import datetime
import json
from pathlib import Path

from pyra.memory import _MEMORY_ROOT
from pyra.utils.paths import safe_chmod

_INDEX_FILE = _MEMORY_ROOT / "MEMORY_INDEX.md"
_JSON_INDEX_FILE = _MEMORY_ROOT / "memory_index.json"

_EXCLUDED = {"MEMORY_INDEX.md", "memory_index.json"}


def _load_json_index() -> dict:
    if not _JSON_INDEX_FILE.exists():
        return {}
    try:
        return json.loads(_JSON_INDEX_FILE.read_text())
    except (json.JSONDecodeError, OSError):
        return {}


def update_index() -> None:
    existing = _load_json_index()

    files = sorted(_MEMORY_ROOT.rglob("*.md"))
    files = [f for f in files if f.name not in _EXCLUDED]

    new_json: dict = {}
    rows: list[str] = []

    for f in files:
        rel = f.relative_to(_MEMORY_ROOT)
        rel_key = rel.as_posix()
        category = rel.parts[0] if len(rel.parts) > 1 else "root"
        mtime = datetime.datetime.fromtimestamp(f.stat().st_mtime)
        mtime_str = mtime.strftime("%Y-%m-%d %H:%M")

        prev = existing.get(rel_key, {})
        new_json[rel_key] = {
            "summary": prev.get("summary", ""),
            "keywords": prev.get("keywords", []),
            "modified": mtime.isoformat(timespec="seconds"),
        }
        rows.append(f"| {rel} | {category} | {mtime_str} |")

    _JSON_INDEX_FILE.write_text(json.dumps(new_json, indent=2))
    safe_chmod(_JSON_INDEX_FILE, 0o600)

    table = "\n".join(rows) if rows else "| _(no memory files)_ | — | — |"
    content = (
        "# Memory Index\n\n"
        "| File | Category | Last Modified |\n"
        "|------|----------|---------------|\n"
        f"{table}\n\n"
        "_Auto-maintained by Pyra. Do not edit manually._\n"
    )
    _INDEX_FILE.write_text(content)
    safe_chmod(_INDEX_FILE, 0o600)


def update_json_entry(rel_path: str, summary: str, keywords: list[str]) -> None:
    """Update the summary and keywords for one entry in the JSON index."""
    index = _load_json_index()
    entry = index.get(rel_path, {})
    entry["summary"] = summary
    entry["keywords"] = keywords
    index[rel_path] = entry
    _JSON_INDEX_FILE.write_text(json.dumps(index, indent=2))
    safe_chmod(_JSON_INDEX_FILE, 0o600)