#!/usr/bin/env python3
"""
Refactoring Opportunity Finder — Engine 10.4
"""

import argparse
import ast
import json
import os
import sys
from dataclasses import dataclass, asdict
from datetime import datetime, timezone
from typing import List, Optional, Tuple


@dataclass
class FileMetrics:
    path: str
    lines: int
    complexity: float
    max_complexity: int
    functions: int
    classes: int
    churn_30d: int = 0
    churn_90d: int = 0
    test_coverage: Optional[float] = None
    refactoring_score: float = 0.0


class ComplexityVisitor(ast.NodeVisitor):
    def __init__(self):
        self.functions = []
        self.classes = 0

    def visit_FunctionDef(self, node):
        complexity = 1
        for child in ast.walk(node):
            if isinstance(child, (ast.If, ast.While, ast.For)):
                complexity += 1
            elif isinstance(child, ast.BoolOp):
                complexity += len(child.values) - 1
            elif isinstance(child, ast.ExceptHandler):
                complexity += 1
            elif isinstance(child, ast.Assert):
                complexity += 1
        self.functions.append((node.name, complexity, node.lineno))
        self.generic_visit(node)

    def visit_AsyncFunctionDef(self, node):
        self.visit_FunctionDef(node)

    def visit_ClassDef(self, node):
        self.classes += 1
        self.generic_visit(node)


def compute_file_complexity(filepath):
    try:
        with open(filepath) as f:
            source = f.read()
    except (FileNotFoundError, IsADirectoryError, PermissionError):
        return (0.0, 0, 0, 0, 0)
    try:
        tree = ast.parse(source)
    except SyntaxError:
        return (0.0, 0, 0, 0, 0)
    lines = source.count("\n") + 1 if source.strip() else 0
    visitor = ComplexityVisitor()
    visitor.visit(tree)
    if not visitor.functions:
        return (0.0, 0, 0, visitor.classes, lines)
    complexities = [c for _, c, _ in visitor.functions]
    avg = sum(complexities) / len(complexities)
    max_c = max(complexities)
    return (round(avg, 1), max_c, len(visitor.functions), visitor.classes, lines)


def calculate_refactoring_score(metrics):
    score = 0.0
    complexity_score = min(40, metrics.complexity * 4)
    if metrics.max_complexity > 10:
        complexity_score = min(40, complexity_score + (metrics.max_complexity - 10))
    score += complexity_score
    if metrics.lines <= 0:
        pass
    elif metrics.lines <= 100:
        score += metrics.lines * 0.1
    elif metrics.lines <= 500:
        score += 10 + (metrics.lines - 100) * 0.0125
    else:
        score += min(20, 15 + (metrics.lines - 500) * 0.01)
    churn_score = (metrics.churn_30d * 2) + (metrics.churn_90d * 0.5)
    score += min(30, churn_score)
    if metrics.test_coverage is None:
        score += 5
    elif metrics.test_coverage < 0.3:
        score += 10
    elif metrics.test_coverage < 0.6:
        score += 7
    elif metrics.test_coverage < 0.8:
        score += 4
    else:
        score += 1
    return round(min(100, max(0, score)), 1)


def generate_proposals(repo_path=".", threshold=30.0):
    proposals = []
    for root, dirs, files in os.walk(repo_path):
        dirs[:] = [d for d in dirs if not d.startswith((".", "__pycache__", "node_modules", ".git", "venv"))]
        for fname in files:
            if not fname.endswith(".py"):
                continue
            filepath = os.path.join(root, fname)
            relpath = os.path.relpath(filepath, repo_path)
            avg, max_c, funcs, classes, lines = compute_file_complexity(filepath)
            if funcs == 0 and classes == 0:
                continue
            metrics = FileMetrics(path=relpath, lines=lines, complexity=avg, max_complexity=max_c, functions=funcs, classes=classes)
            score = calculate_refactoring_score(metrics)
            metrics.refactoring_score = score
            if score >= threshold:
                proposals.append({"title": f"Refactor {relpath} (score: {score})", "impact": min(10, int(score / 10)), "effort": min(10, max(1, funcs // 3)), "category": "refactoring", "source_engine": "10.4", "timestamp": datetime.now(timezone.utc).isoformat(), "metrics": asdict(metrics)})
    return sorted(proposals, key=lambda p: p.get("metrics", {}).get("refactoring_score", 0), reverse=True)


def main():
    parser = argparse.ArgumentParser(description="Find refactoring opportunities")
    parser.add_argument("--repo", default=".")
    parser.add_argument("--output", required=True)
    parser.add_argument("--dry-run", action="store_true")
    parser.add_argument("--threshold", type=float, default=30.0)
    args = parser.parse_args()
    proposals = generate_proposals(args.repo, args.threshold)
    if not args.dry_run:
        with open(args.output, "w") as f:
            json.dump({"proposals": proposals}, f, indent=2)
        print(f"Generated {len(proposals)} proposals -> {args.output}")
    else:
        for p in proposals:
            print(f"  - {p['title']}")

if __name__ == "__main__":
    main()