chainsaw/

report.rs

//! Human-readable output formatting for trace results, diffs, and package lists.

use std::collections::HashMap;
use std::fmt::Write as _;
use std::io::IsTerminal;
use std::path::{Component, Path, PathBuf};

use serde::Serialize;

use crate::graph::{ModuleGraph, ModuleId};
use crate::query::DiffResult;

/// Default number of heavy dependencies to display.
pub const DEFAULT_TOP: i32 = 10;
/// Default number of modules by exclusive weight to display.
pub const DEFAULT_TOP_MODULES: i32 = 20;

/// Determine whether color output should be used for a given stream.
///
/// Color is disabled when any of these hold:
/// - `no_color_flag` is true (`--no-color`)
/// - `no_color_env` is true (`NO_COLOR` set, per <https://no-color.org>)
/// - `term_dumb` is true (`TERM=dumb`)
/// - the stream is not a TTY
#[allow(clippy::fn_params_excessive_bools)]
pub const fn should_use_color(
    stream_is_tty: bool,
    no_color_flag: bool,
    no_color_env: bool,
    term_dumb: bool,
) -> bool {
    if no_color_flag || no_color_env || term_dumb {
        return false;
    }
    stream_is_tty
}

const fn plural(n: u64) -> &'static str {
    if n == 1 { "" } else { "s" }
}

#[derive(Clone, Copy)]
struct C {
    color: bool,
}

impl C {
    fn bold_green(self, s: &str) -> String {
        if self.color {
            format!("\x1b[1;92m{s}\x1b[0m")
        } else {
            s.to_string()
        }
    }

    fn red(self, s: &str) -> String {
        if self.color {
            format!("\x1b[31m{s}\x1b[0m")
        } else {
            s.to_string()
        }
    }

    fn green(self, s: &str) -> String {
        if self.color {
            format!("\x1b[32m{s}\x1b[0m")
        } else {
            s.to_string()
        }
    }

    fn dim(self, s: &str) -> String {
        if self.color {
            format!("\x1b[2m{s}\x1b[0m")
        } else {
            s.to_string()
        }
    }
}

#[derive(Debug, Clone, Copy)]
pub struct StderrColor {
    color: bool,
}

impl StderrColor {
    pub fn new(no_color: bool) -> Self {
        Self {
            color: should_use_color(
                std::io::stderr().is_terminal(),
                no_color,
                std::env::var_os("NO_COLOR").is_some(),
                std::env::var("TERM").is_ok_and(|v| v == "dumb"),
            ),
        }
    }

    pub fn error(self, s: &str) -> String {
        if self.color {
            format!("\x1b[1;91m{s}\x1b[0m")
        } else {
            s.to_string()
        }
    }

    pub fn warning(self, s: &str) -> String {
        if self.color {
            format!("\x1b[1;93m{s}\x1b[0m")
        } else {
            s.to_string()
        }
    }

    pub fn status(self, s: &str) -> String {
        if self.color {
            format!("\x1b[1;92m{s}\x1b[0m")
        } else {
            s.to_string()
        }
    }
}

/// Print the standard graph-load status line plus any warnings.
///
/// Used by the CLI (trace, packages, diff) and the REPL startup to avoid
/// duplicating the same formatting logic.
#[allow(clippy::too_many_arguments)]
pub fn print_load_status(
    from_cache: bool,
    module_count: usize,
    elapsed_ms: f64,
    file_warnings: &[String],
    unresolvable_dynamic_count: usize,
    unresolvable_dynamic_files: &[(PathBuf, usize)],
    root: &Path,
    sc: StderrColor,
) {
    eprintln!(
        "{} ({module_count} modules) in {elapsed_ms:.1}ms",
        sc.status(if from_cache {
            "Loaded cached graph"
        } else {
            "Built graph"
        }),
    );
    for w in file_warnings {
        eprintln!("{} {w}", sc.warning("warning:"));
    }
    if unresolvable_dynamic_count > 0 {
        let n = unresolvable_dynamic_count;
        eprintln!(
            "{} {n} dynamic import{} with non-literal argument{} could not be traced:",
            sc.warning("warning:"),
            if n == 1 { "" } else { "s" },
            if n == 1 { "" } else { "s" },
        );
        let mut files: Vec<_> = unresolvable_dynamic_files.to_vec();
        files.sort_by(|a, b| a.0.cmp(&b.0));
        for (path, file_count) in &files {
            let rel = relative_path(path, root);
            eprintln!("  {rel} ({file_count})");
        }
    }
}

