use codespan_reporting::diagnostic::Diagnostic;
use cranelift_codegen::{CodegenError, settings::SetError, isa::LookupError};
use cranelift_module::ModuleError;
use crate::backend::runtime::RuntimeFunctionError;
use thiserror::Error;

#[derive(Debug, Error)]
pub enum BackendError {
    #[error("Cranelift module error: {0}")]
    Cranelift(#[from] ModuleError),
    #[error("Builtin function error: {0}")]
    BuiltinError(#[from] RuntimeFunctionError),
    #[error("Internal variable lookup error")]
    VariableLookupFailure,
    #[error(transparent)]
    CodegenError(#[from] CodegenError),
    #[error(transparent)]
    SetError(#[from] SetError),
    #[error(transparent)]
    LookupError(#[from] LookupError),
}

impl From<BackendError> for Diagnostic<usize> {
    fn from(value: BackendError) -> Self {
        match value {
            BackendError::Cranelift(me) => {
                Diagnostic::error().with_message(format!("Internal cranelift error: {}", me))
            }
            BackendError::BuiltinError(me) => {
                Diagnostic::error().with_message(format!("Internal runtime function error: {}", me))
            }
            BackendError::VariableLookupFailure => {
                Diagnostic::error().with_message("Internal variable lookup error!")
            }
            BackendError::CodegenError(me) => {
                Diagnostic::error().with_message(format!("Internal codegen error: {}", me))
            }
            BackendError::SetError(me) => {
                Diagnostic::error().with_message(format!("Internal backend setup error: {}", me))
            }
            BackendError::LookupError(me) => {
                Diagnostic::error().with_message(format!("Internal error: {}", me))
            }
        }
    }
}