use crate::ast::*;
use crate::checker_state::{CheckerError, CheckerState, ElementValue};

use tracing::{debug, instrument};

impl Programme {
    pub fn check(&self) -> Result<(), CheckerError> {
        let mut state = CheckerState::default();
        state.check(self)
    }
}

impl CheckerState {
    #[instrument(skip(self, prog), level = "debug")]
    pub fn check(&mut self, prog: &Programme) -> Result<(), CheckerError> {
        let Programme(decls) = prog;

        for decl in decls {
            debug!(%self, %decl);
            match decl {
                Decl::Set { name, set } => {
                    let set = self.check_set(set)?;
                    self.add_set(name, set)
                }

                Decl::Element { name, element, set } => {
                    let set = self.check_set(set)?;
                    let element = self.check_element(element.clone().into(), &set)?;
                    if matches!(element, ElementValue::Hypothetical(_)) {
                        panic!(
                            "invariant violation: from concrete values at the top level we returned a hypothetical value"
                        );
                    }
                    self.add_element(name.clone(), element, set)
                }
                Decl::Signature { .. } => {
                    return Err(CheckerError::Unimplemented("signatures".to_string()));
                }
                Decl::Instance { .. } => {
                    return Err(CheckerError::Unimplemented("instances".to_string()));
                }
            }?;
        }
        debug!(%self);
        Ok(())
    }
}