prql-compiler 0.7.1

pub use anyhow::Result;

use ariadne::{Cache, Config, Label, Report, ReportKind, Source};
use serde::{Deserialize, Serialize};
use std::error::Error as StdError;
use std::fmt::{self, Debug, Display, Formatter};
use std::ops::{Add, Range};

#[derive(Clone, PartialEq, Eq, Copy, Serialize, Deserialize)]
pub struct Span {
    pub start: usize,
    pub end: usize,
}

#[derive(Debug, Clone)]
pub struct Error {
    /// Message kind. Currently only Error is implemented.
    pub kind: MessageKind,
    pub span: Option<Span>,
    pub reason: Reason,
    pub help: Option<String>,
    pub code: Option<&'static str>,
}

#[derive(Debug, Clone)]
pub struct Errors(pub Vec<Error>);

/// Location within the source file.
/// Tuples contain:
/// - line number (0-based),
/// - column number within that line (0-based),
#[derive(Debug, Clone, Serialize)]
pub struct SourceLocation {
    pub start: (usize, usize),

    pub end: (usize, usize),
}

/// Compile message kind. Currently only Error is implemented.
#[derive(Clone, Debug, Serialize)]
pub enum MessageKind {
    Error,
    Warning,
    Lint,
}

#[derive(Debug, Clone)]
pub enum Reason {
    Simple(String),
    Expected {
        who: Option<String>,
        expected: String,
        found: String,
    },
    Unexpected {
        found: String,
    },
    NotFound {
        name: String,
        namespace: String,
    },
}

impl Error {
    pub fn new(reason: Reason) -> Self {
        Error {
            kind: MessageKind::Error,
            span: None,
            reason,
            help: None,
            code: None,
        }
    }

    pub fn new_simple<S: ToString>(reason: S) -> Self {
        Error::new(Reason::Simple(reason.to_string()))
    }

    pub fn with_help<S: Into<String>>(mut self, help: S) -> Self {
        self.help = Some(help.into());
        self
    }

    pub fn with_span(mut self, span: Option<Span>) -> Self {
        self.span = span;
        self
    }

    pub fn with_code(mut self, code: &'static str) -> Self {
        self.code = Some(code);
        self
    }
}

#[derive(Clone, Serialize)]
pub struct ErrorMessage {
    /// Message kind. Currently only Error is implemented.
    pub kind: MessageKind,
    /// Machine-readable identifier of the error
    pub code: Option<String>,
    /// Plain text of the error
    pub reason: String,
    /// A list of suggestions of how to fix the error
    pub hint: Option<String>,
    /// Character offset of error origin within a source file
    pub span: Option<Span>,
    /// Annotated code, containing cause and hints.
    pub display: Option<String>,
    /// Line and column number of error origin within a source file
    pub location: Option<SourceLocation>,
}

impl Display for ErrorMessage {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        // https://github.com/zesterer/ariadne/issues/52
        if let Some(display) = &self.display {
            let message_without_trailing_spaces = display
                .split('\n')
                .map(str::trim_end)
                .collect::<Vec<_>>()
                .join("\n");
            f.write_str(&message_without_trailing_spaces)?;
        } else {
            let code = (self.code.as_ref())
                .map(|c| format!("[{c}] "))
                .unwrap_or_default();

            writeln!(f, "{}Error: {}", code, &self.reason)?;
        }
        Ok(())
    }
}

impl Debug for ErrorMessage {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        Display::fmt(&self, f)
    }
}

// Needed for anyhow
impl StdError for Error {}

// Needed for anyhow
impl StdError for Errors {}

// Needed for StdError
impl Display for Error {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        Debug::fmt(&self, f)
    }
}

// Needed for StdError
impl Display for Errors {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        Debug::fmt(&self, f)
    }
}

