depyler-tooling 4.1.1

//! Typeshed Stub Ingestion for Auto-Generating Module Mappings
//!
//! DEPYLER-O1MAP-001 Section 5: Automation Strategy
//!
//! This module parses Python `.pyi` stub files from typeshed and automatically
//! generates `ModuleMapping` structs for the module mapper.
//!
//! ## Design Principles (Toyota Way)
//!
//! - **Genchi Genbutsu**: Parse actual typeshed stubs, not assumptions
//! - **Jidoka**: Validate mappings against known Rust equivalents
//! - **Kaizen**: Incrementally expand coverage from json → stdlib → ecosystem

use crate::module_mapper::ModuleMapping;
use std::collections::HashMap;

/// Result of parsing a single function signature from a .pyi stub
#[derive(Debug, Clone, PartialEq)]
pub struct ParsedFunction {
    /// Python function name
    pub name: String,
    /// Parameter types (name -> type string)
    pub params: Vec<(String, String)>,
    /// Return type string
    pub return_type: String,
}

/// Configuration for mapping Python types to Rust types
#[derive(Debug, Clone)]
pub struct TypeMappingConfig {
    /// Python type -> Rust type
    pub type_map: HashMap<String, String>,
}

impl Default for TypeMappingConfig {
    fn default() -> Self {
        let mut type_map = HashMap::new();
        // Primitive types
        type_map.insert("str".to_string(), "String".to_string());
        type_map.insert("int".to_string(), "i64".to_string());
        type_map.insert("float".to_string(), "f64".to_string());
        type_map.insert("bool".to_string(), "bool".to_string());
        type_map.insert("None".to_string(), "()".to_string());
        type_map.insert("bytes".to_string(), "Vec<u8>".to_string());
        // Generic types
        type_map.insert("Any".to_string(), "serde_json::Value".to_string());
        type_map.insert("object".to_string(), "serde_json::Value".to_string());
        // Container types (simplified - full generic handling is more complex)
        type_map.insert("list".to_string(), "Vec".to_string());
        type_map.insert("dict".to_string(), "HashMap".to_string());
        type_map.insert("set".to_string(), "HashSet".to_string());
        type_map.insert("tuple".to_string(), "tuple".to_string());
        type_map.insert("List".to_string(), "Vec".to_string());
        type_map.insert("Dict".to_string(), "HashMap".to_string());
        type_map.insert("Set".to_string(), "HashSet".to_string());
        type_map.insert("Tuple".to_string(), "tuple".to_string());
        type_map.insert("Optional".to_string(), "Option".to_string());

        Self { type_map }
    }
}

/// Known Rust crate mappings for Python modules
#[derive(Debug, Clone)]
pub struct CrateMappingConfig {
    /// Python module -> (Rust crate path, is_external, version)
    pub crate_map: HashMap<String, (String, bool, Option<String>)>,
}

impl Default for CrateMappingConfig {
    fn default() -> Self {
        let mut crate_map = HashMap::new();
        // Standard library -> Rust stdlib or well-known crates
        crate_map.insert(
            "json".to_string(),
            ("serde_json".to_string(), true, Some("1.0".to_string())),
        );
        crate_map.insert("os".to_string(), ("std".to_string(), false, None));
        crate_map.insert("sys".to_string(), ("std".to_string(), false, None));
        crate_map.insert("math".to_string(), ("std::f64".to_string(), false, None));
        crate_map.insert(
            "re".to_string(),
            ("regex".to_string(), true, Some("1.10".to_string())),
        );
        crate_map.insert(
            "random".to_string(),
            ("rand".to_string(), true, Some("0.8".to_string())),
        );
        crate_map.insert(
            "datetime".to_string(),
            ("chrono".to_string(), true, Some("0.4".to_string())),
        );
        crate_map.insert(
            "collections".to_string(),
            ("std::collections".to_string(), false, None),
        );
        crate_map.insert(
            "itertools".to_string(),
            ("itertools".to_string(), true, Some("0.12".to_string())),
        );
        crate_map.insert(
            "hashlib".to_string(),
            ("sha2".to_string(), true, Some("0.10".to_string())),
        );
        crate_map.insert(
            "base64".to_string(),
            ("base64".to_string(), true, Some("0.21".to_string())),
        );
        crate_map.insert(
            "csv".to_string(),
            ("csv".to_string(), true, Some("1.3".to_string())),
        );
        crate_map.insert(
            "pathlib".to_string(),
            ("std::path".to_string(), false, None),
        );
        crate_map.insert(
            "tempfile".to_string(),
            ("tempfile".to_string(), true, Some("3.0".to_string())),
        );

