engine.go

//
// Copyright 2023 Bytedance Ltd. and/or its affiliates
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package dddfirework

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"reflect"
	"sort"
	"strings"

	"github.com/go-logr/logr"
	"github.com/rs/xid"

	"github.com/bytedance/dddfirework/logger/stdr"
)

var (
	ErrBreak          = fmt.Errorf("break process") // 中断流程，不返回错误
	ErrEntityNotFound = fmt.Errorf("entity not found")
	ErrEntityRepeated = fmt.Errorf("entity already added")
	ErrEntityLocked   = fmt.Errorf("entity had been locked")
)

var defaultLogger = stdr.NewStdr("ddd_engine")

type ILock interface {
	Lock(ctx context.Context, key string) (keyLock interface{}, err error)
	UnLock(ctx context.Context, keyLock interface{}) error
}

type IIDGenerator interface {
	NewID() (string, error)
}

type defaultIDGenerator struct {
}

func (d *defaultIDGenerator) NewID() (string, error) {
	guid := xid.New()
	return guid.String(), nil
}

// EntityContainer 负责维护领域内所有聚合根实体的实体
type EntityContainer struct {
	BaseEntity

	roots   []IEntity // 保存聚合根实体
	deleted []IEntity // 保存所有被删除实体
}

func (w *EntityContainer) GetChildren() map[string][]IEntity {
	return map[string][]IEntity{"meta": w.roots}
}

func (w *EntityContainer) Has(root IEntity) bool {
	for _, r := range w.roots {
		if r == root {
			return true
		}
	}
	return false
}

func (w *EntityContainer) GetDeleted() []IEntity {
	return w.deleted
}

func (w *EntityContainer) SetChildren(roots []IEntity) {
	// EntityContainer 里面会有修改 roots 的操作，应当拷贝一个新的 slice，隔离输入的影响
	w.roots = make([]IEntity, len(roots))
	copy(w.roots, roots)
}

func (w *EntityContainer) Add(root IEntity) error {
	for _, e := range w.roots {
		if e == root {
			return ErrEntityRepeated
		}
	}

	w.roots = append(w.roots, root)
	return nil
}

func (w *EntityContainer) Remove(root IEntity) error {
	i := 0
	for _, item := range w.roots {
		if item != root {
			w.roots[i] = item
			i++
		}
	}
	if i == len(w.roots) {
		return ErrEntityNotFound
	}
	w.roots = w.roots[:i]
	w.deleted = append(w.deleted, root)
	return nil
}

// Recycle 回收所有被删除的实体
func (w *EntityContainer) Recycle(e IEntity) {
	w.deleted = append(w.deleted, e)
}

type ErrList []error

func (e ErrList) Error() string {
	errs := make([]string, 0)
	for _, err := range e {
		errs = append(errs, err.Error())
	}
	return strings.Join(errs, ", ")
}

type Result struct {
	Error   error
	Break   bool
	Actions []*Action
	Output  interface{}
}

func ResultErrors(err ...error) *Result {
	return &Result{Error: ErrList(err)}
}

func ResultError(err error) *Result {
	return &Result{Error: err}
}

func ResultErrOrBreak(err error) *Result {
	if errors.Is(err, ErrBreak) {
		return &Result{Break: true}
	}
	return ResultError(err)
}

type DomainBuilder struct {
	stage *Stage
}

// Build 查询并构建 parent 以及 children 实体
// parent 必须指定 id，children 为可选，需要是 *IEntity 或者 *[]IEntity 类型
func (h DomainBuilder) Build(ctx context.Context, parent IEntity, children ...interface{}) error {
	return h.stage.BuildEntity(ctx, parent, children...)
}

// RootContainer 聚合根实体容器
type RootContainer struct {
	stage *Stage
	errs  []error
}

// Add 创建聚合根实体
func (h *RootContainer) Add(root IEntity) {
	if err := h.stage.meta.Add(root); err != nil {
		h.errs = append(h.errs, err)
	}
}

// Remove 删除聚合根实体
func (h *RootContainer) Remove(root IEntity) {
	if err := h.stage.meta.Remove(root); err != nil {
		h.errs = append(h.errs, err)
	}
}

// Repository 聚合根实体仓库
type Repository struct {
	stage *Stage
	errs  []error
}

func (r *Repository) appendError(e error) {
	r.errs = append(r.errs, e)
}

func (r *Repository) getError() error {
	return errors.Join(r.errs...)
}

// Get 查询并构建聚合根
// root 必须指定 id，children 为可选，是 root 下面子实体的指针，需要是 *IEntity 或者 *[]IEntity 类型
// 方法会根据 root 与 children 的关系，查询并构建 root 与 children 实体