#[allow(clippy::cast_precision_loss)]
pub fn format_size(bytes: u64) -> String {
    if bytes >= 1_000_000 {
        format!("{:.1} MB", bytes as f64 / 1_000_000.0)
    } else if bytes >= 1_000 {
        format!("{:.0} KB", bytes as f64 / 1_000.0)
    } else {
        format!("{bytes} B")
    }
}

pub fn relative_path(path: &Path, root: &Path) -> String {
    path.strip_prefix(root)
        .unwrap_or(path)
        .to_string_lossy()
        .into_owned()
}

pub(crate) fn display_name(graph: &ModuleGraph, mid: ModuleId, root: &Path) -> String {
    let m = graph.module(mid);
    m.package
        .clone()
        .unwrap_or_else(|| relative_path(&m.path, root))
}

/// Path relative to the package directory (e.g. `dateutil/__init__.py`).
/// Handles scoped packages (`@scope/name` spans two path components).
/// Falls back to the file name if the package name isn't found in path components.
fn package_relative_path(path: &Path, package_name: &str) -> String {
    let components: Vec<_> = path.components().collect();
    // Scan backwards to find the last match — avoids false matches from
    // workspace dirs that share a package name (e.g. pnpm store paths
    // like .pnpm/cloudflare@5.2.0/node_modules/cloudflare/index.js where
    // an ancestor dir is also named "cloudflare").
    if let Some((scope, name)) = package_name.split_once('/') {
        for (i, pair) in components.windows(2).enumerate().rev() {
            if let (Component::Normal(a), Component::Normal(b)) = (&pair[0], &pair[1])
                && a.to_str() == Some(scope)
                && b.to_str() == Some(name)
            {
                let sub: PathBuf = components[i..].iter().collect();
                return sub.to_string_lossy().into_owned();
            }
        }
    } else {
        for (i, comp) in components.iter().enumerate().rev() {
            if let Component::Normal(name) = comp
                && name.to_str() == Some(package_name)
            {
                let sub: PathBuf = components[i..].iter().collect();
                return sub.to_string_lossy().into_owned();
            }
        }
    }
    path.file_name()
        .and_then(|n| n.to_str())
        .unwrap_or("?")
        .to_string()
}

/// Build display names for a chain, expanding duplicate package nodes
/// to package-relative file paths for disambiguation.
pub(crate) fn chain_display_names(
    graph: &ModuleGraph,
    chain: &[ModuleId],
    root: &Path,
) -> Vec<String> {
    let names: Vec<String> = chain
        .iter()
        .map(|&mid| display_name(graph, mid, root))
        .collect();
    let mut counts: HashMap<&str, usize> = HashMap::new();
    for name in &names {
        *counts.entry(name.as_str()).or_default() += 1;
    }
    names
        .iter()
        .enumerate()
        .map(|(i, name)| {
            if counts[name.as_str()] > 1 {
                let m = graph.module(chain[i]);
                if let Some(ref pkg) = m.package {
                    return package_relative_path(&m.path, pkg);
                }
            }
            name.clone()
        })
        .collect()
}

// ---------------------------------------------------------------------------
// Structured report types
// ---------------------------------------------------------------------------

/// Display-ready trace result. Produced by `Session::trace_report()`.
#[derive(Debug, Clone, Serialize)]
pub struct TraceReport {
    pub entry: String,
    pub static_weight_bytes: u64,
    pub static_module_count: usize,
    pub dynamic_only_weight_bytes: u64,
    pub dynamic_only_module_count: usize,
    pub heavy_packages: Vec<PackageEntry>,
    pub modules_by_cost: Vec<ModuleEntry>,
    /// Total modules with non-zero exclusive weight (before truncation).
    pub total_modules_with_cost: usize,
    /// Whether dynamic imports were included in the trace.
    #[serde(skip)]
    pub include_dynamic: bool,
    /// The `--top` value (0 = hide heavy deps section entirely).
    #[serde(skip)]
    pub top: i32,
}

#[derive(Debug, Clone, Serialize)]
pub struct PackageEntry {
    pub name: String,
    pub total_size_bytes: u64,
    pub file_count: u32,
    pub chain: Vec<String>,
}

#[derive(Debug, Clone, Serialize)]
pub struct ModuleEntry {
    pub path: String,
    pub exclusive_size_bytes: u64,
}

