package middleware

import (
	"context"
	"fmt"
	"github.com/google/uuid"
	"github.com/pkg/errors"
	"github.com/sirupsen/logrus"
	"go-micro.dev/v4"
	"go-micro.dev/v4/auth"
	"go-micro.dev/v4/metadata"
	"go-micro.dev/v4/server"
	"sghgogs.com/sghblog/authorization-service/utils/authutil"
	"sghgogs.com/sghblog/common"
	"sghgogs.com/sghblog/common/errorcode"
	"sort"
	"strings"
)

const (
	// BearerScheme used for Authorization header.
	BearerScheme = "Bearer "
	// ScopePublic is the scope applied to a rule to allow access to the public.
	ScopePublic = ""
	// ScopeAccount is the scope applied to a rule to limit to users with any valid account.
	ScopeAccount = "*"
	name         = "authorizationservice"
)

var (
	// ErrInvalidToken is when the token provided is not valid.
	ErrInvalidToken = errors.New("invalid token provided")
	// ErrForbidden is when a user does not have the necessary scope to access a resource.
	ErrForbidden = errors.New("resource forbidden")
)

// type Access int

const (
	// AccessGranted to a resource.
	AccessGranted auth.Access = iota
	// AccessDenied to a resource.
	AccessDenied
)

func Verify(rules []*auth.Rule, acc *auth.Account, res *auth.Resource) error {
	// the rule is only to be applied if the type matches the resource or is catch-all (*)
	validTypes := []string{"*", res.Type}

	// the rule is only to be applied if the name matches the resource or is catch-all (*)
	validNames := []string{"*", res.Name}
	// rules can have wildcard excludes on endpoints since this can also be a path for web services,
	// e.g. /foo/* would include /foo/bar. We also want to check for wildcards and the exact endpoint
	validEndpoints := []string{"*", res.Endpoint}
	if comps := strings.Split(res.Endpoint, "/"); len(comps) > 1 {
		for i := 1; i < len(comps)+1; i++ {
			wildcard := fmt.Sprintf("%v/*", strings.Join(comps[0:i], "/"))
			validEndpoints = append(validEndpoints, wildcard)
		}
	}

	// filter the rules to the ones which match the criteria above
	filteredRules := make([]*auth.Rule, 0)
	for _, rule := range rules {
		if !include(validTypes, rule.Resource.Type) {
			continue
		}
		if !include(validNames, rule.Resource.Name) {
			continue
		}
		if !include(validEndpoints, rule.Resource.Endpoint) {
			continue
		}
		filteredRules = append(filteredRules, rule)
	}

	// sort the filtered rules by priority, highest to lowest
	sort.SliceStable(filteredRules, func(i, j int) bool {
		return filteredRules[i].Priority > filteredRules[j].Priority
	})
	// loop through the rules and check for a rule which applies to this account
	for _, rule := range filteredRules {
		// a blank scope indicates the rule applies to everyone, even nil accounts
		if rule.Scope == ScopePublic && rule.Access == AccessDenied {
			return ErrForbidden
		} else if rule.Scope == ScopePublic && rule.Access == AccessGranted {
			return nil
		}

		// all further checks require an account
		if acc == nil {
			continue
		}
		// this rule applies to any account
		if rule.Scope == ScopeAccount && rule.Access == AccessDenied {
			return ErrForbidden
		} else if rule.Scope == ScopeAccount && rule.Access == AccessGranted {
			return nil
		}
		// 去掉首尾的方括号
		// if the account has the necessary scope
		if include(acc.Scopes, rule.Scope) && rule.Access == AccessDenied {
			return ErrForbidden
		} else if include(acc.Scopes, rule.Scope) && rule.Access == AccessGranted {
			return nil
		}
	}

	// if no rules matched then return forbidden
	return ErrForbidden
}

// include is a helper function which checks to see if the slice contains the value. includes is
// not case sensitive.
func include(slice []string, val string) bool {
	// str := slice
	if len(slice) > 0 {
		if strings.Contains(slice[0], ",") {
			data := strings.Split(slice[0], ",")
			// 打印结果
			for _, s := range data {
				if s == "super_admin" {
					return true
				}
				if strings.EqualFold(s, val) {
					return true
				}
			}
			// 判断超级管理员
		} else {
			// 判断超级管理员
			for _, s := range slice {
				if s == "super_admin" {
					return true
				}
				if strings.EqualFold(s, val) {
					return true
				}
			}
		}
		return false
	}
	return false
}

var (
	catchallResource = &auth.Resource{
		Type:     "*",
		Name:     "*",
		Endpoint: "*",
	}

