cargo-rail 0.22.2

//! TOML formatting utilities
//!
//! Provides consistent, opinionated formatting for all TOML output.
//! Uses template strings + toml_edit parsing (hybrid approach).

use crate::error::{RailError, RailResult};
use toml_edit::DocumentMut;

/// Formatting rules and utilities
#[derive(Debug, Clone)]
pub struct TomlFormatter {
    /// Number of items before breaking array into multiple lines
    pub inline_array_threshold: usize,
    /// Number of features before breaking into multiple lines
    pub inline_feature_threshold: usize,
    /// Indentation string (usually 2 spaces)
    pub indent: &'static str,
}

impl Default for TomlFormatter {
    fn default() -> Self {
        Self {
            inline_array_threshold: 4,
            inline_feature_threshold: 10,
            indent: "  ",
        }
    }
}

impl TomlFormatter {
    /// Create a new formatter with default settings
    pub fn new() -> Self {
        Self::default()
    }

    /// Format string array with optional grouping
    pub fn array_string(&self, items: &[String], groups: Option<Vec<Group>>) -> String {
        if items.is_empty() {
            return "[]".to_string();
        }

        // If we have groups, always use multiline
        if let Some(groups) = groups {
            let mut output = String::from("[\n");
            for group in groups {
                if !group.items.is_empty() {
                    output.push_str(&format!("{}# {}\n", self.indent, group.name));
                    for item in &group.items {
                        output.push_str(&format!("{}\"{}\",\n", self.indent, item));
                    }
                }
            }
            output.push(']');
            return output;
        }

        // Check if we should inline
        if items.len() <= self.inline_array_threshold {
            let content = join_quoted(items.iter().map(String::as_str));
            return format!("[{}]", content);
        }

        // Multiline default
        let mut output = String::from("[\n");
        for item in items {
            output.push_str(&format!("{}\"{}\",\n", self.indent, item));
        }
        output.push(']');
        output
    }

    /// Format features array (for Cargo.toml dependencies)
    pub fn array_features(&self, features: &[String]) -> String {
        if features.is_empty() {
            return "[]".to_string();
        }

        if features.len() > self.inline_feature_threshold {
            let mut output = String::from("[\n");
            for feature in features {
                output.push_str(&format!("{}\"{}\",\n", self.indent, feature));
            }
            output.push(']');
            output
        } else {
            let content = join_quoted(features.iter().map(String::as_str));
            format!("[{}]", content)
        }
    }

    /// Format target array with tier grouping
    pub fn array_targets(&self, targets: &[String]) -> String {
        let groups = group_targets(targets);

        // Convert to generic groups
        let generic_groups = groups.into_iter().map(|(name, items)| Group { name, items }).collect();

        self.array_string(targets, Some(generic_groups))
    }

    /// Format array without grouping (simple multiline for readability)
    pub fn array_simple(&self, items: &[String]) -> String {
        if items.is_empty() {
            return "[]".to_string();
        }
        if items.len() <= self.inline_array_threshold {
            let content = join_quoted(items.iter().map(String::as_str));
            return format!("[{}]", content);
        }
        let mut output = String::from("[\n");
        for item in items {
            output.push_str(&format!("{}\"{}\",\n", self.indent, item));
        }
        output.push(']');
        output
    }

    /// Format section header with box comment
    pub fn section_header(&self, title: &str, description: &str) -> String {
        format!("# {}\n# {}\n[{}]\n", title.to_uppercase(), description, title)
    }

    /// Format inline table
    pub fn inline_table(&self, pairs: &[(String, TomlValue)]) -> String {
        if pairs.is_empty() {
            return "{}".to_string();
        }

        let content = pairs
            .iter()
            .map(|(k, v)| format!("{} = {}", k, v))
            .collect::<Vec<_>>()
            .join(", ");

        format!("{{ {} }}", content)
    }

    /// Validate TOML string parses correctly
    pub fn validate(&self, toml: &str) -> RailResult<()> {
        toml.parse::<DocumentMut>()
            .map(|_| ())
            .map_err(|e| RailError::message(format!("Invalid TOML generated: {}", e)))
    }

