use crate::engine::{EngineState, StateWorkingSet};
use miette::{
    LabeledSpan, MietteHandlerOpts, NarratableReportHandler, ReportHandler, RgbColors, Severity,
    SourceCode,
};
use thiserror::Error;

/// This error exists so that we can defer SourceCode handling. It simply
/// forwards most methods, except for `.source_code()`, which we provide.
#[derive(Error)]
#[error("{0}")]
pub struct CliError<'src>(
    pub &'src (dyn miette::Diagnostic + Send + Sync + 'static),
    pub &'src StateWorkingSet<'src>,
);

pub fn format_error(
    working_set: &StateWorkingSet,
    error: &(dyn miette::Diagnostic + Send + Sync + 'static),
) -> String {
    format!("Error: {:?}", CliError(error, working_set))
}

pub fn report_error(
    working_set: &StateWorkingSet,
    error: &(dyn miette::Diagnostic + Send + Sync + 'static),
) {
    eprintln!("Error: {:?}", CliError(error, working_set));
    // reset vt processing, aka ansi because illbehaved externals can break it
    #[cfg(windows)]
    {
        let _ = nu_utils::enable_vt_processing();
    }
}

pub fn report_error_new(
    engine_state: &EngineState,
    error: &(dyn miette::Diagnostic + Send + Sync + 'static),
) {
    let working_set = StateWorkingSet::new(engine_state);

    report_error(&working_set, error);
}

impl std::fmt::Debug for CliError<'_> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        let config = self.1.get_config();

        let ansi_support = &config.use_ansi_coloring;
        let ansi_support = *ansi_support;

        let error_style = &config.error_style.as_str();
        let errors_style = *error_style;

        let miette_handler: Box<dyn ReportHandler> = match errors_style {
            "plain" => Box::new(NarratableReportHandler::new()),
            _ => Box::new(
                MietteHandlerOpts::new()
                    // For better support of terminal themes use the ANSI coloring
                    .rgb_colors(RgbColors::Never)
                    // If ansi support is disabled in the config disable the eye-candy
                    .color(ansi_support)
                    .unicode(ansi_support)
                    .terminal_links(ansi_support)
                    .build(),
            ),
        };

        // Ignore error to prevent format! panics. This can happen if span points at some
        // inaccessible location, for example by calling `report_error()` with wrong working set.
        let _ = miette_handler.debug(self, f);

        Ok(())
    }
}

impl<'src> miette::Diagnostic for CliError<'src> {
    fn code<'a>(&'a self) -> Option<Box<dyn std::fmt::Display + 'a>> {
        self.0.code()
    }

    fn severity(&self) -> Option<Severity> {
        self.0.severity()
    }

    fn help<'a>(&'a self) -> Option<Box<dyn std::fmt::Display + 'a>> {
        self.0.help()
    }

    fn url<'a>(&'a self) -> Option<Box<dyn std::fmt::Display + 'a>> {
        self.0.url()
    }

    fn labels<'a>(&'a self) -> Option<Box<dyn Iterator<Item = LabeledSpan> + 'a>> {
        self.0.labels()
    }

    // Finally, we redirect the source_code method to our own source.
    fn source_code(&self) -> Option<&dyn SourceCode> {
        if let Some(source_code) = self.0.source_code() {
            Some(source_code)
        } else {
            Some(&self.1)
        }
    }

    fn related<'a>(&'a self) -> Option<Box<dyn Iterator<Item = &'a dyn miette::Diagnostic> + 'a>> {
        self.0.related()
    }
}