/// Display-ready chain result. Produced by `Session::chain_report()`.
#[derive(Debug, Clone, Serialize)]
pub struct ChainReport {
    pub target: String,
    pub found_in_graph: bool,
    pub chain_count: usize,
    pub hop_count: usize,
    pub chains: Vec<Vec<String>>,
}

/// Display-ready cut result. Produced by `Session::cut_report()`.
#[derive(Debug, Clone, Serialize)]
pub struct CutReport {
    pub target: String,
    pub found_in_graph: bool,
    pub chain_count: usize,
    pub direct_import: bool,
    pub cut_points: Vec<CutEntry>,
}

#[derive(Debug, Clone, Serialize)]
pub struct CutEntry {
    pub module: String,
    pub exclusive_size_bytes: u64,
    pub chains_broken: usize,
}

/// Display-ready diff result. Produced by `Session::diff_report()` or
/// `DiffReport::from_diff()`.
#[derive(Debug, Clone, Serialize)]
pub struct DiffReport {
    pub entry_a: String,
    pub entry_b: String,
    pub weight_a: u64,
    pub weight_b: u64,
    pub weight_delta: i64,
    pub dynamic_weight_a: u64,
    pub dynamic_weight_b: u64,
    pub dynamic_weight_delta: i64,
    pub shared_count: usize,
    pub only_in_a: Vec<DiffPackageEntry>,
    pub only_in_b: Vec<DiffPackageEntry>,
    pub dynamic_only_in_a: Vec<DiffPackageEntry>,
    pub dynamic_only_in_b: Vec<DiffPackageEntry>,
    /// Max packages to show per section (-1 for all).
    #[serde(skip)]
    pub limit: i32,
}

#[derive(Debug, Clone, Serialize)]
pub struct DiffPackageEntry {
    pub name: String,
    pub total_size_bytes: u64,
}

/// Display-ready packages list. Produced by `Session::packages_report()`.
#[derive(Debug, Clone, Serialize)]
pub struct PackagesReport {
    pub package_count: usize,
    pub packages: Vec<PackageListEntry>,
}

#[derive(Debug, Clone, Serialize)]
pub struct PackageListEntry {
    pub name: String,
    pub total_size_bytes: u64,
    pub file_count: u32,
}

// ---------------------------------------------------------------------------
// Emit helper — centralizes --json dispatch
// ---------------------------------------------------------------------------

/// Emit a report to stdout, choosing JSON or terminal format.
///
/// Centralizes the `--json` / terminal dispatch so every CLI output path
/// goes through a single function. New output paths that forget the json
/// flag will be caught in code review: the pattern is always
/// `report::emit(json, ...)` rather than ad-hoc if/else.
pub fn emit(json: bool, json_fn: impl FnOnce() -> String, terminal_fn: impl FnOnce() -> String) {
    if json {
        println!("{}", json_fn());
    } else {
        print!("{}", terminal_fn());
    }
}

// ---------------------------------------------------------------------------
// Report rendering
// ---------------------------------------------------------------------------

impl TraceReport {
    pub fn to_json(&self) -> String {
        serde_json::to_string_pretty(self).unwrap()
    }

    pub fn to_terminal(&self, color: bool) -> String {
        let c = C { color };
        let mut out = String::new();
        writeln!(out, "{}", self.entry).unwrap();

        let suffix = if self.include_dynamic {
            ", static + dynamic"
        } else {
            ""
        };
        let weight = format_size(self.static_weight_bytes);
        let modules = format!(
            "{} module{}{}",
            self.static_module_count,
            plural(self.static_module_count as u64),
            suffix,
        );
        let label = if self.include_dynamic {
            "Total transitive weight:"
        } else {
            "Static transitive weight:"
        };
        writeln!(out, "{} {weight} ({modules})", c.bold_green(label)).unwrap();

        if !self.include_dynamic && self.dynamic_only_module_count > 0 {
            writeln!(
                out,
                "{} {} ({} module{}, not loaded at startup)",
                c.bold_green("Dynamic-only weight:"),
                format_size(self.dynamic_only_weight_bytes),
                self.dynamic_only_module_count,
                plural(self.dynamic_only_module_count as u64)
            )
            .unwrap();
        }

