package httpx

import "net/http"
import "strings"

type Params = map[string]string

type HandlerFunc func(http.ResponseWriter, *http.Request, Params)

type route struct {
	method  string
	pattern string
	handler HandlerFunc
}

type Router struct {
	routes []route
}

func NewRouter() *Router {
	return &Router{}
}

func (r *Router) Handle(method, pattern string, handler HandlerFunc) {
	var entry route
	entry.method = method
	entry.pattern = pattern
	entry.handler = handler
	r.routes = append(r.routes, entry)
}

func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	var i int
	var rt route
	var params Params
	var ok bool
	for i = 0; i < len(r.routes); i++ {
		rt = r.routes[i]
		if rt.method != req.Method {
			continue
		}
		params, ok = match(rt.pattern, req.URL.Path)
		if !ok {
			continue
		}
		rt.handler(w, req, params)
		return
	}
	w.WriteHeader(http.StatusNotFound)
}

func match(pattern, path string) (Params, bool) {
	var pParts []string
	var pathParts []string
	var params Params
	var i int
	var p string
	var seg string
	pParts = split(pattern)
	pathParts = split(path)
	if len(pParts) != len(pathParts) {
		return nil, false
	}
	params = Params{}
	for i = 0; i < len(pParts); i++ {
		p = pParts[i]
		seg = pathParts[i]
		if strings.HasPrefix(p, ":") {
			params[p[1:]] = seg
			continue
		}
		if p != seg {
			return nil, false
		}
	}
	return params, true
}

func split(path string) []string {
	path = strings.Trim(path, "/")
	if path == "" {
		return []string{}
	}
	return strings.Split(path, "/")
}