// Copyright 2019-present Facebook Inc. All rights reserved.
// This source code is licensed under the Apache 2.0 license found
// in the LICENSE file in the root directory of this source tree.

// Code generated by ent, DO NOT EDIT.

package ent

import (
	"context"
	"errors"
	"fmt"
	"sync"

	"entgo.io/ent"
	"entgo.io/ent/entc/integration/cascadelete/ent/comment"
	"entgo.io/ent/entc/integration/cascadelete/ent/post"
	"entgo.io/ent/entc/integration/cascadelete/ent/user"
)

const (
	// Operation types.
	OpCreate    = ent.OpCreate
	OpDelete    = ent.OpDelete
	OpDeleteOne = ent.OpDeleteOne
	OpUpdate    = ent.OpUpdate
	OpUpdateOne = ent.OpUpdateOne

	// Node types.
	TypeComment = "Comment"
	TypePost    = "Post"
	TypeUser    = "User"
)

// CommentMutation represents an operation that mutates the Comment nodes in the graph.
type CommentMutation struct {
	comment.Mutation
	config
	id       *int
	done     bool
	oldValue func(context.Context) (*Comment, error)
}

var _ ent.Mutation = (*CommentMutation)(nil)

// commentOption allows management of the mutation configuration using functional options.
type commentOption func(*CommentMutation)

// newCommentMutation creates new mutation for the Comment entity.
func newCommentMutation(c config, op Op, opts ...commentOption) *CommentMutation {
	m := &CommentMutation{
		Mutation: *comment.NewMutation(op),
		config:   c,
	}
	for _, opt := range opts {
		opt(m)
	}
	return m
}

// ID returns the ID value in the mutation. Note that the ID is only available
// if it was provided to the builder or after it was returned from the database.
func (m *CommentMutation) ID() (id int, exists bool) {
	if m.id == nil {
		return
	}
	return *m.id, true
}

// withCommentID sets the ID field of the mutation.
func withCommentID(id int) commentOption {
	return func(m *CommentMutation) {
		var (
			err   error
			once  sync.Once
			value *Comment
		)
		m.oldValue = func(ctx context.Context) (*Comment, error) {
			once.Do(func() {
				if m.done {
					err = errors.New("querying old values post mutation is not allowed")
				} else {
					value, err = m.Client().Comment.Get(ctx, id)
				}
			})
			return value, err
		}
		m.id = &id
	}
}

// withComment sets the old Comment of the mutation.
func withComment(node *Comment) commentOption {
	return func(m *CommentMutation) {
		m.oldValue = func(context.Context) (*Comment, error) {
			return node, nil
		}
		m.id = &node.ID
	}
}

// Client returns a new `ent.Client` from the mutation. If the mutation was
// executed in a transaction (ent.Tx), a transactional client is returned.
func (m CommentMutation) Client() *Client {
	client := &Client{config: m.config}
	client.init()
	return client
}

// Tx returns an `ent.Tx` for mutations that were executed in transactions;
// it returns an error otherwise.
func (m CommentMutation) Tx() (*Tx, error) {
	if _, ok := m.driver.(*txDriver); !ok {
		return nil, errors.New("ent: mutation is not running in a transaction")
	}
	tx := &Tx{config: m.config}
	tx.init()
	return tx, nil
}

// IDs queries the database and returns the entity ids that match the mutation's predicate.
// That means, if the mutation is applied within a transaction with an isolation level such
// as sql.LevelSerializable, the returned ids match the ids of the rows that will be updated
// or updated by the mutation.
func (m *CommentMutation) IDs(ctx context.Context) ([]int, error) {
	switch {
	case m.Op().Is(OpUpdateOne | OpDeleteOne):
		id, exists := m.ID()
		if exists {
			return []int{id}, nil
		}
		fallthrough
	case m.Op().Is(OpUpdate | OpDelete):
		return m.Client().Comment.Query().Where(m.Predicates()...).IDs(ctx)
	default:
		return nil, fmt.Errorf("IDs is not allowed on %s operations", m.Op())
	}
}

// OldText returns the old "text" field's value of the Comment entity.
// If the Comment object wasn't provided to the builder, the object is fetched from the database.
// An error is returned if the mutation operation is not UpdateOne, or the database query fails.
func (m *CommentMutation) OldText(ctx context.Context) (v string, err error) {
	if !m.Op().Is(OpUpdateOne) {
		return v, errors.New("OldText is only allowed on UpdateOne operations")
	}
	if _, exists := m.ID(); !exists || m.oldValue == nil {
		return v, errors.New("OldText requires an ID field in the mutation")
	}
	oldValue, err := m.oldValue(ctx)
	if err != nil {
		return v, fmt.Errorf("querying old value for OldText: %w", err)
	}
	return oldValue.Text, nil
}

