thread-rule-engine 0.1.0

// SPDX-FileCopyrightText: 2022 Herrington Darkholme <2883231+HerringtonDarkholme@users.noreply.github.com>
// SPDX-FileCopyrightText: 2025 Knitli Inc. <knitli@knit.li>
// SPDX-FileContributor: Adam Poulemanos <adam@knit.li>
//
// SPDX-License-Identifier: AGPL-3.0-or-later AND MIT

use crate::{RuleConfig, Severity};
use globset::{Glob, GlobSet, GlobSetBuilder};
use std::path::Path;
use thread_ast_engine::language::Language;

/// RuleBucket stores rules of the same language id.
/// Rules for different language will stay in separate buckets.
pub struct RuleBucket<L: Language> {
    rules: Vec<RuleConfig<L>>,
    lang: L,
}

impl<L: Language> RuleBucket<L> {
    fn new(lang: L) -> Self {
        Self {
            rules: vec![],
            lang,
        }
    }
    pub fn add(&mut self, rule: RuleConfig<L>) {
        self.rules.push(rule);
    }
}

struct ContingentRule<L: Language> {
    rule: RuleConfig<L>,
    files_globs: Option<GlobSet>,
    ignore_globs: Option<GlobSet>,
}

fn build_glob_set(paths: &Vec<String>) -> Result<GlobSet, globset::Error> {
    let mut builder = GlobSetBuilder::new();
    for path in paths {
        builder.add(Glob::new(path)?);
    }
    builder.build()
}

impl<L> TryFrom<RuleConfig<L>> for ContingentRule<L>
where
    L: Language,
{
    type Error = globset::Error;
    fn try_from(rule: RuleConfig<L>) -> Result<Self, Self::Error> {
        let files_globs = rule.files.as_ref().map(build_glob_set).transpose()?;
        let ignore_globs = rule.ignores.as_ref().map(build_glob_set).transpose()?;
        Ok(Self {
            rule,
            files_globs,
            ignore_globs,
        })
    }
}

impl<L: Language> ContingentRule<L> {
    pub fn matches_path<P: AsRef<Path>>(&self, path: P) -> bool {
        if let Some(ignore_globs) = &self.ignore_globs
            && ignore_globs.is_match(&path)
        {
            return false;
        }
        if let Some(files_globs) = &self.files_globs {
            return files_globs.is_match(path);
        }
        true
    }
}

/// A collection of rules to run one round of scanning.
/// Rules will be grouped together based on their language, path globbing and pattern rule.
pub struct RuleCollection<L: Language + Eq> {
    // use vec since we don't have many languages
    /// a list of rule buckets grouped by languages.
    /// Tenured rules will always run against a file of that language type.
    tenured: Vec<RuleBucket<L>>,
    /// contingent rules will run against a file if it matches file/ignore glob.
    contingent: Vec<ContingentRule<L>>,
}

impl<L: Language + Eq> RuleCollection<L> {
    pub fn try_new(configs: Vec<RuleConfig<L>>) -> Result<Self, globset::Error> {
        let mut tenured = vec![];
        let mut contingent = vec![];
        for config in configs {
            if matches!(config.severity, Severity::Off) {
                continue;
            } else if config.files.is_none() && config.ignores.is_none() {
                Self::add_tenured_rule(&mut tenured, config);
            } else {
                contingent.push(ContingentRule::try_from(config)?);
            }
        }
        Ok(Self {
            tenured,
            contingent,
        })
    }

    pub fn get_rule_from_lang(&self, path: &Path, lang: L) -> Vec<&RuleConfig<L>> {
        let mut all_rules = vec![];
        for rule in &self.tenured {
            if rule.lang == lang {
                all_rules = rule.rules.iter().collect();
                break;
            }
        }
        all_rules.extend(self.contingent.iter().filter_map(|cont| {
            if cont.rule.language == lang && cont.matches_path(path) {
                Some(&cont.rule)
            } else {
                None
            }
        }));
        all_rules
    }

    pub fn for_path<P: AsRef<Path>>(&self, path: P) -> Vec<&RuleConfig<L>> {
        let path = path.as_ref();
        let Some(lang) = L::from_path(path) else {
            return vec![];
        };
        let mut ret = self.get_rule_from_lang(path, lang);
        ret.sort_unstable_by_key(|r| &r.id);
        ret
    }

