feat: Basic support of config files

Cargo.toml

@@ -9,3 +9,5 @@ edition = "2021"
 anyhow = "1.0.86"
 clap = { version = "4.5.4", features = ["derive"] }
 comrak = "0.24.1"
+serde = { version = "1.0.203", features = ["derive"] }
+toml = "0.8.14"

README.md

@@ -40,7 +40,20 @@ quickmark /path/to/file.md
 
 ### Configuration
 
-TBD
+Quickmark looks up for `quickmark.toml` configuration file in the current working directory. If the file was not found, the default is used.
+
+Below is a full configuration with default values:
+
+```toml
+[linters.severity]
+# possible values are: 'warn', 'err' and 'off'
+heading-increment = 'err'
+heading-style = 'err'
+
+# see a specific rule's doc for details of configuration
+[linters.settings.heading-style]
+style = 'consistent'
+```
 
 ## Rules
 

src/config/mod.rs

@@ -0,0 +1,179 @@
+use serde::Deserialize;
+use std::{
+    collections::{HashMap, HashSet},
+    fs,
+    path::Path,
+};
+
+use crate::rules::ALL_RULES;
+#[derive(Deserialize, Debug, PartialEq, Clone)]
+pub enum RuleSeverity {
+    #[serde(rename = "err")]
+    Error,
+    #[serde(rename = "warn")]
+    Warning,
+    #[serde(rename = "off")]
+    Off,
+}
+
+#[derive(Deserialize, Debug, PartialEq, Clone)]
+pub enum HeadingStyle {
+    #[serde(rename = "consistent")]
+    Consistent,
+    #[serde(rename = "atx")]
+    ATX,
+    #[serde(rename = "setext")]
+    Setext,
+}
+
+#[derive(Deserialize, Debug, PartialEq, Clone)]
+pub struct MD003HeadingStyleTable {
+    pub style: HeadingStyle,
+}
+
+impl Default for MD003HeadingStyleTable {
+    fn default() -> Self {
+        Self {
+            style: HeadingStyle::Consistent,
+        }
+    }
+}
+
+#[derive(Deserialize, Debug, Default, PartialEq, Clone)]
+pub struct LintersSettingsTable {
+    #[serde(rename = "heading-style")]
+    pub heading_style: MD003HeadingStyleTable,
+}
+
+#[derive(Deserialize, Debug, Default, PartialEq, Clone)]
+pub struct LintersTable {
+    pub severity: HashMap<String, RuleSeverity>,
+    pub settings: LintersSettingsTable,
+}
+
+#[derive(Deserialize, Debug, Default, PartialEq, Clone)]
+pub struct QuickmarkConfig {
+    pub linters: LintersTable,
+}
+
+fn normalize_severities(severities: &mut HashMap<String, RuleSeverity>) {
+    let rule_aliases: HashSet<&str> = ALL_RULES.iter().map(|r| r.alias).collect();
+    severities.retain(|key, _| rule_aliases.contains(key.as_str()));
+    for &rule in &rule_aliases {
+        severities
+            .entry(rule.to_string())
+            .or_insert(RuleSeverity::Error);
+    }
+}
+
+pub fn parse_config(config_str: &str) -> anyhow::Result<QuickmarkConfig> {
+    let mut res: QuickmarkConfig = toml::from_str(config_str)?;
+    normalize_severities(&mut res.linters.severity);
+    Ok(res)
+}
+
+pub fn config_in_path_or_default(path: &Path) -> anyhow::Result<QuickmarkConfig> {
+    let config_file = path.join("quickmark.toml");
+    if config_file.is_file() {
+        let config = fs::read_to_string(config_file)?;
+        return parse_config(&config);
+    };
+    println!(
+        "Config file was not found at {}. Default config will be used.",
+        config_file.to_string_lossy()
+    );
+    let mut config = QuickmarkConfig::default();
+    normalize_severities(&mut config.linters.severity);
+    Ok(config)
+}
+
+#[cfg(test)]
+mod test {
+    use std::path::Path;
+
+    use crate::config::{HeadingStyle, RuleSeverity};
+
+    use super::{config_in_path_or_default, parse_config};
+
+    const FIXTURES_PATH: &str = "tests/fixtures";
+
+    #[test]
+    pub fn test_deser() {
+        let config = r#"
+        [linters.severity]
+        heading-increment = 'warn'
+        heading-style = 'err'
+
+        [linters.settings.heading-style]
+        style = 'atx'
+        "#;
+
+        let parsed = parse_config(config).unwrap();
+        assert_eq!(
+            RuleSeverity::Warning,
+            *parsed.linters.severity.get("heading-increment").unwrap()
+        );
+        assert_eq!(
+            RuleSeverity::Error,
+            *parsed.linters.severity.get("heading-style").unwrap()
+        );
+        assert_eq!(
+            HeadingStyle::ATX,
+            parsed.linters.settings.heading_style.style
+        )
+    }
+
+    #[test]
+    pub fn test_normalize_severities() {
+        let config = r#"
+        [linters.severity]
+        heading-style = 'err'
+        some-bullshit = 'warn'
+
+        [linters.settings.heading-style]
+        style = 'atx'
+        "#;
+
+        let parsed = parse_config(config).unwrap();
+        assert_eq!(
+            RuleSeverity::Error,
+            *parsed.linters.severity.get("heading-increment").unwrap()
+        );
+        assert_eq!(None, parsed.linters.severity.get("some-bullshit"));
+    }
+    #[test]
+    pub fn test_get_config_from_file() {
+        let config = config_in_path_or_default(Path::new(FIXTURES_PATH))
+            .expect("get_config_in_pwd_or_default() failed");
+        assert_eq!(
+            RuleSeverity::Warning,
+            *config.linters.severity.get("heading-increment").unwrap()
+        );
+        assert_eq!(
+            RuleSeverity::Off,
+            *config.linters.severity.get("heading-style").unwrap()
+        );
+        assert_eq!(
+            HeadingStyle::ATX,
+            config.linters.settings.heading_style.style
+        );
+    }
+
+    #[test]
+    pub fn test_get_config_default() {
+        let config = config_in_path_or_default(Path::new("tests"))
+            .expect("get_config_in_pwd_or_default() failed");
+        assert_eq!(
+            RuleSeverity::Error,
+            *config.linters.severity.get("heading-increment").unwrap()
+        );
+        assert_eq!(
+            RuleSeverity::Error,
+            *config.linters.severity.get("heading-style").unwrap()
+        );
+        assert_eq!(
+            HeadingStyle::Consistent,
+            config.linters.settings.heading_style.style
+        );
+    }
+}

src/lib.rs

@@ -1,2 +1,3 @@
+pub mod config;
 pub mod linter;
 pub mod rules;