es_fluent_generate/

lib.rs

#![doc = include_str!("../README.md")]

use clap::ValueEnum;
use es_fluent_derive_core::namer::FluentKey;
use es_fluent_derive_core::registry::{FtlTypeInfo, FtlVariant};
use fluent_syntax::{ast, parser};
use indexmap::IndexMap;
use std::{collections::HashSet, fs, path::Path};

pub mod clean;
pub mod error;
pub mod formatting;
pub mod value;

use es_fluent_derive_core::EsFluentResult;
use value::ValueFormatter;

/// The mode to use when parsing Fluent files.
#[derive(Clone, Debug, Default, strum::Display, PartialEq, ValueEnum)]
#[strum(serialize_all = "snake_case")]
pub enum FluentParseMode {
    /// Overwrite existing translations.
    Aggressive,
    /// Preserve existing translations.
    #[default]
    Conservative,
}

// Internal owned types for merge operations
#[derive(Clone, Debug, Eq, Hash, PartialEq)]
struct OwnedVariant {
    name: String,
    ftl_key: String,
    args: Vec<String>,
}

impl From<&FtlVariant> for OwnedVariant {
    fn from(v: &FtlVariant) -> Self {
        Self {
            name: v.name.to_string(),
            ftl_key: v.ftl_key.to_string(),
            args: v.args.iter().map(|s| s.to_string()).collect(),
        }
    }
}

#[derive(Clone, Debug)]
struct OwnedTypeInfo {
    type_name: String,
    variants: Vec<OwnedVariant>,
}

impl From<&FtlTypeInfo> for OwnedTypeInfo {
    fn from(info: &FtlTypeInfo) -> Self {
        Self {
            type_name: info.type_name.to_string(),
            variants: info.variants.iter().map(OwnedVariant::from).collect(),
        }
    }
}

/// Generates a Fluent translation file from a list of `FtlTypeInfo` objects.
pub fn generate<P: AsRef<Path>, M: AsRef<Path>, I: AsRef<FtlTypeInfo>>(
    crate_name: &str,
    i18n_path: P,
    manifest_dir: M,
    items: &[I],
    mode: FluentParseMode,
    dry_run: bool,
) -> EsFluentResult<bool> {
    let i18n_path = i18n_path.as_ref();
    let manifest_dir = manifest_dir.as_ref();
    let items_ref: Vec<&FtlTypeInfo> = items.iter().map(|i| i.as_ref()).collect();

    // Group items by namespace
    let mut namespaced: IndexMap<Option<String>, Vec<&FtlTypeInfo>> = IndexMap::new();
    for item in &items_ref {
        let namespace = item.resolved_namespace(manifest_dir);
        namespaced.entry(namespace).or_default().push(item);
    }

    let mut any_changed = false;

    for (namespace, ns_items) in namespaced {
        let (dir_path, file_path) = match namespace {
            Some(ns) => {
                // Namespaced items go to {i18n_path}/{crate_name}/{namespace}.ftl
                let dir = i18n_path.join(crate_name);
                let file = dir.join(format!("{}.ftl", ns));
                (dir, file)
            },
            None => {
                // Non-namespaced items go to {i18n_path}/{crate_name}.ftl
                (
                    i18n_path.to_path_buf(),
                    i18n_path.join(format!("{}.ftl", crate_name)),
                )
            },
        };

        if !dry_run {
            fs::create_dir_all(&dir_path)?;
        }

        let existing_resource = read_existing_resource(&file_path)?;

        let final_resource = if matches!(mode, FluentParseMode::Aggressive) {
            build_target_resource(&ns_items)
        } else {
            smart_merge(existing_resource, &ns_items, MergeBehavior::Append)
        };

        if write_updated_resource(
            &file_path,
            &final_resource,
            dry_run,
            formatting::sort_ftl_resource,
        )? {
            any_changed = true;
        }
    }

    Ok(any_changed)
}

pub(crate) fn print_diff(old: &str, new: &str) {
    use colored::Colorize as _;
    use similar::{ChangeTag, TextDiff};

    let diff = TextDiff::from_lines(old, new);

    for (idx, group) in diff.grouped_ops(3).iter().enumerate() {
        if idx > 0 {
            println!("{}", "  ...".dimmed());
        }
        for op in group {
            for change in diff.iter_changes(op) {
                let sign = match change.tag() {
                    ChangeTag::Delete => "-",
                    ChangeTag::Insert => "+",
                    ChangeTag::Equal => " ",
                };
                let line = format!("{} {}", sign, change);
                match change.tag() {
                    ChangeTag::Delete => print!("{}", line.red()),
                    ChangeTag::Insert => print!("{}", line.green()),
                    ChangeTag::Equal => print!("{}", line.dimmed()),
                }
            }
        }
    }
}