#[derive(Debug, Clone, Serialize)]
pub struct ErrorMessages {
    pub inner: Vec<ErrorMessage>,
}
impl StdError for ErrorMessages {}

impl From<ErrorMessage> for ErrorMessages {
    fn from(e: ErrorMessage) -> Self {
        ErrorMessages { inner: vec![e] }
    }
}

impl Display for ErrorMessages {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        for e in &self.inner {
            Display::fmt(&e, f)?;
        }
        Ok(())
    }
}

pub fn downcast(error: anyhow::Error) -> ErrorMessages {
    let mut code = None;
    let mut span = None;
    let mut hint = None;

    let error = match error.downcast::<ErrorMessages>() {
        Ok(messages) => return messages,
        Err(error) => error,
    };

    let error = match error.downcast::<Errors>() {
        Ok(messages) => {
            return ErrorMessages {
                inner: messages
                    .0
                    .into_iter()
                    .flat_map(|e| downcast(e.into()).inner)
                    .collect(),
            }
        }
        Err(error) => error,
    };

    let reason = match error.downcast::<Error>() {
        Ok(error) => {
            code = error.code.map(|x| x.to_string());
            span = error.span;
            hint = error.help;

            error.reason.message()
        }
        Err(error) => {
            // default to basic Display
            format!("{:#?}", error)
        }
    };

    ErrorMessage {
        code,
        kind: MessageKind::Error,
        reason,
        hint,
        span,
        display: None,
        location: None,
    }
    .into()
}

impl From<anyhow::Error> for ErrorMessages {
    fn from(e: anyhow::Error) -> Self {
        downcast(e)
    }
}

impl ErrorMessages {
    pub fn to_json(&self) -> String {
        serde_json::to_string(self).unwrap()
    }

    /// Computes message location and builds the pretty display.
    pub fn composed(mut self, source_id: &str, source: &str, color: bool) -> Self {
        for e in &mut self.inner {
            let source = Source::from(source);
            let cache = (source_id, source);

            e.location = e.compose_location(&cache.1);
            e.display = e.compose_display(source_id, cache, color);
        }
        self
    }
}

impl ErrorMessage {
    fn compose_display<'a, C>(&self, source_id: &'a str, cache: C, color: bool) -> Option<String>
    where
        C: Cache<&'a str>,
    {
        let config = Config::default().with_color(color);

        let span = Range::from(self.span?);

        let mut report = Report::build(ReportKind::Error, source_id, span.start)
            .with_config(config)
            .with_label(Label::new((source_id, span)).with_message(&self.reason));

        if let Some(code) = &self.code {
            report = report.with_code(code);
        }

        if let Some(hint) = &self.hint {
            report.set_help(hint);
        }

        let mut out = Vec::new();
        report.finish().write(cache, &mut out).ok()?;
        String::from_utf8(out).ok()
    }

    fn compose_location(&self, source: &Source) -> Option<SourceLocation> {
        let span = self.span?;

        let start = source.get_offset_line(span.start)?;
        let end = source.get_offset_line(span.end)?;
        Some(SourceLocation {
            start: (start.1, start.2),
            end: (end.1, end.2),
        })
    }
}

impl Reason {
    fn message(&self) -> String {
        match self {
            Reason::Simple(text) => text.clone(),
            Reason::Expected {
                who,
                expected,
                found,
            } => {
                let who = who.clone().map(|x| format!("{x} ")).unwrap_or_default();
                format!("{who}expected {expected}, but found {found}")
            }
            Reason::Unexpected { found } => format!("unexpected {found}"),
            Reason::NotFound { name, namespace } => format!("{namespace} `{name}` not found"),
        }
    }
}

impl From<Span> for Range<usize> {
    fn from(a: Span) -> Self {
        a.start..a.end
    }
}

impl Add<Span> for Span {
    type Output = Span;

    fn add(self, rhs: Span) -> Span {
        Span {
            start: self.start.min(rhs.start),
            end: self.end.max(rhs.end),
        }
    }
}

pub trait WithErrorInfo {
    fn with_help<S: Into<String>>(self, help: S) -> Self;

    fn with_span(self, span: Option<Span>) -> Self;
}

impl<T> WithErrorInfo for Result<T, Error> {
    fn with_help<S: Into<String>>(self, help: S) -> Self {
        self.map_err(|e| e.with_help(help))
    }

    fn with_span(self, span: Option<Span>) -> Self {
        self.map_err(|e| e.with_span(span))
    }
}

impl Debug for Span {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        write!(f, "span-chars-{}-{}", self.start, self.end)
    }
}