        Self { crate_map }
    }
}

/// Known function-to-Rust mappings for specific modules
/// This is the "semantic bridge" that maps Python function names to Rust equivalents
#[derive(Debug, Clone)]
pub struct FunctionMappingConfig {
    /// (module, python_func) -> rust_func
    pub func_map: HashMap<(String, String), String>,
}

impl Default for FunctionMappingConfig {
    fn default() -> Self {
        let mut func_map = HashMap::new();

        // json module
        func_map.insert(
            ("json".to_string(), "loads".to_string()),
            "from_str".to_string(),
        );
        func_map.insert(
            ("json".to_string(), "dumps".to_string()),
            "to_string".to_string(),
        );
        func_map.insert(
            ("json".to_string(), "load".to_string()),
            "from_reader".to_string(),
        );
        func_map.insert(
            ("json".to_string(), "dump".to_string()),
            "to_writer".to_string(),
        );

        // os module
        func_map.insert(
            ("os".to_string(), "getcwd".to_string()),
            "env::current_dir".to_string(),
        );
        func_map.insert(
            ("os".to_string(), "getenv".to_string()),
            "env::var".to_string(),
        );
        func_map.insert(
            ("os".to_string(), "listdir".to_string()),
            "fs::read_dir".to_string(),
        );

        // math module
        func_map.insert(("math".to_string(), "sqrt".to_string()), "sqrt".to_string());
        func_map.insert(("math".to_string(), "sin".to_string()), "sin".to_string());
        func_map.insert(("math".to_string(), "cos".to_string()), "cos".to_string());
        func_map.insert(
            ("math".to_string(), "floor".to_string()),
            "floor".to_string(),
        );
        func_map.insert(("math".to_string(), "ceil".to_string()), "ceil".to_string());
        func_map.insert(("math".to_string(), "abs".to_string()), "abs".to_string());
        func_map.insert(("math".to_string(), "pow".to_string()), "powf".to_string());

        // re module
        func_map.insert(
            ("re".to_string(), "compile".to_string()),
            "Regex::new".to_string(),
        );
        func_map.insert(
            ("re".to_string(), "match".to_string()),
            "Regex::is_match".to_string(),
        );
        func_map.insert(
            ("re".to_string(), "search".to_string()),
            "Regex::find".to_string(),
        );
        func_map.insert(
            ("re".to_string(), "findall".to_string()),
            "Regex::find_iter".to_string(),
        );
        func_map.insert(
            ("re".to_string(), "sub".to_string()),
            "Regex::replace_all".to_string(),
        );

        Self { func_map }
    }
}

/// Parse a .pyi stub file content and extract function signatures
///
/// # Arguments
/// * `content` - The content of the .pyi file
/// * `module_name` - The Python module name (e.g., "json", "os")
///
/// # Returns
/// A `ModuleMapping` ready for use in the module mapper
pub fn parse_pyi(content: &str, module_name: &str) -> ModuleMapping {
    parse_pyi_with_config(
        content,
        module_name,
        &TypeMappingConfig::default(),
        &CrateMappingConfig::default(),
        &FunctionMappingConfig::default(),
    )
}

/// Parse a .pyi stub with custom configuration
pub fn parse_pyi_with_config(
    content: &str,
    module_name: &str,
    _type_config: &TypeMappingConfig,
    crate_config: &CrateMappingConfig,
    func_config: &FunctionMappingConfig,
) -> ModuleMapping {
    let functions = extract_function_signatures(content);

    // Get crate mapping for this module
    let (rust_path, is_external, version) = crate_config
        .crate_map
        .get(module_name)
        .cloned()
        .unwrap_or_else(|| (module_name.to_string(), true, None));

    // Build item map from parsed functions + known mappings
    let mut item_map = HashMap::new();

    for func in &functions {
        // Check if we have a known mapping for this function
        if let Some(rust_func) = func_config
            .func_map
            .get(&(module_name.to_string(), func.name.clone()))
        {
            item_map.insert(func.name.clone(), rust_func.clone());
        } else {
            // Default: use same name (snake_case preserved)
            item_map.insert(func.name.clone(), func.name.clone());
        }
    }

    ModuleMapping {
        rust_path,
        is_external,
        version,
        item_map,
        constructor_patterns: HashMap::new(),
    }
}

/// Extract function signatures from .pyi content
///
/// Parses lines like:
/// - `def loads(s: str) -> Any: ...`
/// - `def dumps(obj: Any, indent: int = None) -> str: ...`
/// - Multiline function definitions (joined before parsing)
fn extract_function_signatures(content: &str) -> Vec<ParsedFunction> {
    let mut functions = Vec::new();

    // First, join multiline function definitions into single lines
    let normalized = normalize_multiline_functions(content);

    // Simple regex-like parsing for function definitions
    // Pattern: def <name>(<params>) -> <return_type>: ...
    for line in normalized.lines() {
        let line = line.trim();

        // Skip non-function lines
        if !line.starts_with("def ") {
            continue;
        }

