import json
import re
from pathlib import Path
from typing import Dict, List, Optional


def list_papers(outputs_dir: str) -> List[str]:
    """List all paper directories in outputs."""
    outputs_path = Path(outputs_dir)

    if not outputs_path.exists():
        return []

    papers = []
    for item in outputs_path.iterdir():
        if item.is_dir() and not item.name.startswith("."):
            papers.append(item.name)

    return sorted(papers)


def list_compression_levels(outputs_dir: str, paper_name: str) -> List[int]:
    """List available compression levels (token limits) for a paper."""
    paper_path = Path(outputs_dir) / paper_name

    if not paper_path.exists():
        return []

    levels = set()
    for file in paper_path.glob("distilled_*.txt"):
        match = re.search(r"distilled_(\d+)\.txt", file.name)
        if match:
            levels.add(int(match.group(1)))

    return sorted(list(levels), reverse=True)


def load_distilled(
    outputs_dir: str, paper_name: str, token_limit: int
) -> Optional[str]:
    """Load distilled summary text for a paper at given compression level."""
    file_path = Path(outputs_dir) / paper_name / f"distilled_{token_limit}.txt"

    if not file_path.exists():
        return None

    try:
        return file_path.read_text(encoding="utf-8")
    except Exception:
        return None


def load_theorem(outputs_dir: str, paper_name: str, token_limit: int) -> Optional[str]:
    """Load derived theorem markdown for a paper at given compression level."""
    file_path = Path(outputs_dir) / paper_name / f"theorem_{token_limit}.md"

    if not file_path.exists():
        return None

    try:
        return file_path.read_text(encoding="utf-8")
    except Exception:
        return None


def load_result(outputs_dir: str, paper_name: str, token_limit: int) -> Optional[Dict]:
    """Load analysis result JSON for a paper at given compression level."""
    file_path = Path(outputs_dir) / paper_name / f"result_{token_limit}.json"

    if not file_path.exists():
        return None

    try:
        with open(file_path, "r", encoding="utf-8") as f:
            return json.load(f)
    except Exception:
        return None


def load_prompt(prompts_dir: str, agent_type: str, prompt_file: str) -> Optional[str]:
    """Load a prompt file for a given agent type."""
    file_path = Path(prompts_dir) / agent_type / prompt_file

    if not file_path.exists():
        return None

    try:
        return file_path.read_text(encoding="utf-8")
    except Exception:
        return None