package redirection

import (
	"errors"
	"net/http"
	"strings"
)

/*
	handler.go

	This script store the handlers use for handling
	redirection request
*/

// Check if a request URL is a redirectable URI
func (t *RuleTable) IsRedirectable(r *http.Request) bool {
	requestPath := r.Host + r.URL.Path
	rr := t.MatchRedirectRule(requestPath)
	return rr != nil
}

// Handle the redirect request, return after calling this function to prevent
// multiple write to the response writer
// Return the status code of the redirection handling
func (t *RuleTable) HandleRedirect(w http.ResponseWriter, r *http.Request) int {
	requestPath := r.Host + r.URL.Path
	rr := t.MatchRedirectRule(requestPath)
	if rr != nil {
		redirectTarget := rr.TargetURL

		if rr.ForwardChildpath {
			//Remove the first / in the path if the redirect target already have tailing slash
			if strings.HasSuffix(redirectTarget, "/") {
				redirectTarget += strings.TrimPrefix(r.URL.Path, "/")
			} else {
				redirectTarget += r.URL.Path
			}

			if r.URL.RawQuery != "" {
				redirectTarget += "?" + r.URL.RawQuery
			}
		}

		if !strings.HasPrefix(redirectTarget, "http://") && !strings.HasPrefix(redirectTarget, "https://") {
			redirectTarget = "http://" + redirectTarget
		}

		http.Redirect(w, r, redirectTarget, rr.StatusCode)
		return rr.StatusCode
	} else {
		//Invalid usage
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte("500 - Internal Server Error"))
		t.log("Target request URL do not have matching redirect rule. Check with IsRedirectable before calling HandleRedirect!", errors.New("invalid usage"))
		return 500
	}
}