from pathlib import Path
from datetime import datetime
import re
import yaml

def slug(text):
    text = re.sub(r"[^\w\s-]", "", text.lower(), flags=re.UNICODE)
    return re.sub(r"[\s_-]+", "-", text).strip("-") or "chat"

def chat_path(directory, title):
    directory.mkdir(parents=True, exist_ok=True)
    path = directory / f"{datetime.now():%Y-%m-%d}-{slug(title)}.md"
    number = 2

    while path.exists():
        path = directory / f"{datetime.now():%Y-%m-%d}-{slug(title)}-{number}.md"
        number += 1

    return path

def save(path, title, messages, model):
    meta = {
        "title": title,
        "created": datetime.now().astimezone().isoformat(),
        "model": model,
    }

    out = [
        "---",
        yaml.safe_dump(meta, allow_unicode=True, sort_keys=False).strip(),
        "---",
        "",
    ]

    for message in messages:
        role = "You" if message["role"] == "user" else "AI"
        out += [f"## {role}", "", message["content"].rstrip(), ""]

    path.write_text("\n".join(out), encoding="utf-8")

def load(path):
    text = path.read_text(encoding="utf-8")
    title = path.stem

    if text.startswith("---"):
        _, meta, body = text.split("---", 2)
        title = (yaml.safe_load(meta) or {}).get("title", title)
        text = body

    messages = []
    role = None
    buffer = []

    for line in text.splitlines():
        if line == "## You":
            if role:
                messages.append({"role": role, "content": "\n".join(buffer).strip()})
            role, buffer = "user", []
        elif line == "## AI":
            if role:
                messages.append({"role": role, "content": "\n".join(buffer).strip()})
            role, buffer = "assistant", []
        elif role:
            buffer.append(line)

    if role:
        messages.append({"role": role, "content": "\n".join(buffer).strip()})

    return title, [m for m in messages if m["content"]]