use sexp::SourcePosition;

use crate::asm::error::CrsnError;

pub trait TryRemove {
    type Item;
    fn try_remove(&mut self, index: usize) -> Option<Self::Item>;

    fn remove_or_err(&mut self, index: usize, pos: &SourcePosition, err: &'static str) -> Result<Self::Item, CrsnError>;
}

impl<T> TryRemove for Vec<T> {
    type Item = T;

    fn try_remove(&mut self, index: usize) -> Option<T> {
        if self.is_empty() {
            None
        } else {
            Some(self.remove(index))
        }
    }

    fn remove_or_err(&mut self, index: usize, pos: &SourcePosition, err: &'static str) -> Result<Self::Item, CrsnError> {
        match self.try_remove(index) {
            None => {
                Err(CrsnError::Parse(err.into(), pos.clone()))
            }
            Some(removed) => Ok(removed)
        }
    }
}

pub trait NextOrErr<T> {
    fn next_or_err(&mut self, pos: SourcePosition, err: &'static str) -> Result<T, CrsnError>;
}

impl<T, K: Iterator<Item=T>> NextOrErr<T> for K {
    fn next_or_err(&mut self, pos: SourcePosition, err: &'static str) -> Result<T, CrsnError> {
        match self.next() {
            None => {
                Err(CrsnError::Parse(err.into(), pos))
            }
            Some(removed) => Ok(removed)
        }
    }
}

pub trait ErrWithPos<T> {
    fn err_pos(self, pos: &SourcePosition) -> Result<T, CrsnError>;
}

impl<T, E: std::error::Error + Send + Sync + 'static> ErrWithPos<T> for Result<T, E> {
    fn err_pos(self, pos: &SourcePosition) -> Result<T, CrsnError> {
        match self {
            Ok(v) => Ok(v),
            Err(e) => Err(CrsnError::ParseOther(Box::new(e), pos.clone()))
        }
    }
}

pub trait ErrSetFile<T> {
    fn err_file(self, file: u32) -> Result<T, CrsnError>;
}

impl<T> ErrSetFile<T> for Result<T, CrsnError> {
    /// Set file context in the error
    fn err_file(self, file: u32) -> Result<T, CrsnError> {
        match self {
            Ok(v) => Ok(v),
            Err(CrsnError::Parse(a, p)) => Err(CrsnError::Parse(a, p.with_file(file))),
            Err(CrsnError::ParseOther(a, p)) => Err(CrsnError::ParseOther(a, p.with_file(file))),
            Err(CrsnError::Asm(a, p)) => Err(CrsnError::Asm(a, p.with_file(file))),
            Err(CrsnError::Sexp(mut se)) => {
                se.pos.file = file;
                Err(CrsnError::Sexp(se))
            },
            Err(other @ CrsnError::IOError(_)) => Err(other),
        }
    }
}