package service

import (
	"errors"
	"fmt"

	casbin "github.com/casbin/casbin/v2"
	"github.com/casbin/casbin/v2/model"
	gormadapter "github.com/casbin/gorm-adapter/v3"
	"gorm.io/gorm"
)

type (
	Auth struct {
		enforcer *casbin.Enforcer
	}
	// Permission 权限信息
	Permission struct {
		request []*AuthRequest // 请求信息
		tenant  string         // 租户信息
		roles   []string       // 角色信息
		user    string         // 用户唯一表示
	}
	// AuthRequest 请求验证
	AuthRequest struct {
		Url    string
		Method string
	}
	IdentityPermission func(tenant, user string) *Permission

	PermissionOptions func(permission *Permission)
)

var auth *Auth

// adapter 规则
var adapter = map[string]func(params ...interface{}) interface{}{
	"mysql": adapterForOrm, "sqlite": adapterForOrm,
}

// adapterForOrm 规则引擎
func adapterForOrm(params ...interface{}) interface{} {
	db := params[0].(*gorm.DB)
	obj := params[1].(string)
	adapter, _ := gormadapter.NewAdapterByDBUseTableName(db, "", obj)
	return adapter
}

func WithAuthRequest(request []*AuthRequest) PermissionOptions {
	return func(permission *Permission) {
		permission.request = request
	}
}

func WithAuthTenant(tenant string) PermissionOptions {
	return func(permission *Permission) {
		permission.tenant = tenant
	}
}

func WithAuthRoles(roles []string) PermissionOptions {
	return func(permission *Permission) {
		permission.roles = roles
	}
}

func WithAuthUser(user string) PermissionOptions {
	return func(permission *Permission) {
		permission.user = user
	}
}

// Register 注册权限
// 多平台 admin tenant1, data1, read （角色-域-用户-事件）
// p admin tenant1, data1, read （角色-域-用户-事件）
// g alice, admin, tenant1 (用户-角色-域)
func (this *Auth) Register() func(mode string, params ...interface{}) interface{} {
	return func(mode string, params ...interface{}) interface{} {
		m := model.NewModel()
		m.AddDef("r", "r", "sub, dom, obj, act")
		m.AddDef("p", "p", "sub, dom, obj, act")
		m.AddDef("g", "g", "_, _, _")
		m.AddDef("e", "e", "some(where (p.eft == allow))")
		m.AddDef("m", "m", "g(r.sub, p.sub, r.dom) && r.dom == p.dom && r.obj == p.obj && r.act == p.act")

		a, has := adapter[mode]

		if has {
			this.enforcer, _ = casbin.NewEnforcer(m, a(params...))
			this.enforcer.EnableAutoSave(true)
		} else {
			this.enforcer, _ = casbin.NewEnforcer(m)
		}
		auth = this

		return nil
	}
}

// tenantFormat 平台信息
func (this *Permission) tenantFormat() string {
	return fmt.Sprintf("%s%s", "t_", this.tenant)
}

// userFormat 用户信息
func (this *Permission) userFormat() string {
	return fmt.Sprintf("%s%s", "u_", this.user)
}

// roleFormat 角色信息
func (this *Permission) roleFormat() []string {
	roles := make([]string, 0)

	for _, v := range this.roles {
		roles = append(roles, fmt.Sprintf("%s%s", "r_", v))
	}
	return roles
}

// AddTenant 追加租户
func (this *Permission) AddTenant(tenant string) {
	this.tenant = tenant
}

// AddRole 追加角色
func (this *Permission) AddRole(roles []string) {
	this.roles = roles
}

// AddUser 追加用户
func (this *Permission) AddUser(user string) {
	this.user = user
}

// AddRoleForUser 增加用户角色
func (this *Permission) AddRoleForUser() (bool, error) {
	if len(this.roles) <= 0 {
		return false, errors.New("not role")
	}
	for _, role := range this.roleFormat() {
		if _, err := auth.enforcer.AddRoleForUser(this.userFormat(), role, this.tenantFormat()); err != nil {
			return false, err
		}
	}
	return true, nil
}

// DeleteRolesForUser 删除用户所有角色
func (this *Permission) DeleteRolesForUser(allTenant bool) (bool, error) {
	if allTenant {
		return auth.enforcer.DeleteRolesForUser(this.userFormat())
	}
	return auth.enforcer.DeleteRolesForUser(this.userFormat(), this.tenantFormat())
}

// AddPolicies TODO:增加多个规则
func (this *Permission) AddPolicies() (bool, error) {
	if len(this.request) <= 0 {
		return false, errors.New("not request")
	}
	rules := make([][]string, 0)

	for _, s := range this.request {
		rules = append(rules, []string{
			this.roleFormat()[0], this.tenantFormat(), s.Url, s.Method,
		})
	}
	return auth.enforcer.AddPolicies(rules)
}

// RemoveRolePolicies 删除角色指定规则
func (this *Permission) RemoveRolePolicies() (bool, error) {
	if len(this.roles) <= 0 {
		return false, errors.New("not role")
	}
	rules := make([][]string, 0)

	tenantFormat := this.tenantFormat()

	for _, v := range this.roleFormat() {

		for _, request := range this.request {
			rules = append(rules, []string{
				v, tenantFormat, request.Url, request.Method,
			})
		}
	}
	return auth.enforcer.RemovePolicies(rules)
}

// RemoveSingleRolePolicy 删除角色的所有规则
func (this *Permission) RemoveSingleRolePolicy() (bool, error) {
	if len(this.roles) <= 0 {
		return false, errors.New("not role")
	}
	return auth.enforcer.RemoveFilteredPolicy(0, this.roleFormat()[0], this.tenantFormat())
}

// RemoveNamedGroupingPolicies 删除租户下角色的权限
func (this *Permission) RemoveNamedGroupingPolicies() (bool, error) {
	rules := make([][]string, 0)

	for _, role := range this.roleFormat() {
		rule := make([]string, 0)
		for _, request := range this.request {
			rule = append(rule, role, this.tenantFormat(), request.Url, request.Method)
		}
		rules = append(rules, rule)
	}
	return auth.enforcer.RemoveNamedGroupingPolicies("g", rules)
}

// RemoveFilteredGroupingPolicy 删除组权限规则
func (this *Permission) RemoveFilteredGroupingPolicy() (bool, error) {
	return auth.enforcer.RemoveFilteredGroupingPolicy(0, this.tenantFormat())
}

// Enforce 检查访问权限
func (this *Permission) Enforce() (bool, error) {
	if len(this.request) <= 0 {
		return false, errors.New("not request")
	}
	return auth.enforcer.Enforce(this.userFormat(), this.tenantFormat(), this.request[0].Url, "*")
}

// NewAuth 创建验证
func NewAuth() *Auth {
	return &Auth{}
}

// NewPermission 创建权限
func NewPermission(options ...PermissionOptions) *Permission {
	out := new(Permission)

	for _, option := range options {
		option(out)
	}
	return out
}