#!/usr/bin/env python3
"""Auto-import declarative project files into mem0.

Runs in the background from the SessionStart hook (startup only).
Imports CLAUDE.md, AGENTS.md, .cursorrules, .windsurfrules, mem0.md
into mem0 as project profile memories, skipping unchanged files via
SHA-256 hashing.

Input:  MEM0_CWD env var (optional, defaults to os.getcwd())
Output: stderr logs only (exit 0 always — must not block)
"""

from __future__ import annotations

import hashlib
import json
import logging
import os
import sys
import urllib.error
import urllib.request

sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
from _identity import resolve_user_id
from _project import resolve_project_id

log = logging.getLogger("mem0-auto-import")
log.setLevel(logging.DEBUG)
_handler = logging.StreamHandler(sys.stderr)
_handler.setFormatter(logging.Formatter("[mem0-auto-import] %(message)s"))
log.addHandler(_handler)

if os.environ.get("MEM0_DEBUG"):
    _log_dir = os.path.expanduser("~/.mem0")
    try:
        os.makedirs(_log_dir, exist_ok=True)
        _file_handler = logging.FileHandler(os.path.join(_log_dir, "hooks.log"))
        _file_handler.setFormatter(logging.Formatter("[mem0-auto-import] %(asctime)s %(message)s"))
        log.addHandler(_file_handler)
    except OSError:
        pass

API_URL = "https://api.mem0.ai"
MAX_FILE_SIZE = 100_000  # skip files over 100 KB
TARGET_FILES = ["CLAUDE.md", "AGENTS.md", ".cursorrules", ".windsurfrules", "mem0.md"]
HASH_STORE = os.path.expanduser("~/.mem0/file_hashes.json")


def sha256_file(path: str) -> str:
    """Return the hex SHA-256 digest of a file."""
    h = hashlib.sha256()
    with open(path, "rb") as f:
        for chunk in iter(lambda: f.read(65536), b""):
            h.update(chunk)
    return h.hexdigest()


def load_hashes() -> dict[str, str]:
    """Load the hash store from disk; return empty dict on any error."""
    if not os.path.isfile(HASH_STORE):
        return {}
    try:
        with open(HASH_STORE) as f:
            return json.load(f)
    except (OSError, json.JSONDecodeError):
        return {}


def save_hashes(hashes: dict[str, str]) -> None:
    """Persist the hash store to disk."""
    mem0_dir = os.path.expanduser("~/.mem0")
    os.makedirs(mem0_dir, exist_ok=True)
    try:
        with open(HASH_STORE, "w") as f:
            json.dump(hashes, f, indent=2)
    except OSError as e:
        log.warning("Could not save hash store: %s", e)


def post_memory(api_key: str, content: str, user_id: str, filename: str, project_id: str) -> bool:
    """POST a project profile memory to the Mem0 REST API."""
    body = {
        "messages": [
            {
                "role": "user",
                "content": f"## Project Profile: {filename}\n\nProject: {project_id}\n\n{content}",
            }
        ],
        "user_id": user_id,
        "metadata": {
            "type": "project_profile",
            "file": filename,
            "project_id": project_id,
            "source": "auto-import",
        },
        "infer": False,
    }

    data = json.dumps(body).encode("utf-8")
    req = urllib.request.Request(
        f"{API_URL}/v1/memories/",
        data=data,
        headers={
            "Content-Type": "application/json",
            "Authorization": f"Token {api_key}",
        },
        method="POST",
    )

    try:
        with urllib.request.urlopen(req, timeout=15) as resp:
            if resp.status in (200, 201):
                log.info("Imported %s (project=%s)", filename, project_id)
                return True
            log.warning("API returned status %d for %s", resp.status, filename)
            return False
    except urllib.error.URLError as e:
        log.warning("API call failed for %s: %s", filename, e)
        return False


def main() -> None:
    api_key = os.environ.get("MEM0_API_KEY", "")
    if not api_key:
        log.debug("MEM0_API_KEY not set, skipping auto-import")
        return

    cwd = os.environ.get("MEM0_CWD", "").strip() or os.getcwd()
    user_id = resolve_user_id()
    project_id = resolve_project_id(cwd)

    log.debug("Auto-import started: cwd=%s project=%s user=%s", cwd, project_id, user_id)

    hashes = load_hashes()
    updated = False

    for filename in TARGET_FILES:
        filepath = os.path.join(cwd, filename)

        if not os.path.isfile(filepath):
            log.debug("Not found, skipping: %s", filename)
            continue

        try:
            file_size = os.path.getsize(filepath)
        except OSError:
            log.debug("Cannot stat %s, skipping", filename)
            continue

        if file_size > MAX_FILE_SIZE:
            log.debug("Skipping %s: size %d exceeds %d bytes", filename, file_size, MAX_FILE_SIZE)
            continue

        try:
            current_hash = sha256_file(filepath)
        except OSError as e:
            log.debug("Cannot hash %s: %s", filename, e)
            continue

        hash_key = f"{project_id}:{filename}"
        if hashes.get(hash_key) == current_hash:
            log.debug("Unchanged, skipping: %s", filename)
            continue

        try:
            with open(filepath, encoding="utf-8", errors="replace") as f:
                content = f.read()
        except OSError as e:
            log.debug("Cannot read %s: %s", filename, e)
            continue

        if post_memory(api_key, content, user_id, filename, project_id):
            hashes[hash_key] = current_hash
            updated = True
        # on API failure we don't update the hash — retry next session

    if updated:
        save_hashes(hashes)
    else:
        log.debug("No files imported this run")


if __name__ == "__main__":
    try:
        main()
    except Exception as e:
        log.error("Unexpected error: %s", e)
    sys.exit(0)