"""Scenario loader — supports .md (frontmatter + markdown) and .yaml."""

import os
import re
import yaml


def load_scenario(path: str) -> dict:
    with open(path, encoding="utf-8") as f:
        content = f.read()

    if path.endswith((".md", ".markdown")):
        return _parse_markdown(content)
    elif path.endswith((".yaml", ".yml")):
        return yaml.safe_load(content)
    else:
        try:
            return _parse_markdown(content)
        except Exception:
            return yaml.safe_load(content)


def _parse_markdown(content: str) -> dict:
    match = re.match(r"^---\s*\n(.*?)\n---\s*\n(.*)", content, re.DOTALL)
    if not match:
        raise ValueError("No YAML frontmatter found. Expected --- at the top.")

    meta = yaml.safe_load(match.group(1))
    body = match.group(2).strip()
    meta["problem"] = body
    if "name" not in meta:
        meta["name"] = "Без названия"
    return meta


def list_scenarios(scenarios_dir: str) -> list[dict]:
    results = []
    if not os.path.isdir(scenarios_dir):
        return results

    for fname in sorted(os.listdir(scenarios_dir)):
        if not fname.endswith((".md", ".markdown", ".yaml", ".yml")):
            continue
        path = os.path.join(scenarios_dir, fname)
        try:
            data = load_scenario(path)
            results.append({
                "file": fname,
                "path": path,
                "name": data.get("name", "Без названия"),
                "participants": data.get("participants", []),
            })
        except Exception as e:
            results.append({
                "file": fname,
                "path": path,
                "name": f"[Ошибка: {e}]",
                "participants": [],
            })
    return results