/// Read and parse an existing FTL resource file.
///
/// Returns an empty resource if the file doesn't exist or is empty.
/// Logs warnings for parsing errors but continues with partial parse.
fn read_existing_resource(file_path: &Path) -> EsFluentResult<ast::Resource<String>> {
    if !file_path.exists() {
        return Ok(ast::Resource { body: Vec::new() });
    }

    let content = fs::read_to_string(file_path)?;
    if content.trim().is_empty() {
        return Ok(ast::Resource { body: Vec::new() });
    }

    match parser::parse(content) {
        Ok(res) => Ok(res),
        Err((res, errors)) => {
            tracing::warn!(
                "Warning: Encountered parsing errors in {}: {:?}",
                file_path.display(),
                errors
            );
            Ok(res)
        },
    }
}

/// Write an updated resource to disk, handling change detection and dry-run mode.
///
/// Returns `true` if the file was changed (or would be changed in dry-run mode).
fn write_updated_resource(
    file_path: &Path,
    resource: &ast::Resource<String>,
    dry_run: bool,
    formatter: impl Fn(&ast::Resource<String>) -> String,
) -> EsFluentResult<bool> {
    let is_empty = resource.body.is_empty();
    let final_content = if is_empty {
        String::new()
    } else {
        formatter(resource)
    };

    let current_content = if file_path.exists() {
        fs::read_to_string(file_path)?
    } else {
        String::new()
    };

    // Determine if content has changed
    let has_changed = match is_empty {
        true => current_content != final_content && !current_content.trim().is_empty(),
        false => current_content.trim() != final_content.trim(),
    };

    if !has_changed {
        log_unchanged(file_path, is_empty, dry_run);
        return Ok(false);
    }

    write_or_preview(
        file_path,
        &current_content,
        &final_content,
        is_empty,
        dry_run,
    )?;
    Ok(true)
}

/// Log that a file was unchanged (only when not in dry-run mode).
fn log_unchanged(file_path: &Path, is_empty: bool, dry_run: bool) {
    if dry_run {
        return;
    }
    let msg = match is_empty {
        true => format!(
            "FTL file unchanged (empty or no items): {}",
            file_path.display()
        ),
        false => format!("FTL file unchanged: {}", file_path.display()),
    };
    tracing::debug!("{}", msg);
}

/// Write changes to disk or preview them in dry-run mode.
fn write_or_preview(
    file_path: &Path,
    current_content: &str,
    final_content: &str,
    is_empty: bool,
    dry_run: bool,
) -> EsFluentResult<()> {
    if dry_run {
        let display_path = fs::canonicalize(file_path).unwrap_or_else(|_| file_path.to_path_buf());
        let msg = match (is_empty, !current_content.trim().is_empty()) {
            (true, true) => format!(
                "Would write empty FTL file (no items): {}",
                display_path.display()
            ),
            (true, false) => format!("Would write empty FTL file: {}", display_path.display()),
            (false, _) => format!("Would update FTL file: {}", display_path.display()),
        };
        println!("{}", msg);
        print_diff(current_content, final_content);
        println!();
        return Ok(());
    }

    if let Some(parent) = file_path.parent() {
        fs::create_dir_all(parent)?;
    }

    fs::write(file_path, final_content)?;
    let msg = match is_empty {
        true => format!("Wrote empty FTL file (no items): {}", file_path.display()),
        false => format!("Updated FTL file: {}", file_path.display()),
    };
    tracing::info!("{}", msg);
    Ok(())
}

/// Compares two type infos, putting "this" types first.
fn compare_type_infos(a: &OwnedTypeInfo, b: &OwnedTypeInfo) -> std::cmp::Ordering {
    // Infer is_this from variants
    let a_is_this = a
        .variants
        .iter()
        .any(|v| v.ftl_key.ends_with(FluentKey::THIS_SUFFIX));
    let b_is_this = b
        .variants
        .iter()
        .any(|v| v.ftl_key.ends_with(FluentKey::THIS_SUFFIX));

    formatting::compare_with_this_priority(a_is_this, &a.type_name, b_is_this, &b.type_name)
}

