typst-bake 0.1.9

//! Compression statistics for embedded files.
//!
//! All embedded resources (templates, fonts, packages) are compressed with zstd
//! and decompressed lazily at runtime.

/// Compression statistics for all embedded content.
///
/// Resources are compressed with zstd at compile time and decompressed lazily at runtime.
#[derive(Debug, Clone)]
pub struct EmbedStats {
    /// Template files statistics.
    pub templates: CategoryStats,
    /// Package files statistics.
    pub packages: PackageStats,
    /// Font files statistics.
    pub fonts: CategoryStats,
    /// Deduplication statistics.
    pub dedup: DedupStats,
    /// Zstd compression level used.
    pub compression_level: i32,
}

/// Statistics for content deduplication across all categories.
#[derive(Debug, Clone, Copy)]
pub struct DedupStats {
    /// Total number of files (before dedup).
    pub total_files: usize,
    /// Number of unique blobs after dedup.
    pub unique_blobs: usize,
    /// Number of duplicate files removed.
    pub duplicate_count: usize,
    /// Bytes saved by deduplication.
    pub saved_bytes: usize,
}

/// Statistics for a category of files (templates, fonts).
#[derive(Debug, Clone, Copy)]
pub struct CategoryStats {
    /// Original uncompressed size in bytes.
    pub original_size: usize,
    /// Compressed size in bytes.
    pub compressed_size: usize,
    /// Number of files.
    pub file_count: usize,
}

/// Statistics for all packages.
#[derive(Debug, Clone)]
pub struct PackageStats {
    /// Per-package statistics.
    pub packages: Vec<PackageInfo>,
    /// Original uncompressed size in bytes.
    pub original_size: usize,
    /// Compressed size in bytes.
    pub compressed_size: usize,
}

/// Statistics for a single package.
#[derive(Debug, Clone)]
pub struct PackageInfo {
    /// Package name with version (e.g., "gentle-clues:1.2.0").
    pub name: String,
    /// Original uncompressed size in bytes.
    pub original_size: usize,
    /// Compressed size in bytes.
    pub compressed_size: usize,
    /// Number of files in this package.
    pub file_count: usize,
}

impl EmbedStats {
    /// Calculate total original size across all categories.
    pub fn total_original(&self) -> usize {
        self.templates.original_size + self.packages.original_size + self.fonts.original_size
    }

    /// Calculate total compressed size across all categories.
    pub fn total_compressed(&self) -> usize {
        self.templates.compressed_size + self.packages.compressed_size + self.fonts.compressed_size
    }

    /// Calculate compression ratio (0.0 to 1.0, where 0.0 means no compression).
    pub fn compression_ratio(&self) -> f64 {
        compression_ratio(self.total_original(), self.total_compressed())
    }

    /// Total size after deduplication (actual binary footprint).
    pub fn total_deduplicated(&self) -> usize {
        self.total_compressed() - self.dedup.saved_bytes
    }

    /// Overall reduction ratio from original to deduplicated.
    pub fn overall_ratio(&self) -> f64 {
        compression_ratio(self.total_original(), self.total_deduplicated())
    }

    /// Total number of files across all categories.
    fn total_file_count(&self) -> usize {
        self.templates.file_count
            + self.fonts.file_count
            + self
                .packages
                .packages
                .iter()
                .map(|p| p.file_count)
                .sum::<usize>()
    }

    /// Display compression statistics in a human-readable format.
    pub fn display(&self) {
        print!("{self}");
    }
}

impl std::fmt::Display for EmbedStats {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        writeln!(f, "Embed Summary")?;
        writeln!(f, "========================")?;

        // Templates
        if self.templates.file_count > 0 {
            writeln!(
                f,
                "Templates:  {:>9} -> {:>9} ({:>5.1}% reduced, {} files)",
                format_size(self.templates.original_size),
                format_size(self.templates.compressed_size),
                self.templates.compression_ratio() * 100.0,
                self.templates.file_count
            )?;
        }

        // Fonts
        if self.fonts.file_count > 0 {
            writeln!(
                f,
                "Fonts:      {:>9} -> {:>9} ({:>5.1}% reduced, {} files)",
                format_size(self.fonts.original_size),
                format_size(self.fonts.compressed_size),
                self.fonts.compression_ratio() * 100.0,
                self.fonts.file_count
            )?;
        }

        // Packages
        if !self.packages.packages.is_empty() {
            writeln!(f, "Packages:")?;

            // Calculate column widths for package alignment
            let (name_width, orig_width, comp_width) =
                self.packages
                    .packages
                    .iter()
                    .fold((0, 0, 0), |(nw, ow, cw), p| {
                        (
                            nw.max(p.name.len()),
                            ow.max(format_size(p.original_size).len()),
                            cw.max(format_size(p.compressed_size).len()),
                        )
                    });

            for pkg in &self.packages.packages {
                writeln!(
                    f,
                    "  {:<name_w$}  {:>orig_w$} -> {:>comp_w$}  ({:>5.1}%)",
                    pkg.name,
                    format_size(pkg.original_size),
                    format_size(pkg.compressed_size),
                    pkg.compression_ratio() * 100.0,
                    name_w = name_width,
                    orig_w = orig_width,
                    comp_w = comp_width,
                )?;
            }
        }

