/**
 * file: types/logicprovider.go
 * author: theo technicguy
 * license: apache 2.0
 *
 * Logic provider interface
 */

package types

import "errors"

var (
	ErrIDNotFound = errors.New("identifer not found")
)

// UseDatasource creates a LogicProvider bound to the passed
// data source, used to persist data.
type UseDatasource func(*Datasource) *LogicProvider

// A LogicProvidier is the part of the server that implements
// the logic of the application.
type LogicProvider interface {

	// CreateProduct creates a new product in the data source
	// using the passed product. The product ID is updated to
	// match the one assigned in the data source and the tags
	// are the full tags assigned.
	// TODO: Populate product with OFF data.
	CreateProduct(*Product) error

	// GetAllProducts returns all products saved in the data
	// source.
	GetAllProducts() ([]*Product, error)

	// GetProductByID returns the product saved in the data
	// source matching the ID. If no product matches,
	// GetProductByID returns an empty product and ErrIDNotFound.
	GetProductByID(uint) (*Product, error)

	// GetProductsLike returns all products saved in the data
	// source matching the requested search. If no product
	// matches, GetProductsLike returns an empty array of
	// products and a nil error.
	GetProductsLike(*ProductSearch) ([]*Product, error)

	// UpdateProduct checks if the product ID exists. If
	// it does, it updates the product with the ID to match
	// the data passed. Otherwise, it returns ErrIDNotFound.
	UpdateProduct(*Product) (*Product, error)

	// DeleteProduct checks if the product ID exists. If it
	// does, it requests deletion of the product to the data
	// source and returns the deleted product. Otherwise, it
	// returns an empty produt and ErrIDNotFound.
	DeleteProduct(uint) (*Product, error)

	// CreateProductTag creates a new product tag in the data
	// source using the passed tag. The product tag ID is
	// updated to match the one assigned in the data source.
	CreateProductTag(*Tag) error

	// GetAllProductTags returns all product tags saved in
	// the data source.
	GetAllProductTags() ([]*Tag, error)

	// GetProductTagByID and GetProductTagByName return the
	// product tag matching the ID and name respectively.
	// If no product tag matches, they both return an empty
	// product tag and ErrIDNotFound.
	GetProductTagByID(uint) (*Tag, error)
	GetProductTagByName(string) (*Tag, error)

	// GetProductTagsLikeName returns all product tags
	// matching the requested name. If no product tags match,
	// GetProductTagsLikeName returns an empty array of
	// product tags and a nil error.
	GetProductTagsLikeName(string) ([]*Tag, error)

	// UpdateProductTag checks if the product tag ID exists.
	// If it does, it updates the product tag with the ID to
	// match the data passed. Otherwise, it returns
	// ErrIDNotFound.
	UpdateProductTag(*Tag) (*Tag, error)

	// DeleteProductTag checks if the product tag ID exists.
	// If it does, it requests deletion of the product tag
	// to the data source and returns the deleted product tag.
	// Otherwise, it returns an empty product tag and
	// ErrIDNotFound.
	DeleteProductTag(uint) (*Tag, error)
}