        // Skip private/dunder methods for now
        if line.starts_with("def _") && !line.starts_with("def __init__") {
            continue;
        }

        if let Some(func) = parse_function_line(line) {
            functions.push(func);
        }
    }

    functions
}

/// Normalize multiline function definitions into single lines
fn normalize_multiline_functions(content: &str) -> String {
    let mut result = String::new();
    let mut current_def = String::new();
    let mut in_def = false;
    let mut paren_depth = 0;

    for line in content.lines() {
        let trimmed = line.trim();

        // Skip empty lines and non-function content when not in a def
        if trimmed.is_empty() && !in_def {
            continue;
        }

        if trimmed.starts_with("def ") {
            // If we were in a def, flush it first (shouldn't happen normally)
            if in_def && !current_def.is_empty() {
                result.push_str(&current_def);
                result.push('\n');
            }
            // Start of a new function definition
            in_def = true;
            current_def = trimmed.to_string();
            paren_depth = count_parens(trimmed);
        } else if in_def {
            // Continuation of function definition
            current_def.push(' ');
            current_def.push_str(trimmed);
            paren_depth += count_parens(trimmed);
        }

        // Check if function definition is complete (parens balanced and has closing pattern)
        if in_def
            && paren_depth == 0
            && (current_def.ends_with(": ...") || current_def.ends_with("):"))
        {
            result.push_str(&current_def);
            result.push('\n');
            current_def.clear();
            in_def = false;
        }
    }

    // Flush any remaining definition
    if !current_def.is_empty() {
        result.push_str(&current_def);
        result.push('\n');
    }

    result
}

/// Count net paren depth change in a line
fn count_parens(s: &str) -> i32 {
    let mut depth = 0;
    for ch in s.chars() {
        match ch {
            '(' => depth += 1,
            ')' => depth -= 1,
            _ => {}
        }
    }
    depth
}

/// Parse a single function definition line
fn parse_function_line(line: &str) -> Option<ParsedFunction> {
    // Remove "def " prefix
    let line = line.strip_prefix("def ")?;

    // Find function name (up to open paren)
    let paren_idx = line.find('(')?;
    let name = line[..paren_idx].trim().to_string();

    // Find the closing paren and return type
    let close_paren_idx = line.rfind(')')?;
    let params_str = &line[paren_idx + 1..close_paren_idx];

    // Parse return type (after "->")
    let return_type = if let Some(arrow_idx) = line.find("->") {
        let ret_part = &line[arrow_idx + 2..];
        // Remove trailing ": ..." if present
        let ret_type = ret_part.trim().trim_end_matches(": ...");
        ret_type.trim().to_string()
    } else {
        "None".to_string()
    };

    // Parse parameters
    let params = parse_params(params_str);

    Some(ParsedFunction {
        name,
        params,
        return_type,
    })
}

/// Parse parameter list from function signature
fn parse_params(params_str: &str) -> Vec<(String, String)> {
    let mut params = Vec::new();

    if params_str.trim().is_empty() {
        return params;
    }

    // Simple splitting (doesn't handle nested generics perfectly)
    // For production, use a proper parser
    let mut depth = 0;
    let mut current = String::new();
    let mut parts = Vec::new();

    for ch in params_str.chars() {
        match ch {
            '[' | '(' => {
                depth += 1;
                current.push(ch);
            }
            ']' | ')' => {
                depth -= 1;
                current.push(ch);
            }
            ',' if depth == 0 => {
                parts.push(current.trim().to_string());
                current = String::new();
            }
            _ => current.push(ch),
        }
    }
    if !current.trim().is_empty() {
        parts.push(current.trim().to_string());
    }

    // Parse each parameter
    for part in parts {
        // Skip *args, **kwargs, self
        if part.starts_with('*') || part == "self" {
            continue;
        }

        // Handle: name: type or name: type = default
        if let Some(colon_idx) = part.find(':') {
            let param_name = part[..colon_idx].trim().to_string();
            let type_part = &part[colon_idx + 1..];

            // Remove default value if present
            let param_type = if let Some(eq_idx) = type_part.find('=') {
                type_part[..eq_idx].trim().to_string()
            } else {
                type_part.trim().to_string()
            };

            params.push((param_name, param_type));
        } else {
            // Untyped parameter
            params.push((part.clone(), "Any".to_string()));
        }
    }

    params
}

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

    /// TDD RED: Test ingestion of json.pyi stub
    /// This is the primary acceptance test for the typeshed ingestion system
    #[test]
    fn test_ingest_json_stub() {
        // Mock json.pyi content (simplified from actual typeshed)
        let json_pyi = r#"
from typing import Any, IO, Optional

def loads(
    s: str,
    *,
    cls: Optional[type] = None,
    object_hook: Optional[Any] = None,
    parse_float: Optional[Any] = None,
    parse_int: Optional[Any] = None,
    parse_constant: Optional[Any] = None,
    object_pairs_hook: Optional[Any] = None,
) -> Any: ...

