package core

import (
	"fmt"
	"html/template"
	"io/ioutil"
	"net/http"
	"os"
	"regexp"
)

const (
	defaultLruSize = int64(1024 * 1024 * 50)
)

type ErrorResponse struct {
	Code    int
	Message string
}

type (
	Servlet struct {
		Port   string
		Routes []*ServletRoute
		Cache  *Lru
	}

	ServletRoute struct {
		Pattern *regexp.Regexp
		Handler ServletHandleFunction
	}

	ServletHandleFunction func(w http.ResponseWriter, req *http.Request)
)

func NewServlet(port string) *Servlet {
	lru := NewLRU(defaultLruSize)
	srv := Servlet{Port: port, Cache: lru}

	return &srv
}

func NewServletRoute(routePattern string, handleFunc ServletHandleFunction) *ServletRoute {
	route := ServletRoute{}

	pattern := regexp.MustCompile(routePattern)

	route.Pattern = pattern
	route.Handler = handleFunc

	return &route
}

func (s *Servlet) AddRoute(route *ServletRoute) {
	s.Routes = append(s.Routes, route)
}

func (s *Servlet) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	path := req.URL.Path
	fmt.Println("Attempting to match request for " + path)
	for _, route := range s.Routes {
		if route.Pattern.MatchString(path) {
			route.Handler(w, req)
			return
		}
	}
}

func StartServerGood(s *Servlet) {
	err := http.ListenAndServe(s.Port, s)

	if err != nil {
		panic(err)
	}

}

func SendError(w http.ResponseWriter, code int, msg string) {
	errorFile := "templates/error.html"
	errorResp := ErrorResponse{code, msg}
	tmplManager := template.New("error")

	f, err := os.OpenFile(errorFile, os.O_RDONLY, 0777)
	if err != nil {
		panic(err)
	}
	defer f.Close()

	content, err := ioutil.ReadAll(f)
	if err != nil {
		panic(err)
	}

	tmpl, err := tmplManager.Parse(string(content))
	if err != nil {
		panic(err)
	}

	w.WriteHeader(code)
	err = tmpl.Execute(w, errorResp)
	if err != nil {
		panic(err)
	}
}

func renderTemplate(w http.ResponseWriter, pathlike string, data any) {
	templateHelper := template.New(pathlike)
	f, err := os.OpenFile(pathlike, os.O_RDONLY, 0777)
	if err != nil {
		panic(err)
	}
	defer f.Close()

	content, err := ioutil.ReadAll(f)
	if err != nil {
		panic(err)
	}

	templ, err := templateHelper.Parse(string(content))
	err = templ.Execute(w, data)
	if err != nil {
		panic(err)
	}

}