	adminLogout = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "CommonService.AdminLogout",
	}
	adminProfile = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "CommonService.AdminProfile",
	}
	listAdminRoles = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "AdminRoleService.ListAdminRoles",
	}
	updateAdminRole = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "AdminRoleService.UpdateAdminRole",
	}
	createAdminRole = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "AdminRoleService.CreateAdminRole",
	}
	deleteAdminRole = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "AdminRoleService.DeleteAdminRole",
	}
	getAdminRole = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "AdminRoleService.GetAdminRole",
	}
	toggleAdminRole = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "AdminRoleService.ToggleAdminRole",
	}
	retrieveEnabledRoles = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "AdminRoleService.RetrieveEnabledRoles",
	}

	getUnassignedAdminRoles = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "AdminUserService.GetUnassignedAdminRoles",
	}
	getAdminUser = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "AdminUserService.GetAdminUser",
	}
	createAdminUser = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "AdminUserService.CreateAdminUser",
	}
	associateAdminUserWithRole = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "AdminUserService.AssociateAdminUserWithRole",
	}
	updateAdminUser = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "AdminUserService.UpdateAdminUser",
	}
	revokeAdminUserWithRole = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "AdminUserService.RevokeAdminUserWithRole",
	}
	listAdminUsers = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "AdminUserService.ListAdminUsers",
	}
	retrieveEnabledUsers = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "AdminUserService.RetrieveEnabledUsers",
	}

	deleteAdminUser = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "AdminUserService.DeleteAdminUser",
	}
	toggleAdminUser = &auth.Resource{
		Type:     "user",
		Name:     name,
		Endpoint: "AdminUserService.ToggleAdminUser",
	}
	// catchallResource
	rulesItems = []*auth.Rule{
		// {Scope: "*", Resource: catchallResource}, toggleAdminRole
		{Scope: "admin", Resource: adminLogout, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: adminProfile, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: listAdminRoles, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: updateAdminRole, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: createAdminRole, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: toggleAdminRole, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: getUnassignedAdminRoles, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: deleteAdminRole, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: getAdminRole, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: retrieveEnabledRoles, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: getAdminUser, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: createAdminUser, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: associateAdminUserWithRole, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: updateAdminUser, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: revokeAdminUserWithRole, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: listAdminUsers, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: retrieveEnabledUsers, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: deleteAdminUser, ID: uuid.New().String(), Priority: 1},
		{Scope: "admin", Resource: toggleAdminUser, ID: uuid.New().String(), Priority: 1},
	}
)

func NewAuthWrapper(service micro.Service) server.HandlerWrapper {
	return func(h server.HandlerFunc) server.HandlerFunc {
		return func(ctx context.Context, req server.Request, rsp interface{}) error {
			logrus.Infof("[wrapper] server request: %v", req.Endpoint())
			if req.Endpoint() == "CommonService.AdminLogin" {
				return h(ctx, req, rsp)
			}
			if req.Endpoint() == "AdminUserService.GetAdminUserAssociatedRoles" {
				return h(ctx, req, rsp)
			}
			// Fetch metadata from context (request headers).
			md, b := metadata.FromContext(ctx)
			if !b {
				return errorcode.Unauthorized("authorization service", common.ErrorMessage[common.UnauthorizedErrorCode])
				// errors.New("no metadata found")
			}

			// local ip of service
			fmt.Println("local ip is", md["Local"])

			// remote ip of caller
			fmt.Println("remote ip is", md["Remote"])

			// Get auth header.
			authHeader, ok := md["Authorization"]

			if !ok || !strings.HasPrefix(authHeader, auth.BearerScheme) {
				logrus.Error("no auth token provided")
				return errorcode.Unauthorized("authorization service", common.ErrorMessage[common.UnauthorizedErrorCode])
			}

			// Extract auth token.
			token := strings.TrimPrefix(authHeader, auth.BearerScheme)

			// Extract account from token.
			token = strings.TrimSpace(token)
			a := service.Options().Auth
			acc, err := a.Inspect(token)
			fmt.Println("acc", acc)
			if err != nil {
				return errorcode.Unauthorized("authorization service", common.ErrorMessage[common.TokenInvalidErrorCode])
			}

			// 校验redis 存储数据
			blacklisted, err := authutil.JWTAuthService.IsBlacklisted(token)
			if err == nil && blacklisted {
				return errorcode.Unauthorized("authorization service", common.ErrorMessage[common.ExpiredLonInAgainErrorCode])
			}

			// Create resource for current endpoint from request headers.
			currentResource := auth.Resource{
				Type:     "user",
				Name:     md["Micro-Service"],
				Endpoint: md["Micro-Endpoint"],
			}

			// Verify if account has access. 验证帐户是否具有访问权限。
			if err = Verify(rulesItems, acc, &currentResource); err != nil {
				return errorcode.Unauthorized("authorization service", common.ErrorMessage[common.NoAccessErrorCode])
			}
			// 验证通过后记录操作日志
			logrus.Infof("User %s is performing operation %s body %v", acc.ID, req.Endpoint(), req.Body())
			return h(ctx, req, rsp)
		}
	}
}