def dumps(
    obj: Any,
    *,
    skipkeys: bool = False,
    ensure_ascii: bool = True,
    check_circular: bool = True,
    allow_nan: bool = True,
    cls: Optional[type] = None,
    indent: Optional[int] = None,
    separators: Optional[tuple[str, str]] = None,
    default: Optional[Any] = None,
    sort_keys: bool = False,
) -> str: ...

def load(
    fp: IO[str],
    *,
    cls: Optional[type] = None,
    object_hook: Optional[Any] = None,
    parse_float: Optional[Any] = None,
    parse_int: Optional[Any] = None,
    parse_constant: Optional[Any] = None,
    object_pairs_hook: Optional[Any] = None,
) -> Any: ...

def dump(
    obj: Any,
    fp: IO[str],
    *,
    skipkeys: bool = False,
    ensure_ascii: bool = True,
    check_circular: bool = True,
    allow_nan: bool = True,
    cls: Optional[type] = None,
    indent: Optional[int] = None,
    separators: Optional[tuple[str, str]] = None,
    default: Optional[Any] = None,
    sort_keys: bool = False,
) -> None: ...
"#;

        let mapping = parse_pyi(json_pyi, "json");

        // Verify crate mapping
        assert_eq!(mapping.rust_path, "serde_json");
        assert!(mapping.is_external);
        assert_eq!(mapping.version, Some("1.0".to_string()));

        // Verify function mappings
        assert_eq!(mapping.item_map.get("loads"), Some(&"from_str".to_string()));
        assert_eq!(
            mapping.item_map.get("dumps"),
            Some(&"to_string".to_string())
        );
        assert_eq!(
            mapping.item_map.get("load"),
            Some(&"from_reader".to_string())
        );
        assert_eq!(mapping.item_map.get("dump"), Some(&"to_writer".to_string()));
    }

    #[test]
    fn test_parse_simple_function() {
        let line = "def sqrt(x: float) -> float: ...";
        let func = parse_function_line(line).unwrap();

        assert_eq!(func.name, "sqrt");
        assert_eq!(func.params.len(), 1);
        assert_eq!(func.params[0], ("x".to_string(), "float".to_string()));
        assert_eq!(func.return_type, "float");
    }

    #[test]
    fn test_parse_function_with_defaults() {
        let line = "def round(number: float, ndigits: int = None) -> float: ...";
        let func = parse_function_line(line).unwrap();

        assert_eq!(func.name, "round");
        assert_eq!(func.params.len(), 2);
        assert_eq!(func.params[0], ("number".to_string(), "float".to_string()));
        assert_eq!(func.params[1], ("ndigits".to_string(), "int".to_string()));
        assert_eq!(func.return_type, "float");
    }

    #[test]
    fn test_parse_function_with_generic_return() {
        let line = "def keys(self) -> list[str]: ...";
        let func = parse_function_line(line).unwrap();

        assert_eq!(func.name, "keys");
        assert_eq!(func.return_type, "list[str]");
    }

    #[test]
    fn test_extract_multiple_functions() {
        let content = r#"
def func_a(x: int) -> int: ...
def func_b(s: str) -> str: ...
def _private() -> None: ...
"#;

        let funcs = extract_function_signatures(content);

        // Should have 2 functions (private one excluded)
        assert_eq!(funcs.len(), 2);
        assert_eq!(funcs[0].name, "func_a");
        assert_eq!(funcs[1].name, "func_b");
    }

    #[test]
    fn test_ingest_math_stub() {
        let math_pyi = r#"
def sqrt(x: float) -> float: ...
def sin(x: float) -> float: ...
def cos(x: float) -> float: ...
def floor(x: float) -> int: ...
def ceil(x: float) -> int: ...
def pow(x: float, y: float) -> float: ...
pi: float
e: float
"#;

        let mapping = parse_pyi(math_pyi, "math");

        assert_eq!(mapping.rust_path, "std::f64");
        assert!(!mapping.is_external);

        // Verify known mappings applied
        assert_eq!(mapping.item_map.get("sqrt"), Some(&"sqrt".to_string()));
        assert_eq!(mapping.item_map.get("sin"), Some(&"sin".to_string()));
        assert_eq!(mapping.item_map.get("cos"), Some(&"cos".to_string()));
        assert_eq!(mapping.item_map.get("pow"), Some(&"powf".to_string()));
    }