        if self.top != 0 {
            writeln!(out).unwrap();
            let deps_label = if self.include_dynamic {
                "Heavy dependencies (static + dynamic):"
            } else {
                "Heavy dependencies (static):"
            };
            writeln!(out, "{}", c.bold_green(deps_label)).unwrap();
            if self.heavy_packages.is_empty() {
                writeln!(
                    out,
                    "  (none \u{2014} all reachable modules are first-party)"
                )
                .unwrap();
            } else {
                for pkg in &self.heavy_packages {
                    writeln!(
                        out,
                        "  {:<35} {}  {} file{}",
                        pkg.name,
                        format_size(pkg.total_size_bytes),
                        pkg.file_count,
                        plural(u64::from(pkg.file_count))
                    )
                    .unwrap();
                    if pkg.chain.len() > 1 {
                        writeln!(out, "    -> {}", pkg.chain.join(" -> ")).unwrap();
                    }
                }
            }
            writeln!(out).unwrap();
        }

        if !self.modules_by_cost.is_empty() {
            writeln!(
                out,
                "{}",
                c.bold_green("Modules (sorted by exclusive weight):")
            )
            .unwrap();
            for mc in &self.modules_by_cost {
                writeln!(
                    out,
                    "  {:<55} {}",
                    mc.path,
                    format_size(mc.exclusive_size_bytes)
                )
                .unwrap();
            }
            if self.total_modules_with_cost > self.modules_by_cost.len() {
                let remaining = self.total_modules_with_cost - self.modules_by_cost.len();
                writeln!(
                    out,
                    "  ... and {remaining} more module{}",
                    plural(remaining as u64)
                )
                .unwrap();
            }
        }

        out
    }
}

impl ChainReport {
    pub fn to_json(&self) -> String {
        serde_json::to_string_pretty(self).unwrap()
    }

    pub fn to_terminal(&self, color: bool) -> String {
        let c = C { color };
        let mut out = String::new();

        if self.chains.is_empty() {
            if self.found_in_graph {
                writeln!(
                    out,
                    "\"{}\" exists in the graph but is not reachable from this entry point.",
                    self.target
                )
                .unwrap();
            } else {
                writeln!(
                    out,
                    "\"{}\" is not in the dependency graph. Check the spelling or verify it's installed.",
                    self.target
                )
                .unwrap();
            }
            return out;
        }

        writeln!(
            out,
            "{}\n",
            c.bold_green(&format!(
                "{} chain{} to \"{}\" ({} hop{}):",
                self.chain_count,
                if self.chain_count == 1 { "" } else { "s" },
                self.target,
                self.hop_count,
                if self.hop_count == 1 { "" } else { "s" },
            )),
        )
        .unwrap();
        for (i, chain) in self.chains.iter().enumerate() {
            writeln!(out, "  {}. {}", i + 1, chain.join(" -> ")).unwrap();
        }

        out
    }
}

impl CutReport {
    pub fn to_json(&self) -> String {
        serde_json::to_string_pretty(self).unwrap()
    }

    pub fn to_terminal(&self, color: bool) -> String {
        let c = C { color };
        let mut out = String::new();

        if self.chain_count == 0 {
            if self.found_in_graph {
                writeln!(
                    out,
                    "\"{}\" exists in the graph but is not reachable from this entry point.",
                    self.target
                )
                .unwrap();
            } else {
                writeln!(
                    out,
                    "\"{}\" is not in the dependency graph. Check the spelling or verify it's installed.",
                    self.target
                )
                .unwrap();
            }
            return out;
        }

        if self.cut_points.is_empty() {
            if self.direct_import {
                writeln!(
                    out,
                    "Entry file directly imports \"{}\" \u{2014} remove the import to sever the dependency.",
                    self.target
                )
                .unwrap();
            } else {
                writeln!(
                    out,
                    "No single cut point can sever all {} chain{} to \"{}\".",
                    self.chain_count,
                    if self.chain_count == 1 { "" } else { "s" },
                    self.target,
                )
                .unwrap();
                writeln!(
                    out,
                    "Each chain takes a different path \u{2014} multiple fixes needed."
                )
                .unwrap();
            }
            return out;
        }