    /// Format a Cargo.toml document in-place
    ///
    /// Applies standard formatting rules:
    /// 1. Sorts dependencies deterministically
    /// 2. Standardizes table format (inline vs block)
    pub fn format_manifest(&self, doc: &mut DocumentMut) -> RailResult<()> {
        // 1. Sort dependencies deterministically
        self.sort_deps(doc);

        // 2. Standardize table formatting (inline vs block)
        self.standardize_tables(doc);

        Ok(())
    }

    /// Sort dependencies in all dependency sections
    ///
    fn sort_deps(&self, doc: &mut DocumentMut) {
        let sections = [
            "dependencies",
            "dev-dependencies",
            "build-dependencies",
            "workspace.dependencies",
        ];

        for section in sections {
            if let Some(table) = self.get_table_mut(doc, section) {
                table.sort_values();
            }
        }

        // Also handle target-specific dependencies
        // [target.'cfg(...)'.dependencies]
        if let Some(target_table) = doc.get_mut("target").and_then(|t| t.as_table_mut()) {
            for (_, cfg_item) in target_table.iter_mut() {
                if let Some(cfg_table) = cfg_item.as_table_mut() {
                    for section in ["dependencies", "dev-dependencies", "build-dependencies"] {
                        if let Some(deps) = cfg_table.get_mut(section).and_then(|d| d.as_table_mut()) {
                            deps.sort_values();
                        }
                    }
                }
            }
        }
    }

    /// Standardize table formatting
    /// - Simple dependencies (version only or path only) -> Inline
    /// - Complex dependencies -> Inline if possible
    fn standardize_tables(&self, doc: &mut DocumentMut) {
        let sections = [
            "dependencies",
            "dev-dependencies",
            "build-dependencies",
            "workspace.dependencies",
        ];

        for section in sections {
            if let Some(table) = self.get_table_mut(doc, section) {
                for (_, item) in table.iter_mut() {
                    if let Some(inline) = item.as_inline_table_mut() {
                        // Ensure it stays inline
                        inline.fmt();
                    } else if let Some(t) = item.as_table_mut() {
                        // Convert standard table to inline if it's a dependency
                        // But only if it doesn't have sub-tables (which deps shouldn't have usually)
                        t.set_implicit(true);
                    }
                }
            }
        }
    }

    /// Helper to get a mutable table reference from a dotted path
    fn get_table_mut<'a>(&self, doc: &'a mut DocumentMut, path: &str) -> Option<&'a mut toml_edit::Table> {
        let parts: Vec<&str> = path.split('.').collect();
        let mut current = doc.as_item_mut();

        for part in parts {
            let table = current.as_table_mut()?;
            current = table.get_mut(part)?;
        }

        current.as_table_mut()
    }
}

/// Target tier classification
#[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
pub enum TargetTier {
    /// Tier 1: Guaranteed to work
    Tier1,
    /// Tier 2: Guaranteed to build
    Tier2,
    /// Tier 3: No guarantees
    Tier3,
    /// Other/Unknown
    Other,
}

/// Classify a target triple into a tier
pub fn classify_target_tier(target: &str) -> TargetTier {
    match target {
        "x86_64-unknown-linux-gnu"
        | "aarch64-unknown-linux-gnu"
        | "x86_64-pc-windows-msvc"
        | "aarch64-apple-darwin" => TargetTier::Tier1,
        "aarch64-pc-windows-msvc" => TargetTier::Tier2,
        t if t.contains("musl") || t.contains("wasm") => TargetTier::Tier2,
        _ => TargetTier::Other,
    }
}

/// Group targets by tier
pub fn group_targets(targets: &[String]) -> Vec<(String, Vec<String>)> {
    // Pre-allocate based on expected distribution (most targets are Tier 1/2)
    let mut tier1 = Vec::with_capacity(targets.len() / 2);
    let mut tier2 = Vec::with_capacity(targets.len() / 2);
    let mut other = Vec::new();