    #[test]
    fn test_ingest_os_stub() {
        let os_pyi = r#"
def getcwd() -> str: ...
def getenv(key: str, default: str = None) -> str: ...
def listdir(path: str = ".") -> list[str]: ...
"#;

        let mapping = parse_pyi(os_pyi, "os");

        assert_eq!(mapping.rust_path, "std");
        assert!(!mapping.is_external);

        assert_eq!(
            mapping.item_map.get("getcwd"),
            Some(&"env::current_dir".to_string())
        );
        assert_eq!(
            mapping.item_map.get("getenv"),
            Some(&"env::var".to_string())
        );
        assert_eq!(
            mapping.item_map.get("listdir"),
            Some(&"fs::read_dir".to_string())
        );
    }

    #[test]
    fn test_unknown_module_fallback() {
        let unknown_pyi = r#"
def custom_func(x: int) -> int: ...
"#;

        let mapping = parse_pyi(unknown_pyi, "unknown_module");

        // Should fallback to module name as crate
        assert_eq!(mapping.rust_path, "unknown_module");
        assert!(mapping.is_external);

        // Unknown function should map to itself
        assert_eq!(
            mapping.item_map.get("custom_func"),
            Some(&"custom_func".to_string())
        );
    }

    // ============================================================
    // DEPYLER-COVERAGE-95: Additional comprehensive tests
    // ============================================================

    #[test]
    fn test_type_mapping_config_default() {
        let config = TypeMappingConfig::default();

        // Primitive types
        assert_eq!(config.type_map.get("str"), Some(&"String".to_string()));
        assert_eq!(config.type_map.get("int"), Some(&"i64".to_string()));
        assert_eq!(config.type_map.get("float"), Some(&"f64".to_string()));
        assert_eq!(config.type_map.get("bool"), Some(&"bool".to_string()));
        assert_eq!(config.type_map.get("None"), Some(&"()".to_string()));
        assert_eq!(config.type_map.get("bytes"), Some(&"Vec<u8>".to_string()));
    }

    #[test]
    fn test_type_mapping_config_generic_types() {
        let config = TypeMappingConfig::default();

        assert_eq!(
            config.type_map.get("Any"),
            Some(&"serde_json::Value".to_string())
        );
        assert_eq!(
            config.type_map.get("object"),
            Some(&"serde_json::Value".to_string())
        );
    }

    #[test]
    fn test_type_mapping_config_containers() {
        let config = TypeMappingConfig::default();

        assert_eq!(config.type_map.get("list"), Some(&"Vec".to_string()));
        assert_eq!(config.type_map.get("dict"), Some(&"HashMap".to_string()));
        assert_eq!(config.type_map.get("set"), Some(&"HashSet".to_string()));
        assert_eq!(config.type_map.get("tuple"), Some(&"tuple".to_string()));
        assert_eq!(config.type_map.get("Optional"), Some(&"Option".to_string()));
    }

    #[test]
    fn test_type_mapping_config_capitalized_containers() {
        let config = TypeMappingConfig::default();

        assert_eq!(config.type_map.get("List"), Some(&"Vec".to_string()));
        assert_eq!(config.type_map.get("Dict"), Some(&"HashMap".to_string()));
        assert_eq!(config.type_map.get("Set"), Some(&"HashSet".to_string()));
        assert_eq!(config.type_map.get("Tuple"), Some(&"tuple".to_string()));
    }

    #[test]
    fn test_crate_mapping_config_default() {
        let config = CrateMappingConfig::default();

        // Check stdlib modules
        let (path, is_ext, _) = config.crate_map.get("os").unwrap();
        assert_eq!(path, "std");
        assert!(!is_ext);
    }

    #[test]
    fn test_crate_mapping_config_external_crates() {
        let config = CrateMappingConfig::default();

        let (path, is_ext, version) = config.crate_map.get("json").unwrap();
        assert_eq!(path, "serde_json");
        assert!(is_ext);
        assert_eq!(version, &Some("1.0".to_string()));
    }

    #[test]
    fn test_crate_mapping_config_regex() {
        let config = CrateMappingConfig::default();

        let (path, is_ext, version) = config.crate_map.get("re").unwrap();
        assert_eq!(path, "regex");
        assert!(is_ext);
        assert_eq!(version, &Some("1.10".to_string()));
    }

    #[test]
    fn test_crate_mapping_config_random() {
        let config = CrateMappingConfig::default();

        let (path, is_ext, version) = config.crate_map.get("random").unwrap();
        assert_eq!(path, "rand");
        assert!(is_ext);
        assert_eq!(version, &Some("0.8".to_string()));
    }

    #[test]
    fn test_crate_mapping_config_datetime() {
        let config = CrateMappingConfig::default();

        let (path, is_ext, version) = config.crate_map.get("datetime").unwrap();
        assert_eq!(path, "chrono");
        assert!(is_ext);
        assert_eq!(version, &Some("0.4".to_string()));
    }

    #[test]
    fn test_crate_mapping_config_itertools() {
        let config = CrateMappingConfig::default();

        let (path, is_ext, version) = config.crate_map.get("itertools").unwrap();
        assert_eq!(path, "itertools");
        assert!(is_ext);
        assert_eq!(version, &Some("0.12".to_string()));
    }