        writeln!(
            out,
            "{}\n",
            c.bold_green(&format!(
                "{} cut point{} to sever all {} chain{} to \"{}\":",
                self.cut_points.len(),
                if self.cut_points.len() == 1 { "" } else { "s" },
                self.chain_count,
                if self.chain_count == 1 { "" } else { "s" },
                self.target,
            )),
        )
        .unwrap();
        for cut in &self.cut_points {
            if self.chain_count == 1 {
                writeln!(
                    out,
                    "  {:<45} {:>8}",
                    cut.module,
                    format_size(cut.exclusive_size_bytes),
                )
                .unwrap();
            } else {
                writeln!(
                    out,
                    "  {:<45} {:>8}  (breaks {}/{} chains)",
                    cut.module,
                    format_size(cut.exclusive_size_bytes),
                    cut.chains_broken,
                    self.chain_count
                )
                .unwrap();
            }
        }

        out
    }
}

impl DiffReport {
    pub fn to_json(&self) -> String {
        serde_json::to_string_pretty(self).unwrap()
    }

    pub fn from_diff(diff: &DiffResult, entry_a: &str, entry_b: &str, limit: i32) -> Self {
        Self {
            entry_a: entry_a.to_string(),
            entry_b: entry_b.to_string(),
            weight_a: diff.entry_a_weight,
            weight_b: diff.entry_b_weight,
            weight_delta: diff.weight_delta,
            dynamic_weight_a: diff.dynamic_a_weight,
            dynamic_weight_b: diff.dynamic_b_weight,
            dynamic_weight_delta: diff.dynamic_weight_delta,
            shared_count: diff.shared_count,
            only_in_a: diff
                .only_in_a
                .iter()
                .map(|p| DiffPackageEntry {
                    name: p.name.clone(),
                    total_size_bytes: p.total_size_bytes,
                })
                .collect(),
            only_in_b: diff
                .only_in_b
                .iter()
                .map(|p| DiffPackageEntry {
                    name: p.name.clone(),
                    total_size_bytes: p.total_size_bytes,
                })
                .collect(),
            dynamic_only_in_a: diff
                .dynamic_only_in_a
                .iter()
                .map(|p| DiffPackageEntry {
                    name: p.name.clone(),
                    total_size_bytes: p.total_size_bytes,
                })
                .collect(),
            dynamic_only_in_b: diff
                .dynamic_only_in_b
                .iter()
                .map(|p| DiffPackageEntry {
                    name: p.name.clone(),
                    total_size_bytes: p.total_size_bytes,
                })
                .collect(),
            limit,
        }
    }

    #[allow(clippy::cast_sign_loss, clippy::too_many_lines)]
    pub fn to_terminal(&self, color: bool) -> String {
        let c = C { color };
        let mut out = String::new();
        writeln!(out, "Diff: {} vs {}", self.entry_a, self.entry_b).unwrap();
        writeln!(out).unwrap();
        writeln!(out, "  {:<40} {}", self.entry_a, format_size(self.weight_a)).unwrap();
        writeln!(out, "  {:<40} {}", self.entry_b, format_size(self.weight_b)).unwrap();
        let sign = if self.weight_delta >= 0 { "+" } else { "-" };
        writeln!(
            out,
            "  {:<40} {sign}{}",
            "Delta",
            format_size(self.weight_delta.unsigned_abs())
        )
        .unwrap();

        let has_dynamic = self.dynamic_weight_a > 0 || self.dynamic_weight_b > 0;
        if has_dynamic {
            writeln!(out).unwrap();
            writeln!(
                out,
                "  {:<40} {}",
                "Dynamic-only (before)",
                format_size(self.dynamic_weight_a)
            )
            .unwrap();
            writeln!(
                out,
                "  {:<40} {}",
                "Dynamic-only (after)",
                format_size(self.dynamic_weight_b)
            )
            .unwrap();
            let dyn_sign = if self.dynamic_weight_delta >= 0 {
                "+"
            } else {
                "-"
            };
            writeln!(
                out,
                "  {:<40} {dyn_sign}{}",
                "Dynamic delta",
                format_size(self.dynamic_weight_delta.unsigned_abs())
            )
            .unwrap();
        }

        writeln!(out).unwrap();

        let limit = self.limit;
        let show_count = |total: usize| -> usize {
            if limit < 0 {
                total
            } else {
                total.min(limit as usize)
            }
        };