// OldPostID returns the old "post_id" field's value of the Comment entity.
// If the Comment object wasn't provided to the builder, the object is fetched from the database.
// An error is returned if the mutation operation is not UpdateOne, or the database query fails.
func (m *CommentMutation) OldPostID(ctx context.Context) (v int, err error) {
	if !m.Op().Is(OpUpdateOne) {
		return v, errors.New("OldPostID is only allowed on UpdateOne operations")
	}
	if _, exists := m.ID(); !exists || m.oldValue == nil {
		return v, errors.New("OldPostID requires an ID field in the mutation")
	}
	oldValue, err := m.oldValue(ctx)
	if err != nil {
		return v, fmt.Errorf("querying old value for OldPostID: %w", err)
	}
	return oldValue.PostID, nil
}

// OldField returns the old value of the field from the database. An error is
// returned if the mutation operation is not UpdateOne, or the query to the
// database failed.
func (m *CommentMutation) OldField(ctx context.Context, name string) (ent.Value, error) {
	switch name {
	case comment.FieldText:
		return m.OldText(ctx)
	case comment.FieldPostID:
		return m.OldPostID(ctx)
	}
	return nil, fmt.Errorf("unknown Comment field %s", name)
}

// PostMutation represents an operation that mutates the Post nodes in the graph.
type PostMutation struct {
	post.Mutation
	config
	id       *int
	done     bool
	oldValue func(context.Context) (*Post, error)
}

var _ ent.Mutation = (*PostMutation)(nil)

// postOption allows management of the mutation configuration using functional options.
type postOption func(*PostMutation)

// newPostMutation creates new mutation for the Post entity.
func newPostMutation(c config, op Op, opts ...postOption) *PostMutation {
	m := &PostMutation{
		Mutation: *post.NewMutation(op),
		config:   c,
	}
	for _, opt := range opts {
		opt(m)
	}
	return m
}

// ID returns the ID value in the mutation. Note that the ID is only available
// if it was provided to the builder or after it was returned from the database.
func (m *PostMutation) ID() (id int, exists bool) {
	if m.id == nil {
		return
	}
	return *m.id, true
}

// withPostID sets the ID field of the mutation.
func withPostID(id int) postOption {
	return func(m *PostMutation) {
		var (
			err   error
			once  sync.Once
			value *Post
		)
		m.oldValue = func(ctx context.Context) (*Post, error) {
			once.Do(func() {
				if m.done {
					err = errors.New("querying old values post mutation is not allowed")
				} else {
					value, err = m.Client().Post.Get(ctx, id)
				}
			})
			return value, err
		}
		m.id = &id
	}
}

// withPost sets the old Post of the mutation.
func withPost(node *Post) postOption {
	return func(m *PostMutation) {
		m.oldValue = func(context.Context) (*Post, error) {
			return node, nil
		}
		m.id = &node.ID
	}
}

// Client returns a new `ent.Client` from the mutation. If the mutation was
// executed in a transaction (ent.Tx), a transactional client is returned.
func (m PostMutation) Client() *Client {
	client := &Client{config: m.config}
	client.init()
	return client
}

// Tx returns an `ent.Tx` for mutations that were executed in transactions;
// it returns an error otherwise.
func (m PostMutation) Tx() (*Tx, error) {
	if _, ok := m.driver.(*txDriver); !ok {
		return nil, errors.New("ent: mutation is not running in a transaction")
	}
	tx := &Tx{config: m.config}
	tx.init()
	return tx, nil
}

// IDs queries the database and returns the entity ids that match the mutation's predicate.
// That means, if the mutation is applied within a transaction with an isolation level such
// as sql.LevelSerializable, the returned ids match the ids of the rows that will be updated
// or updated by the mutation.
func (m *PostMutation) IDs(ctx context.Context) ([]int, error) {
	switch {
	case m.Op().Is(OpUpdateOne | OpDeleteOne):
		id, exists := m.ID()
		if exists {
			return []int{id}, nil
		}
		fallthrough
	case m.Op().Is(OpUpdate | OpDelete):
		return m.Client().Post.Query().Where(m.Predicates()...).IDs(ctx)
	default:
		return nil, fmt.Errorf("IDs is not allowed on %s operations", m.Op())
	}
}

// OldText returns the old "text" field's value of the Post entity.
// If the Post object wasn't provided to the builder, the object is fetched from the database.
// An error is returned if the mutation operation is not UpdateOne, or the database query fails.
func (m *PostMutation) OldText(ctx context.Context) (v string, err error) {
	if !m.Op().Is(OpUpdateOne) {
		return v, errors.New("OldText is only allowed on UpdateOne operations")
	}
	if _, exists := m.ID(); !exists || m.oldValue == nil {
		return v, errors.New("OldText requires an ID field in the mutation")
	}
	oldValue, err := m.oldValue(ctx)
	if err != nil {
		return v, fmt.Errorf("querying old value for OldText: %w", err)
	}
	return oldValue.Text, nil
}

