"""
VoiceForge Syntax & Import Checker
-----------------------------------
Validates all Python files for:
- Syntax errors (AST parsing)
- Circular import detection
- Missing __init__.py files
- Undefined imports
"""

import os
import ast
import sys
from pathlib import Path
from collections import defaultdict

def check_syntax(file_path: Path) -> tuple[bool, str]:
    """Check if a Python file has valid syntax"""
    try:
        with open(file_path, 'r', encoding='utf-8', errors='ignore') as f:
            source = f.read()
        ast.parse(source)
        return True, ""
    except SyntaxError as e:
        return False, f"Line {e.lineno}: {e.msg}"

def check_init_files(root_dir: Path) -> list[Path]:
    """Find directories missing __init__.py"""
    missing = []
    for dir_path in root_dir.rglob("*"):
        if dir_path.is_dir() and '__pycache__' not in str(dir_path):
            py_files = list(dir_path.glob("*.py"))
            init_file = dir_path / "__init__.py"
            if py_files and not init_file.exists():
                missing.append(dir_path)
    return missing

def build_import_graph(root_dir: Path) -> dict[str, list[str]]:
    """Build a graph of module imports"""
    graph = defaultdict(list)
    
    for py_file in root_dir.rglob("*.py"):
        if '__pycache__' in str(py_file):
            continue
        
        try:
            with open(py_file, 'r', encoding='utf-8', errors='ignore') as f:
                source = f.read()
            tree = ast.parse(source)
            
            module_name = py_file.stem
            for node in ast.walk(tree):
                if isinstance(node, ast.ImportFrom) and node.module:
                    if node.module.startswith('app.'):
                        graph[module_name].append(node.module.split('.')[-1])
        except Exception:
            pass
    
    return graph

def detect_circular_imports(graph: dict) -> list[tuple]:
    """Detect circular imports in the dependency graph"""
    cycles = []
    visited = set()
    rec_stack = set()
    
    def dfs(node, path):
        visited.add(node)
        rec_stack.add(node)
        
        for neighbor in graph.get(node, []):
            if neighbor not in visited:
                if dfs(neighbor, path + [neighbor]):
                    return True
            elif neighbor in rec_stack:
                cycle = path[path.index(neighbor):] + [neighbor]
                cycles.append(tuple(cycle))
                return True
        
        rec_stack.remove(node)
        return False
    
    for node in graph:
        if node not in visited:
            dfs(node, [node])
    
    return cycles

def run_checks(root_dir: str = "app"):
    """Run all syntax and import checks"""
    print("=" * 60)
    print("🔧 VoiceForge Syntax & Import Checker")
    print("=" * 60)
    
    root = Path(root_dir)
    if not root.exists():
        print(f"❌ Directory not found: {root_dir}")
        sys.exit(1)
    
    all_files = [f for f in root.rglob("*.py") if '__pycache__' not in str(f)]
    print(f"\n📁 Checking {len(all_files)} Python files...\n")
    
    syntax_errors = []
    
    # Check syntax
    print("1️⃣ SYNTAX CHECK")
    print("-" * 40)
    for py_file in all_files:
        valid, error = check_syntax(py_file)
        if not valid:
            syntax_errors.append((py_file.relative_to(root), error))
            print(f"  ❌ {py_file.relative_to(root)}: {error}")
    
    if not syntax_errors:
        print("  ✅ All files have valid syntax!")
    
    # Check __init__.py
    print("\n2️⃣ MISSING __init__.py")
    print("-" * 40)
    missing_inits = check_init_files(root)
    if missing_inits:
        for dir_path in missing_inits:
            print(f"  ⚠️ {dir_path.relative_to(root)}")
    else:
        print("  ✅ All packages have __init__.py!")
    
    # Check circular imports
    print("\n3️⃣ CIRCULAR IMPORT DETECTION")
    print("-" * 40)
    graph = build_import_graph(root)
    cycles = detect_circular_imports(graph)
    if cycles:
        for cycle in cycles[:5]:
            print(f"  ⚠️ Cycle: {' → '.join(cycle)}")
    else:
        print("  ✅ No circular imports detected!")
    
    print("\n" + "=" * 60)
    
    if syntax_errors:
        print("❌ Syntax Check: FAILED")
        return 1
    else:
        print("✅ Syntax Check: PASSED")
        return 0

if __name__ == "__main__":
    import argparse
    parser = argparse.ArgumentParser(description="Check VoiceForge syntax and imports")
    parser.add_argument("--path", default="app", help="Root directory to check")
    args = parser.parse_args()
    
    sys.exit(run_checks(args.path))