    // Build indices per tier to avoid cloning during classification
    let mut tier1_idx = Vec::with_capacity(targets.len() / 2);
    let mut tier2_idx = Vec::with_capacity(targets.len() / 2);
    let mut other_idx = Vec::new();

    for (idx, target) in targets.iter().enumerate() {
        match classify_target_tier(target) {
            TargetTier::Tier1 => tier1_idx.push(idx),
            TargetTier::Tier2 => tier2_idx.push(idx),
            _ => other_idx.push(idx),
        }
    }

    // Sort indices by target name, then clone only the sorted targets
    tier1_idx.sort_by(|&a, &b| targets[a].cmp(&targets[b]));
    tier2_idx.sort_by(|&a, &b| targets[a].cmp(&targets[b]));
    other_idx.sort_by(|&a, &b| targets[a].cmp(&targets[b]));

    tier1.extend(tier1_idx.iter().map(|&i| targets[i].clone()));
    tier2.extend(tier2_idx.iter().map(|&i| targets[i].clone()));
    other.extend(other_idx.iter().map(|&i| targets[i].clone()));

    let mut groups = Vec::with_capacity(3);
    if !tier1.is_empty() {
        groups.push(("Tier 1 (Guaranteed)".to_string(), tier1));
    }
    if !tier2.is_empty() {
        groups.push(("Tier 2 (Common)".to_string(), tier2));
    }
    if !other.is_empty() {
        groups.push(("Other".to_string(), other));
    }

    groups
}

/// Value types for inline tables
#[derive(Debug, Clone)]
pub enum TomlValue {
    /// String value
    String(String),
    /// Boolean value
    Bool(bool),
    /// Integer value
    Integer(i64),
    /// Array of strings
    Array(Vec<String>),
}

impl std::fmt::Display for TomlValue {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            TomlValue::String(s) => write!(f, "\"{}\"", s),
            TomlValue::Bool(b) => write!(f, "{}", b),
            TomlValue::Integer(i) => write!(f, "{}", i),
            TomlValue::Array(arr) => {
                let content = join_quoted(arr.iter().map(String::as_str));
                write!(f, "[{}]", content)
            }
        }
    }
}

fn join_quoted<'a, I>(items: I) -> String
where
    I: IntoIterator<Item = &'a str>,
{
    let mut out = String::new();
    for (idx, item) in items.into_iter().enumerate() {
        if idx > 0 {
            out.push_str(", ");
        }
        out.push('"');
        out.push_str(item);
        out.push('"');
    }
    out
}

/// A named group of items for array formatting
#[derive(Debug, Clone)]
pub struct Group {
    /// Name of the group (displayed in comment)
    pub name: String,
    /// Items in the group
    pub items: Vec<String>,
}

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

    #[test]
    fn test_inline_array() {
        let formatter = TomlFormatter::new();
        let items = vec!["a".to_string(), "b".to_string()];
        assert_eq!(formatter.array_string(&items, None), "[\"a\", \"b\"]");
    }

    #[test]
    fn test_multiline_array() {
        let formatter = TomlFormatter::new();
        let items = vec![
            "a".to_string(),
            "b".to_string(),
            "c".to_string(),
            "d".to_string(),
            "e".to_string(),
        ];
        let output = formatter.array_string(&items, None);
        assert!(output.contains("\n"));
        assert!(output.contains("  \"a\","));
    }

    #[test]
    fn test_grouped_targets() {
        let formatter = TomlFormatter::new();
        let targets = vec![
            "x86_64-unknown-linux-gnu".to_string(),
            "wasm32-unknown-unknown".to_string(),
        ];
        let output = formatter.array_targets(&targets);
        assert!(output.contains("# Tier 1"));
        assert!(output.contains("# Tier 2"));
    }

    #[test]
    fn test_inline_table() {
        let formatter = TomlFormatter::new();
        let pairs = vec![
            ("version".to_string(), TomlValue::String("1.0".to_string())),
            ("features".to_string(), TomlValue::Array(vec!["a".to_string()])),
        ];
        let output = formatter.inline_table(&pairs);
        assert_eq!(output, "{ version = \"1.0\", features = [\"a\"] }");
    }
}