package fr.celticinfo.lox

/**
 * The StmtVisitor interface is used to visit the different types of statements that can be parsed by the Parser.
 */
interface StmtVisitor<R> {
    fun visitBlock(stmt: Block): R
    fun visitClassStmt(stmt: ClassStmt): R
    fun visitExpression(stmt: Expression): R
    fun visitFunction(stmt: Function): R
    fun visitIf(stmt: If): R
    fun visitPrint(stmt: Print): R
    fun visitReturn(stmt: Return): R
    fun visitVar(stmt: Var): R
    fun visitWhile(stmt: While): R
}

/**
 * The Stmt class represents the different types of statements that can be parsed by the Parser.
 */
sealed class Stmt {
    abstract fun <R> accept(visitor: StmtVisitor<R>): R
}

data class Block(
    val statements: List<Stmt?>
) : Stmt() {
    override fun <R> accept(visitor: StmtVisitor<R>): R {
        return visitor.visitBlock(this)
    }
}

data class ClassStmt(
    val name: Token,
    val superClass: Variable?,
    val methods: List<Function>
) : Stmt() {
    override fun <R> accept(visitor: StmtVisitor<R>): R {
        return visitor.visitClassStmt(this)
    }
}

data class Expression(
    val expression: Expr
) : Stmt() {
    override fun <R> accept(visitor: StmtVisitor<R>): R {
        return visitor.visitExpression(this)
    }
}

data class Function(
    val name: Token,
    val params: List<Token>,
    val body: List<Stmt?>
) : Stmt() {
    override fun <R> accept(visitor: StmtVisitor<R>): R {
        return visitor.visitFunction(this)
    }
}

data class If(
    val condition: Expr,
    val thenBranch: Stmt,
    val elseBranch: Stmt?
) : Stmt() {
    override fun <R> accept(visitor: StmtVisitor<R>): R {
        return visitor.visitIf(this)
    }
}
data class Print(
    val expression: Expr
) : Stmt() {
    override fun <R> accept(visitor: StmtVisitor<R>): R {
        return visitor.visitPrint(this)
    }
}

data class Return(
    val keyword: Token,
    val value: Expr?
) : Stmt() {
    override fun <R> accept(visitor: StmtVisitor<R>): R {
        return visitor.visitReturn(this)
    }
}

data class Var(
    val name: Token,
    val initializer: Expr?
) : Stmt() {
    override fun <R> accept(visitor: StmtVisitor<R>): R {
        return visitor.visitVar(this)
    }
}

data class While(
    val condition: Expr,
    val body: Stmt
) : Stmt() {
    override fun <R> accept(visitor: StmtVisitor<R>): R {
        return visitor.visitWhile(this)
    }
}