// Copyright (c) 2022 BitMaelum Authors
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of
// this software and associated documentation files (the "Software"), to deal in
// the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software is furnished to do so,
// subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

package auth

import (
	"context"
	"net/http"
	"strings"

	"github.com/bitmaelum/bitmaelum-suite/cmd/bm-server/internal/container"
	"github.com/bitmaelum/bitmaelum-suite/cmd/bm-server/middleware"
	"github.com/bitmaelum/bitmaelum-suite/internal/api"
	"github.com/bitmaelum/bitmaelum-suite/internal/key"
	"github.com/bitmaelum/bitmaelum-suite/pkg/hash"
	"github.com/gorilla/mux"
	"github.com/sirupsen/logrus"
)

// OnBehalfJwtAuth is a middleware that automatically verifies given JWT token
type OnBehalfJwtAuth struct{}

// Authenticate will check if an API key matches the request
func (mw *OnBehalfJwtAuth) Authenticate(req *http.Request, _ string) (middleware.AuthStatus, context.Context, error) {
	// Check if the address actually exists
	haddr, err := hash.NewFromHash(mux.Vars(req)["addr"])
	if err != nil {
		return middleware.AuthStatusPass, nil, err
	}

	accountRepo := container.Instance.GetAccountRepo()
	if !accountRepo.Exists(*haddr) {
		logrus.Trace("auth: address not found")
		return middleware.AuthStatusPass, nil, nil
	}

	// Check token
	k, err := checkOnBehalfToken(req.Header.Get("Authorization"), *haddr)
	if err != nil {
		if err == api.ErrTokenTimeNotValid {
			logrus.Trace("auth: invalid time for token: ", err)
			return middleware.AuthStatusFailure, nil, err
		}

		logrus.Trace("auth: incorrect token: ", err)
		return middleware.AuthStatusPass, nil, nil
	}

	ctx := req.Context()
	ctx = context.WithValue(ctx, middleware.AuthKeyContext, k)
	ctx = context.WithValue(ctx, middleware.AddressContext, haddr.String())

	return middleware.AuthStatusSuccess, ctx, nil
}

// Check if the authorization contains a valid JWT token for the given address
func checkOnBehalfToken(bearerToken string, addr hash.Hash) (*key.AuthKeyType, error) {
	if bearerToken == "" {
		logrus.Trace("auth: empty auth string")
		return nil, api.ErrTokenNotValid
	}

	if len(bearerToken) <= 6 || strings.ToUpper(bearerToken[0:7]) != "BEARER " {
		logrus.Trace("auth: bearer not found")
		return nil, api.ErrTokenNotValid
	}
	tokenString := bearerToken[7:]

	authRepo := container.Instance.GetAuthKeyRepo()
	keys, err := authRepo.FetchByHash(addr.String())
	if err != nil {
		logrus.Trace("auth: cannot fetch keys: ", err)
		return nil, api.ErrTokenNotValid
	}

	for _, k := range keys {
		_, err := api.ValidateJWTToken(tokenString, addr, *k.PublicKey)
		if err != nil {
			continue
		}

		// If the token is not valid in time, we can fail directly
		if err == api.ErrTokenTimeNotValid {
			logrus.Trace("auth: time not valid")
			return nil, err
		}

		// All is good
		return &k, nil
	}

	logrus.Trace("auth: no key found that validates the token")
	return nil, api.ErrTokenNotValid
}
