package commandkit

import "fmt"

// Register adds a batch of root commands to the application. The batch is
// validated before the registry is changed.
func (a *App) Register(commands ...Command) error {
	return a.installBatch(commands...)
}

func (a *App) installBatch(commands ...Command) error {
	if a == nil {
		return fmt.Errorf("cannot register commands on a nil app")
	}

	pending := make(map[string]*commandNode, len(commands))
	for _, command := range commands {
		if err := validateCommandPlacement(command); err != nil {
			return err
		}
		if command.record.absent {
			continue
		}
		name := command.record.name
		if _, exists := a.commands[name]; exists {
			return fmt.Errorf("command path %q is already registered", name)
		}
		if _, exists := pending[name]; exists {
			return fmt.Errorf("command path %q is already registered", name)
		}
		pending[name] = &commandNode{command: command}
	}
	if len(pending) == 0 {
		return nil
	}
	if a.commands == nil {
		a.commands = make(map[string]*commandNode, len(pending))
	}
	for name, node := range pending {
		a.commands[name] = node
	}
	a.commandTree = nil
	return nil
}