componego

type Application interface {
	// ApplicationName returns the name of the application.
	ApplicationName() string
	// ApplicationAction describes the main action of the current application.
	// This function is called last when the application is fully initialized
	ApplicationAction(env Environment, options any) (int, error)
}

type ApplicationComponents interface {
	// Application belongs to the application.
	Application
	// ApplicationComponents return a list of components that the application depends on.
	// They will be sorted based on the dependent components.
	ApplicationComponents() ([]Component, error)
}

type ApplicationConfigInit interface {
	// Application belongs to the application.
	Application
	// ApplicationConfigInit returns configuration for all application entities.
	// This function is called only once.
	ApplicationConfigInit(appMode ApplicationMode, options any) (map[string]any, error)
}

type ApplicationDependencies interface {
	// Application belongs to the application.
	Application
	// ApplicationDependencies returns a list of dependencies that the application provides.
	// This function must return an array of objects or functions that returns objects.
	ApplicationDependencies() ([]Dependency, error)
}

type ApplicationErrorHandler interface {
	// Application belongs to the application.
	Application
	// ApplicationErrorHandler catches all application errors that are not handled in the main application code.
	ApplicationErrorHandler(err error, appIO ApplicationIO, appMode ApplicationMode) error
}

type ApplicationIO interface {
	// InputReader returns a pointer to read data into the application.
	InputReader() io.Reader
	// OutputWriter returns a pointer to output data from the application.
	OutputWriter() io.Writer
	// ErrorOutputWriter returns a pointer to output errors from the application.
	ErrorOutputWriter() io.Writer
}

type ApplicationMode int

type Component interface {
	// ComponentIdentifier returns the component ID.
	// If the identifier in several components is the same, then the last component will be used.
	// This can be used to overwrite components.
	ComponentIdentifier() string
	// ComponentVersion returns the component version.
	ComponentVersion() string
}

type ComponentComponents interface {
	// Component belongs to the component.
	Component
	// ComponentComponents returns list of components that the component depends on.
	// They will be sorted based on the dependent components.
	ComponentComponents() ([]Component, error)
}

type ComponentDependencies interface {
	// Component belongs to the component.
	Component
	// ComponentDependencies returns a list of dependencies that the component provides
	// This function must return an array of objects or functions that returns objects.
	ComponentDependencies() ([]Dependency, error)
}

type ComponentInit interface {
	// Component belongs to the component.
	Component
	// ComponentInit is called during component initialization.
	ComponentInit(env Environment) error
}

type ComponentProvider interface {
	// Components returns a list of sorted application components.
	Components() []Component
}

type ComponentStop interface {
	// Component belongs to the component.
	Component
	// ComponentStop is called when the component stops.
	// You can handle previous error (return a new or old error).
	ComponentStop(env Environment, prevErr error) error
}

type ConfigProvider interface {
	// ConfigValue returns the configuration by key.
	// The value can be modified by the Processor which validates or converts the value.
	ConfigValue(configKey string, processor Processor) (any, error)
}

type Dependency any

type DependencyInvoker interface {
	// Invoke uses dependencies.
	// You can only pass a function as an argument.
	// If the passed function returns an error, then it will be returned.
	Invoke(function any) (any, error)
	// Populate is similar to Invoke, but it can only take objects that are a reference.
	// The passed object will be filled with dependencies.
	Populate(target any) error
	// PopulateFields fills the struct fields passed as an argument with dependencies.
	// Fields must have a special tag: `componego:"inject"`.
	// Fields without this tag are ignored.
	PopulateFields(target any) error
}

type Environment interface {
	// GetContext returns a current application context.
	GetContext() context.Context
	// SetContext sets a new application context.
	// The new context must inherit from the previous context.
	SetContext(ctx context.Context) error
	// Application returns a current application object.
	Application() Application
	// ApplicationIO returns an object for getting application input and output.
	ApplicationIO() ApplicationIO
	// ApplicationMode returns the mode in which the application is started.
	ApplicationMode() ApplicationMode
	// ConfigProvider returns an object for getting config.
	ConfigProvider() ConfigProvider
	// Components returns a sorted list of active application components.
	Components() []Component
	// DependencyInvoker returns an object to invoke dependencies.
	DependencyInvoker() DependencyInvoker
}

type Processor interface {
	// ProcessData validates and converts data.
	// The method returns a new value or an error.
	ProcessData(value any) (any, error)
}