// 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 entc, DO NOT EDIT.

package ent

import (
	"context"
	"fmt"

	"github.com/facebook/ent/dialect/gremlin"
	"github.com/facebook/ent/dialect/gremlin/graph/dsl"
	"github.com/facebook/ent/dialect/gremlin/graph/dsl/g"
	"github.com/facebook/ent/entc/integration/gremlin/ent/item"
	"github.com/facebook/ent/entc/integration/gremlin/ent/predicate"
)

// ItemUpdate is the builder for updating Item entities.
type ItemUpdate struct {
	config
	hooks    []Hook
	mutation *ItemMutation
}

// Where adds a new predicate for the ItemUpdate builder.
func (iu *ItemUpdate) Where(ps ...predicate.Item) *ItemUpdate {
	iu.mutation.predicates = append(iu.mutation.predicates, ps...)
	return iu
}

// Mutation returns the ItemMutation object of the builder.
func (iu *ItemUpdate) Mutation() *ItemMutation {
	return iu.mutation
}

// Save executes the query and returns the number of nodes affected by the update operation.
func (iu *ItemUpdate) Save(ctx context.Context) (int, error) {
	var (
		err      error
		affected int
	)
	if len(iu.hooks) == 0 {
		affected, err = iu.gremlinSave(ctx)
	} else {
		var mut Mutator = MutateFunc(func(ctx context.Context, m Mutation) (Value, error) {
			mutation, ok := m.(*ItemMutation)
			if !ok {
				return nil, fmt.Errorf("unexpected mutation type %T", m)
			}
			iu.mutation = mutation
			affected, err = iu.gremlinSave(ctx)
			mutation.done = true
			return affected, err
		})
		for i := len(iu.hooks) - 1; i >= 0; i-- {
			mut = iu.hooks[i](mut)
		}
		if _, err := mut.Mutate(ctx, iu.mutation); err != nil {
			return 0, err
		}
	}
	return affected, err
}

// SaveX is like Save, but panics if an error occurs.
func (iu *ItemUpdate) SaveX(ctx context.Context) int {
	affected, err := iu.Save(ctx)
	if err != nil {
		panic(err)
	}
	return affected
}

// Exec executes the query.
func (iu *ItemUpdate) Exec(ctx context.Context) error {
	_, err := iu.Save(ctx)
	return err
}

// ExecX is like Exec, but panics if an error occurs.
func (iu *ItemUpdate) ExecX(ctx context.Context) {
	if err := iu.Exec(ctx); err != nil {
		panic(err)
	}
}

func (iu *ItemUpdate) gremlinSave(ctx context.Context) (int, error) {
	res := &gremlin.Response{}
	query, bindings := iu.gremlin().Query()
	if err := iu.driver.Exec(ctx, query, bindings, res); err != nil {
		return 0, err
	}
	if err, ok := isConstantError(res); ok {
		return 0, err
	}
	return res.ReadInt()
}

func (iu *ItemUpdate) gremlin() *dsl.Traversal {
	v := g.V().HasLabel(item.Label)
	for _, p := range iu.mutation.predicates {
		p(v)
	}
	var (
		trs []*dsl.Traversal
	)
	v.Count()
	trs = append(trs, v)
	return dsl.Join(trs...)
}

// ItemUpdateOne is the builder for updating a single Item entity.
type ItemUpdateOne struct {
	config
	hooks    []Hook
	mutation *ItemMutation
}

// Mutation returns the ItemMutation object of the builder.
func (iuo *ItemUpdateOne) Mutation() *ItemMutation {
	return iuo.mutation
}

// Save executes the query and returns the updated Item entity.
func (iuo *ItemUpdateOne) Save(ctx context.Context) (*Item, error) {
	var (
		err  error
		node *Item
	)
	if len(iuo.hooks) == 0 {
		node, err = iuo.gremlinSave(ctx)
	} else {
		var mut Mutator = MutateFunc(func(ctx context.Context, m Mutation) (Value, error) {
			mutation, ok := m.(*ItemMutation)
			if !ok {
				return nil, fmt.Errorf("unexpected mutation type %T", m)
			}
			iuo.mutation = mutation
			node, err = iuo.gremlinSave(ctx)
			mutation.done = true
			return node, err
		})
		for i := len(iuo.hooks) - 1; i >= 0; i-- {
			mut = iuo.hooks[i](mut)
		}
		if _, err := mut.Mutate(ctx, iuo.mutation); err != nil {
			return nil, err
		}
	}
	return node, err
}

// SaveX is like Save, but panics if an error occurs.
func (iuo *ItemUpdateOne) SaveX(ctx context.Context) *Item {
	node, err := iuo.Save(ctx)
	if err != nil {
		panic(err)
	}
	return node
}

// Exec executes the query on the entity.
func (iuo *ItemUpdateOne) Exec(ctx context.Context) error {
	_, err := iuo.Save(ctx)
	return err
}

// ExecX is like Exec, but panics if an error occurs.
func (iuo *ItemUpdateOne) ExecX(ctx context.Context) {
	if err := iuo.Exec(ctx); err != nil {
		panic(err)
	}
}

func (iuo *ItemUpdateOne) gremlinSave(ctx context.Context) (*Item, error) {
	res := &gremlin.Response{}
	id, ok := iuo.mutation.ID()
	if !ok {
		return nil, &ValidationError{Name: "ID", err: fmt.Errorf("missing Item.ID for update")}
	}
	query, bindings := iuo.gremlin(id).Query()
	if err := iuo.driver.Exec(ctx, query, bindings, res); err != nil {
		return nil, err
	}
	if err, ok := isConstantError(res); ok {
		return nil, err
	}
	i := &Item{config: iuo.config}
	if err := i.FromResponse(res); err != nil {
		return nil, err
	}
	return i, nil
}

func (iuo *ItemUpdateOne) gremlin(id string) *dsl.Traversal {
	v := g.V(id)
	var (
		trs []*dsl.Traversal
	)
	v.ValueMap(true)
	trs = append(trs, v)
	return dsl.Join(trs...)
}