    #[test]
    fn test_crate_mapping_config_hashlib() {
        let config = CrateMappingConfig::default();

        let (path, is_ext, version) = config.crate_map.get("hashlib").unwrap();
        assert_eq!(path, "sha2");
        assert!(is_ext);
        assert_eq!(version, &Some("0.10".to_string()));
    }

    #[test]
    fn test_crate_mapping_config_base64() {
        let config = CrateMappingConfig::default();

        let (path, is_ext, version) = config.crate_map.get("base64").unwrap();
        assert_eq!(path, "base64");
        assert!(is_ext);
        assert_eq!(version, &Some("0.21".to_string()));
    }

    #[test]
    fn test_crate_mapping_config_csv() {
        let config = CrateMappingConfig::default();

        let (path, is_ext, version) = config.crate_map.get("csv").unwrap();
        assert_eq!(path, "csv");
        assert!(is_ext);
        assert_eq!(version, &Some("1.3".to_string()));
    }

    #[test]
    fn test_crate_mapping_config_pathlib() {
        let config = CrateMappingConfig::default();

        let (path, is_ext, _) = config.crate_map.get("pathlib").unwrap();
        assert_eq!(path, "std::path");
        assert!(!is_ext);
    }

    #[test]
    fn test_crate_mapping_config_tempfile() {
        let config = CrateMappingConfig::default();

        let (path, is_ext, version) = config.crate_map.get("tempfile").unwrap();
        assert_eq!(path, "tempfile");
        assert!(is_ext);
        assert_eq!(version, &Some("3.0".to_string()));
    }

    #[test]
    fn test_crate_mapping_config_sys() {
        let config = CrateMappingConfig::default();

        let (path, is_ext, _) = config.crate_map.get("sys").unwrap();
        assert_eq!(path, "std");
        assert!(!is_ext);
    }

    #[test]
    fn test_crate_mapping_config_math() {
        let config = CrateMappingConfig::default();

        let (path, is_ext, _) = config.crate_map.get("math").unwrap();
        assert_eq!(path, "std::f64");
        assert!(!is_ext);
    }

    #[test]
    fn test_crate_mapping_config_collections() {
        let config = CrateMappingConfig::default();

        let (path, is_ext, _) = config.crate_map.get("collections").unwrap();
        assert_eq!(path, "std::collections");
        assert!(!is_ext);
    }

    #[test]
    fn test_function_mapping_config_json() {
        let config = FunctionMappingConfig::default();

        assert_eq!(
            config
                .func_map
                .get(&("json".to_string(), "loads".to_string())),
            Some(&"from_str".to_string())
        );
        assert_eq!(
            config
                .func_map
                .get(&("json".to_string(), "dumps".to_string())),
            Some(&"to_string".to_string())
        );
        assert_eq!(
            config
                .func_map
                .get(&("json".to_string(), "load".to_string())),
            Some(&"from_reader".to_string())
        );
        assert_eq!(
            config
                .func_map
                .get(&("json".to_string(), "dump".to_string())),
            Some(&"to_writer".to_string())
        );
    }

    #[test]
    fn test_function_mapping_config_os() {
        let config = FunctionMappingConfig::default();

        assert_eq!(
            config
                .func_map
                .get(&("os".to_string(), "getcwd".to_string())),
            Some(&"env::current_dir".to_string())
        );
        assert_eq!(
            config
                .func_map
                .get(&("os".to_string(), "getenv".to_string())),
            Some(&"env::var".to_string())
        );
        assert_eq!(
            config
                .func_map
                .get(&("os".to_string(), "listdir".to_string())),
            Some(&"fs::read_dir".to_string())
        );
    }

    #[test]
    fn test_function_mapping_config_math() {
        let config = FunctionMappingConfig::default();

        assert_eq!(
            config
                .func_map
                .get(&("math".to_string(), "sqrt".to_string())),
            Some(&"sqrt".to_string())
        );
        assert_eq!(
            config
                .func_map
                .get(&("math".to_string(), "sin".to_string())),
            Some(&"sin".to_string())
        );
        assert_eq!(
            config
                .func_map
                .get(&("math".to_string(), "cos".to_string())),
            Some(&"cos".to_string())
        );
        assert_eq!(
            config
                .func_map
                .get(&("math".to_string(), "floor".to_string())),
            Some(&"floor".to_string())
        );
        assert_eq!(
            config
                .func_map
                .get(&("math".to_string(), "ceil".to_string())),
            Some(&"ceil".to_string())
        );
        assert_eq!(
            config
                .func_map
                .get(&("math".to_string(), "abs".to_string())),
            Some(&"abs".to_string())
        );
        assert_eq!(
            config
                .func_map
                .get(&("math".to_string(), "pow".to_string())),
            Some(&"powf".to_string())
        );
    }