        if !self.only_in_a.is_empty() {
            let show = show_count(self.only_in_a.len());
            writeln!(out, "{}", c.red(&format!("Only in {}:", self.entry_a))).unwrap();
            for pkg in &self.only_in_a[..show] {
                writeln!(
                    out,
                    "{}",
                    c.red(&format!(
                        "  - {:<35} {}",
                        pkg.name,
                        format_size(pkg.total_size_bytes)
                    ))
                )
                .unwrap();
            }
            let remaining = self.only_in_a.len() - show;
            if remaining > 0 {
                writeln!(out, "{}", c.dim(&format!("  - ... and {remaining} more"))).unwrap();
            }
        }
        if !self.only_in_b.is_empty() {
            let show = show_count(self.only_in_b.len());
            writeln!(out, "{}", c.green(&format!("Only in {}:", self.entry_b))).unwrap();
            for pkg in &self.only_in_b[..show] {
                writeln!(
                    out,
                    "{}",
                    c.green(&format!(
                        "  + {:<35} {}",
                        pkg.name,
                        format_size(pkg.total_size_bytes)
                    ))
                )
                .unwrap();
            }
            let remaining = self.only_in_b.len() - show;
            if remaining > 0 {
                writeln!(out, "{}", c.dim(&format!("  + ... and {remaining} more"))).unwrap();
            }
        }

        if !self.dynamic_only_in_a.is_empty() {
            let show = show_count(self.dynamic_only_in_a.len());
            writeln!(
                out,
                "{}",
                c.red(&format!("Dynamic only in {}:", self.entry_a))
            )
            .unwrap();
            for pkg in &self.dynamic_only_in_a[..show] {
                writeln!(
                    out,
                    "{}",
                    c.red(&format!(
                        "  - {:<35} {}",
                        pkg.name,
                        format_size(pkg.total_size_bytes)
                    ))
                )
                .unwrap();
            }
            let remaining = self.dynamic_only_in_a.len() - show;
            if remaining > 0 {
                writeln!(out, "{}", c.dim(&format!("  - ... and {remaining} more"))).unwrap();
            }
        }
        if !self.dynamic_only_in_b.is_empty() {
            let show = show_count(self.dynamic_only_in_b.len());
            writeln!(
                out,
                "{}",
                c.green(&format!("Dynamic only in {}:", self.entry_b))
            )
            .unwrap();
            for pkg in &self.dynamic_only_in_b[..show] {
                writeln!(
                    out,
                    "{}",
                    c.green(&format!(
                        "  + {:<35} {}",
                        pkg.name,
                        format_size(pkg.total_size_bytes)
                    ))
                )
                .unwrap();
            }
            let remaining = self.dynamic_only_in_b.len() - show;
            if remaining > 0 {
                writeln!(out, "{}", c.dim(&format!("  + ... and {remaining} more"))).unwrap();
            }
        }

        if self.shared_count > 0 {
            writeln!(
                out,
                "{}",
                c.dim(&format!(
                    "Shared: {} package{}",
                    self.shared_count,
                    if self.shared_count == 1 { "" } else { "s" }
                ))
            )
            .unwrap();
        }

        out
    }
}

impl PackagesReport {
    pub fn to_json(&self) -> String {
        serde_json::to_string_pretty(self).unwrap()
    }

    #[allow(clippy::cast_sign_loss)]
    pub fn to_terminal(&self, color: bool) -> String {
        let c = C { color };
        let mut out = String::new();

        if self.packages.is_empty() {
            writeln!(
                out,
                "No third-party packages found in the dependency graph."
            )
            .unwrap();
            return out;
        }

        writeln!(
            out,
            "{}\n",
            c.bold_green(&format!(
                "{} package{}:",
                self.package_count,
                plural(self.package_count as u64)
            ))
        )
        .unwrap();
        for pkg in &self.packages {
            writeln!(
                out,
                "  {:<40} {:>8}  {} file{}",
                pkg.name,
                format_size(pkg.total_size_bytes),
                pkg.file_count,
                plural(u64::from(pkg.file_count))
            )
            .unwrap();
        }
        if self.package_count > self.packages.len() {
            let remaining = self.package_count - self.packages.len();
            writeln!(
                out,
                "  ... and {remaining} more package{}",
                plural(remaining as u64)
            )
            .unwrap();
        }

        out
    }
}

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

    #[test]
    fn color_enabled_when_tty_and_no_overrides() {
        assert!(should_use_color(true, false, false, false));
    }

    #[test]
    fn color_disabled_when_not_tty() {
        assert!(!should_use_color(false, false, false, false));
    }

    #[test]
    fn color_disabled_by_flag() {
        assert!(!should_use_color(true, true, false, false));
    }

    #[test]
    fn color_disabled_by_no_color_env() {
        assert!(!should_use_color(true, false, true, false));
    }

