package core

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

// Scope represents an independent code block.
type Scope struct {
	variables map[string]*Variable
	inLoop    bool
	cpu.State
}

// Scope returns the current scope.
func (s *state) Scope() *Scope {
	return s.scopes[len(s.scopes)-1]
}

// pushScope pushes a new scope to the top of the stack.
func (f *Function) pushScope(body ast.AST) *Scope {
	scope := &Scope{}

	if len(f.scopes) > 0 {
		lastScope := f.scopes[len(f.scopes)-1]
		scope.State = lastScope.State
		scope.variables = make(map[string]*Variable, len(lastScope.variables))
		scope.inLoop = lastScope.inLoop

		for k, v := range lastScope.variables {
			count := ast.Count(body, token.Identifier, v.Name)

			if count == 0 {
				continue
			}

			scope.variables[k] = &Variable{
				Name:     v.Name,
				Register: v.Register,
				Alive:    count,
			}
		}
	} else {
		scope.variables = map[string]*Variable{}
	}

	f.scopes = append(f.scopes, scope)

	if config.Comments {
		f.Comment("scope %d start", len(f.scopes))
	}

	return scope
}

// popScope removes the scope at the top of the stack.
func (f *Function) popScope() {
	if config.Comments {
		f.Comment("scope %d end", len(f.scopes))
	}

	f.scopes = f.scopes[:len(f.scopes)-1]
}