    #[test]
    fn test_function_mapping_config_re() {
        let config = FunctionMappingConfig::default();

        assert_eq!(
            config
                .func_map
                .get(&("re".to_string(), "compile".to_string())),
            Some(&"Regex::new".to_string())
        );
        assert_eq!(
            config
                .func_map
                .get(&("re".to_string(), "match".to_string())),
            Some(&"Regex::is_match".to_string())
        );
        assert_eq!(
            config
                .func_map
                .get(&("re".to_string(), "search".to_string())),
            Some(&"Regex::find".to_string())
        );
        assert_eq!(
            config
                .func_map
                .get(&("re".to_string(), "findall".to_string())),
            Some(&"Regex::find_iter".to_string())
        );
        assert_eq!(
            config.func_map.get(&("re".to_string(), "sub".to_string())),
            Some(&"Regex::replace_all".to_string())
        );
    }

    #[test]
    fn test_count_parens_balanced() {
        assert_eq!(count_parens("()"), 0);
        assert_eq!(count_parens("(())"), 0);
        assert_eq!(count_parens("((()))"), 0);
    }

    #[test]
    fn test_count_parens_unbalanced() {
        assert_eq!(count_parens("("), 1);
        assert_eq!(count_parens("(("), 2);
        assert_eq!(count_parens(")"), -1);
        assert_eq!(count_parens("))"), -2);
    }

    #[test]
    fn test_count_parens_with_content() {
        assert_eq!(count_parens("def foo(x: int,"), 1);
        assert_eq!(count_parens("y: str) -> int:"), -1);
    }

    #[test]
    fn test_parse_params_empty() {
        let params = parse_params("");
        assert!(params.is_empty());
    }

    #[test]
    fn test_parse_params_single() {
        let params = parse_params("x: int");
        assert_eq!(params.len(), 1);
        assert_eq!(params[0], ("x".to_string(), "int".to_string()));
    }

    #[test]
    fn test_parse_params_multiple() {
        let params = parse_params("x: int, y: str, z: float");
        assert_eq!(params.len(), 3);
        assert_eq!(params[0], ("x".to_string(), "int".to_string()));
        assert_eq!(params[1], ("y".to_string(), "str".to_string()));
        assert_eq!(params[2], ("z".to_string(), "float".to_string()));
    }

    #[test]
    fn test_parse_params_with_defaults() {
        let params = parse_params("x: int = 0, y: str = \"\"");
        assert_eq!(params.len(), 2);
        assert_eq!(params[0], ("x".to_string(), "int".to_string()));
        assert_eq!(params[1], ("y".to_string(), "str".to_string()));
    }

    #[test]
    fn test_parse_params_skip_self() {
        let params = parse_params("self, x: int");
        assert_eq!(params.len(), 1);
        assert_eq!(params[0], ("x".to_string(), "int".to_string()));
    }

    #[test]
    fn test_parse_params_skip_args_kwargs() {
        let params = parse_params("x: int, *args, **kwargs");
        assert_eq!(params.len(), 1);
        assert_eq!(params[0], ("x".to_string(), "int".to_string()));
    }

    #[test]
    fn test_parse_params_untyped() {
        let params = parse_params("x");
        assert_eq!(params.len(), 1);
        assert_eq!(params[0], ("x".to_string(), "Any".to_string()));
    }

    #[test]
    fn test_parse_params_generic() {
        let params = parse_params("x: list[int], y: dict[str, int]");
        assert_eq!(params.len(), 2);
        assert_eq!(params[0], ("x".to_string(), "list[int]".to_string()));
        assert_eq!(params[1], ("y".to_string(), "dict[str, int]".to_string()));
    }

    #[test]
    fn test_parse_function_line_no_return_type() {
        let func = parse_function_line("def foo(x: int):").unwrap();
        assert_eq!(func.name, "foo");
        assert_eq!(func.return_type, "None");
    }

    #[test]
    fn test_parse_function_line_no_params() {
        let func = parse_function_line("def foo() -> int: ...").unwrap();
        assert_eq!(func.name, "foo");
        assert!(func.params.is_empty());
        assert_eq!(func.return_type, "int");
    }

    #[test]
    fn test_parse_function_line_invalid() {
        assert!(parse_function_line("not a function").is_none());
        assert!(parse_function_line("class Foo:").is_none());
    }

    #[test]
    fn test_normalize_multiline_single_line() {
        let content = "def foo(x: int) -> int: ...";
        let normalized = normalize_multiline_functions(content);
        assert!(normalized.contains("def foo(x: int) -> int: ..."));
    }

