package hub

import (
	"errors"
	"log"
	"net/http"
	"vppn/hub/api"
	"vppn/hub/errs"

	"git.crumpington.com/lib/webutil"
)

type handlerFunc func(s *api.Session, w http.ResponseWriter, r *http.Request) error

func (app *App) handlePub(pattern string, fn handlerFunc) {
	wrapped := func(w http.ResponseWriter, r *http.Request) {
		sessionID := app.getCookie(r, sessionIDCookieName)
		s := app.api.Session_Get(sessionID)

		if r.Method == http.MethodPost {
			r.Body = http.MaxBytesReader(w, r.Body, 128*1024)
			r.ParseMultipartForm(64 * 1024)
		} else {
			r.ParseForm()
		}

		if err := fn(&s, w, r); err != nil {
			handleError(w, err)
		}
	}

	app.mux.HandleFunc(pattern, wrapped)
}

func (app *App) handleNotSignedIn(pattern string, fn handlerFunc) {
	app.handlePub(pattern, func(s *api.Session, w http.ResponseWriter, r *http.Request) error {
		if s.SessionID != "" {
			http.Redirect(w, r, "/", http.StatusSeeOther)
			return nil
		}
		return fn(s, w, r)
	})
}

func (app *App) handleSignedIn(pattern string, fn handlerFunc) {
	app.handlePub(pattern, func(s *api.Session, w http.ResponseWriter, r *http.Request) error {
		if s.SessionID == "" {
			http.Redirect(w, r, "/", http.StatusSeeOther)
			return nil
		}
		return fn(s, w, r)
	})
}

type peerHandlerFunc func(p *api.Peer, w http.ResponseWriter, r *http.Request) error

func (app *App) handlePeer(pattern string, fn peerHandlerFunc) {
	wrapped := func(w http.ResponseWriter, r *http.Request) {
		_, apiKey, ok := r.BasicAuth()
		if !ok {
			http.Error(w, "Not authorized", http.StatusUnauthorized)
			return
		}

		// Not doing constant time compare because index lookup time dominates.
		peer, err := app.api.Peer_GetByAPIKey(apiKey)
		if err != nil {
			http.Error(w, "Not authorized", http.StatusUnauthorized)
			return
		}

		r.ParseForm()
		if err := fn(peer, w, r); err != nil {
			handleError(w, err)
		}
	}

	app.mux.HandleFunc(pattern,
		webutil.WithLogging(
			wrapped))
}

func handleError(w http.ResponseWriter, err error) {
	var e *errs.Error
	if errors.As(err, &e) {
		http.Error(w, e.Msg, e.Code)
	} else {
		log.Printf("Unexpected error: %v", err)
		http.Error(w, "Internal server error.", http.StatusInternalServerError)
	}
}