#[derive(Clone, Copy, Debug, PartialEq)]
pub(crate) enum MergeBehavior {
    /// Add new keys and preserve existing ones.
    Append,
    /// Remove orphan keys and empty groups, do not add new keys.
    Clean,
}

pub(crate) fn smart_merge(
    existing: ast::Resource<String>,
    items: &[&FtlTypeInfo],
    behavior: MergeBehavior,
) -> ast::Resource<String> {
    let mut pending_items = merge_ftl_type_infos(items);
    pending_items.sort_by(compare_type_infos);

    let mut item_map: IndexMap<String, OwnedTypeInfo> = pending_items
        .into_iter()
        .map(|i| (i.type_name.clone(), i))
        .collect();
    let mut key_to_group: IndexMap<String, String> = IndexMap::new();
    for (group_name, info) in &item_map {
        for variant in &info.variants {
            key_to_group.insert(variant.ftl_key.clone(), group_name.clone());
        }
    }
    let mut relocated_by_group: IndexMap<String, Vec<ast::Entry<String>>> = IndexMap::new();
    let mut late_relocated_by_group: IndexMap<String, Vec<ast::Entry<String>>> = IndexMap::new();
    let mut seen_groups: HashSet<String> = HashSet::new();
    let existing_keys = collect_existing_keys(&existing);
    let mut seen_keys: HashSet<String> = HashSet::new();

    let mut new_body = Vec::new();
    let mut current_group_name: Option<String> = None;
    let cleanup = matches!(behavior, MergeBehavior::Clean);

    for entry in existing.body {
        match entry {
            ast::Entry::GroupComment(ref comment) => {
                if let Some(ref old_group) = current_group_name
                    && let Some(info) = item_map.get_mut(old_group)
                {
                    // Only append missing variants if we are appending
                    if matches!(behavior, MergeBehavior::Append) {
                        if let Some(entries) = relocated_by_group.shift_remove(old_group) {
                            new_body.extend(entries);
                        }
                        if !info.variants.is_empty() {
                            for variant in &info.variants {
                                if !existing_keys.contains(&variant.ftl_key) {
                                    seen_keys.insert(variant.ftl_key.clone());
                                    new_body.push(create_message_entry(variant));
                                }
                            }
                        }
                    }
                    info.variants.clear();
                }

                if let Some(content) = comment.content.first() {
                    let trimmed = content.trim();
                    current_group_name = Some(trimmed.to_string());
                } else {
                    current_group_name = None;
                }

                let keep_group = if let Some(ref group_name) = current_group_name {
                    !cleanup || item_map.contains_key(group_name)
                } else {
                    true
                };

                if keep_group {
                    new_body.push(entry);
                }

                if let Some(ref group_name) = current_group_name {
                    seen_groups.insert(group_name.clone());
                }
            },
            ast::Entry::Message(msg) => {
                let key = msg.id.name.clone();
                let mut handled = false;
                let mut relocate_to: Option<String> = None;

                if seen_keys.contains(&key) {
                    continue;
                }

                if let Some(expected_group) = key_to_group.get(&key).cloned() {
                    if current_group_name.as_deref() != Some(expected_group.as_str())
                        && matches!(behavior, MergeBehavior::Append)
                    {
                        relocate_to = Some(expected_group.clone());
                    }
                    handled = true;

                    if let Some(info) = item_map.get_mut(&expected_group)
                        && let Some(idx) = info.variants.iter().position(|v| v.ftl_key == key)
                    {
                        info.variants.remove(idx);
                    }
                } else if !handled {
                    for info in item_map.values_mut() {
                        if let Some(idx) = info.variants.iter().position(|v| v.ftl_key == key) {
                            info.variants.remove(idx);
                            handled = true;
                            break;
                        }
                    }
                }

