package core

import (
	"git.akyoto.dev/cli/q/src/build/ast"
	"git.akyoto.dev/cli/q/src/build/errors"
	"git.akyoto.dev/cli/q/src/build/token"
)

// CompileDefinition compiles a variable definition.
func (f *Function) CompileDefinition(node *ast.Define) error {
	name := node.Name.Text()

	if f.identifierExists(name) {
		return errors.New(&errors.VariableAlreadyExists{Name: name}, f.File, node.Name.Position)
	}

	uses := token.Count(f.Body, token.Identifier, name) - 1

	if uses == 0 {
		return errors.New(&errors.UnusedVariable{Name: name}, f.File, node.Name.Position)
	}

	return f.storeVariableInRegister(name, node.Value, uses)
}