    #[test]
    fn color_disabled_by_term_dumb() {
        assert!(!should_use_color(true, false, false, true));
    }

    #[test]
    fn package_relative_path_pnpm_store() {
        // pnpm store path where workspace dir matches package name
        let path = PathBuf::from(
            "/dev/cloudflare/workers-sdk/node_modules/.pnpm/cloudflare@5.2.0/node_modules/cloudflare/index.js",
        );
        assert_eq!(
            package_relative_path(&path, "cloudflare"),
            "cloudflare/index.js"
        );
    }

    #[test]
    fn package_relative_path_scoped_pnpm() {
        let path = PathBuf::from(
            "/project/node_modules/.pnpm/@babel+parser@7.25.0/node_modules/@babel/parser/lib/index.js",
        );
        assert_eq!(
            package_relative_path(&path, "@babel/parser"),
            "@babel/parser/lib/index.js"
        );
    }

    #[test]
    fn package_relative_path_simple() {
        // Non-pnpm: straightforward node_modules/pkg/file
        let path = PathBuf::from("/project/node_modules/lodash/fp/map.js");
        assert_eq!(package_relative_path(&path, "lodash"), "lodash/fp/map.js");
    }

    #[test]
    fn trace_report_json_field_names() {
        let report = TraceReport {
            entry: "src/index.ts".into(),
            static_weight_bytes: 1000,
            static_module_count: 5,
            dynamic_only_weight_bytes: 200,
            dynamic_only_module_count: 1,
            heavy_packages: vec![PackageEntry {
                name: "zod".into(),
                total_size_bytes: 500,
                file_count: 3,
                chain: vec!["src/index.ts".into(), "zod".into()],
            }],
            modules_by_cost: vec![ModuleEntry {
                path: "src/utils.ts".into(),
                exclusive_size_bytes: 100,
            }],
            total_modules_with_cost: 10,
            include_dynamic: false,
            top: 10,
        };
        let json: serde_json::Value = serde_json::from_str(&report.to_json()).unwrap();
        assert!(json["entry"].is_string());
        assert!(json["static_weight_bytes"].is_number());
        assert!(json["heavy_packages"][0]["total_size_bytes"].is_number());
        assert!(json["modules_by_cost"][0]["exclusive_size_bytes"].is_number());
        assert_eq!(json["total_modules_with_cost"], 10);
        // include_dynamic should not appear in JSON (serde skip)
        assert!(json.get("include_dynamic").is_none());
    }

    #[test]
    fn chain_report_json_fields() {
        let report = ChainReport {
            target: "zod".into(),
            found_in_graph: true,
            chain_count: 1,
            hop_count: 2,
            chains: vec![vec![
                "src/index.ts".into(),
                "src/lib.ts".into(),
                "zod".into(),
            ]],
        };
        let json: serde_json::Value = serde_json::from_str(&report.to_json()).unwrap();
        assert!(json["target"].is_string());
        assert!(json["found_in_graph"].is_boolean());
        assert!(json["chains"][0].is_array());
    }

    #[test]
    fn cut_report_json_fields() {
        let report = CutReport {
            target: "zod".into(),
            found_in_graph: true,
            chain_count: 2,
            direct_import: false,
            cut_points: vec![CutEntry {
                module: "src/bridge.ts".into(),
                exclusive_size_bytes: 5000,
                chains_broken: 2,
            }],
        };
        let json: serde_json::Value = serde_json::from_str(&report.to_json()).unwrap();
        assert!(json["cut_points"][0]["exclusive_size_bytes"].is_number());
        assert!(json["cut_points"][0]["chains_broken"].is_number());
    }

    #[test]
    fn diff_report_json_skips_limit() {
        let report = DiffReport {
            entry_a: "a.ts".into(),
            entry_b: "b.ts".into(),
            weight_a: 1000,
            weight_b: 800,
            weight_delta: -200,
            dynamic_weight_a: 0,
            dynamic_weight_b: 0,
            dynamic_weight_delta: 0,
            shared_count: 1,
            only_in_a: vec![],
            only_in_b: vec![],
            dynamic_only_in_a: vec![],
            dynamic_only_in_b: vec![],
            limit: 10,
        };
        let json: serde_json::Value = serde_json::from_str(&report.to_json()).unwrap();
        assert!(json["weight_delta"].is_number());
        // limit should not appear in JSON (serde skip)
        assert!(json.get("limit").is_none());
    }