                if let Some(group_name) = relocate_to {
                    seen_keys.insert(key);
                    if seen_groups.contains(&group_name) {
                        late_relocated_by_group
                            .entry(group_name)
                            .or_default()
                            .push(ast::Entry::Message(msg));
                    } else {
                        relocated_by_group
                            .entry(group_name)
                            .or_default()
                            .push(ast::Entry::Message(msg));
                    }
                } else if handled || !cleanup {
                    seen_keys.insert(key);
                    new_body.push(ast::Entry::Message(msg));
                }
            },
            ast::Entry::Term(ref term) => {
                let key = format!("{}{}", FluentKey::DELIMITER, term.id.name);
                let mut handled = false;
                if seen_keys.contains(&key) {
                    continue;
                }
                for info in item_map.values_mut() {
                    if let Some(idx) = info.variants.iter().position(|v| v.ftl_key == key) {
                        info.variants.remove(idx);
                        handled = true;
                        break;
                    }
                }

                if handled || !cleanup {
                    seen_keys.insert(key);
                    new_body.push(entry);
                }
            },
            ast::Entry::Junk { .. } => {
                new_body.push(entry);
            },
            _ => {
                new_body.push(entry);
            },
        }
    }

    // Correctly handle the end of the last group
    if let Some(ref last_group) = current_group_name
        && let Some(info) = item_map.get_mut(last_group)
    {
        // Only append missing variants if we are appending
        if matches!(behavior, MergeBehavior::Append) {
            if let Some(entries) = relocated_by_group.shift_remove(last_group) {
                new_body.extend(entries);
            }
            if !info.variants.is_empty() {
                for variant in &info.variants {
                    if !existing_keys.contains(&variant.ftl_key) {
                        seen_keys.insert(variant.ftl_key.clone());
                        new_body.push(create_message_entry(variant));
                    }
                }
            }
        }
        info.variants.clear();
    }

    // Only append remaining new groups if we are appending
    if matches!(behavior, MergeBehavior::Append) {
        let mut remaining_groups: Vec<_> = item_map.into_iter().collect();
        remaining_groups.sort_by(|(_, a), (_, b)| compare_type_infos(a, b));

        for (type_name, info) in remaining_groups {
            let relocated = relocated_by_group.shift_remove(&type_name);
            let has_missing = info
                .variants
                .iter()
                .any(|variant| !existing_keys.contains(&variant.ftl_key));
            if has_missing || relocated.is_some() {
                new_body.push(create_group_comment_entry(&type_name));
                if let Some(entries) = relocated {
                    new_body.extend(entries);
                }
                for variant in info.variants {
                    if !existing_keys.contains(&variant.ftl_key) {
                        seen_keys.insert(variant.ftl_key.clone());
                        new_body.push(create_message_entry(&variant));
                    }
                }
            }
        }
    }

    let mut resource = ast::Resource { body: new_body };

    if matches!(behavior, MergeBehavior::Append) && !late_relocated_by_group.is_empty() {
        insert_late_relocated(&mut resource.body, &late_relocated_by_group);
    }
    if cleanup {
        remove_empty_group_comments(resource)
    } else {
        resource
    }
}

fn group_comment_name(comment: &ast::Comment<String>) -> Option<String> {
    comment
        .content
        .first()
        .map(|line| line.trim())
        .filter(|line| !line.is_empty())
        .map(|line| line.to_string())
}

fn collect_existing_keys(resource: &ast::Resource<String>) -> HashSet<String> {
    let mut keys = HashSet::new();
    for entry in &resource.body {
        match entry {
            ast::Entry::Message(msg) => {
                keys.insert(msg.id.name.clone());
            },
            ast::Entry::Term(term) => {
                keys.insert(format!("{}{}", FluentKey::DELIMITER, term.id.name));
            },
            _ => {},
        }
    }
    keys
}

fn insert_late_relocated(
    body: &mut Vec<ast::Entry<String>>,
    late_relocated_by_group: &IndexMap<String, Vec<ast::Entry<String>>>,
) {
    let mut group_positions: Vec<(String, usize)> = Vec::new();
    for (idx, entry) in body.iter().enumerate() {
        if let ast::Entry::GroupComment(comment) = entry
            && let Some(name) = group_comment_name(comment)
        {
            group_positions.push((name, idx));
        }
    }

    if group_positions.is_empty() {
        return;
    }

    let mut inserted: HashSet<String> = HashSet::new();
    for (i, (name, _start)) in group_positions.iter().enumerate().rev() {
        if inserted.contains(name) {
            continue;
        }
        let end = if i + 1 < group_positions.len() {
            group_positions[i + 1].1
        } else {
            body.len()
        };
        if let Some(entries) = late_relocated_by_group.get(name)
            && !entries.is_empty()
        {
            body.splice(end..end, entries.clone());
        }
        inserted.insert(name.clone());
    }
}