    #[test]
    fn test_normalize_multiline_actual_multiline() {
        let content = r#"def foo(
    x: int,
    y: str
) -> int: ..."#;
        let normalized = normalize_multiline_functions(content);
        assert!(normalized.contains("def foo("));
        assert!(normalized.contains("x: int,"));
        // Should be joined into a single logical line
    }

    #[test]
    fn test_extract_function_signatures_empty() {
        let content = "";
        let funcs = extract_function_signatures(content);
        assert!(funcs.is_empty());
    }

    #[test]
    fn test_extract_function_signatures_skip_private() {
        let content = r#"
def public_func() -> None: ...
def _private_func() -> None: ...
def __dunder_func() -> None: ...
"#;
        let funcs = extract_function_signatures(content);
        // Should only have public_func
        assert_eq!(funcs.len(), 1);
        assert_eq!(funcs[0].name, "public_func");
    }

    #[test]
    fn test_extract_function_signatures_include_init() {
        let content = r#"
def __init__(self, x: int) -> None: ...
"#;
        let funcs = extract_function_signatures(content);
        assert_eq!(funcs.len(), 1);
        assert_eq!(funcs[0].name, "__init__");
    }

    #[test]
    fn test_parsed_function_struct() {
        let func = ParsedFunction {
            name: "test".to_string(),
            params: vec![("x".to_string(), "int".to_string())],
            return_type: "str".to_string(),
        };

        assert_eq!(func.name, "test");
        assert_eq!(func.params.len(), 1);
        assert_eq!(func.return_type, "str");
    }

    #[test]
    fn test_parsed_function_equality() {
        let func1 = ParsedFunction {
            name: "test".to_string(),
            params: vec![],
            return_type: "int".to_string(),
        };
        let func2 = ParsedFunction {
            name: "test".to_string(),
            params: vec![],
            return_type: "int".to_string(),
        };
        assert_eq!(func1, func2);
    }

    #[test]
    fn test_parse_pyi_with_config_custom_crate() {
        let content = "def custom_fn() -> None: ...";
        let type_config = TypeMappingConfig::default();
        let mut crate_config = CrateMappingConfig::default();
        crate_config.crate_map.insert(
            "custom".to_string(),
            ("my_crate".to_string(), true, Some("2.0".to_string())),
        );
        let func_config = FunctionMappingConfig::default();

        let mapping =
            parse_pyi_with_config(content, "custom", &type_config, &crate_config, &func_config);

        assert_eq!(mapping.rust_path, "my_crate");
        assert!(mapping.is_external);
        assert_eq!(mapping.version, Some("2.0".to_string()));
    }

    #[test]
    fn test_ingest_re_stub() {
        let re_pyi = r#"
def compile(pattern: str) -> Pattern: ...
def match(pattern: str, string: str) -> Match: ...
def search(pattern: str, string: str) -> Match: ...
def findall(pattern: str, string: str) -> list[str]: ...
def sub(pattern: str, repl: str, string: str) -> str: ...
"#;

        let mapping = parse_pyi(re_pyi, "re");

        assert_eq!(mapping.rust_path, "regex");
        assert!(mapping.is_external);
        assert_eq!(mapping.version, Some("1.10".to_string()));

        assert_eq!(
            mapping.item_map.get("compile"),
            Some(&"Regex::new".to_string())
        );
        assert_eq!(
            mapping.item_map.get("match"),
            Some(&"Regex::is_match".to_string())
        );
        assert_eq!(
            mapping.item_map.get("search"),
            Some(&"Regex::find".to_string())
        );
        assert_eq!(
            mapping.item_map.get("findall"),
            Some(&"Regex::find_iter".to_string())
        );
        assert_eq!(
            mapping.item_map.get("sub"),
            Some(&"Regex::replace_all".to_string())
        );
    }

    #[test]
    fn test_module_mapping_constructor_patterns() {
        let mapping = parse_pyi("def foo() -> None: ...", "test");
        // Constructor patterns should be empty by default
        assert!(mapping.constructor_patterns.is_empty());
    }

    #[test]
    fn test_type_mapping_config_clone() {
        let config = TypeMappingConfig::default();
        let cloned = config.clone();
        assert_eq!(config.type_map.len(), cloned.type_map.len());
    }

    #[test]
    fn test_crate_mapping_config_clone() {
        let config = CrateMappingConfig::default();
        let cloned = config.clone();
        assert_eq!(config.crate_map.len(), cloned.crate_map.len());
    }

    #[test]
    fn test_function_mapping_config_clone() {
        let config = FunctionMappingConfig::default();
        let cloned = config.clone();
        assert_eq!(config.func_map.len(), cloned.func_map.len());
    }

    #[test]
    fn test_parsed_function_clone() {
        let func = ParsedFunction {
            name: "test".to_string(),
            params: vec![("x".to_string(), "int".to_string())],
            return_type: "str".to_string(),
        };
        let cloned = func.clone();
        assert_eq!(func, cloned);
    }
}