docs: Add comprehensive rustdoc to common module functions

Co-authored-by: aider (openai/andrew/openrouter/sonoma-sky-alpha) <aider@aider.chat>

src/modes/common.rs

@@ -1,3 +1,17 @@
+/// Common utilities shared across different modes in the Keep application.
+///
+/// This module provides helper functions for formatting, configuration parsing,
+/// table creation, and environment variable handling used by various CLI modes.
+///
+/// # Usage
+///
+/// These utilities are typically used internally by mode implementations:
+///
+/// ```
+/// use crate::modes::common::{format_size, OutputFormat};
+/// let formatted = format_size(1024, true); // "1.0K"
+/// let format = OutputFormat::from_str("json")?;
+/// ```
 use crate::config;
 use crate::compression_engine::CompressionType;
 use crate::meta_plugin::MetaPluginType;
@@ -11,6 +25,16 @@ use std::env;
 use std::io::IsTerminal;
 use std::str::FromStr;
 use strum::IntoEnumIterator;
+
+/// Enum representing supported output formats for structured data.
+///
+/// Used to determine how to display lists, info, and status information.
+///
+/// # Variants
+///
+/// * `Table` - Formatted table output (default).
+/// * `Json` - JSON structured output.
+/// * `Yaml` - YAML structured output.
 #[derive(Debug, Clone, strum::EnumString, strum::Display, PartialEq)]
 #[strum(ascii_case_insensitive)]
 pub enum OutputFormat {
@@ -19,6 +43,23 @@ pub enum OutputFormat {
     Yaml,
 }
 
+/// Extracts metadata from KEEP_META_* environment variables.
+///
+/// Scans environment for variables prefixed with KEEP_META_ and extracts
+/// key-value pairs for initial item metadata.
+///
+/// # Returns
+///
+/// `HashMap<String, String>` - Metadata from environment variables.
+///
+/// # Examples
+///
+/// ```
+/// # use std::env;
+/// env::set_var("KEEP_META_COMMAND", "ls -la");
+/// let meta = get_meta_from_env();
+/// assert_eq!(meta.get("COMMAND"), Some(&"ls -la".to_string()));
+/// ```
 pub fn get_meta_from_env() -> HashMap<String, String> {
     debug!("COMMON: Getting meta from KEEP_META_*");
     let re = Regex::new(r"^KEEP_META_(.+)$").unwrap();
@@ -36,6 +77,23 @@ pub fn get_meta_from_env() -> HashMap<String, String> {
     meta_env
 }
 
+/// Formats a file size in bytes to human-readable or raw format.
+///
+/// # Arguments
+///
+/// * `size` - Size in bytes.
+/// * `human_readable` - If true, use units like KB, MB; otherwise, raw bytes.
+///
+/// # Returns
+///
+/// `String` - Formatted size string.
+///
+/// # Examples
+///
+/// ```
+/// let raw = format_size(1024, false); // "1024"
+/// let human = format_size(1024, true); // "1.0K"
+/// ```
 pub fn format_size(size: u64, human_readable: bool) -> String {
     match human_readable {
         true => humansize::format_size(size, humansize::DECIMAL),
@@ -43,8 +101,20 @@ pub fn format_size(size: u64, human_readable: bool) -> String {
     }
 }
 
-
+/// Enum representing column types for table display.
-
+///
+/// Defines standard and meta columns for list/info modes.
+///
+/// # Variants
+///
+/// * `Id` - Item ID column.
+/// * `Time` - Timestamp column.
+/// * `Size` - Content size column.
+/// * `Compression` - Compression type column.
+/// * `FileSize` - On-disk file size column.
+/// * `FilePath` - File path column.
+/// * `Tags` - Tags column.
+/// * `Meta` - Metadata column (with sub-type via string parsing).
 #[derive(Debug, Eq, PartialEq, Clone, strum::EnumIter, strum::Display, strum::EnumString)]
 #[strum(ascii_case_insensitive)]
 pub enum ColumnType {
@@ -59,7 +129,22 @@ pub enum ColumnType {
 }
 
 impl ColumnType {
-    /// Returns a Result with error message if the string is not a valid ColumnType
+    /// Parses a string to a ColumnType, handling "meta:<name>" pattern.
+    ///
+    /// # Arguments
+    ///
+    /// * `s` - Input string to parse.
+    ///
+    /// # Returns
+    ///
+    /// * `anyhow::Result<ColumnType>` - Parsed type or error.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let meta = ColumnType::from_str("meta:hostname")?;
+    /// assert_eq!(meta, ColumnType::Meta);
+    /// ```
     pub fn from_str(s: &str) -> anyhow::Result<Self> {
         if s.starts_with("meta:") {
             // Handle meta:<name> pattern - this is still a Meta column type
@@ -71,13 +156,22 @@ impl ColumnType {
     }
 }
 
