cfgmatic_source/infrastructure/

file_source.rs

//! File source implementation.
//!
//! [`FileSource`] loads configuration from files in various formats
//! (TOML, JSON, YAML). It supports single files and directories.

use std::path::{Path, PathBuf};

use cfgmatic_merge::Merge;

use crate::domain::{Format, RawContent, Result, Source, SourceError, SourceKind, SourceMetadata};

/// Builder for [`FileSource`].
#[derive(Debug)]
pub struct FileSourceBuilder {
    paths: Vec<PathBuf>,
    required: bool,
}

impl FileSourceBuilder {
    /// Create a new builder.
    #[must_use]
    pub fn new() -> Self {
        Self {
            paths: Vec::new(),
            required: true,
        }
    }

    /// Add a file path.
    #[must_use]
    pub fn path(mut self, path: impl Into<PathBuf>) -> Self {
        self.paths.push(path.into());
        self
    }

    /// Add multiple file paths.
    #[must_use]
    pub fn paths(mut self, paths: impl IntoIterator<Item = impl Into<PathBuf>>) -> Self {
        self.paths.extend(paths.into_iter().map(|p| p.into()));
        self
    }

    /// Set whether the source is required.
    #[must_use]
    pub fn required(mut self, required: bool) -> Self {
        self.required = required;
        self
    }

    /// Build the file source.
    ///
    /// # Errors
    ///
    /// Returns an error if no paths are configured.
    pub fn build(self) -> Result<FileSource> {
        if self.paths.is_empty() {
            return Err(SourceError::validation("No file paths configured"));
        }
        Ok(FileSource {
            paths: self.paths,
            required: self.required,
        })
    }
}

impl Default for FileSourceBuilder {
    fn default() -> Self {
        Self::new()
    }
}

/// File-based configuration source.
///
/// Loads configuration from files in various formats.
///
/// # Example
///
/// ```rust,ignore
/// use cfgmatic_source::FileSource;
///
/// let source = FileSource::builder()
///     .path("config.toml")
///     .path("config.local.toml")
///     .required(false)
///     .build()?;
///
/// let raw = source.load_raw()?;
/// ```
#[derive(Debug)]
pub struct FileSource {
    /// File paths to load.
    pub(crate) paths: Vec<PathBuf>,
    /// Whether the source is required.
    required: bool,
}

impl FileSource {
    /// Create a new file source.
    #[must_use]
    pub fn new(path: impl Into<PathBuf>) -> Self {
        Self {
            paths: vec![path.into()],
            required: true,
        }
    }

    /// Create a builder for file source.
    #[must_use]
    pub fn builder() -> FileSourceBuilder {
        FileSourceBuilder::new()
    }

    /// Detect format from file extension.
    fn detect_format_from_path(path: &Path) -> Option<Format> {
        Format::from_path(path)
    }

    /// Read file contents.
    fn read_file(path: &Path) -> Result<String> {
        std::fs::read_to_string(path)
            .map_err(|e| SourceError::read_failed(&format!("{}: {}", path.display(), e)))
    }

    /// Parse content based on format and convert to JSON value.
    fn parse_to_json_value(
        content: &str,
        format: Format,
        path: &Path,
    ) -> Result<serde_json::Value> {
        match format {
            #[cfg(feature = "toml")]
            Format::Toml => {
                let v: toml::Value = toml::from_str(content).map_err(|e| {
                    SourceError::parse_failed(&path.display().to_string(), "toml", &e.to_string())
                })?;
                serde_json::to_value(v).map_err(|e| SourceError::serialization(&e.to_string()))
            }

            #[cfg(feature = "json")]
            Format::Json => serde_json::from_str(content).map_err(|e| {
                SourceError::parse_failed(&path.display().to_string(), "json", &e.to_string())
            }),

            #[cfg(feature = "yaml")]
            Format::Yaml => serde_yaml::from_str(content).map_err(|e| {
                SourceError::parse_failed(&path.display().to_string(), "yaml", &e.to_string())
            }),

            Format::Unknown => Err(SourceError::unsupported("unknown format")),
        }
    }
}

impl Source for FileSource {
    fn kind(&self) -> SourceKind {
        SourceKind::File
    }

    fn metadata(&self) -> SourceMetadata {
        let path = self.paths.first().cloned().unwrap_or_default();
        SourceMetadata::new("file")
            .with_path(path)
            .with_priority(100)
            .with_optional(!self.required)
    }

    fn load_raw(&self) -> Result<RawContent> {
        // For single file, just load it
        if self.paths.len() == 1 {
            let path = &self.paths[0];
            if !path.exists() {
                if self.required {
                    return Err(SourceError::not_found(&path.display().to_string()));
                }
                return Ok(RawContent::from_string(""));
            }

            let content = Self::read_file(path)?;
            return Ok(RawContent::from_string(content).with_source_path(path.clone()));
        }

