlewares = append(self.middlewares, middleware)
	return self
}

func (self *Group) Use(middleware Middleware) *Group {
	self.middlewares = append(self.middlewares, middleware)
	return self
}

func (self *Router) Register(method Method, route string, handler Handler) {
	_, ok := self.routes[method]
	if !ok {
		self.routes[method] = make(map[string]Handler)
	}

	for _, middleware := range self.middlewares {
		handler = middleware(handler)
	}
	self.routes[method][route] = handler
}

func (self *Group) Register(method Method, route string, handler Handler) {
	for _, middleware := range self.middlewares {
		handler = middleware(handler)
	}

	if self.pRouter != nil {
		self.pRouter.Register(method, self.path+route, handler)
	}
	if self.pGroup != nil {
		self.pGroup.Register(method, self.path+route, handler)
	}
}

func (self *Router) GET(route string, handler Handler) {
	self.Register(MethodGET, route, handler)
}

func (self *Group) GET(route string, handler Handler) {
	self.Register(MethodGET, route, handler)
}

func (self *Router) POST(route string, handler Handler) {
	self.Register(MethodPOST, route, handler)
}

func (self *Group) POST(route string, handler Handler) {
	self.Register(MethodPOST, route, handler)
}

func (self *Router) PUT(route string, handler Handler) {
	self.Register(MethodPUT, route, handler)
}

func (self *Group) PUT(route string, handler Handler) {
	self.Register(MethodPUT, route, handler)
}

func (self *Router) DELETE(route string, handler Handler) {
	self.Register(MethodDELETE, route, handler)
}

func (self *Group) DELETE(route string, handler Handler) {
	self.Register(MethodDELETE, route, handler)
}

func (self *Router) SOCKET(route string, handler Handler) {
	self.Register(MethodSOCKET, route, handler)
}

func (self *Group) SOCKET(route string, handler Handler) {
	self.Register(MethodSOCKET, route, handler)
}

func (self *Router) run(conn net.Conn, req *Request) {
	handler, ok := self.routes[req.Method][req.Route]
	if !ok {
		zap.L().Warn("route not exist",
			zap.String("route", req.Route))
		return
	}

	w := NewResponseBuilder(conn)
	err := handler(w, req)
	if err != nil {
		zap.L().Error("failed to run handler",
			zap.Error(err))
		return
	}

	res := w.Build(req)
	header, err := res.Header()
	if err != nil {
		zap.L().Error("failed to marshal header",
			zap.Error(err))
		return
	}
	if err := sendFrame(conn, header); err != nil {
		zap.L().Error("failed to write header",
			zap.Error(err))
		return
	}
	if err := sendFrame(conn, res.Body); err != nil {
		zap.L().Error("failed to write body",
			zap.Error(err))
		return
	}
}

func (self *Router) listen(listener net.Listener) {
	defer listener.Close()
	for {
		conn, err := listener.Accept()
		if err != nil {
			self.doneCh <- err
			return
		}

		rawHeader, err := readFrame(conn)
		if err != nil {
			if err == io.EOF {
				self.doneCh <- nil
				return
			}
			self.doneCh <- err
			return
		}

		body, err := readFrame(conn)
		if err != nil {
			if err == io.EOF {
				self.doneCh <- nil
				return
			}
			self.doneCh <- err
			return
		}

		var header RequestHeader
		if err := json.Unmarshal(rawHeader, &header); err != nil {
			self.doneCh <- err
			return
		}
		req := NewRequest(conn, header, body)
		go self.run(conn, req)
	}
}

func (self *Router) WaitFor() error {
	return <-self.doneCh
}

func (self *Router) ListenAddr() string {
	conn, _ := net.Dial("udp", "8.8.8.8:80")
	addr := conn.LocalAddr().(*net.UDPAddr).IP.String()
	conn.Close()
	ss2 := strings.Split(self.listenAddr, ":")
	return addr + ":" + ss2[len(ss2)-1]
}

func (self *Router) Listen(addr string) error {
	listener, err := net.Listen("tcp", addr)
	if err != nil {
		return err
	}

	self.listenAddr = listener.Addr().String()
	go self.listen(listener)
	return nil
}