    pub fn get_rule(&self, id: &str) -> Option<&RuleConfig<L>> {
        for rule in &self.tenured {
            for r in &rule.rules {
                if r.id == id {
                    return Some(r);
                }
            }
        }
        for rule in &self.contingent {
            if rule.rule.id == id {
                return Some(&rule.rule);
            }
        }
        None
    }

    pub fn total_rule_count(&self) -> usize {
        let mut ret = self.tenured.iter().map(|bucket| bucket.rules.len()).sum();
        ret += self.contingent.len();
        ret
    }

    pub fn for_each_rule(&self, mut f: impl FnMut(&RuleConfig<L>)) {
        for bucket in &self.tenured {
            for rule in &bucket.rules {
                f(rule);
            }
        }
        for rule in &self.contingent {
            f(&rule.rule);
        }
    }

    fn add_tenured_rule(tenured: &mut Vec<RuleBucket<L>>, rule: RuleConfig<L>) {
        let lang = rule.language.clone();
        for bucket in tenured.iter_mut() {
            if bucket.lang == lang {
                bucket.add(rule);
                return;
            }
        }
        let mut bucket = RuleBucket::new(lang);
        bucket.add(rule);
        tenured.push(bucket);
    }
}

impl<L: Language + Eq> Default for RuleCollection<L> {
    fn default() -> Self {
        Self {
            tenured: vec![],
            contingent: vec![],
        }
    }
}

#[cfg(test)]
mod test {
    use super::*;
    use crate::GlobalRules;
    use crate::from_yaml_string;
    use crate::test::TypeScript;

    fn make_rule(files: &str) -> RuleCollection<TypeScript> {
        let globals = GlobalRules::default();
        let rule_config = from_yaml_string(
            &format!(
                r"
id: test
message: test rule
severity: info
language: Tsx
rule:
  all: [kind: number]
{files}"
            ),
            &globals,
        )
        .unwrap()
        .pop()
        .unwrap();
        RuleCollection::try_new(vec![rule_config]).expect("should parse")
    }

    fn assert_match_path(collection: &RuleCollection<TypeScript>, path: &str) {
        let rules = collection.for_path(path);
        assert_eq!(rules.len(), 1);
        assert_eq!(rules[0].id, "test");
    }

    fn assert_ignore_path(collection: &RuleCollection<TypeScript>, path: &str) {
        let rules = collection.for_path(path);
        assert!(rules.is_empty());
    }

    #[test]
    fn test_ignore_rule() {
        let src = r#"
ignores:
  - ./manage.py
  - "**/test*"
"#;
        let collection = make_rule(src);
        assert_ignore_path(&collection, "./manage.py");
        assert_ignore_path(&collection, "./src/test.py");
        assert_match_path(&collection, "./src/app.py");
    }

    #[test]
    fn test_files_rule() {
        let src = r#"
files:
  - ./manage.py
  - "**/test*"
"#;
        let collection = make_rule(src);
        assert_match_path(&collection, "./manage.py");
        assert_match_path(&collection, "./src/test.py");
        assert_ignore_path(&collection, "./src/app.py");
    }

    #[test]
    fn test_files_with_ignores_rule() {
        let src = r#"
files:
  - ./src/**/*.py
ignores:
  - ./src/excluded/*.py
"#;
        let collection = make_rule(src);
        assert_match_path(&collection, "./src/test.py");
        assert_match_path(&collection, "./src/some_folder/test.py");
        assert_ignore_path(&collection, "./src/excluded/app.py");
    }

    #[test]
    fn test_rule_collection_get_contingent_rule() {
        let src = r#"
files:
  - ./manage.py
  - "**/test*"
"#;
        let collection = make_rule(src);
        assert!(collection.get_rule("test").is_some());
    }

    #[test]
    fn test_rule_collection_get_tenured_rule() {
        let src = r#""#;
        let collection = make_rule(src);
        assert!(collection.get_rule("test").is_some());
    }

    #[test]
    #[ignore]
    fn test_rules_for_path() {
        todo!()
    }
}