        // For multiple files, merge them
        let mut merged = serde_json::Value::Object(serde_json::Map::new());
        let mut any_loaded = false;

        for path in &self.paths {
            if !path.exists() {
                if self.required {
                    return Err(SourceError::not_found(&path.display().to_string()));
                }
                continue;
            }

            let content = Self::read_file(path)?;
            let format = Self::detect_format_from_path(path).ok_or_else(|| {
                SourceError::invalid_format(
                    "config",
                    &path.extension().unwrap_or_default().to_string_lossy(),
                )
            })?;

            let value = Self::parse_to_json_value(&content, format, path)?;

            merged = merged
                .merge_deep(value)
                .map_err(|e| SourceError::serialization(&e.to_string()))?;
            any_loaded = true;
        }

        if !any_loaded && self.required {
            return Err(SourceError::not_found("No configuration files found"));
        }

        let content = serde_json::to_string(&merged)
            .map_err(|e| SourceError::serialization(&e.to_string()))?;

        Ok(RawContent::from_string(content))
    }

    fn detect_format(&self) -> Option<Format> {
        self.paths.first().and_then(|p| Format::from_path(p))
    }

    fn is_required(&self) -> bool {
        self.required
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::io::Write;
    use tempfile::NamedTempFile;

    fn create_temp_file(content: &str, extension: &str) -> NamedTempFile {
        let mut file = NamedTempFile::with_suffix(extension).unwrap();
        write!(file, "{}", content).unwrap();
        file
    }

    #[test]
    fn test_file_source_builder() {
        let source = FileSource::builder()
            .path("/etc/config.toml")
            .required(false)
            .build()
            .unwrap();

        assert!(!source.is_required());
        assert_eq!(source.paths.len(), 1);
    }

    #[test]
    fn test_file_source_builder_no_paths() {
        let result = FileSource::builder().build();
        assert!(result.is_err());
    }

    #[test]
    fn test_detect_format() {
        assert_eq!(
            FileSource::detect_format_from_path(Path::new("config.toml")),
            Some(Format::Toml)
        );
        assert_eq!(
            FileSource::detect_format_from_path(Path::new("config.json")),
            Some(Format::Json)
        );
        #[cfg(feature = "yaml")]
        {
            assert_eq!(
                FileSource::detect_format_from_path(Path::new("config.yaml")),
                Some(Format::Yaml)
            );
            assert_eq!(
                FileSource::detect_format_from_path(Path::new("config.yml")),
                Some(Format::Yaml)
            );
        }
        assert_eq!(
            FileSource::detect_format_from_path(Path::new("config.txt")),
            None
        );
    }

    #[cfg(feature = "toml")]
    #[test]
    fn test_load_raw_toml() {
        let content = r#"
        name = "test"
        value = 42
        "#;
        let file = create_temp_file(content, ".toml");

        let source = FileSource::new(file.path());
        let raw = source.load_raw().unwrap();
        let str_content = raw.as_str().unwrap();
        assert!(str_content.as_ref().contains("test"));
    }

    #[cfg(feature = "json")]
    #[test]
    fn test_load_raw_json() {
        let content = r#"{"name": "test", "value": 42}"#;
        let file = create_temp_file(content, ".json");

        let source = FileSource::new(file.path());
        let raw = source.load_raw().unwrap();
        let str_content = raw.as_str().unwrap();
        assert!(str_content.as_ref().contains("test"));
    }

    #[test]
    fn test_load_file_not_found() {
        let source = FileSource::new("/nonexistent/config.toml");
        let result = source.load_raw();
        assert!(result.is_err());
    }

    #[test]
    fn test_load_optional_file_not_found() {
        let source = FileSource::builder()
            .path("/nonexistent/config.toml")
            .required(false)
            .build()
            .unwrap();

        let raw = source.load_raw().unwrap();
        assert!(raw.is_empty());
    }

    #[test]
    fn test_metadata() {
        let source = FileSource::new("config.toml");
        let meta = source.metadata();

        assert_eq!(meta.name, "file");
        assert_eq!(source.kind(), SourceKind::File);
        assert_eq!(meta.priority, 100);
    }
}