        // Compressed total
        writeln!(f, "------------------------")?;
        writeln!(
            f,
            "Compressed: {} -> {} (level {}, {:.1}% reduced, {} files)",
            format_size(self.total_original()),
            format_size(self.total_compressed()),
            self.compression_level,
            self.compression_ratio() * 100.0,
            self.total_file_count()
        )?;

        // Deduplicated (only shown when there are duplicates)
        if self.dedup.duplicate_count > 0 {
            writeln!(
                f,
                "Deduplicated: {} unique blobs, {} duplicates removed (-{})",
                self.dedup.unique_blobs,
                self.dedup.duplicate_count,
                format_size(self.dedup.saved_bytes)
            )?;
        }

        // Total (actual binary footprint)
        writeln!(
            f,
            "Total: {} -> {} ({:.1}% reduced)",
            format_size(self.total_original()),
            format_size(self.total_deduplicated()),
            self.overall_ratio() * 100.0
        )
    }
}

/// Trait for types that have original/compressed sizes and can compute a compression ratio.
pub trait HasCompressionRatio {
    fn original_size(&self) -> usize;
    fn compressed_size(&self) -> usize;

    fn compression_ratio(&self) -> f64 {
        compression_ratio(self.original_size(), self.compressed_size())
    }
}

macro_rules! impl_has_compression_ratio {
    ($($ty:ty),*) => {
        $(impl HasCompressionRatio for $ty {
            fn original_size(&self) -> usize { self.original_size }
            fn compressed_size(&self) -> usize { self.compressed_size }
        })*
    };
}

impl_has_compression_ratio!(CategoryStats, PackageInfo, PackageStats);

/// Calculate compression ratio from original and compressed sizes.
/// Returns 0.0 when original is 0, otherwise 1.0 - (compressed / original).
fn compression_ratio(original: usize, compressed: usize) -> f64 {
    if original == 0 {
        return 0.0;
    }
    1.0 - (compressed as f64 / original as f64)
}

/// Format bytes into a human-readable size string.
fn format_size(bytes: usize) -> String {
    const KB: usize = 1024;
    const MB: usize = KB * 1024;

    if bytes >= MB {
        format!("{:.2} MB", bytes as f64 / MB as f64)
    } else if bytes >= KB {
        format!("{:.1} KB", bytes as f64 / KB as f64)
    } else {
        format!("{bytes} B")
    }
}

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

    #[test]
    fn test_format_size_bytes() {
        assert_eq!(format_size(0), "0 B");
        assert_eq!(format_size(512), "512 B");
        assert_eq!(format_size(1023), "1023 B");
    }

    #[test]
    fn test_format_size_kilobytes() {
        assert_eq!(format_size(1024), "1.0 KB");
        assert_eq!(format_size(1536), "1.5 KB");
        assert_eq!(format_size(10240), "10.0 KB");
    }

    #[test]
    fn test_format_size_megabytes() {
        assert_eq!(format_size(1048576), "1.00 MB");
        assert_eq!(format_size(1572864), "1.50 MB");
    }

    #[test]
    fn test_compression_ratio_zero_original() {
        let stats = CategoryStats {
            original_size: 0,
            compressed_size: 0,
            file_count: 0,
        };
        assert_eq!(stats.compression_ratio(), 0.0);
    }

    #[test]
    fn test_compression_ratio_75_percent() {
        // Asymmetric values to distinguish from incorrect calculation (original/compressed)
        // Correct: 1 - (250/1000) = 0.75
        // Wrong:   1 - (1000/250) = -3.0
        let stats = CategoryStats {
            original_size: 1000,
            compressed_size: 250,
            file_count: 1,
        };
        assert!((stats.compression_ratio() - 0.75).abs() < 0.001);
    }

    #[test]
    fn test_embed_stats_totals() {
        let stats = EmbedStats {
            templates: CategoryStats {
                original_size: 1000,
                compressed_size: 200, // 80% compression
                file_count: 1,
            },
            fonts: CategoryStats {
                original_size: 2000,
                compressed_size: 600, // 70% compression
                file_count: 2,
            },
            packages: PackageStats {
                packages: vec![],
                original_size: 1000,
                compressed_size: 200, // 80% compression
            },
            dedup: DedupStats {
                total_files: 4,
                unique_blobs: 3,
                duplicate_count: 1,
                saved_bytes: 100,
            },
            compression_level: 19,
        };
        // Total: 4000 -> 1000 (75% compression)
        assert_eq!(stats.total_original(), 4000);
        assert_eq!(stats.total_compressed(), 1000);
        assert!((stats.compression_ratio() - 0.75).abs() < 0.001);
        // Deduplicated: 1000 - 100 = 900
        assert_eq!(stats.total_deduplicated(), 900);
    }
}