-// impl TryFrom<&str> for ColumnType is already implemented by strum_macros
+/// Extracts configured meta plugin types from settings and command.
-// so we remove this conflicting implementation
+///
-
+/// Handles comma-separated plugin names and validates against registered types.
-
+///
-
+/// # Arguments
-
+///
-
+/// * `cmd` - Mutable Clap command for error reporting.
+/// * `settings` - Application settings with plugin config.
+///
+/// # Returns
+///
+/// `Vec<MetaPluginType>` - List of enabled plugin types.
+///
+/// # Panics
+///
+/// Exits via Clap error if unknown plugin type specified.
 pub fn settings_meta_plugin_types(cmd: &mut Command, settings: &config::Settings) -> Vec<MetaPluginType> {
     let mut meta_plugin_types = Vec::new();
     
@@ -115,7 +209,22 @@ pub fn settings_meta_plugin_types(cmd: &mut Command, settings: &config::Settings
     meta_plugin_types
 }
 
-
+/// Determines compression type from settings and command arguments.
+///
+/// Validates the compression name and returns the corresponding enum variant.
+///
+/// # Arguments
+///
+/// * `cmd` - Mutable Clap command for error reporting.
+/// * `settings` - Application settings.
+///
+/// # Returns
+///
+/// `CompressionType` - The resolved compression type.
+///
+/// # Panics
+///
+/// Exits via Clap error if invalid compression specified.
 pub fn settings_compression_type(cmd: &mut Command, settings: &config::Settings) -> CompressionType {
     let compression_name = settings
         .compression()
@@ -133,6 +242,17 @@ pub fn settings_compression_type(cmd: &mut Command, settings: &config::Settings)
     compression_type_opt.unwrap()
 }
 
+/// Parses output format from settings.
+///
+/// Defaults to `Table` if not specified or invalid.
+///
+/// # Arguments
+///
+/// * `settings` - Application settings.
+///
+/// # Returns
+///
+/// `OutputFormat` - Parsed or default format.
 pub fn settings_output_format(settings: &config::Settings) -> OutputFormat {
     settings.output_format
         .as_ref()
@@ -140,7 +260,24 @@ pub fn settings_output_format(settings: &config::Settings) -> OutputFormat {
         .unwrap_or(OutputFormat::Table)
 }
 
-/// Trim whitespace from the end of each line in a string
+/// Trims trailing whitespace from each line in a multi-line string.
+///
+/// Useful for cleaning up table output before printing.
+///
+/// # Arguments
+///
+/// * `s` - Input string with potential trailing whitespace.
+///
+/// # Returns
+///
+/// `String` - Cleaned string with trimmed lines.
+///
+/// # Examples
+///
+/// ```
+/// let cleaned = trim_lines_end("line1  \nline2   ");
+/// assert_eq!(cleaned, "line1\nline2");
+/// ```
 pub fn trim_lines_end(s: &str) -> String {
     s.lines()
         .map(|line| line.trim_end())
@@ -148,7 +285,24 @@ pub fn trim_lines_end(s: &str) -> String {
         .join("\n")
 }
 
-/// Create a table with consistent styling and terminal detection
+/// Creates a new table with styling based on terminal detection.
+///
+/// Loads appropriate preset (UTF8 or ASCII) if styling is enabled.
+///
+/// # Arguments
+///
+/// * `use_styling` - If true, apply visual styling.
+///
+/// # Returns
+///
+/// `Table` - Configured table instance.
+///
+/// # Examples
+///
+/// ```
+/// let table = create_table(true);
+/// table.add_row(vec!["Header1", "Header2"]);
+/// ```
 pub fn create_table(use_styling: bool) -> Table {
     let mut table = Table::new();
     table.set_content_arrangement(ContentArrangement::Dynamic);
@@ -171,7 +325,24 @@ pub fn create_table(use_styling: bool) -> Table {
     table
 }
 
-/// Create a table using the provided table configuration
+/// Creates a table configured from application table settings.
+///
+/// Applies style presets, modifiers, content arrangement, and truncation indicators.
+///
+/// # Arguments
+///
+/// * `table_config` - Table configuration from settings.
+///
+/// # Returns
+///
+/// `Table` - Fully configured table.
+///
+/// # Examples
+///
+/// ```
+/// let config = TableConfig::default();
+/// let table = create_table_with_config(&config);
+/// ```
 pub fn create_table_with_config(table_config: &crate::config::TableConfig) -> Table {
     let mut table = Table::new();
     
@@ -235,3 +406,5 @@ pub fn create_table_with_config(table_config: &crate::config::TableConfig) -> Ta
     table
 }
 
+/// Exports public types and functions for use in other modules.
+pub use self::{ColumnType, OutputFormat, format_size, settings_output_format};