decollate 0.0.1

//! # decollate
//!
//! A high-performance, context-free collation library that provides
//! blazing-fast locale-aware string comparison by deconstructing
//! complex collation rules to their essential components.
//!
//! This library is in active development.

use std::cmp::Ordering;

/// Main collator structure that holds configuration and collation data
#[derive(Debug, Clone)]
pub struct Collator {
    // This will eventually hold the compressed CLDR data
    // and configuration options
    locale: String,
}

/// Options for configuring collation behavior
#[derive(Debug, Clone, Copy)]
pub struct CollationOptions {
    /// Collation strength (primary, secondary, tertiary, etc.)
    pub strength: CollationStrength,
    /// Whether to consider case differences
    pub case_sensitive: bool,
}

/// Defines the comparison strength level
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum CollationStrength {
    /// Base character comparison only
    Primary,
    /// Base characters and accents
    Secondary,
    /// Base characters, accents, and case
    Tertiary,
}

/// Error types for collation operations
#[derive(Debug, thiserror::Error)]
pub enum CollationError {
    #[error("Unsupported locale: {0}")]
    UnsupportedLocale(String),
    #[error("Invalid collation data")]
    InvalidData,
}

impl Collator {
    /// Creates a new Collator for the specified locale
    ///
    /// # Examples
    ///
    /// ```
    /// use decollate::Collator;
    /// let collator = Collator::new("en").unwrap();
    /// ```
    pub fn new(locale: &str) -> Result<Self, CollationError> {
        // For now, we just validate the locale format
        if locale.is_empty() {
            return Err(CollationError::UnsupportedLocale(locale.to_string()));
        }

        Ok(Collator {
            locale: locale.to_string(),
        })
    }

    /// Creates a new Collator with custom options
    pub fn with_options(locale: &str, _options: CollationOptions) -> Result<Self, CollationError> {
        // Placeholder implementation
        Self::new(locale)
    }

    /// Compares two strings according to the collation rules
    ///
    /// # Examples
    ///
    /// ```
    /// use decollate::Collator;
    /// use std::cmp::Ordering;
    ///
    /// let collator = Collator::new("en").unwrap();
    /// assert_eq!(collator.compare("a", "b"), Ordering::Less);
    /// ```
    pub fn compare(&self, a: &str, b: &str) -> Ordering {
        // Placeholder implementation - basic string comparison
        // This will be replaced with actual collation logic
        a.cmp(b)
    }

    /// Generates a sort key for the given string
    ///
    /// Sort keys can be compared directly for faster repeated comparisons
    pub fn sort_key(&self, _s: &str) -> Vec<u8> {
        // Placeholder implementation
        // This will be replaced with actual sort key generation
        Vec::new()
    }
}

impl Default for Collator {
    fn default() -> Self {
        // Default to English collation
        Collator {
            locale: "en".to_string(),
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_basic_creation() {
        let collator = Collator::new("en").unwrap();
        assert_eq!(collator.locale, "en");
    }

    #[test]
    fn test_compare() {
        let collator = Collator::new("en").unwrap();
        assert_eq!(collator.compare("a", "b"), Ordering::Less);
        assert_eq!(collator.compare("b", "a"), Ordering::Greater);
        assert_eq!(collator.compare("a", "a"), Ordering::Equal);
    }
}