fn remove_empty_group_comments(resource: ast::Resource<String>) -> ast::Resource<String> {
    let mut body: Vec<ast::Entry<String>> = Vec::with_capacity(resource.body.len());
    let mut pending_group: Option<ast::Entry<String>> = None;
    let mut pending_entries: Vec<ast::Entry<String>> = Vec::new();
    let mut has_message = false;

    let flush_pending = |body: &mut Vec<ast::Entry<String>>,
                         pending_group: &mut Option<ast::Entry<String>>,
                         pending_entries: &mut Vec<ast::Entry<String>>,
                         has_message: &mut bool| {
        if let Some(group_comment) = pending_group.take() {
            if *has_message {
                body.push(group_comment);
            }
            body.append(pending_entries);
        }
        *has_message = false;
    };

    for entry in resource.body {
        match entry {
            ast::Entry::GroupComment(_) => {
                flush_pending(
                    &mut body,
                    &mut pending_group,
                    &mut pending_entries,
                    &mut has_message,
                );
                pending_group = Some(entry);
                pending_entries = Vec::new();
            },
            ast::Entry::Message(_) | ast::Entry::Term(_) => {
                if pending_group.is_some() {
                    has_message = true;
                    pending_entries.push(entry);
                } else {
                    body.push(entry);
                }
            },
            _ => {
                if pending_group.is_some() {
                    pending_entries.push(entry);
                } else {
                    body.push(entry);
                }
            },
        }
    }

    flush_pending(
        &mut body,
        &mut pending_group,
        &mut pending_entries,
        &mut has_message,
    );

    ast::Resource { body }
}

fn create_group_comment_entry(type_name: &str) -> ast::Entry<String> {
    ast::Entry::GroupComment(ast::Comment {
        content: vec![type_name.to_owned()],
    })
}

fn create_message_entry(variant: &OwnedVariant) -> ast::Entry<String> {
    let message_id = ast::Identifier {
        name: variant.ftl_key.clone(),
    };

    let base_value = ValueFormatter::expand(&variant.name);

    let mut elements = vec![ast::PatternElement::TextElement { value: base_value }];

    for arg_name in &variant.args {
        elements.push(ast::PatternElement::TextElement { value: " ".into() });

        elements.push(ast::PatternElement::Placeable {
            expression: ast::Expression::Inline(ast::InlineExpression::VariableReference {
                id: ast::Identifier {
                    name: arg_name.clone(),
                },
            }),
        });
    }

    let pattern = ast::Pattern { elements };

    ast::Entry::Message(ast::Message {
        id: message_id,
        value: Some(pattern),
        attributes: Vec::new(),
        comment: None,
    })
}

fn merge_ftl_type_infos(items: &[&FtlTypeInfo]) -> Vec<OwnedTypeInfo> {
    use std::collections::BTreeMap;

    // Group by type_name. Callers already separate items by namespace.
    let mut grouped: BTreeMap<String, Vec<OwnedVariant>> = BTreeMap::new();

    for item in items {
        let entry = grouped.entry(item.type_name.to_string()).or_default();
        entry.extend(item.variants.iter().map(OwnedVariant::from));
    }

    grouped
        .into_iter()
        .map(|(type_name, mut variants)| {
            variants.sort_by(|a, b| {
                let a_is_this = a.ftl_key.ends_with(FluentKey::THIS_SUFFIX);
                let b_is_this = b.ftl_key.ends_with(FluentKey::THIS_SUFFIX);
                formatting::compare_with_this_priority(a_is_this, &a.name, b_is_this, &b.name)
            });
            variants.dedup();

            OwnedTypeInfo {
                type_name,
                variants,
            }
        })
        .collect()
}

fn build_target_resource(items: &[&FtlTypeInfo]) -> ast::Resource<String> {
    let items = merge_ftl_type_infos(items);
    let mut body: Vec<ast::Entry<String>> = Vec::new();
    let mut sorted_items = items.to_vec();
    sorted_items.sort_by(compare_type_infos);

    for info in &sorted_items {
        body.push(create_group_comment_entry(&info.type_name));

        for variant in &info.variants {
            body.push(create_message_entry(variant));
        }
    }

    ast::Resource { body }
}