omnitype 0.1.1

//! Static analysis for type inference and checking.

use std::collections::HashMap;
use std::path::Path;
use tree_sitter::{Node, Tree};

use crate::error::Result;
use crate::parser::Parser;
use crate::types::Type;

/// Simple diagnostic record produced by lightweight analysis.
#[derive(Debug, Clone, serde::Serialize)]
pub struct Diagnostic {
    /// File path of the diagnostic.
    pub path: String,
    /// 0-based line number where the issue was found.
    pub line: usize,
    /// 0-based column number where the issue was found.
    pub column: usize,
    /// Human-readable message.
    pub message: String,
    /// Severity string (e.g., "warning", "error").
    pub severity: String,
}

/// Per-file, lightweight analysis summary.
#[derive(Debug, Clone, serde::Serialize)]
pub struct AnalysisResult {
    /// Absolute or input path of the analyzed file.
    pub path: String,
    /// Number of top-level or nested Python function definitions.
    pub function_count: usize,
    /// Number of Python class definitions.
    pub class_count: usize,
    /// Collected diagnostics for this file.
    pub diagnostics: Vec<Diagnostic>,
}

/// The main analyzer that performs static type checking and inference.
#[allow(dead_code)]
pub struct Analyzer {
    /// Type environment storing variable types in different scopes.
    type_env: HashMap<String, Type>,
}

impl Default for Analyzer {
    fn default() -> Self {
        Self::new()
    }
}

impl Analyzer {
    /// Creates a new analyzer with an empty type environment.
    pub fn new() -> Self {
        Self { type_env: HashMap::new() }
    }

    /// Analyzes a syntax tree and infers types.
    pub fn analyze(&mut self, tree: &Tree, source: &[u8]) -> Result<()> {
        let root_node = tree.root_node();
        self.visit_node(&root_node, source)?;
        Ok(())
    }

    /// Visits a node in the syntax tree and processes it.
    #[allow(clippy::only_used_in_recursion)]
    fn visit_node(&mut self, _node: &Node, _source: &[u8]) -> Result<()> {
        // TODO: Implement node visiting logic for type inference

        // Recursively visit children
        let mut cursor = _node.walk();
        for child in _node.children(&mut cursor) {
            self.visit_node(&child, _source)?;
        }

        Ok(())
    }

    /// Infers the type of an expression node.
    #[allow(dead_code)]
    fn infer_expression_type(&self, _node: &Node, _source: &[u8]) -> Result<Type> {
        // TODO: Implement expression type inference
        Ok(Type::Unknown)
    }
}

impl Analyzer {
    /// Performs a minimal analysis on a Python source file: counts functions and classes.
    pub fn analyze_python_file(path: &Path) -> Result<AnalysisResult> {
        let mut parser = Parser::new()?;
        let tree = parser.parse_file(path)?;

        let root = tree.root_node();
        let mut cursor = root.walk();
        let mut function_count = 0usize;
        let mut class_count = 0usize;
        let mut diagnostics: Vec<Diagnostic> = Vec::new();

        // Simple DFS over all nodes
        let mut stack: Vec<Node> = Vec::new();
        for child in root.children(&mut cursor) {
            stack.push(child);
        }

        while let Some(node) = stack.pop() {
            let kind = node.kind();
            match kind {
                "function_definition" => {
                    function_count += 1;

                    // Check for missing parameter and return annotations
                    // parameters node is available via field name
                    if let Some(params) = node.child_by_field_name("parameters") {
                        // Iterate over parameters' children
                        let mut c = params.walk();
                        for p in params.children(&mut c) {
                            let p_kind = p.kind();
                            let is_typed = p_kind == "typed_parameter";
                            // If it's clearly a parameter and not typed, flag it
                            if !is_typed
                                && (p_kind == "identifier" || p_kind == "default_parameter")
                            {
                                let pos = p.start_position();
                                diagnostics.push(Diagnostic {
                                    path: path.to_string_lossy().to_string(),
                                    line: pos.row,
                                    column: pos.column,
                                    message: "Missing type annotation for parameter".to_string(),
                                    severity: "warning".to_string(),
                                });
                            }
                        }
                    }

                    // Return annotation: field name is often "return_type" in tree-sitter-python
                    if node.child_by_field_name("return_type").is_none() {
                        let pos = node.start_position();
                        diagnostics.push(Diagnostic {
                            path: path.to_string_lossy().to_string(),
                            line: pos.row,
                            column: pos.column,
                            message: "Missing return type annotation".to_string(),
                            severity: "warning".to_string(),
                        });
                    }
                },
                "class_definition" => class_count += 1,
                _ => {},
            }

            let mut child_cursor = node.walk();
            for child in node.children(&mut child_cursor) {
                stack.push(child);
            }
        }

        Ok(AnalysisResult {
            path: path.to_string_lossy().to_string(),
            function_count,
            class_count,
            diagnostics,
        })
    }
}

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

    #[test]
    fn test_analyzer_initialization() {
        let analyzer = Analyzer::new();
        assert!(analyzer.type_env.is_empty());
    }
}