kind-driver 0.1.3

//! Transforms a single book into a book by
//! reading it and it's dependencies. In the end
//! it returns a desugared book of all of the
//! depedencies.

use core::fmt;
use fxhash::FxHashSet;
use kind_pass::expand::expand_module;
use kind_pass::expand::uses::expand_uses;
use std::error::Error;
use std::fs;
use std::path::{Path, PathBuf};
use std::rc::Rc;
use strsim::jaro;

use kind_pass::unbound::{self, UnboundCollector};
use kind_report::data::Diagnostic;
use kind_tree::concrete::visitor::Visitor;
use kind_tree::concrete::{Book, Module, TopLevel};
use kind_tree::symbol::{Ident, QualifiedIdent};

use crate::{diagnostic::DriverDiagnostic, session::Session};

/// The extension of kind2 files.
const EXT: &str = "kind2";

#[derive(Debug)]
pub struct ResolutionError;

impl fmt::Display for ResolutionError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "resolution error")
    }
}

impl Error for ResolutionError {}

/// Tries to accumulate on a buffer all of the
/// paths that exists (so we can just throw an
/// error about ambiguous resolution to the user)
fn accumulate_neighbour_paths(
    ident: &QualifiedIdent,
    raw_path: &Path,
) -> Result<Option<PathBuf>, Box<dyn Diagnostic>> {
    let mut canon_path = raw_path.to_path_buf();
    let mut dir_file_path = canon_path.clone();
    let dir_path = canon_path.clone();

    canon_path.set_extension(EXT);

    dir_file_path.push("_");
    dir_file_path.set_extension(EXT);

    if canon_path.exists() && dir_path.exists() && canon_path.is_file() && dir_path.is_dir() {
        Err(Box::new(DriverDiagnostic::MultiplePaths(
            ident.clone(),
            vec![canon_path, dir_path],
        )))
    } else if canon_path.is_file() {
        Ok(Some(canon_path))
    } else if dir_file_path.is_file() {
        Ok(Some(dir_file_path))
    } else {
        Ok(None)
    }
}

/// Gets an identifier and tries to get all of the
/// paths that it can refer into a single path. If
/// multiple paths are found then we just throw an
/// error about ambiguous paths.
fn ident_to_path(
    root: &Path,
    ident: &QualifiedIdent,
    search_on_parent: bool,
) -> Result<Option<PathBuf>, Box<dyn Diagnostic>> {
    let name = ident.to_string();
    let segments = name.as_str().split('.').collect::<Vec<&str>>();
    let mut raw_path = root.to_path_buf();

    raw_path.push(PathBuf::from(segments.join("/")));

    match accumulate_neighbour_paths(ident, &raw_path) {
        Ok(None) if search_on_parent => {
            raw_path.pop();
            accumulate_neighbour_paths(ident, &raw_path)
        }
        rest => rest,
    }
}

fn try_to_insert_new_name<'a>(
    failed: &mut bool,
    session: &'a Session,
    ident: QualifiedIdent,
    book: &'a mut Book,
) -> bool {
    if let Some(first_occorence) = book.names.get(ident.to_string().as_str()) {
        let err = Box::new(DriverDiagnostic::DefinedMultipleTimes(
            first_occorence.clone(),
            ident,
        ));

        session.diagnostic_sender.send(err).unwrap();
        *failed = true;
        false
    } else {
        book.names.insert(ident.to_string(), ident);
        true
    }
}

fn module_to_book<'a>(
    failed: &mut bool,
    session: &'a Session,
    module: Module,
    book: &'a mut Book,
) -> FxHashSet<String> {
    let mut public_names = FxHashSet::default();

    for entry in module.entries {
        match entry {
            TopLevel::SumType(sum) => {
                let name = sum.name.to_string();

                public_names.insert(name.clone());

                for cons in &sum.constructors {
                    let mut cons_ident = sum.name.add_segment(cons.name.to_str());
                    cons_ident.range = cons.name.range;
                    if try_to_insert_new_name(failed, session, cons_ident.clone(), book) {
                        let cons_name = cons_ident.to_string();
                        public_names.insert(cons_name.clone());
                        book.meta.insert(cons_name, cons.extract_book_info(&sum));
                    }
                }

                if try_to_insert_new_name(failed, session, sum.name.clone(), book) {
                    book.meta.insert(name.clone(), sum.extract_book_info());
                    book.entries.insert(name, TopLevel::SumType(sum));
                }
            }
            TopLevel::RecordType(rec) => {
                let name = rec.name.to_string();
                public_names.insert(name.clone());
                book.meta.insert(name.clone(), rec.extract_book_info());

                try_to_insert_new_name(failed, session, rec.name.clone(), book);

                let cons_ident = rec.name.add_segment(rec.constructor.to_str());
                public_names.insert(cons_ident.to_string());
                book.meta.insert(
                    cons_ident.to_string(),
                    rec.extract_book_info_of_constructor(),
                );

                try_to_insert_new_name(failed, session, cons_ident, book);

