use crate::{
    expression::Composite,
    selection::{Selection, VectoriseError},
    selection_functions::{evaluate_selection_function, SFError},
    state::{EditorState, StateResult},
};

use thiserror::Error;

#[derive(Error, Debug)]
pub enum EvaluationError {
    #[error("{0}")]
    SelectionFunctionError(VectoriseError<SFError>),
    #[error("Not yet implemented {0}")]
    UnimplementedError(&'static str),
}

pub fn evaluate(
    es: &EditorState,
    comp: Composite,
    left: Option<Selection>,
    right: Option<Selection>,
) -> Result<StateResult, EvaluationError> {
    match comp {
        Composite::SelectionFunction {
            func,
            search_mod,
            result_transform,
        } => {
            let sel =
                evaluate_selection_function(es, func, search_mod, result_transform, left, right)
                    .map_err(EvaluationError::SelectionFunctionError)?;
            Ok((sel, Vec::new()))
        }
        Composite::TextFunction { func, swapped } => {
            Err(EvaluationError::UnimplementedError("text function"))
        }
        Composite::Hook { kind, left, right } => Err(EvaluationError::UnimplementedError("hook")),
        Composite::Train2 { f, g } => Err(EvaluationError::UnimplementedError("train2")),
        Composite::Train3 { f, g, h } => Err(EvaluationError::UnimplementedError("train3")),
        Composite::Group { operations } => Err(EvaluationError::UnimplementedError("group")),
    }
}