#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Extract Chapter Context

Extracts context from chapters for various processing tasks.
"""

import argparse
import json
import sys
from pathlib import Path
from typing import Optional

try:
    from runtime_compat import enable_windows_utf8_stdio
except ImportError:
    enable_windows_utf8_stdio = lambda: None


def main():
    if __name__ == "__main__":
        enable_windows_utf8_stdio()

    parser = argparse.ArgumentParser(description="Extract chapter context")
    parser.add_argument("--chapter", type=str, required=True, help="Chapter file path")
    parser.add_argument("--project-root", type=str, default=".", help="Project root")
    parser.add_argument("--output", type=str, help="Output file path")

    args = parser.parse_args()

    chapter_path = Path(args.chapter)
    if not chapter_path.exists():
        print(f"Error: Chapter file not found: {chapter_path}", file=sys.stderr)
        sys.exit(1)

    try:
        content = chapter_path.read_text(encoding="utf-8")

        # Simple extraction - just return the first N characters
        result = {
            "chapter": str(chapter_path),
            "length": len(content),
            "preview": content[:500] if len(content) > 500 else content
        }

        if args.output:
            output_path = Path(args.output)
            output_path.write_text(json.dumps(result, ensure_ascii=False, indent=2), encoding="utf-8")
            print(f"Context extracted to: {output_path}")
        else:
            print(json.dumps(result, ensure_ascii=False, indent=2))

    except Exception as e:
        print(f"Error: {e}", file=sys.stderr)
        sys.exit(1)


if __name__ == "__main__":
    main()