                book.entries.insert(name.clone(), TopLevel::RecordType(rec));
            }
            TopLevel::Entry(entr) => {
                let name = entr.name.to_string();

                try_to_insert_new_name(failed, session, entr.name.clone(), book);
                public_names.insert(name.clone());
                book.meta.insert(name.clone(), entr.extract_book_info());
                book.entries.insert(name, TopLevel::Entry(entr));
            }
        }
    }

    public_names
}

fn parse_and_store_book_by_identifier(
    session: &mut Session,
    ident: &QualifiedIdent,
    book: &mut Book,
) -> bool {
    if book.entries.contains_key(ident.to_string().as_str()) {
        return false;
    }

    match ident_to_path(&session.root, ident, true) {
        Ok(Some(path)) => parse_and_store_book_by_path(session, &path, book, false),
        Ok(None) => false,
        Err(err) => {
            session.diagnostic_sender.send(err).unwrap();
            true
        }
    }
}

fn read_file(session: &mut Session, path: &Path) -> Option<String> {
    match fs::read_to_string(path) {
        Ok(res) => Some(res),
        Err(_) => {
            session
                .diagnostic_sender
                .send(Box::new(DriverDiagnostic::CannotFindFile(
                    path.to_str().unwrap().to_string(),
                )))
                .unwrap();
            None
        }
    }
}

fn parse_and_store_book_by_path(session: &mut Session, path: &PathBuf, book: &mut Book, immediate: bool) -> bool {
    if !path.exists() {
        let err = Box::new(DriverDiagnostic::CannotFindFile(
            path.to_str().unwrap().to_string(),
        ));

        session.diagnostic_sender.send(err).unwrap();
        return true;
    }

    let canon_path = &fs::canonicalize(path).unwrap();

    if session.loaded_paths_map.contains_key(canon_path) {
        return false;
    }

    let Some(input) = read_file(session, path) else { return true };

    let ctx_id = session.book_counter;
    session.add_path(Rc::new(fs::canonicalize(path).unwrap()), input.clone());

    let tx = session.diagnostic_sender.clone();

    let (mut module, mut failed) = kind_parser::parse_book(tx.clone(), ctx_id, &input);

    expand_uses(&mut module, tx.clone());
    expand_module(tx.clone(), &mut module);

    let mut state = UnboundCollector::new(tx.clone(), false);
    state.visit_module(&mut module);

    module_to_book(&mut failed, session, module, book);

    for idents in state.unbound_top_level.values() {
        let fst = idents.iter().next().unwrap();

        if immediate && session.show_immediate_deps {
            println!("{}", fst);
        }

        if !book.names.contains_key(&fst.to_string()) {
            failed |= parse_and_store_book_by_identifier(session, fst, book);
        }
    }

    failed
}

pub fn get_unbound_variables(session: &mut Session, path: &Path) -> Option<Vec<String>> {
    let tx = session.diagnostic_sender.clone();

    let Some(input) = read_file(session, path) else { return None };

    let (mut module, _) = kind_parser::parse_book(tx.clone(), 0, &input);

    expand_uses(&mut module, tx.clone());
    expand_module(tx.clone(), &mut module);

    let mut state = UnboundCollector::new(tx.clone(), false);
    state.visit_module(&mut module);

    Some(state.unbound_top_level.keys().cloned().collect())
}


fn unbound_variable(session: &mut Session, book: &Book, idents: &[Ident]) {
    let mut similar_names = book
        .names
        .keys()
        .map(|x| (jaro(x, idents[0].to_str()).abs(), x))
        .filter(|x| x.0 > 0.8)
        .collect::<Vec<_>>();

    similar_names.sort_by(|x, y| x.0.total_cmp(&y.0));

    let err = Box::new(DriverDiagnostic::UnboundVariable(
        idents.to_vec(),
        similar_names.iter().take(5).map(|x| x.1.clone()).collect(),
    ));

    session.diagnostic_sender.send(err).unwrap();
}

pub fn parse_and_store_book(session: &mut Session, path: &PathBuf) -> anyhow::Result<Book> {
    let mut book = Book::default();
    if parse_and_store_book_by_path(session, path, &mut book, true) {
        Err(ResolutionError.into())
    } else {
        Ok(book)
    }
}

pub fn check_unbound_top_level(session: &mut Session, book: &mut Book) -> anyhow::Result<()> {
    let mut failed = false;

    let (unbound_names, unbound_tops) =
        unbound::get_book_unbound(session.diagnostic_sender.clone(), book, true);

    for unbound in unbound_tops.values() {
        let res: Vec<Ident> = unbound
            .iter()
            .filter(|x| !x.generated)
            .map(|x| x.to_ident())
            .collect();

        if !res.is_empty() {
            unbound_variable(session, book, &res);
            failed = true;
        }
    }

    for unbound in unbound_names.values() {
        unbound_variable(session, book, unbound);
        failed = true;
    }

    if failed {
        Err(ResolutionError.into())
    } else {
        Ok(())
    }
}