use std::{error::Error, fmt};

#[derive(Clone, Debug)]
pub struct ShaderError<E> {
    /// The source code of the shader.
    pub source: String,
    pub label: Option<String>,
    pub inner: Box<E>,
}

#[cfg(feature = "wgsl-in")]
impl fmt::Display for ShaderError<crate::front::wgsl::ParseError> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let label = self.label.as_deref().unwrap_or_default();
        let string = self.inner.emit_to_string(&self.source);
        write!(f, "\nShader '{label}' parsing {string}")
    }
}
#[cfg(feature = "glsl-in")]
impl fmt::Display for ShaderError<crate::front::glsl::ParseErrors> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let label = self.label.as_deref().unwrap_or_default();
        let string = self.inner.emit_to_string(&self.source);
        write!(f, "\nShader '{label}' parsing {string}")
    }
}
#[cfg(feature = "spv-in")]
impl fmt::Display for ShaderError<crate::front::spv::Error> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let label = self.label.as_deref().unwrap_or_default();
        let string = self.inner.emit_to_string(&self.source);
        write!(f, "\nShader '{label}' parsing {string}")
    }
}
impl fmt::Display for ShaderError<crate::WithSpan<crate::valid::ValidationError>> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        use codespan_reporting::{
            diagnostic::{Diagnostic, Label},
            files::SimpleFile,
            term,
        };

        let label = self.label.as_deref().unwrap_or_default();
        let files = SimpleFile::new(label, &self.source);
        let config = term::Config::default();
        let mut writer = term::termcolor::NoColor::new(Vec::new());

        let diagnostic = Diagnostic::error().with_labels(
            self.inner
                .spans()
                .map(|&(span, ref desc)| {
                    Label::primary((), span.to_range().unwrap()).with_message(desc.to_owned())
                })
                .collect(),
        );

        term::emit(&mut writer, &config, &files, &diagnostic).expect("cannot write error");

        write!(
            f,
            "\nShader validation {}",
            String::from_utf8_lossy(&writer.into_inner())
        )
    }
}
impl<E> Error for ShaderError<E>
where
    ShaderError<E>: fmt::Display,
    E: Error + 'static,
{
    fn source(&self) -> Option<&(dyn Error + 'static)> {
        Some(&self.inner)
    }
}