bynk-project 0.303.4

use std::collections::{BTreeMap, HashMap};
use std::path::{Path, PathBuf};

use bynk_syntax::error::CompileError;

use crate::discovery::ParsedFile;
use crate::paths::unit_path_matches;
use crate::roots::UnitKind;

/// Within a multi-file unit (i.e., 2+ files in the same directory that share
/// a qualified name), every file must declare exactly the same name.
///
/// In v0.4 the same directory may contain multiple *single-file* units (one
/// commons and one context, say), provided each file's path matches the
/// last segment of its declared qualified name. Mixed-name files in one
/// directory are only flagged when they collide on the same name (handled by
/// [`check_group_kind_consistency`]) or when path/name alignment fails.
///
/// Each error is paired with the project-relative `identity_path` of the file
/// its **primary** span belongs to (#696) so the CLI can render it against that
/// file's source. The "first file" it compares against is a *different* file, so
/// its location is carried as a note (not a label, which would underline this
/// file's own text).
pub fn check_directory_name_consistency(
    parsed: &[ParsedFile],
) -> Result<(), Vec<(PathBuf, CompileError)>> {
    let mut errors: Vec<(PathBuf, CompileError)> = Vec::new();
    // For each unit (group of files sharing the same name), verify they all
    // live in the same directory. Tests are excluded — their files are
    // grouped by target, not by their own physical layout.
    let mut by_name: HashMap<String, Vec<usize>> = HashMap::new();
    for (i, pf) in parsed.iter().enumerate() {
        if matches!(pf.kind, UnitKind::Test | UnitKind::Integration) {
            continue;
        }
        by_name.entry(pf.unit.name().joined()).or_default().push(i);
    }
    for indices in by_name.values() {
        if indices.len() < 2 {
            continue;
        }
        let first_dir = parsed[indices[0]]
            .source_path
            .parent()
            .unwrap_or(Path::new(""))
            .to_path_buf();
        for &idx in indices.iter().skip(1) {
            let dir = parsed[idx]
                .source_path
                .parent()
                .unwrap_or(Path::new(""))
                .to_path_buf();
            if dir != first_dir {
                errors.push((
                    parsed[idx].identity_path.clone(),
                    CompileError::new(
                        "bynk.project.inconsistent_commons_name",
                        parsed[idx].unit.span(),
                        format!(
                            "files declaring `{}` are spread across different directories: `{}` vs `{}`",
                            parsed[idx].unit.name().joined(),
                            first_dir.display(),
                            dir.display(),
                        ),
                    )
                    // The first file is a *different* file than the one this error
                    // is attributed to (`parsed[idx]`), so its span can't be a
                    // label here — it would underline this file's own text (#696).
                    // Carry its location as a note instead.
                    .with_note(format!(
                        "the first file declaring `{}` is `{}`",
                        parsed[idx].unit.name().joined(),
                        parsed[indices[0]].identity_path.to_string_lossy().replace('\\', "/"),
                    ))
                    .with_note(
                        "all files of a multi-file commons or context must live in the same directory",
                    ),
                ));
            }
        }
    }
    if errors.is_empty() {
        Ok(())
    } else {
        Err(errors)
    }
}

/// Within a multi-file unit (files sharing a qualified name), every file must
/// agree on kind. Handled by [`check_group_kind_consistency`]; this check is
/// the v0.4-style directory-level guard which now defers to it.
pub fn check_directory_kind_consistency(_parsed: &[ParsedFile]) -> Result<(), Vec<CompileError>> {
    Ok(())
}

/// Each file's relative path must match its declared qualified name. Two
/// arrangements are valid:
/// - **Single-file**: `a/b/c.bynk` declaring `a.b.c`.
/// - **Multi-file**: `a/b/c/<any>.bynk` declaring `a.b.c`.
pub fn check_path_name_alignment(
    parsed: &[ParsedFile],
) -> Result<(), Vec<(PathBuf, CompileError)>> {
    let mut errors: Vec<(PathBuf, CompileError)> = Vec::new();
    for pf in parsed {
        if matches!(pf.kind, UnitKind::Test | UnitKind::Integration) {
            // Test files are not required to match their target's path.
            continue;
        }
        let name = pf.unit.name().joined();
        let name_parts: Vec<&str> = name.split('.').collect();
        let rel = &pf.source_path;
        if !unit_path_matches(rel, &name) {
            errors.push((
                pf.identity_path.clone(),
                CompileError::new(
                    "bynk.project.inconsistent_commons_name",
                    pf.unit.span(),
                    format!(
                        "file `{}` declares `{name}`, but its path doesn't match — expected either `{}.bynk` (single-file) or `{}/...bynk` (multi-file)",
                        rel.display(),
                        name_parts.join("/"),
                        name_parts.join("/"),
                    ),
                )
                .with_note(
                    "the source-tree layout determines a unit's identity: each commons or context's qualified name must match its path",
                ),
            ));
        }
    }
    if errors.is_empty() {
        Ok(())
    } else {
        Err(errors)
    }
}

/// Files grouped by qualified name must agree on kind (even across directories).
pub fn check_group_kind_consistency(
    parsed: &[ParsedFile],
    groups: &BTreeMap<String, Vec<usize>>,
) -> Result<(), Vec<(PathBuf, CompileError)>> {
    let mut errors: Vec<(PathBuf, CompileError)> = Vec::new();
    for (name, indices) in groups {
        if indices.len() < 2 {
            continue;
        }
        let first_kind = parsed[indices[0]].kind;
        for &idx in indices.iter().skip(1) {
            if parsed[idx].kind != first_kind {
                errors.push((
                    parsed[idx].identity_path.clone(),
                    CompileError::new(
                        "bynk.project.kind_conflict",
                        parsed[idx].unit.span(),
                        format!(
                            "name `{name}` is declared as both a {} and a {}",
                            first_kind.display(),
                            parsed[idx].kind.display(),
                        ),
                    )
                    // A kind conflict is *always* cross-file (two files sharing a
                    // name), so the "first declared" site lives in another file
                    // (#696) — carry it as a note, not a label that would
                    // underline this file's own declaration.
                    .with_note(format!(
                        "first declared as a {} in `{}`",
                        first_kind.display(),
                        parsed[indices[0]]
                            .identity_path
                            .to_string_lossy()
                            .replace('\\', "/"),
                    )),
                ));
            }
        }
    }
    if errors.is_empty() {
        Ok(())
    } else {
        Err(errors)
    }
}