// OldAuthorID returns the old "author_id" field's value of the Post entity.
// If the Post object wasn't provided to the builder, the object is fetched from the database.
// An error is returned if the mutation operation is not UpdateOne, or the database query fails.
func (m *PostMutation) OldAuthorID(ctx context.Context) (v int, err error) {
	if !m.Op().Is(OpUpdateOne) {
		return v, errors.New("OldAuthorID is only allowed on UpdateOne operations")
	}
	if _, exists := m.ID(); !exists || m.oldValue == nil {
		return v, errors.New("OldAuthorID requires an ID field in the mutation")
	}
	oldValue, err := m.oldValue(ctx)
	if err != nil {
		return v, fmt.Errorf("querying old value for OldAuthorID: %w", err)
	}
	return oldValue.AuthorID, nil
}

// OldField returns the old value of the field from the database. An error is
// returned if the mutation operation is not UpdateOne, or the query to the
// database failed.
func (m *PostMutation) OldField(ctx context.Context, name string) (ent.Value, error) {
	switch name {
	case post.FieldText:
		return m.OldText(ctx)
	case post.FieldAuthorID:
		return m.OldAuthorID(ctx)
	}
	return nil, fmt.Errorf("unknown Post field %s", name)
}

// UserMutation represents an operation that mutates the User nodes in the graph.
type UserMutation struct {
	user.Mutation
	config
	id       *int
	done     bool
	oldValue func(context.Context) (*User, error)
}

var _ ent.Mutation = (*UserMutation)(nil)

// userOption allows management of the mutation configuration using functional options.
type userOption func(*UserMutation)

// newUserMutation creates new mutation for the User entity.
func newUserMutation(c config, op Op, opts ...userOption) *UserMutation {
	m := &UserMutation{
		Mutation: *user.NewMutation(op),
		config:   c,
	}
	for _, opt := range opts {
		opt(m)
	}
	return m
}

// ID returns the ID value in the mutation. Note that the ID is only available
// if it was provided to the builder or after it was returned from the database.
func (m *UserMutation) ID() (id int, exists bool) {
	if m.id == nil {
		return
	}
	return *m.id, true
}

// withUserID sets the ID field of the mutation.
func withUserID(id int) userOption {
	return func(m *UserMutation) {
		var (
			err   error
			once  sync.Once
			value *User
		)
		m.oldValue = func(ctx context.Context) (*User, error) {
			once.Do(func() {
				if m.done {
					err = errors.New("querying old values post mutation is not allowed")
				} else {
					value, err = m.Client().User.Get(ctx, id)
				}
			})
			return value, err
		}
		m.id = &id
	}
}

// withUser sets the old User of the mutation.
func withUser(node *User) userOption {
	return func(m *UserMutation) {
		m.oldValue = func(context.Context) (*User, error) {
			return node, nil
		}
		m.id = &node.ID
	}
}

// Client returns a new `ent.Client` from the mutation. If the mutation was
// executed in a transaction (ent.Tx), a transactional client is returned.
func (m UserMutation) Client() *Client {
	client := &Client{config: m.config}
	client.init()
	return client
}

// Tx returns an `ent.Tx` for mutations that were executed in transactions;
// it returns an error otherwise.
func (m UserMutation) Tx() (*Tx, error) {
	if _, ok := m.driver.(*txDriver); !ok {
		return nil, errors.New("ent: mutation is not running in a transaction")
	}
	tx := &Tx{config: m.config}
	tx.init()
	return tx, nil
}

// IDs queries the database and returns the entity ids that match the mutation's predicate.
// That means, if the mutation is applied within a transaction with an isolation level such
// as sql.LevelSerializable, the returned ids match the ids of the rows that will be updated
// or updated by the mutation.
func (m *UserMutation) IDs(ctx context.Context) ([]int, error) {
	switch {
	case m.Op().Is(OpUpdateOne | OpDeleteOne):
		id, exists := m.ID()
		if exists {
			return []int{id}, nil
		}
		fallthrough
	case m.Op().Is(OpUpdate | OpDelete):
		return m.Client().User.Query().Where(m.Predicates()...).IDs(ctx)
	default:
		return nil, fmt.Errorf("IDs is not allowed on %s operations", m.Op())
	}
}

// OldName returns the old "name" field's value of the User entity.
// If the User object wasn't provided to the builder, the object is fetched from the database.
// An error is returned if the mutation operation is not UpdateOne, or the database query fails.
func (m *UserMutation) OldName(ctx context.Context) (v string, err error) {
	if !m.Op().Is(OpUpdateOne) {
		return v, errors.New("OldName is only allowed on UpdateOne operations")
	}
	if _, exists := m.ID(); !exists || m.oldValue == nil {
		return v, errors.New("OldName requires an ID field in the mutation")
	}
	oldValue, err := m.oldValue(ctx)
	if err != nil {
		return v, fmt.Errorf("querying old value for OldName: %w", err)
	}
	return oldValue.Name, nil
}

// OldField returns the old value of the field from the database. An error is
// returned if the mutation operation is not UpdateOne, or the query to the
// database failed.
func (m *UserMutation) OldField(ctx context.Context, name string) (ent.Value, error) {
	switch name {
	case user.FieldName:
		return m.OldName(ctx)
	}
	return nil, fmt.Errorf("unknown User field %s", name)
}