use crate::*;

use std::collections::HashMap;


pub struct Environment {
    pub scopes: Vec<Scope>,
}

impl Environment {
    pub fn get_integer(&self, name: &str) -> Result<usize, ()> {
        for scope in self.scopes.iter().rev() {
            if let Ok(value) = scope.get_integer(name, &self) {
                return Ok(value);
            }
        }
        return Err(());
    }

    pub fn get_block(&self, name: &str) -> Result<usize, ()> {
        for scope in self.scopes.iter().rev() {
            if let Ok(value) = scope.get_block(name, &self) {
                return Ok(value);
            }
        }
        return Err(());
    }
}

pub struct Scope {
    pub definitions: HashMap<String, Definition>,
}

impl Scope {
    pub fn get_integer(&self, name: &str, environment: &Environment) -> Result<usize, ()> {
        use IntegerDefinition as IntDef;
        if let Some(definition) = self.definitions.get(name) {
            if let Definition::Integer(integer) = definition {
                match integer {
                    IntDef::Literal(value) => return Ok(*value),
                    IntDef::ConstantExpression(expr) => match expr.evaluate(environment) {
                        Ok(_) | Err(_) => todo!(),
                    },
                };
            }
        }
        return Err(());
    }

    pub fn get_block(&self, _name: &str, _environment: &Environment) -> Result<usize, ()> {
        todo!()
    }
}

pub enum Definition {
    Integer(IntegerDefinition),
    Block,
}

pub enum IntegerDefinition {
    Literal(usize),
    ConstantExpression(ConstantExpression),
}