package mycasbin

import (
	"errors"
	"fmt"
	"github.com/casbin/casbin/v2"
	"github.com/casbin/casbin/v2/model"
	"github.com/casbin/casbin/v2/util"
	"gorm.io/gorm"
	"net/http"
)

// Model语法 https://casbin.org/docs/zh-CN/syntax-for-models
// sub, obj, act 表示经典三元组: 访问实体 (Subject)，访问资源 (Object) 和访问方法 (Action)。
// sub:希望访问资源的用户
// dom:域/域租户 https://casbin.org/docs/zh-CN/rbac-with-domains
// obj:要访问的资源
// act:用户对资源执行的操作
var text = `
[request_definition]
r = sub, dom, obj, act

[policy_definition]
p = sub, dom, obj, act

[role_definition]
g = _, _, _

[policy_effect]
e = some(where (p.eft == allow))

[matchers]
m = g(r.sub, p.sub, r.dom) && r.dom == p.dom && (keyMatch2(r.obj, p.obj) || keyMatch(r.obj, p.obj)) && r.act == p.act || r.sub == "role:admin"
`
// m = g(r.sub, p.sub, r.dom) && MyDomKeyMatch2(r.obj, p.obj, r.dom, p.dom) && MyRegexMatch(r.act, p.act, r.dom, p.dom) || r.sub == "role:admin")

//m = r.sub == p.sub && (keyMatch2(r.obj, p.obj) || keyMatch(r.obj, p.obj)) && (r.act == p.act || p.act == "*")

func Setup(db *gorm.DB) *casbin.SyncedEnforcer {
	Apter, err := NewAdapterByDB(db)
	if err != nil {
		panic(err)
	}
	m, err := model.NewModelFromString(text)
	if err != nil {
		panic(err)
	}
	e, err := casbin.NewSyncedEnforcer(m, Apter)
	if err != nil {
		panic(err)
	}
	err = e.LoadPolicy()
	if err != nil {
		panic(err)
	}
	//e.StartAutoLoadPolicy(time.Minute)

	//e.AddFunction("MyDomKeyMatch2", MyDomKeyMatch2Func)
	//e.AddFunction("MyRegexMatch", MyRegexMatchFunc)

	e.EnableLog(true)
	return e
}

// validate the variadic parameter size and type as string
func validateVariadicArgs(expectedLen int, args ...interface{}) error {
	if len(args) != expectedLen {
		return fmt.Errorf("Expected %d arguments, but got %d", expectedLen, len(args))
	}

	for _, p := range args {
		_, ok := p.(string)
		if !ok {
			return errors.New("Argument must be a string")
		}
	}

	return nil
}

// MyDomKeyMatch2Func 定义域KeyMatch2
func MyDomKeyMatch2Func(args ...interface{}) (interface{}, error) {
	if err := validateVariadicArgs(4, args...); err != nil {
		return false,fmt.Errorf("%s: %s", "keyMatch2", err)
	}
	name1 := args[0].(string)
	name2 := args[1].(string)
	dom1 := args[2].(string)
	dom2 := args[3].(string)
	return (bool)(dom1 == dom2 && util.KeyMatch2(name1, name2)),nil
}

// MyRegexMatchFunc 定义域RegexMatch
func MyRegexMatchFunc(args ...interface{}) (interface{}, error) {
	if err := validateVariadicArgs(4, args...); err != nil {
		return false, fmt.Errorf("%s: %s", "RegexMatch", err)
	}
	name1 := args[0].(string)
	name2 := args[1].(string)
	dom1 := args[2].(string)
	dom2 := args[3].(string)
	return (bool)(dom1 == dom2 && util.RegexMatch(name1, name2)),nil
}

// EnforceRoute 验证web路由
func EnforceRoute(roleKey, serviceID string, req *http.Request, enforcer casbin.IEnforcer) (bool, error) {
	sub := fmt.Sprintf("role:%s", roleKey)          // 希望访问资源的用户
	dom := fmt.Sprintf("service:%s:api", serviceID) // 域/域租户,这里以资源为单位
	obj := req.URL.Path                             // 要访问的资源
	act := req.Method                               // 用户对资源执行的操作
	return enforcer.Enforce(sub, dom, obj, act)
}

// EnforceRouteForScopeCode 验证web路由
func EnforceRouteForScopeCode(roleKey, serviceID string, req *http.Request, enforcer casbin.IEnforcer) (bool, error) {
	sub := fmt.Sprintf("scope:%s", roleKey)         // 希望访问资源的用户
	dom := fmt.Sprintf("service:%s:api", serviceID) // 域/域租户,这里以资源为单位
	obj := req.URL.Path                             // 要访问的资源
	act := req.Method                               // 用户对资源执行的操作
	return enforcer.Enforce(sub, dom, obj, act)
}