    #[test]
    fn diff_report_json_package_fields() {
        let report = DiffReport {
            entry_a: "a.ts".into(),
            entry_b: "b.ts".into(),
            weight_a: 1000,
            weight_b: 800,
            weight_delta: -200,
            dynamic_weight_a: 0,
            dynamic_weight_b: 0,
            dynamic_weight_delta: 0,
            shared_count: 0,
            only_in_a: vec![DiffPackageEntry {
                name: "zod".into(),
                total_size_bytes: 500,
            }],
            only_in_b: vec![],
            dynamic_only_in_a: vec![],
            dynamic_only_in_b: vec![],
            limit: 10,
        };
        let json: serde_json::Value = serde_json::from_str(&report.to_json()).unwrap();
        assert_eq!(json["only_in_a"][0]["name"], "zod");
        assert_eq!(json["only_in_a"][0]["total_size_bytes"], 500);
        assert!(json["only_in_a"][0].get("size").is_none());
    }

    #[test]
    fn packages_report_json_fields() {
        let report = PackagesReport {
            package_count: 2,
            packages: vec![PackageListEntry {
                name: "zod".into(),
                total_size_bytes: 500,
                file_count: 3,
            }],
        };
        let json: serde_json::Value = serde_json::from_str(&report.to_json()).unwrap();
        assert_eq!(json["package_count"], 2);
        assert_eq!(json["packages"][0]["name"], "zod");
        assert_eq!(json["packages"][0]["total_size_bytes"], 500);
        assert_eq!(json["packages"][0]["file_count"], 3);
    }

    #[test]
    fn trace_report_terminal_contains_entry() {
        let report = TraceReport {
            entry: "src/index.ts".into(),
            static_weight_bytes: 1000,
            static_module_count: 5,
            dynamic_only_weight_bytes: 0,
            dynamic_only_module_count: 0,
            heavy_packages: vec![],
            modules_by_cost: vec![],
            total_modules_with_cost: 0,
            include_dynamic: false,
            top: 10,
        };
        let output = report.to_terminal(false);
        assert!(output.contains("src/index.ts"));
        assert!(output.contains("Static transitive weight:"));
        assert!(output.contains("1 KB"));
    }

    #[test]
    fn trace_report_top_zero_hides_heavy_deps() {
        let report = TraceReport {
            entry: "src/index.ts".into(),
            static_weight_bytes: 1000,
            static_module_count: 5,
            dynamic_only_weight_bytes: 0,
            dynamic_only_module_count: 0,
            heavy_packages: vec![],
            modules_by_cost: vec![],
            total_modules_with_cost: 0,
            include_dynamic: false,
            top: 0,
        };
        let output = report.to_terminal(false);
        assert!(!output.contains("Heavy dependencies"));
        assert!(!output.contains("all reachable modules are first-party"));
    }

    #[test]
    fn trace_report_top_zero_json_skips_field() {
        let report = TraceReport {
            entry: "src/index.ts".into(),
            static_weight_bytes: 1000,
            static_module_count: 5,
            dynamic_only_weight_bytes: 0,
            dynamic_only_module_count: 0,
            heavy_packages: vec![],
            modules_by_cost: vec![],
            total_modules_with_cost: 0,
            include_dynamic: false,
            top: 0,
        };
        let json: serde_json::Value = serde_json::from_str(&report.to_json()).unwrap();
        assert!(json.get("top").is_none());
    }

    #[test]
    fn diff_report_from_diff_roundtrip() {
        use crate::query::{self, TraceSnapshot};
        let a = TraceSnapshot {
            entry: "a.ts".into(),
            static_weight: 1000,
            packages: [("zod".into(), 500)].into_iter().collect(),
            dynamic_weight: 0,
            dynamic_packages: HashMap::new(),
        };
        let b = TraceSnapshot {
            entry: "b.ts".into(),
            static_weight: 800,
            packages: [("chalk".into(), 300)].into_iter().collect(),
            dynamic_weight: 0,
            dynamic_packages: HashMap::new(),
        };
        let diff = query::diff_snapshots(&a, &b);
        let report = DiffReport::from_diff(&diff, "a.ts", "b.ts", 10);
        assert_eq!(report.weight_a, 1000);
        assert_eq!(report.weight_b, 800);
        assert_eq!(report.weight_delta, -200);
        assert_eq!(report.only_in_a.len(), 1);
        assert_eq!(report.only_in_a[0].name, "zod");
    }
}